initial import from gnunet.git

15 files changed, 9617 insertions, 0 deletions

diff --git a/src/psycstore/.gitignore b/src/psycstore/.gitignore
new file mode 100644
index 0000000..5ec7832
--- /dev/null
+++ b/src/psycstore/.gitignore
@@ -0,0 +1,5 @@
+gnunet-service-psycstore
+test_plugin_psycstore_mysql
+test_plugin_psycstore_sqlite
+test_plugin_psycstore_postgres
+test_psycstore
diff --git a/src/psycstore/Makefile.am b/src/psycstore/Makefile.am
new file mode 100644
index 0000000..557bb42
--- /dev/null
+++ b/src/psycstore/Makefile.am
@@ -0,0 +1,155 @@
+# This Makefile.am is in the public domain
+AM_CPPFLAGS = -I$(top_srcdir)/src/include
+
+plugindir = $(libdir)/gnunet
+
+pkgcfgdir= $(pkgdatadir)/config.d/
+
+libexecdir= $(pkglibdir)/libexec/
+
+pkgcfg_DATA = \
+  psycstore.conf
+
+
+if MINGW
+ WINFLAGS = -Wl,--no-undefined -Wl,--export-all-symbols
+endif
+
+if USE_COVERAGE
+  AM_CFLAGS = --coverage -O0
+  XLIB = -lgcov
+endif
+
+if HAVE_MYSQL
+MYSQL_PLUGIN = libgnunet_plugin_psycstore_mysql.la
+if HAVE_TESTING
+MYSQL_TESTS = test_plugin_psycstore_mysql
+endif
+endif
+
+if HAVE_POSTGRESQL
+POSTGRES_PLUGIN = libgnunet_plugin_psycstore_postgres.la
+if HAVE_TESTING
+POSTGRES_TESTS = test_plugin_psycstore_postgres
+endif
+endif
+
+if HAVE_SQLITE
+SQLITE_PLUGIN = libgnunet_plugin_psycstore_sqlite.la
+if HAVE_TESTING
+SQLITE_TESTS = test_plugin_psycstore_sqlite
+endif
+endif
+
+lib_LTLIBRARIES = libgnunetpsycstore.la
+
+libgnunetpsycstore_la_SOURCES = \
+  psycstore_api.c \
+  psycstore.h
+libgnunetpsycstore_la_LIBADD = \
+  $(top_builddir)/src/util/libgnunetutil.la \
+  $(GN_LIBINTL) $(XLIB)
+libgnunetpsycstore_la_LDFLAGS = \
+  $(GN_LIB_LDFLAGS)  $(WINFLAGS) \
+  -version-info 0:0:0
+
+bin_PROGRAMS =
+
+libexec_PROGRAMS = \
+ gnunet-service-psycstore
+
+gnunet_service_psycstore_SOURCES = \
+ gnunet-service-psycstore.c
+gnunet_service_psycstore_LDADD = \
+  $(top_builddir)/src/statistics/libgnunetstatistics.la \
+  $(top_builddir)/src/util/libgnunetutil.la \
+  $(top_builddir)/src/psycutil/libgnunetpsycutil.la \
+  $(GN_LIBINTL)
+
+plugin_LTLIBRARIES = \
+  $(SQLITE_PLUGIN) \
+  $(MYSQL_PLUGIN) \
+  $(POSTGRES_PLUGIN)
+
+
+libgnunet_plugin_psycstore_mysql_la_SOURCES = \
+  plugin_psycstore_mysql.c
+libgnunet_plugin_psycstore_mysql_la_LIBADD = \
+  libgnunetpsycstore.la  \
+  $(top_builddir)/src/my/libgnunetmy.la \
+  $(top_builddir)/src/mysql/libgnunetmysql.la \
+  $(top_builddir)/src/statistics/libgnunetstatistics.la \
+  $(top_builddir)/src/util/libgnunetutil.la $(XLIBS) \
+  $(LTLIBINTL)
+libgnunet_plugin_psycstore_mysql_la_LDFLAGS = \
+ $(GN_PLUGIN_LDFLAGS)
+
+libgnunet_plugin_psycstore_postgres_la_SOURCES = \
+  plugin_psycstore_postgres.c
+libgnunet_plugin_psycstore_postgres_la_LIBADD = \
+  libgnunetpsycstore.la  \
+  $(top_builddir)/src/pq/libgnunetpq.la  \
+  $(top_builddir)/src/statistics/libgnunetstatistics.la \
+  $(top_builddir)/src/util/libgnunetutil.la $(XLIBS) -lpq \
+  $(LTLIBINTL)
+libgnunet_plugin_psycstore_postgres_la_LDFLAGS = \
+  $(GN_PLUGIN_LDFLAGS) $(POSTGRESQL_LDFLAGS)
+libgnunet_plugin_psycstore_postgres_la_CPPFLAGS = \
+  $(POSTGRESQL_CPPFLAGS) $(AM_CPPFLAGS)
+
+
+libgnunet_plugin_psycstore_sqlite_la_SOURCES = \
+  plugin_psycstore_sqlite.c
+libgnunet_plugin_psycstore_sqlite_la_LIBADD = \
+  libgnunetpsycstore.la  \
+  $(top_builddir)/src/statistics/libgnunetstatistics.la \
+  $(top_builddir)/src/util/libgnunetutil.la $(XLIBS) -lsqlite3 \
+  $(LTLIBINTL)
+libgnunet_plugin_psycstore_sqlite_la_LDFLAGS = \
+ $(GN_PLUGIN_LDFLAGS)
+
+
+if HAVE_SQLITE
+if HAVE_TESTING
+check_PROGRAMS = \
+ $(SQLITE_TESTS) \
+ $(MYSQL_TESTS) \
+ $(POSTGRES_TESTS) \
+ test_psycstore
+endif
+endif
+
+if ENABLE_TEST_RUN
+AM_TESTS_ENVIRONMENT=export GNUNET_PREFIX=$${GNUNET_PREFIX:-@libdir@};export PATH=$${GNUNET_PREFIX:-@prefix@}/bin:$$PATH;unset XDG_DATA_HOME;unset XDG_CONFIG_HOME;
+TESTS = $(check_PROGRAMS)
+endif
+
+test_psycstore_SOURCES = \
+ test_psycstore.c
+test_psycstore_LDADD = \
+  libgnunetpsycstore.la \
+  $(top_builddir)/src/testing/libgnunettesting.la \
+  $(top_builddir)/src/util/libgnunetutil.la
+
+EXTRA_DIST = \
+  test_psycstore.conf
+
+
+test_plugin_psycstore_sqlite_SOURCES = \
+ test_plugin_psycstore.c
+test_plugin_psycstore_sqlite_LDADD = \
+  $(top_builddir)/src/testing/libgnunettesting.la \
+  $(top_builddir)/src/util/libgnunetutil.la
+
+test_plugin_psycstore_mysql_SOURCES = \
+ test_plugin_psycstore.c
+test_plugin_psycstore_mysql_LDADD = \
+  $(top_builddir)/src/testing/libgnunettesting.la \
+  $(top_builddir)/src/util/libgnunetutil.la
+
+test_plugin_psycstore_postgres_SOURCES = \
+ test_plugin_psycstore.c
+test_plugin_psycstore_postgres_LDADD = \
+ $(top_builddir)/src/testing/libgnunettesting.la \
+ $(top_builddir)/src/util/libgnunetutil.la
+
diff --git a/src/psycstore/gnunet-service-psycstore.c b/src/psycstore/gnunet-service-psycstore.c
new file mode 100644
index 0000000..9aebd3e
--- /dev/null
+++ b/src/psycstore/gnunet-service-psycstore.c
@@ -0,0 +1,1049 @@
+/**
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/gnunet-service-psycstore.c
+ * @brief PSYCstore service
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ */
+
+#include <inttypes.h>
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_constants.h"
+#include "gnunet_protocols.h"
+#include "gnunet_statistics_service.h"
+#include "gnunet_psyc_util_lib.h"
+#include "gnunet_psycstore_service.h"
+#include "gnunet_psycstore_plugin.h"
+#include "psycstore.h"
+
+
+/**
+ * Handle to our current configuration.
+ */
+static const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+/**
+ * Service handle.
+ */
+static struct GNUNET_SERVICE_Handle *service;
+
+/**
+ * Handle to the statistics service.
+ */
+static struct GNUNET_STATISTICS_Handle *stats;
+
+/**
+ * Database handle
+ */
+static struct GNUNET_PSYCSTORE_PluginFunctions *db;
+
+/**
+ * Name of the database plugin
+ */
+static char *db_lib_name;
+
+
+/**
+ * Task run during shutdown.
+ *
+ * @param cls unused
+ */
+static void
+shutdown_task (void *cls)
+{
+  if (NULL != stats)
+  {
+    GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
+    stats = NULL;
+  }
+  GNUNET_break (NULL == GNUNET_PLUGIN_unload (db_lib_name, db));
+  GNUNET_free (db_lib_name);
+  db_lib_name = NULL;
+}
+
+
+/**
+ * Send a result code back to the client.
+ *
+ * @param client
+ *        Client that should receive the result code.
+ * @param result_code
+ *        Code to transmit.
+ * @param op_id
+ *        Operation ID in network byte order.
+ * @param err_msg
+ *        Error message to include (or NULL for none).
+ */
+static void
+send_result_code (struct GNUNET_SERVICE_Client *client,
+                  uint64_t op_id,
+                  int64_t result_code,
+                  const char *err_msg)
+{
+  struct OperationResult *res;
+  size_t err_size = 0;
+
+  if (NULL != err_msg)
+    err_size = strnlen (err_msg,
+                        GNUNET_MAX_MESSAGE_SIZE - sizeof (*res) - 1) + 1;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (res, err_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_CODE);
+  res->result_code = GNUNET_htonll (result_code - INT64_MIN);
+  res->op_id = op_id;
+  if (0 < err_size)
+  {
+    GNUNET_memcpy (&res[1], err_msg, err_size);
+    ((char *) &res[1])[err_size - 1] = '\0';
+  }
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+	      "Sending result to client: %" PRId64 " (%s)\n",
+	      result_code, err_msg);
+  GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (client), env);
+}
+
+
+enum
+{
+  MEMBERSHIP_TEST_NOT_NEEDED = 0,
+  MEMBERSHIP_TEST_NEEDED = 1,
+  MEMBERSHIP_TEST_DONE = 2,
+} MessageMembershipTest;
+
+
+struct SendClosure
+{
+  struct GNUNET_SERVICE_Client *client;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Slave's public key.
+   */
+  struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id;
+
+  /**
+   * Membership test result.
+   */
+  int membership_test_result;
+
+  /**
+   * Do membership test with @a slave_key before returning fragment?
+   * @see enum MessageMembershipTest
+   */
+  uint8_t membership_test;
+};
+
+
+static int
+send_fragment (void *cls, struct GNUNET_MULTICAST_MessageHeader *msg,
+               enum GNUNET_PSYCSTORE_MessageFlags flags)
+{
+  struct SendClosure *sc = cls;
+  struct FragmentResult *res;
+
+  if (MEMBERSHIP_TEST_NEEDED == sc->membership_test)
+  {
+    sc->membership_test = MEMBERSHIP_TEST_DONE;
+    sc->membership_test_result
+      = db->membership_test (db->cls, &sc->channel_key, &sc->slave_key,
+                             GNUNET_ntohll (msg->message_id));
+    switch (sc->membership_test_result)
+    {
+    case GNUNET_YES:
+      break;
+
+    case GNUNET_NO:
+    case GNUNET_SYSERR:
+      return GNUNET_NO;
+    }
+  }
+
+  size_t msg_size = ntohs (msg->header.size);
+
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (res, msg_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_FRAGMENT);
+  res->op_id = sc->op_id;
+  res->psycstore_flags = htonl (flags);
+  GNUNET_memcpy (&res[1], msg, msg_size);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+	      "Sending fragment %llu to client\n",
+	      (unsigned long long) GNUNET_ntohll (msg->fragment_id));
+  GNUNET_free (msg);
+
+  GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (sc->client), env);
+  return GNUNET_YES;
+}
+
+
+static int
+send_state_var (void *cls, const char *name,
+                const void *value, uint32_t value_size)
+{
+  struct SendClosure *sc = cls;
+  struct StateResult *res;
+  size_t name_size = strlen (name) + 1;
+
+  /** @todo FIXME: split up value into 64k chunks */
+
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (res, name_size + value_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_STATE);
+  res->op_id = sc->op_id;
+  res->name_size = htons (name_size);
+  GNUNET_memcpy (&res[1], name, name_size);
+  GNUNET_memcpy ((char *) &res[1] + name_size, value, value_size);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Sending state variable %s to client\n", name);
+
+  GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (sc->client), env);
+  return GNUNET_OK;
+}
+
+
+static void
+handle_client_membership_store (void *cls,
+                                const struct MembershipStoreRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  int ret = db->membership_store (db->cls, &req->channel_key, &req->slave_key,
+                                  req->did_join,
+                                  GNUNET_ntohll (req->announced_at),
+                                  GNUNET_ntohll (req->effective_since),
+                                  GNUNET_ntohll (req->group_generation));
+
+  if (ret != GNUNET_OK)
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to store membership information!\n"));
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static void
+handle_client_membership_test (void *cls,
+                               const struct MembershipTestRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  int ret = db->membership_test (db->cls, &req->channel_key, &req->slave_key,
+                                 GNUNET_ntohll (req->message_id));
+  switch (ret)
+  {
+  case GNUNET_YES:
+  case GNUNET_NO:
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to test membership!\n"));
+  }
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static int
+check_client_fragment_store (void *cls,
+                             const struct FragmentStoreRequest *req)
+{
+  return GNUNET_OK;
+}
+
+
+static void
+handle_client_fragment_store (void *cls,
+                              const struct FragmentStoreRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  const struct GNUNET_MessageHeader *
+    msg = GNUNET_MQ_extract_nested_mh (req);
+  if (NULL == msg
+      || ntohs (msg->size) < sizeof (struct GNUNET_MULTICAST_MessageHeader))
+  {
+    GNUNET_break (0);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Dropping invalid fragment\n"));
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+
+  int ret = db->fragment_store (db->cls, &req->channel_key,
+                                (const struct GNUNET_MULTICAST_MessageHeader *)
+                                msg, ntohl (req->psycstore_flags));
+
+  if (ret != GNUNET_OK)
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to store fragment\n"));
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static void
+handle_client_fragment_get (void *cls,
+                            const struct FragmentGetRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  struct SendClosure
+    sc = { .op_id = req->op_id,
+           .client = client,
+           .channel_key = req->channel_key,
+           .slave_key = req->slave_key,
+           .membership_test = req->do_membership_test };
+
+  int64_t ret;
+  uint64_t ret_frags = 0;
+  uint64_t first_fragment_id = GNUNET_ntohll (req->first_fragment_id);
+  uint64_t last_fragment_id = GNUNET_ntohll (req->last_fragment_id);
+  uint64_t limit = GNUNET_ntohll (req->fragment_limit);
+
+  if (0 == limit)
+    ret = db->fragment_get (db->cls, &req->channel_key,
+                            first_fragment_id, last_fragment_id,
+                            &ret_frags, send_fragment, &sc);
+  else
+    ret = db->fragment_get_latest (db->cls, &req->channel_key, limit,
+                                   &ret_frags, send_fragment, &sc);
+
+  switch (ret)
+  {
+  case GNUNET_YES:
+  case GNUNET_NO:
+    if (MEMBERSHIP_TEST_DONE == sc.membership_test)
+    {
+      switch (sc.membership_test_result)
+      {
+      case GNUNET_YES:
+        break;
+
+      case GNUNET_NO:
+        ret = GNUNET_PSYCSTORE_MEMBERSHIP_TEST_FAILED;
+        break;
+
+      case GNUNET_SYSERR:
+        ret = GNUNET_SYSERR;
+        break;
+      }
+    }
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to get fragment!\n"));
+  }
+  send_result_code (client, req->op_id, (ret < 0) ? ret : ret_frags, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static int
+check_client_message_get (void *cls,
+                          const struct MessageGetRequest *req)
+{
+  return GNUNET_OK;
+}
+
+
+static void
+handle_client_message_get (void *cls,
+                           const struct MessageGetRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  uint16_t size = ntohs (req->header.size);
+  const char *method_prefix = (const char *) &req[1];
+
+  if (size < sizeof (*req) + 1
+      || '\0' != method_prefix[size - sizeof (*req) - 1])
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Message get: invalid method prefix. size: %u < %u?\n",
+                size,
+                (unsigned int) (sizeof (*req) + 1));
+    GNUNET_break (0);
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+
+  struct SendClosure
+    sc = { .op_id = req->op_id,
+           .client = client,
+           .channel_key = req->channel_key,
+           .slave_key = req->slave_key,
+           .membership_test = req->do_membership_test };
+
+  int64_t ret;
+  uint64_t ret_frags = 0;
+  uint64_t first_message_id = GNUNET_ntohll (req->first_message_id);
+  uint64_t last_message_id = GNUNET_ntohll (req->last_message_id);
+  uint64_t msg_limit = GNUNET_ntohll (req->message_limit);
+  uint64_t frag_limit = GNUNET_ntohll (req->fragment_limit);
+
+  /** @todo method_prefix */
+  if (0 == msg_limit)
+    ret = db->message_get (db->cls, &req->channel_key,
+                           first_message_id, last_message_id, frag_limit,
+                           &ret_frags, send_fragment, &sc);
+  else
+    ret = db->message_get_latest (db->cls, &req->channel_key, msg_limit,
+                                  &ret_frags, send_fragment, &sc);
+
+  switch (ret)
+  {
+  case GNUNET_YES:
+  case GNUNET_NO:
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to get message!\n"));
+  }
+
+  send_result_code (client, req->op_id, (ret < 0) ? ret : ret_frags, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static void
+handle_client_message_get_fragment (void *cls,
+                                    const struct MessageGetFragmentRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  struct SendClosure
+    sc = { .op_id = req->op_id, .client = client,
+           .channel_key = req->channel_key, .slave_key = req->slave_key,
+           .membership_test = req->do_membership_test };
+
+  int ret = db->message_get_fragment (db->cls, &req->channel_key,
+                                      GNUNET_ntohll (req->message_id),
+                                      GNUNET_ntohll (req->fragment_offset),
+                                      &send_fragment, &sc);
+  switch (ret)
+  {
+  case GNUNET_YES:
+  case GNUNET_NO:
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to get message fragment!\n"));
+  }
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static void
+handle_client_counters_get (void *cls,
+                            const struct OperationRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  struct CountersResult *res;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (res, GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_COUNTERS);
+
+  int ret = db->counters_message_get (db->cls, &req->channel_key,
+                                      &res->max_fragment_id, &res->max_message_id,
+                                      &res->max_group_generation);
+  switch (ret)
+  {
+  case GNUNET_OK:
+    ret = db->counters_state_get (db->cls, &req->channel_key,
+                                  &res->max_state_message_id);
+  case GNUNET_NO:
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to get master counters!\n"));
+  }
+
+  res->result_code = htonl (ret);
+  res->op_id = req->op_id;
+  res->max_fragment_id = GNUNET_htonll (res->max_fragment_id);
+  res->max_message_id = GNUNET_htonll (res->max_message_id);
+  res->max_group_generation = GNUNET_htonll (res->max_group_generation);
+  res->max_state_message_id = GNUNET_htonll (res->max_state_message_id);
+
+  GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (client), env);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+struct StateModifyClosure
+{
+  const struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+  struct GNUNET_PSYC_ReceiveHandle *recv;
+  enum GNUNET_PSYC_MessageState msg_state;
+  char mod_oper;
+  char *mod_name;
+  char *mod_value;
+  uint32_t mod_value_size;
+  uint32_t mod_value_remaining;
+};
+
+
+static void
+recv_state_message_part (void *cls,
+                         const struct GNUNET_PSYC_MessageHeader *msg,
+                         const struct GNUNET_MessageHeader *pmsg)
+{
+  struct StateModifyClosure *scls = cls;
+  uint16_t psize;
+
+  if (NULL == msg)
+  { // FIXME: error on unknown message
+    return;
+  }
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "recv_state_message_part()  message_id: %" PRIu64
+              ", fragment_offset: %" PRIu64 ", flags: %u\n",
+              GNUNET_ntohll (msg->message_id),
+              GNUNET_ntohll (msg->fragment_offset),
+              ntohl (msg->flags));
+
+  if (NULL == pmsg)
+  {
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_ERROR;
+    return;
+  }
+
+  switch (ntohs (pmsg->type))
+  {
+  case GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD:
+  {
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_METHOD;
+    break;
+  }
+
+  case GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER:
+  {
+    struct GNUNET_PSYC_MessageModifier *
+      pmod = (struct GNUNET_PSYC_MessageModifier *) pmsg;
+    psize = ntohs (pmod->header.size);
+    uint16_t name_size = ntohs (pmod->name_size);
+    uint32_t value_size = ntohl (pmod->value_size);
+
+    const char *name = (const char *) &pmod[1];
+    const void *value = name + name_size;
+
+    if (GNUNET_PSYC_OP_SET != pmod->oper)
+    { // Apply non-transient operation.
+      if (psize == sizeof (*pmod) + name_size + value_size)
+      {
+        db->state_modify_op (db->cls, &scls->channel_key,
+                             pmod->oper, name, value, value_size);
+      }
+      else
+      {
+        scls->mod_oper = pmod->oper;
+        scls->mod_name = GNUNET_malloc (name_size);
+        GNUNET_memcpy (scls->mod_name, name, name_size);
+
+        scls->mod_value_size = value_size;
+        scls->mod_value = GNUNET_malloc (scls->mod_value_size);
+        scls->mod_value_remaining
+          = scls->mod_value_size - (psize - sizeof (*pmod) - name_size);
+        GNUNET_memcpy (scls->mod_value, value, value_size - scls->mod_value_remaining);
+      }
+    }
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_MODIFIER;
+    break;
+  }
+
+  case GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT:
+    if (GNUNET_PSYC_OP_SET != scls->mod_oper)
+    {
+      if (scls->mod_value_remaining == 0)
+      {
+        GNUNET_break_op (0);
+        scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_ERROR;
+      }
+      psize = ntohs (pmsg->size);
+      GNUNET_memcpy (scls->mod_value + (scls->mod_value_size - scls->mod_value_remaining),
+              &pmsg[1], psize - sizeof (*pmsg));
+      scls->mod_value_remaining -= psize - sizeof (*pmsg);
+      if (0 == scls->mod_value_remaining)
+      {
+        db->state_modify_op (db->cls, &scls->channel_key,
+                             scls->mod_oper, scls->mod_name,
+                             scls->mod_value, scls->mod_value_size);
+        GNUNET_free (scls->mod_name);
+        GNUNET_free (scls->mod_value);
+        scls->mod_oper = 0;
+        scls->mod_name = NULL;
+        scls->mod_value = NULL;
+        scls->mod_value_size = 0;
+      }
+    }
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_MOD_CONT;
+    break;
+
+  case GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA:
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_DATA;
+    break;
+
+  case GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_END:
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_END;
+    break;
+
+  default:
+    scls->msg_state = GNUNET_PSYC_MESSAGE_STATE_ERROR;
+  }
+}
+
+
+static int
+recv_state_fragment (void *cls, struct GNUNET_MULTICAST_MessageHeader *msg,
+                     enum GNUNET_PSYCSTORE_MessageFlags flags)
+{
+  struct StateModifyClosure *scls = cls;
+
+  if (NULL == scls->recv)
+  {
+    scls->recv = GNUNET_PSYC_receive_create (NULL, recv_state_message_part,
+                                             scls);
+  }
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "recv_state_fragment: %" PRIu64 "\n", GNUNET_ntohll (msg->fragment_id));
+
+  struct GNUNET_PSYC_MessageHeader *
+    pmsg = GNUNET_PSYC_message_header_create (msg, flags);
+  GNUNET_PSYC_receive_message (scls->recv, pmsg);
+  GNUNET_free (pmsg);
+
+  return GNUNET_YES;
+}
+
+
+static void
+handle_client_state_modify (void *cls,
+                            const struct StateModifyRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  uint64_t message_id = GNUNET_ntohll (req->message_id);
+  uint64_t state_delta = GNUNET_ntohll (req->state_delta);
+  uint64_t ret_frags = 0;
+  struct StateModifyClosure
+    scls = { .channel_key = req->channel_key };
+
+  int ret = db->state_modify_begin (db->cls, &req->channel_key,
+                                    message_id, state_delta);
+
+  if (GNUNET_OK != ret)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                _("Failed to begin modifying state: %d\n"), ret);
+  }
+  else
+  {
+    ret = db->message_get (db->cls, &req->channel_key,
+                           message_id, message_id, 0,
+                           &ret_frags, recv_state_fragment, &scls);
+    if (GNUNET_OK != ret)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  _("Failed to modify state: %d\n"), ret);
+      GNUNET_break (0);
+    }
+    else
+    {
+      if (GNUNET_OK != db->state_modify_end (db->cls, &req->channel_key, message_id))
+      {
+        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                    _("Failed to end modifying state!\n"));
+        GNUNET_break (0);
+      }
+    }
+    if (NULL != scls.recv)
+    {
+      GNUNET_PSYC_receive_destroy (scls.recv);
+    }
+  }
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static int
+check_client_state_sync (void *cls,
+                         const struct StateSyncRequest *req)
+{
+  return GNUNET_OK;
+}
+
+
+/** @todo FIXME: stop processing further state sync messages after an error */
+static void
+handle_client_state_sync (void *cls,
+                          const struct StateSyncRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  int ret = GNUNET_SYSERR;
+  const char *name = (const char *) &req[1];
+  uint16_t name_size = ntohs (req->name_size);
+
+  if (name_size <= 2 || '\0' != name[name_size - 1])
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Tried to set invalid state variable name!\n"));
+    GNUNET_break_op (0);
+  }
+  else
+  {
+    ret = GNUNET_OK;
+
+    if (req->flags & STATE_OP_FIRST)
+    {
+      ret = db->state_sync_begin (db->cls, &req->channel_key);
+    }
+    if (ret != GNUNET_OK)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  _("Failed to begin synchronizing state!\n"));
+    }
+    else
+    {
+      ret = db->state_sync_assign (db->cls, &req->channel_key, name,
+                                   name + ntohs (req->name_size),
+                                   ntohs (req->header.size) - sizeof (*req)
+                                   - ntohs (req->name_size));
+    }
+
+    if (GNUNET_OK == ret && req->flags & STATE_OP_LAST)
+    {
+      ret = db->state_sync_end (db->cls, &req->channel_key,
+                                GNUNET_ntohll (req->max_state_message_id),
+                                GNUNET_ntohll (req->state_hash_message_id));
+      if (ret != GNUNET_OK)
+        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                    _("Failed to end synchronizing state!\n"));
+    }
+  }
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static void
+handle_client_state_reset (void *cls,
+                           const struct OperationRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  int ret = db->state_reset (db->cls, &req->channel_key);
+
+  if (ret != GNUNET_OK)
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to reset state!\n"));
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static void
+handle_client_state_hash_update (void *cls,
+                                 const struct StateHashUpdateRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  int ret = db->state_reset (db->cls, &req->channel_key);
+  if (ret != GNUNET_OK)
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to reset state!\n"));
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static int
+check_client_state_get (void *cls,
+                        const struct OperationRequest *req)
+{
+  return GNUNET_OK;
+}
+
+
+static void
+handle_client_state_get (void *cls,
+                         const struct OperationRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  struct SendClosure sc = { .op_id = req->op_id, .client = client };
+  int64_t ret = GNUNET_SYSERR;
+  const char *name = (const char *) &req[1];
+  uint16_t name_size = ntohs (req->header.size) - sizeof (*req);
+
+  if (name_size <= 2 || '\0' != name[name_size - 1])
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Tried to get invalid state variable name!\n"));
+    GNUNET_break (0);
+  }
+  else
+  {
+    ret = db->state_get (db->cls, &req->channel_key, name,
+                         &send_state_var, &sc);
+    if (GNUNET_NO == ret && name_size >= 5) /* min: _a_b\0 */
+    {
+      char *p, *n = GNUNET_malloc (name_size);
+      GNUNET_memcpy (n, name, name_size);
+      while (&n[1] < (p = strrchr (n, '_')) && GNUNET_NO == ret)
+      {
+        *p = '\0';
+        ret = db->state_get (db->cls, &req->channel_key, n,
+                             &send_state_var, &sc);
+      }
+      GNUNET_free (n);
+    }
+  }
+  switch (ret)
+  {
+  case GNUNET_OK:
+  case GNUNET_NO:
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to get state variable!\n"));
+  }
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+static int
+check_client_state_get_prefix (void *cls,
+                               const struct OperationRequest *req)
+{
+  return GNUNET_OK;
+}
+
+
+static void
+handle_client_state_get_prefix (void *cls,
+                                const struct OperationRequest *req)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+
+  struct SendClosure sc = { .op_id = req->op_id, .client = client };
+  int64_t ret = GNUNET_SYSERR;
+  const char *name = (const char *) &req[1];
+  uint16_t name_size = ntohs (req->header.size) - sizeof (*req);
+
+  if (name_size <= 1 || '\0' != name[name_size - 1])
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Tried to get invalid state variable name!\n"));
+    GNUNET_break (0);
+  }
+  else
+  {
+    ret = db->state_get_prefix (db->cls, &req->channel_key, name,
+                                &send_state_var, &sc);
+  }
+  switch (ret)
+  {
+  case GNUNET_OK:
+  case GNUNET_NO:
+    break;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Failed to get state variable!\n"));
+  }
+
+  send_result_code (client, req->op_id, ret, NULL);
+  GNUNET_SERVICE_client_continue (client);
+}
+
+
+/**
+ * A new client connected.
+ *
+ * @param cls NULL
+ * @param client client to add
+ * @param mq message queue for @a client
+ * @return @a client
+ */
+static void *
+client_notify_connect (void *cls,
+                       struct GNUNET_SERVICE_Client *client,
+                       struct GNUNET_MQ_Handle *mq)
+{
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Client connected: %p\n", client);
+
+  return client;
+}
+
+
+/**
+ * Called whenever a client is disconnected.
+ * Frees our resources associated with that client.
+ *
+ * @param cls closure
+ * @param client identification of the client
+ * @param app_ctx must match @a client
+ */
+static void
+client_notify_disconnect (void *cls,
+                          struct GNUNET_SERVICE_Client *client,
+                          void *app_ctx)
+{
+}
+
+
+/**
+ * Initialize the PSYCstore service.
+ *
+ * @param cls Closure.
+ * @param server The initialized server.
+ * @param c Configuration to use.
+ */
+static void
+run (void *cls,
+     const struct GNUNET_CONFIGURATION_Handle *c,
+     struct GNUNET_SERVICE_Handle *svc)
+{
+  cfg = c;
+  service = svc;
+
+  /* Loading database plugin */
+  char *database;
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_string (cfg, "psycstore", "database",
+                                             &database))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+			       "psycstore",
+			       "database");
+  }
+  else
+  {
+    GNUNET_asprintf (&db_lib_name,
+		     "libgnunet_plugin_psycstore_%s",
+		     database);
+    db = GNUNET_PLUGIN_load (db_lib_name, (void *) cfg);
+    GNUNET_free (database);
+  }
+  if (NULL == db)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+		"Could not load database backend `%s'\n",
+		db_lib_name);
+    GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
+    return;
+  }
+
+  stats = GNUNET_STATISTICS_create ("psycstore", cfg);
+  GNUNET_SCHEDULER_add_shutdown (shutdown_task,
+				 NULL);
+}
+
+/**
+ * Define "main" method using service macro.
+ */
+GNUNET_SERVICE_MAIN
+("psycstore",
+ GNUNET_SERVICE_OPTION_NONE,
+ run,
+ client_notify_connect,
+ client_notify_disconnect,
+ NULL,
+ GNUNET_MQ_hd_fixed_size (client_membership_store,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_MEMBERSHIP_STORE,
+                          struct MembershipStoreRequest,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_membership_test,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_MEMBERSHIP_TEST,
+                          struct MembershipTestRequest,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_fragment_store,
+                        GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_STORE,
+                        struct FragmentStoreRequest,
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_fragment_get,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_GET,
+                          struct FragmentGetRequest,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_message_get,
+                        GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_GET,
+                        struct MessageGetRequest,
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_message_get_fragment,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_GET_FRAGMENT,
+                          struct MessageGetFragmentRequest,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_counters_get,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_COUNTERS_GET,
+                          struct OperationRequest,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_state_modify,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_MODIFY,
+                          struct StateModifyRequest,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_state_sync,
+                        GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_SYNC,
+                        struct StateSyncRequest,
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_state_reset,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_RESET,
+                          struct OperationRequest,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_state_hash_update,
+                          GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_HASH_UPDATE,
+                          struct StateHashUpdateRequest,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_state_get,
+                        GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_GET,
+                        struct OperationRequest,
+                        NULL),
+ GNUNET_MQ_hd_var_size (client_state_get_prefix,
+                        GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_GET_PREFIX,
+                        struct OperationRequest,
+                        NULL));
+
+/* end of gnunet-service-psycstore.c */
diff --git a/src/psycstore/plugin_psycstore_mysql.c b/src/psycstore/plugin_psycstore_mysql.c
new file mode 100644
index 0000000..c36b6f7
--- /dev/null
+++ b/src/psycstore/plugin_psycstore_mysql.c
@@ -0,0 +1,1960 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/plugin_psycstore_mysql.c
+ * @brief mysql-based psycstore backend
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ * @author Christophe Genevey
+ */
+
+#include "platform.h"
+#include "gnunet_psycstore_plugin.h"
+#include "gnunet_psycstore_service.h"
+#include "gnunet_multicast_service.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_psyc_util_lib.h"
+#include "psycstore.h"
+#include "gnunet_my_lib.h"
+#include "gnunet_mysql_lib.h"
+#include <mysql/mysql.h>
+
+/**
+ * After how many ms "busy" should a DB operation fail for good?  A
+ * low value makes sure that we are more responsive to requests
+ * (especially PUTs).  A high value guarantees a higher success rate
+ * (SELECTs in iterate can take several seconds despite LIMIT=1).
+ *
+ * The default value of 1s should ensure that users do not experience
+ * huge latencies while at the same time allowing operations to
+ * succeed with reasonable probability.
+ */
+#define BUSY_TIMEOUT_MS 1000
+
+#define DEBUG_PSYCSTORE GNUNET_EXTRA_LOGGING
+
+/**
+ * Log an error message at log-level 'level' that indicates
+ * a failure of the command 'cmd' on file 'filename'
+ * with the message given by strerror(errno).
+ */
+#define LOG_MYSQL(db, level, cmd, stmt)                                 \
+  do {                                                                  \
+    GNUNET_log_from (level, "psycstore-mysql",                          \
+                     _("`%s' failed at %s:%d with error: %s\n"),        \
+                     cmd, __FILE__, __LINE__,                           \
+                     mysql_stmt_error (GNUNET_MYSQL_statement_get_stmt(stmt))); \
+  } while (0)
+
+#define LOG(kind,...) GNUNET_log_from (kind, "psycstore-mysql", __VA_ARGS__)
+
+enum Transactions {
+  TRANSACTION_NONE = 0,
+  TRANSACTION_STATE_MODIFY,
+  TRANSACTION_STATE_SYNC,
+};
+
+/**
+ * Context for all functions in this plugin.
+ */
+struct Plugin
+{
+
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * MySQL context.
+   */
+  struct GNUNET_MYSQL_Context *mc;
+
+  /**
+   * Current transaction.
+   */
+  enum Transactions transaction;
+
+  /**
+   * Precompiled SQL for channel_key_store()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_channel_key;
+
+  /**
+   * Precompiled SQL for slave_key_store()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_slave_key;
+
+  /**
+   * Precompiled SQL for membership_store()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_membership;
+
+  /**
+   * Precompiled SQL for membership_test()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_membership;
+
+  /**
+   * Precompiled SQL for fragment_store()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_fragment;
+
+  /**
+   * Precompiled SQL for message_add_flags()
+   */
+  struct GNUNET_MYSQL_StatementHandle *update_message_flags;
+
+  /**
+   * Precompiled SQL for fragment_get()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_fragments;
+
+  /**
+   * Precompiled SQL for fragment_get()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_latest_fragments;
+
+  /**
+   * Precompiled SQL for message_get()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_messages;
+
+  /**
+   * Precompiled SQL for message_get()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_latest_messages;
+
+  /**
+   * Precompiled SQL for message_get_fragment()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_message_fragment;
+
+  /**
+   * Precompiled SQL for counters_get_message()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_counters_message;
+
+  /**
+   * Precompiled SQL for counters_get_state()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_counters_state;
+
+  /**
+   * Precompiled SQL for state_modify_end()
+   */
+  struct GNUNET_MYSQL_StatementHandle *update_state_hash_message_id;
+
+  /**
+   * Precompiled SQL for state_sync_end()
+   */
+  struct GNUNET_MYSQL_StatementHandle *update_max_state_message_id;
+
+  /**
+   * Precompiled SQL for state_modify_op()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_state_current;
+
+  /**
+   * Precompiled SQL for state_modify_end()
+   */
+  struct GNUNET_MYSQL_StatementHandle *delete_state_empty;
+
+  /**
+   * Precompiled SQL for state_set_signed()
+   */
+  struct GNUNET_MYSQL_StatementHandle *update_state_signed;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_state_sync;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  struct GNUNET_MYSQL_StatementHandle *delete_state;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  struct GNUNET_MYSQL_StatementHandle *insert_state_from_sync;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  struct GNUNET_MYSQL_StatementHandle *delete_state_sync;
+
+  /**
+   * Precompiled SQL for state_get_signed()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_state_signed;
+
+  /**
+   * Precompiled SQL for state_get()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_state_one;
+
+  /**
+   * Precompiled SQL for state_get_prefix()
+   */
+  struct GNUNET_MYSQL_StatementHandle *select_state_prefix;
+
+};
+
+#if DEBUG_PSYCSTORE
+
+static void
+mysql_trace (void *cls, const char *sql)
+{
+  LOG(GNUNET_ERROR_TYPE_DEBUG, "MYSQL query:\n%s\n", sql);
+}
+
+#endif
+
+
+/**
+ * @brief Prepare a SQL statement
+ *
+ * @param dbh handle to the database
+ * @param sql SQL statement, UTF-8 encoded
+ * @param stmt set to the prepared statement
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
+ */
+static int
+mysql_prepare (struct GNUNET_MYSQL_Context *mc,
+              const char *sql,
+              struct GNUNET_MYSQL_StatementHandle **stmt)
+{
+  *stmt = GNUNET_MYSQL_statement_prepare (mc,
+                                          sql);
+
+  if (NULL == *stmt)
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         _("Error preparing SQL query: %s\n  %s\n"),
+         mysql_stmt_error (GNUNET_MYSQL_statement_get_stmt (*stmt)),
+         sql);
+    return GNUNET_SYSERR;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Prepared `%s' / %p\n",
+       sql,
+       stmt);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Initialize the database connections and associated
+ * data structures (create tables and indices
+ * as needed as well).
+ *
+ * @param plugin the plugin context (state for this module)
+ * @return #GNUNET_OK on success
+ */
+static int
+database_setup (struct Plugin *plugin)
+{
+  /* Open database and precompile statements */
+  plugin->mc = GNUNET_MYSQL_context_create (plugin->cfg,
+                                            "psycstore-mysql");
+
+  if (NULL == plugin->mc)
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         _("Unable to initialize Mysql.\n"));
+    return GNUNET_SYSERR;
+  }
+
+#define STMT_RUN(sql) \
+  if (GNUNET_OK != \
+      GNUNET_MYSQL_statement_run (plugin->mc, \
+                                  sql)) \
+  { \
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, \
+                _("Failed to run SQL statement `%s'\n"), \
+                sql); \
+    return GNUNET_SYSERR; \
+  }
+
+  /* Create tables */
+  STMT_RUN ("CREATE TABLE IF NOT EXISTS channels (\n"
+            " id BIGINT UNSIGNED AUTO_INCREMENT,\n"
+            " pub_key BLOB(32),\n"
+            " max_state_message_id BIGINT UNSIGNED,\n"
+            " state_hash_message_id BIGINT UNSIGNED,\n"
+            " PRIMARY KEY(id),\n"
+            " UNIQUE KEY(pub_key(32))\n"
+            ");");
+
+  STMT_RUN ("CREATE TABLE IF NOT EXISTS slaves (\n"
+            " id BIGINT UNSIGNED AUTO_INCREMENT,\n"
+            " pub_key BLOB(32),\n"
+            " PRIMARY KEY(id),\n"
+            " UNIQUE KEY(pub_key(32))\n"
+            ");");
+
+  STMT_RUN ("CREATE TABLE IF NOT EXISTS membership (\n"
+            "  channel_id BIGINT UNSIGNED NOT NULL REFERENCES channels(id),\n"
+            "  slave_id BIGINT UNSIGNED NOT NULL REFERENCES slaves(id),\n"
+            "  did_join TINYINT NOT NULL,\n"
+            "  announced_at BIGINT UNSIGNED NOT NULL,\n"
+            "  effective_since BIGINT UNSIGNED NOT NULL,\n"
+            "  group_generation BIGINT UNSIGNED NOT NULL\n"
+            ");");
+
+/*** FIX because IF NOT EXISTS doesn't work ***/
+  GNUNET_MYSQL_statement_run (plugin->mc,
+                              "CREATE INDEX idx_membership_channel_id_slave_id "
+                              "ON membership (channel_id, slave_id);");
+
+  /** @todo messages table: add method_name column */
+  STMT_RUN ("CREATE TABLE IF NOT EXISTS messages (\n"
+            "  channel_id BIGINT UNSIGNED NOT NULL REFERENCES channels(id),\n"
+            "  hop_counter BIGINT UNSIGNED NOT NULL,\n"
+            "  signature BLOB,\n"
+            "  purpose BLOB,\n"
+            "  fragment_id BIGINT UNSIGNED NOT NULL,\n"
+            "  fragment_offset BIGINT UNSIGNED NOT NULL,\n"
+                              "  message_id BIGINT UNSIGNED NOT NULL,\n"
+            "  group_generation BIGINT UNSIGNED NOT NULL,\n"
+            "  multicast_flags BIGINT UNSIGNED NOT NULL,\n"
+            "  psycstore_flags BIGINT UNSIGNED NOT NULL,\n"
+            "  data BLOB,\n"
+            "  PRIMARY KEY (channel_id, fragment_id),\n"
+            "  UNIQUE KEY(channel_id, message_id, fragment_offset)\n"
+            ");");
+
+  STMT_RUN ("CREATE TABLE IF NOT EXISTS state (\n"
+            "  channel_id BIGINT UNSIGNED NOT NULL REFERENCES channels(id),\n"
+            "  name TEXT NOT NULL,\n"
+            "  value_current BLOB,\n"
+            "  value_signed BLOB\n"
+            //"  PRIMARY KEY (channel_id, name(255))\n"
+            ");");
+
+  STMT_RUN ("CREATE TABLE IF NOT EXISTS state_sync (\n"
+            "  channel_id BIGINT UNSIGNED NOT NULL REFERENCES channels(id),\n"
+            "  name TEXT NOT NULL,\n"
+            "  value BLOB\n"
+            //"  PRIMARY KEY (channel_id, name(255))\n"
+            ");");
+#undef STMT_RUN
+
+  /* Prepare statements */
+#define PREP(stmt,handle)                                    \
+  if (GNUNET_OK != mysql_prepare (plugin->mc, stmt, handle)) \
+  { \
+    GNUNET_break (0); \
+    return GNUNET_SYSERR; \
+  }
+  PREP ("INSERT IGNORE INTO channels (pub_key) VALUES (?);",
+        &plugin->insert_channel_key);
+  PREP ("INSERT IGNORE INTO slaves (pub_key) VALUES (?);",
+        &plugin->insert_slave_key);
+  PREP ("INSERT INTO membership\n"
+        " (channel_id, slave_id, did_join, announced_at,\n"
+        "  effective_since, group_generation)\n"
+        "VALUES ((SELECT id FROM channels WHERE pub_key = ?),\n"
+        "        (SELECT id FROM slaves WHERE pub_key = ?),\n"
+        "        ?, ?, ?, ?);",
+        &plugin->insert_membership);
+  PREP ("SELECT did_join FROM membership\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND slave_id = (SELECT id FROM slaves WHERE pub_key = ?)\n"
+        "      AND effective_since <= ? AND did_join = 1\n"
+        "ORDER BY announced_at DESC LIMIT 1;",
+        &plugin->select_membership);
+
+  PREP ("INSERT IGNORE INTO messages\n"
+        " (channel_id, hop_counter, signature, purpose,\n"
+        "  fragment_id, fragment_offset, message_id,\n"
+        "  group_generation, multicast_flags, psycstore_flags, data)\n"
+        "VALUES ((SELECT id FROM channels WHERE pub_key = ?),\n"
+        "        ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);",
+        &plugin->insert_fragment);
+
+  PREP ("UPDATE messages\n"
+        "SET psycstore_flags = psycstore_flags | ?\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND message_id = ? AND fragment_offset = 0;",
+        &plugin->update_message_flags);
+
+  PREP ("SELECT hop_counter, signature, purpose, fragment_id,\n"
+        "       fragment_offset, message_id, group_generation,\n"
+        "       multicast_flags, psycstore_flags, data\n"
+        "FROM messages\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND ? <= fragment_id AND fragment_id <= ? LIMIT 1;",
+        &plugin->select_fragments);
+
+  /** @todo select_messages: add method_prefix filter */
+  PREP ("SELECT hop_counter, signature, purpose, fragment_id,\n"
+        "       fragment_offset, message_id, group_generation,\n"
+        "       multicast_flags, psycstore_flags, data\n"
+        "FROM messages\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND ? <= message_id AND message_id <= ?\n"
+        "LIMIT ?;",
+        &plugin->select_messages);
+
+  PREP ("SELECT * FROM\n"
+        "(SELECT hop_counter, signature, purpose, fragment_id,\n"
+        "        fragment_offset, message_id, group_generation,\n"
+        "        multicast_flags, psycstore_flags, data\n"
+        " FROM messages\n"
+        " WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        " ORDER BY fragment_id DESC\n"
+        " LIMIT ?)\n"
+        "ORDER BY fragment_id;",
+        &plugin->select_latest_fragments);
+
+  /** @todo select_latest_messages: add method_prefix filter */
+  PREP ("SELECT hop_counter, signature, purpose, fragment_id,\n"
+        "       fragment_offset, message_id, group_generation,\n"
+        "        multicast_flags, psycstore_flags, data\n"
+        "FROM messages\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND message_id IN\n"
+        "      (SELECT message_id\n"
+        "       FROM messages\n"
+        "       WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "       GROUP BY message_id\n"
+        "       ORDER BY message_id\n"
+        "       DESC LIMIT ?)\n"
+        "ORDER BY fragment_id;",
+        &plugin->select_latest_messages);
+
+  PREP ("SELECT hop_counter, signature, purpose, fragment_id,\n"
+        "       fragment_offset, message_id, group_generation,\n"
+        "       multicast_flags, psycstore_flags, data\n"
+        "FROM messages\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND message_id = ? AND fragment_offset = ?;",
+        &plugin->select_message_fragment);
+
+  PREP ("SELECT fragment_id, message_id, group_generation\n"
+        "FROM messages\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "ORDER BY fragment_id DESC LIMIT 1;",
+        &plugin->select_counters_message);
+
+  PREP ("SELECT max_state_message_id\n"
+        "FROM channels\n"
+        "WHERE pub_key = ? AND max_state_message_id IS NOT NULL;",
+        &plugin->select_counters_state);
+
+  PREP ("UPDATE channels\n"
+        "SET max_state_message_id = ?\n"
+        "WHERE pub_key = ?;",
+        &plugin->update_max_state_message_id);
+
+  PREP ("UPDATE channels\n"
+        "SET state_hash_message_id = ?\n"
+        "WHERE pub_key = ?;",
+        &plugin->update_state_hash_message_id);
+
+  PREP ("REPLACE INTO state\n"
+        "  (channel_id, name, value_current, value_signed)\n"
+        "SELECT new.channel_id, new.name, new.value_current, old.value_signed\n"
+        "FROM (SELECT (SELECT id FROM channels WHERE pub_key = ?) AS channel_id,\n"
+        "             (SELECT ?) AS name,\n"
+        "             (SELECT ?) AS value_current\n"
+        "     ) AS new\n"
+        "LEFT JOIN (SELECT channel_id, name, value_signed\n"
+        "           FROM state) AS old\n"
+        "ON new.channel_id = old.channel_id AND new.name = old.name;",
+        &plugin->insert_state_current);
+
+  PREP ("DELETE FROM state\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND (value_current IS NULL OR length(value_current) = 0)\n"
+        "      AND (value_signed IS NULL OR length(value_signed) = 0);",
+        &plugin->delete_state_empty);
+
+  PREP ("UPDATE state\n"
+        "SET value_signed = value_current\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+        &plugin->update_state_signed);
+
+  PREP ("DELETE FROM state\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+        &plugin->delete_state);
+
+  PREP ("INSERT INTO state_sync (channel_id, name, value)\n"
+        "VALUES ((SELECT id FROM channels WHERE pub_key = ?), ?, ?);",
+        &plugin->insert_state_sync);
+
+  PREP ("INSERT INTO state\n"
+        " (channel_id, name, value_current, value_signed)\n"
+        "SELECT channel_id, name, value, value\n"
+        "FROM state_sync\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+        &plugin->insert_state_from_sync);
+
+  PREP ("DELETE FROM state_sync\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+        &plugin->delete_state_sync);
+
+  PREP ("SELECT value_current\n"
+        "FROM state\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND name = ?;",
+        &plugin->select_state_one);
+
+  PREP ("SELECT name, value_current\n"
+        "FROM state\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+        "      AND (name = ? OR substr(name, 1, ?) = ?);",
+        &plugin->select_state_prefix);
+
+  PREP ("SELECT name, value_signed\n"
+        "FROM state\n"
+        "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)"
+        "      AND value_signed IS NOT NULL;",
+        &plugin->select_state_signed);
+#undef PREP
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Shutdown database connection and associate data
+ * structures.
+ * @param plugin the plugin context (state for this module)
+ */
+static void
+database_shutdown (struct Plugin *plugin)
+{
+  GNUNET_MYSQL_context_destroy (plugin->mc);
+}
+
+
+/**
+ * Execute a prepared statement with a @a channel_key argument.
+ *
+ * @param plugin Plugin handle.
+ * @param stmt Statement to execute.
+ * @param channel_key Public key of the channel.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+exec_channel (struct Plugin *plugin, struct GNUNET_MYSQL_StatementHandle *stmt,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct GNUNET_MY_QueryParam params[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_channel", stmt);
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Begin a transaction.
+ */
+static int
+transaction_begin (struct Plugin *plugin, enum Transactions transaction)
+{
+  if (GNUNET_OK != GNUNET_MYSQL_statement_run (plugin->mc, "BEGIN"))
+  {
+    LOG(GNUNET_ERROR_TYPE_ERROR, "transaction_begin failed");
+    return GNUNET_SYSERR;
+  }
+
+  plugin->transaction = transaction;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Commit current transaction.
+ */
+static int
+transaction_commit (struct Plugin *plugin)
+{
+  if (GNUNET_OK != GNUNET_MYSQL_statement_run (plugin->mc, "COMMIT"))
+  {
+    LOG(GNUNET_ERROR_TYPE_ERROR, "transaction_commit failed");
+    return GNUNET_SYSERR;
+  }
+
+  plugin->transaction = TRANSACTION_NONE;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Roll back current transaction.
+ */
+static int
+transaction_rollback (struct Plugin *plugin)
+{
+  if (GNUNET_OK != GNUNET_MYSQL_statement_run (plugin->mc, "ROLLBACK"))
+  {
+    LOG(GNUNET_ERROR_TYPE_ERROR, "transaction_rollback failed");
+    return GNUNET_SYSERR;
+  }
+
+  plugin->transaction = TRANSACTION_NONE;
+  return GNUNET_OK;
+}
+
+
+static int
+channel_key_store (struct Plugin *plugin,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->insert_channel_key;
+
+  struct GNUNET_MY_QueryParam params[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+static int
+slave_key_store (struct Plugin *plugin,
+                 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key)
+{
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->insert_slave_key;
+
+  struct GNUNET_MY_QueryParam params[] = {
+    GNUNET_MY_query_param_auto_from_type (slave_key),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Store join/leave events for a PSYC channel in order to be able to answer
+ * membership test queries later.
+ *
+ * @see GNUNET_PSYCSTORE_membership_store()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+mysql_membership_store (void *cls,
+                         const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                         const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                         int did_join,
+                         uint64_t announced_at,
+                         uint64_t effective_since,
+                         uint64_t group_generation)
+{
+  struct Plugin *plugin = cls;
+
+  uint32_t idid_join = (uint32_t)did_join;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->insert_membership;
+
+  GNUNET_assert (TRANSACTION_NONE == plugin->transaction);
+
+  if (announced_at > INT64_MAX ||
+      effective_since > INT64_MAX ||
+      group_generation > INT64_MAX)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != channel_key_store (plugin, channel_key)
+      || GNUNET_OK != slave_key_store (plugin, slave_key))
+    return GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_auto_from_type (slave_key),
+    GNUNET_MY_query_param_uint32 (&idid_join),
+    GNUNET_MY_query_param_uint64 (&announced_at),
+    GNUNET_MY_query_param_uint64 (&effective_since),
+    GNUNET_MY_query_param_uint64 (&group_generation),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+/**
+ * Test if a member was admitted to the channel at the given message ID.
+ *
+ * @see GNUNET_PSYCSTORE_membership_test()
+ *
+ * @return #GNUNET_YES if the member was admitted, #GNUNET_NO if not,
+ *         #GNUNET_SYSERR if there was en error.
+ */
+static int
+membership_test (void *cls,
+                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                 uint64_t message_id)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_membership;
+
+  uint32_t did_join = 0;
+
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_auto_from_type (slave_key),
+    GNUNET_MY_query_param_uint64 (&message_id),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "mysql execute prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  struct GNUNET_MY_ResultSpec results_select[] = {
+    GNUNET_MY_result_spec_uint32 (&did_join),
+    GNUNET_MY_result_spec_end
+  };
+
+  switch (GNUNET_MY_extract_result (stmt, results_select))
+  {
+    case GNUNET_NO:
+      ret = GNUNET_NO;
+      break;
+    case GNUNET_OK:
+      ret = GNUNET_YES;
+      break;
+    default:
+      LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "mysql extract_result", stmt);
+      return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+/**
+ * Store a message fragment sent to a channel.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_store()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_store (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                const struct GNUNET_MULTICAST_MessageHeader *msg,
+                uint32_t psycstore_flags)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->insert_fragment;
+
+  GNUNET_assert (TRANSACTION_NONE == plugin->transaction);
+
+  uint64_t fragment_id = GNUNET_ntohll (msg->fragment_id);
+
+  uint64_t fragment_offset = GNUNET_ntohll (msg->fragment_offset);
+  uint64_t message_id = GNUNET_ntohll (msg->message_id);
+  uint64_t group_generation = GNUNET_ntohll (msg->group_generation);
+
+  uint64_t hop_counter = ntohl(msg->hop_counter);
+  uint64_t flags = ntohl(msg->flags);
+
+  if (fragment_id > INT64_MAX || fragment_offset > INT64_MAX ||
+      message_id > INT64_MAX || group_generation > INT64_MAX)
+  {
+    LOG(GNUNET_ERROR_TYPE_ERROR,
+         "Tried to store fragment with a field > INT64_MAX: "
+         "%lu, %lu, %lu, %lu\n", fragment_id, fragment_offset,
+         message_id, group_generation);
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != channel_key_store (plugin, channel_key))
+    return GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params_insert[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&hop_counter),
+    GNUNET_MY_query_param_auto_from_type (&msg->signature),
+    GNUNET_MY_query_param_auto_from_type (&msg->purpose),
+    GNUNET_MY_query_param_uint64 (&fragment_id),
+    GNUNET_MY_query_param_uint64 (&fragment_offset),
+    GNUNET_MY_query_param_uint64 (&message_id),
+    GNUNET_MY_query_param_uint64 (&group_generation),
+    GNUNET_MY_query_param_uint64 (&flags),
+    GNUNET_MY_query_param_uint32 (&psycstore_flags),
+    GNUNET_MY_query_param_fixed_size (&msg[1], ntohs (msg->header.size)
+                                                  - sizeof (*msg)),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_insert))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql execute prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+/**
+ * Set additional flags for a given message.
+ *
+ * They are OR'd with any existing flags set.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_add_flags (void *cls,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                   uint64_t message_id,
+                   uint32_t psycstore_flags)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->update_message_flags;
+
+  int sql_ret;
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params_update[] = {
+    GNUNET_MY_query_param_uint32 (&psycstore_flags),
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&message_id),
+    GNUNET_MY_query_param_end
+  };
+
+  sql_ret = GNUNET_MY_exec_prepared (plugin->mc, stmt, params_update);
+  switch (sql_ret)
+  {
+    case GNUNET_OK:
+      ret = GNUNET_OK;
+      break;
+
+    default:
+       LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql execute prepared", stmt);
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+static int
+fragment_row (struct GNUNET_MYSQL_StatementHandle *stmt,
+              GNUNET_PSYCSTORE_FragmentCallback cb,
+              void *cb_cls,
+              uint64_t *returned_fragments)
+{
+
+  uint32_t hop_counter;
+  void *signature = NULL;
+  void *purpose = NULL;
+  size_t signature_size;
+  size_t purpose_size;
+  uint64_t fragment_id;
+  uint64_t fragment_offset;
+  uint64_t message_id;
+  uint64_t group_generation;
+  uint64_t flags;
+  void *buf;
+  size_t buf_size;
+  int ret = GNUNET_SYSERR;
+  int sql_ret;
+  struct GNUNET_MULTICAST_MessageHeader *mp;
+  uint64_t msg_flags;
+  struct GNUNET_MY_ResultSpec results[] = {
+    GNUNET_MY_result_spec_uint32 (&hop_counter),
+    GNUNET_MY_result_spec_variable_size (&signature, &signature_size),
+    GNUNET_MY_result_spec_variable_size (&purpose, &purpose_size),
+    GNUNET_MY_result_spec_uint64 (&fragment_id),
+    GNUNET_MY_result_spec_uint64 (&fragment_offset),
+    GNUNET_MY_result_spec_uint64 (&message_id),
+    GNUNET_MY_result_spec_uint64 (&group_generation),
+    GNUNET_MY_result_spec_uint64 (&msg_flags),
+    GNUNET_MY_result_spec_uint64 (&flags),
+    GNUNET_MY_result_spec_variable_size (&buf,
+                                         &buf_size),
+    GNUNET_MY_result_spec_end
+  };
+
+  do
+  {
+    sql_ret = GNUNET_MY_extract_result (stmt, results);
+    switch (sql_ret)
+    {
+    case GNUNET_NO:
+      if (ret != GNUNET_YES)
+        ret = GNUNET_NO;
+      break;
+
+    case GNUNET_YES:
+      mp = GNUNET_malloc (sizeof (*mp) + buf_size);
+
+      mp->header.size = htons (sizeof (*mp) + buf_size);
+      mp->header.type = htons (GNUNET_MESSAGE_TYPE_MULTICAST_MESSAGE);
+      mp->hop_counter = htonl (hop_counter);
+      GNUNET_memcpy (&mp->signature,
+                     signature,
+                     signature_size);
+      GNUNET_memcpy (&mp->purpose,
+                     purpose,
+                     purpose_size);
+      mp->fragment_id = GNUNET_htonll (fragment_id);
+      mp->fragment_offset = GNUNET_htonll (fragment_offset);
+      mp->message_id = GNUNET_htonll (message_id);
+      mp->group_generation = GNUNET_htonll (group_generation);
+      mp->flags = htonl(msg_flags);
+
+      GNUNET_memcpy (&mp[1],
+                     buf,
+                     buf_size);
+      ret = cb (cb_cls, mp, (enum GNUNET_PSYCSTORE_MessageFlags) flags);
+      if (NULL != returned_fragments)
+        (*returned_fragments)++;
+      GNUNET_MY_cleanup_result (results);
+      break;
+
+    default:
+      LOG_MYSQL (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                 "mysql extract_result", stmt);
+    }
+  }
+  while (GNUNET_YES == sql_ret);
+
+  // for debugging
+  if (GNUNET_NO == ret)
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK,
+               "Empty result set\n");
+
+  return ret;
+}
+
+
+static int
+fragment_select (struct Plugin *plugin,
+                 struct GNUNET_MYSQL_StatementHandle *stmt,
+                 struct GNUNET_MY_QueryParam *params,
+                 uint64_t *returned_fragments,
+                 GNUNET_PSYCSTORE_FragmentCallback cb,
+                 void *cb_cls)
+{
+  int ret = GNUNET_SYSERR;
+  int sql_ret;
+
+  sql_ret = GNUNET_MY_exec_prepared (plugin->mc, stmt, params);
+  switch (sql_ret)
+  {
+    case GNUNET_NO:
+      if (ret != GNUNET_YES)
+        ret = GNUNET_NO;
+      break;
+
+    case GNUNET_YES:
+      ret = fragment_row (stmt, cb, cb_cls, returned_fragments);
+      break;
+
+    default:
+      LOG_MYSQL (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                 "mysql exec_prepared", stmt);
+  }
+  return ret;
+}
+
+
+/**
+ * Retrieve a message fragment range by fragment ID.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_get (void *cls,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+              uint64_t first_fragment_id,
+              uint64_t last_fragment_id,
+              uint64_t *returned_fragments,
+              GNUNET_PSYCSTORE_FragmentCallback cb,
+              void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_fragments;
+  int ret = GNUNET_SYSERR;
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&first_fragment_id),
+    GNUNET_MY_query_param_uint64 (&last_fragment_id),
+    GNUNET_MY_query_param_end
+  };
+
+  *returned_fragments = 0;
+  ret = fragment_select (plugin, stmt, params_select, returned_fragments, cb, cb_cls);
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve a message fragment range by fragment ID.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_get_latest()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_get_latest (void *cls,
+                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                     uint64_t fragment_limit,
+                     uint64_t *returned_fragments,
+                     GNUNET_PSYCSTORE_FragmentCallback cb,
+                     void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_latest_fragments;
+
+  int ret = GNUNET_SYSERR;
+  *returned_fragments = 0;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&fragment_limit),
+    GNUNET_MY_query_param_end
+  };
+
+  ret = fragment_select (plugin, stmt, params_select, returned_fragments, cb, cb_cls);
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all fragments of a message ID range.
+ *
+ * @see GNUNET_PSYCSTORE_message_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get (void *cls,
+             const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+             uint64_t first_message_id,
+             uint64_t last_message_id,
+             uint64_t fragment_limit,
+             uint64_t *returned_fragments,
+             GNUNET_PSYCSTORE_FragmentCallback cb,
+             void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_messages;
+  int ret;
+
+  if (0 == fragment_limit)
+    fragment_limit = UINT64_MAX;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&first_message_id),
+    GNUNET_MY_query_param_uint64 (&last_message_id),
+    GNUNET_MY_query_param_uint64 (&fragment_limit),
+    GNUNET_MY_query_param_end
+  };
+
+  *returned_fragments = 0;
+  ret = fragment_select (plugin, stmt, params_select, returned_fragments, cb, cb_cls);
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all fragments of the latest messages.
+ *
+ * @see GNUNET_PSYCSTORE_message_get_latest()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get_latest (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t message_limit,
+                    uint64_t *returned_fragments,
+                    GNUNET_PSYCSTORE_FragmentCallback cb,
+                    void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_latest_messages;
+
+  int ret = GNUNET_SYSERR;
+  *returned_fragments = 0;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&message_limit),
+    GNUNET_MY_query_param_end
+  };
+
+  ret = fragment_select (plugin, stmt, params_select, returned_fragments, cb, cb_cls);
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve a fragment of message specified by its message ID and fragment
+ * offset.
+ *
+ * @see GNUNET_PSYCSTORE_message_get_fragment()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get_fragment (void *cls,
+                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                      uint64_t message_id,
+                      uint64_t fragment_offset,
+                      GNUNET_PSYCSTORE_FragmentCallback cb,
+                      void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_message_fragment;
+  int sql_ret;
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_uint64 (&message_id),
+    GNUNET_MY_query_param_uint64 (&fragment_offset),
+    GNUNET_MY_query_param_end
+  };
+
+  sql_ret = GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select);
+  switch (sql_ret)
+  {
+    case GNUNET_NO:
+      ret = GNUNET_NO;
+      break;
+
+    case GNUNET_OK:
+      ret = fragment_row (stmt, cb, cb_cls, NULL);
+      break;
+
+    default:
+      LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql execute prepared", stmt);
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+/**
+ * Retrieve the max. values of message counters for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+counters_message_get (void *cls,
+                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                      uint64_t *max_fragment_id,
+                      uint64_t *max_message_id,
+                      uint64_t *max_group_generation)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_counters_message;
+
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql execute prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  struct GNUNET_MY_ResultSpec results_select[] = {
+    GNUNET_MY_result_spec_uint64 (max_fragment_id),
+    GNUNET_MY_result_spec_uint64 (max_message_id),
+    GNUNET_MY_result_spec_uint64 (max_group_generation),
+    GNUNET_MY_result_spec_end
+  };
+
+  ret = GNUNET_MY_extract_result (stmt, results_select);
+
+  if (GNUNET_OK != ret)
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql extract_result", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+/**
+ * Retrieve the max. values of state counters for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+counters_state_get (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t *max_state_message_id)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_counters_state;
+
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql execute prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  struct GNUNET_MY_ResultSpec results_select[] = {
+    GNUNET_MY_result_spec_uint64 (max_state_message_id),
+    GNUNET_MY_result_spec_end
+  };
+
+  ret = GNUNET_MY_extract_result (stmt, results_select);
+
+  if (GNUNET_OK != ret)
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql extract_result", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Assign a value to a state variable.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_assign (struct Plugin *plugin, struct GNUNET_MYSQL_StatementHandle *stmt,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+              const char *name, const void *value, size_t value_size)
+{
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MY_QueryParam params[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_string (name),
+    GNUNET_MY_query_param_fixed_size(value, value_size),
+    GNUNET_MY_query_param_end
+  };
+
+  ret = GNUNET_MY_exec_prepared (plugin->mc, stmt, params);
+  if (GNUNET_OK != ret)
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+static int
+update_message_id (struct Plugin *plugin, struct GNUNET_MYSQL_StatementHandle *stmt,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                   uint64_t message_id)
+{
+  struct GNUNET_MY_QueryParam params[] = {
+    GNUNET_MY_query_param_uint64 (&message_id),
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc,
+                                            stmt,
+                                            params))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql execute prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Begin modifying current state.
+ */
+static int
+state_modify_begin (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t message_id, uint64_t state_delta)
+{
+  struct Plugin *plugin = cls;
+
+  if (state_delta > 0)
+  {
+    /**
+     * We can only apply state modifiers in the current message if modifiers in
+     * the previous stateful message (message_id - state_delta) were already
+     * applied.
+     */
+
+    uint64_t max_state_message_id = 0;
+    int ret = counters_state_get (plugin, channel_key, &max_state_message_id);
+    switch (ret)
+    {
+    case GNUNET_OK:
+    case GNUNET_NO: // no state yet
+      ret = GNUNET_OK;
+      break;
+    default:
+      return ret;
+    }
+
+    if (max_state_message_id < message_id - state_delta)
+      return GNUNET_NO; /* some stateful messages not yet applied */
+    else if (message_id - state_delta < max_state_message_id)
+      return GNUNET_NO; /* changes already applied */
+  }
+
+  if (TRANSACTION_NONE != plugin->transaction)
+  {
+    /** @todo FIXME: wait for other transaction to finish  */
+    return GNUNET_SYSERR;
+  }
+  return transaction_begin (plugin, TRANSACTION_STATE_MODIFY);
+}
+
+
+/**
+ * Set the current value of state variable.
+ *
+ * @see GNUNET_PSYCSTORE_state_modify()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_modify_op (void *cls,
+                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                 enum GNUNET_PSYC_Operator op,
+                 const char *name, const void *value, size_t value_size)
+{
+  struct Plugin *plugin = cls;
+  GNUNET_assert (TRANSACTION_STATE_MODIFY == plugin->transaction);
+
+  switch (op)
+  {
+  case GNUNET_PSYC_OP_ASSIGN:
+    return state_assign (plugin, plugin->insert_state_current,
+                         channel_key, name, value, value_size);
+
+  default: /** @todo implement more state operations */
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * End modifying current state.
+ */
+static int
+state_modify_end (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  uint64_t message_id)
+{
+  struct Plugin *plugin = cls;
+  GNUNET_assert (TRANSACTION_STATE_MODIFY == plugin->transaction);
+
+  return
+    GNUNET_OK == exec_channel (plugin, plugin->delete_state_empty, channel_key)
+    && GNUNET_OK == update_message_id (plugin,
+                                       plugin->update_max_state_message_id,
+                                       channel_key, message_id)
+    && GNUNET_OK == transaction_commit (plugin)
+    ? GNUNET_OK : GNUNET_SYSERR;
+}
+
+
+/**
+ * Begin state synchronization.
+ */
+static int
+state_sync_begin (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, plugin->delete_state_sync, channel_key);
+}
+
+
+/**
+ * Assign current value of a state variable.
+ *
+ * @see GNUNET_PSYCSTORE_state_modify()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_sync_assign (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                const char *name, const void *value, size_t value_size)
+{
+  struct Plugin *plugin = cls;
+  return state_assign (cls, plugin->insert_state_sync,
+                       channel_key, name, value, value_size);
+}
+
+
+/**
+ * End modifying current state.
+ */
+static int
+state_sync_end (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                uint64_t max_state_message_id,
+                uint64_t state_hash_message_id)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  if (TRANSACTION_NONE != plugin->transaction)
+  {
+    /** @todo FIXME: wait for other transaction to finish  */
+    return GNUNET_SYSERR;
+  }
+
+  GNUNET_OK == transaction_begin (plugin, TRANSACTION_STATE_SYNC)
+    && GNUNET_OK == exec_channel (plugin, plugin->delete_state, channel_key)
+    && GNUNET_OK == exec_channel (plugin, plugin->insert_state_from_sync,
+                                  channel_key)
+    && GNUNET_OK == exec_channel (plugin, plugin->delete_state_sync,
+                                  channel_key)
+    && GNUNET_OK == update_message_id (plugin,
+                                       plugin->update_state_hash_message_id,
+                                       channel_key, state_hash_message_id)
+    && GNUNET_OK == update_message_id (plugin,
+                                       plugin->update_max_state_message_id,
+                                       channel_key, max_state_message_id)
+    && GNUNET_OK == transaction_commit (plugin)
+    ? ret = GNUNET_OK
+    : transaction_rollback (plugin);
+  return ret;
+}
+
+
+/**
+ * Delete the whole state.
+ *
+ * @see GNUNET_PSYCSTORE_state_reset()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_reset (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, plugin->delete_state, channel_key);
+}
+
+
+/**
+ * Update signed values of state variables in the state store.
+ *
+ * @see GNUNET_PSYCSTORE_state_hash_update()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_update_signed (void *cls,
+                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, plugin->update_state_signed, channel_key);
+}
+
+
+/**
+ * Retrieve a state variable by name.
+ *
+ * @see GNUNET_PSYCSTORE_state_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+           const char *name, GNUNET_PSYCSTORE_StateCallback cb, void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+  int sql_ret ;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_state_one;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_string (name),
+    GNUNET_MY_query_param_end
+  };
+
+  void *value_current = NULL;
+  size_t value_size = 0;
+
+  struct GNUNET_MY_ResultSpec results[] = {
+    GNUNET_MY_result_spec_variable_size (&value_current, &value_size),
+    GNUNET_MY_result_spec_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+  }
+  else
+  {
+    sql_ret = GNUNET_MY_extract_result (stmt, results);
+    switch (sql_ret)
+    {
+    case GNUNET_NO:
+      ret = GNUNET_NO;
+      break;
+
+    case GNUNET_YES:
+      ret = cb (cb_cls, name, value_current, value_size);
+      break;
+
+    default:
+      LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "mysql extract_result", stmt);
+    }
+  }
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all state variables for a channel with the given prefix.
+ *
+ * @see GNUNET_PSYCSTORE_state_get_prefix()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get_prefix (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  const char *name, GNUNET_PSYCSTORE_StateCallback cb,
+                  void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_state_prefix;
+
+  uint32_t name_len = (uint32_t) strlen (name);
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_string (name),
+    GNUNET_MY_query_param_uint32 (&name_len),
+    GNUNET_MY_query_param_string (name),
+    GNUNET_MY_query_param_end
+  };
+
+  char *name2 = "";
+  void *value_current = NULL;
+  size_t value_size = 0;
+
+  struct GNUNET_MY_ResultSpec results[] = {
+    GNUNET_MY_result_spec_string (&name2),
+    GNUNET_MY_result_spec_variable_size (&value_current, &value_size),
+    GNUNET_MY_result_spec_end
+  };;
+
+  int sql_ret;
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  do
+  {
+    sql_ret = GNUNET_MY_extract_result (stmt, results);
+    switch (sql_ret)
+    {
+      case GNUNET_NO:
+        if (ret != GNUNET_YES)
+          ret = GNUNET_NO;
+        break;
+
+      case GNUNET_YES:
+        ret = cb (cb_cls, (const char *) name2, value_current, value_size);
+
+        if (ret != GNUNET_YES)
+          sql_ret = GNUNET_NO;
+        break;
+
+      default:
+        LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "mysql extract_result", stmt);
+    }
+  }
+  while (sql_ret == GNUNET_YES);
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all signed state variables for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_state_get_signed()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get_signed (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  GNUNET_PSYCSTORE_StateCallback cb, void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  struct GNUNET_MYSQL_StatementHandle *stmt = plugin->select_state_signed;
+
+  struct GNUNET_MY_QueryParam params_select[] = {
+    GNUNET_MY_query_param_auto_from_type (channel_key),
+    GNUNET_MY_query_param_end
+  };
+
+  int sql_ret;
+
+  char *name = "";
+  void *value_signed = NULL;
+  size_t value_size = 0;
+
+  struct GNUNET_MY_ResultSpec results[] = {
+    GNUNET_MY_result_spec_string (&name),
+    GNUNET_MY_result_spec_variable_size (&value_signed, &value_size),
+    GNUNET_MY_result_spec_end
+  };
+
+  if (GNUNET_OK != GNUNET_MY_exec_prepared (plugin->mc, stmt, params_select))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql exec_prepared", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  do
+  {
+    sql_ret = GNUNET_MY_extract_result (stmt, results);
+    switch (sql_ret)
+    {
+      case GNUNET_NO:
+        if (ret != GNUNET_YES)
+          ret = GNUNET_NO;
+        break;
+
+      case GNUNET_YES:
+        ret = cb (cb_cls, (const char *) name, value_signed, value_size);
+
+        if (ret != GNUNET_YES)
+            sql_ret = GNUNET_NO;
+        break;
+
+      default:
+         LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql extract_result", stmt);
+    }
+  }
+  while (sql_ret == GNUNET_YES);
+
+  if (0 != mysql_stmt_reset (GNUNET_MYSQL_statement_get_stmt (stmt)))
+  {
+    LOG_MYSQL(plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+              "mysql_stmt_reset", stmt);
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+/**
+ * Entry point for the plugin.
+ *
+ * @param cls The struct GNUNET_CONFIGURATION_Handle.
+ * @return NULL on error, otherwise the plugin context
+ */
+void *
+libgnunet_plugin_psycstore_mysql_init (void *cls)
+{
+  static struct Plugin plugin;
+  const struct GNUNET_CONFIGURATION_Handle *cfg = cls;
+  struct GNUNET_PSYCSTORE_PluginFunctions *api;
+
+  if (NULL != plugin.cfg)
+    return NULL;                /* can only initialize once! */
+  memset (&plugin, 0, sizeof (struct Plugin));
+  plugin.cfg = cfg;
+  if (GNUNET_OK != database_setup (&plugin))
+  {
+    database_shutdown (&plugin);
+    return NULL;
+  }
+  api = GNUNET_new (struct GNUNET_PSYCSTORE_PluginFunctions);
+  api->cls = &plugin;
+  api->membership_store = &mysql_membership_store;
+  api->membership_test = &membership_test;
+  api->fragment_store = &fragment_store;
+  api->message_add_flags = &message_add_flags;
+  api->fragment_get = &fragment_get;
+  api->fragment_get_latest = &fragment_get_latest;
+  api->message_get = &message_get;
+  api->message_get_latest = &message_get_latest;
+  api->message_get_fragment = &message_get_fragment;
+  api->counters_message_get = &counters_message_get;
+  api->counters_state_get = &counters_state_get;
+  api->state_modify_begin = &state_modify_begin;
+  api->state_modify_op = &state_modify_op;
+  api->state_modify_end = &state_modify_end;
+  api->state_sync_begin = &state_sync_begin;
+  api->state_sync_assign = &state_sync_assign;
+  api->state_sync_end = &state_sync_end;
+  api->state_reset = &state_reset;
+  api->state_update_signed = &state_update_signed;
+  api->state_get = &state_get;
+  api->state_get_prefix = &state_get_prefix;
+  api->state_get_signed = &state_get_signed;
+
+  LOG (GNUNET_ERROR_TYPE_INFO, _("Mysql database running\n"));
+  return api;
+}
+
+
+/**
+ * Exit point from the plugin.
+ *
+ * @param cls The plugin context (as returned by "init")
+ * @return Always NULL
+ */
+void *
+libgnunet_plugin_psycstore_mysql_done (void *cls)
+{
+  struct GNUNET_PSYCSTORE_PluginFunctions *api = cls;
+  struct Plugin *plugin = api->cls;
+
+  database_shutdown (plugin);
+  plugin->cfg = NULL;
+  GNUNET_free (api);
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Mysql plugin is finished\n");
+  return NULL;
+}
+
+/* end of plugin_psycstore_mysql.c */
diff --git a/src/psycstore/plugin_psycstore_postgres.c b/src/psycstore/plugin_psycstore_postgres.c
new file mode 100644
index 0000000..33c9960
--- /dev/null
+++ b/src/psycstore/plugin_psycstore_postgres.c
@@ -0,0 +1,1530 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2016 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/plugin_psycstore_postgres.c
+ * @brief PostgresQL-based psycstore backend
+ * @author Daniel Golle
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ * @author Christophe Genevey
+ * @author Jeffrey Burdges
+ */
+
+#include "platform.h"
+#include "gnunet_psycstore_plugin.h"
+#include "gnunet_psycstore_service.h"
+#include "gnunet_multicast_service.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_psyc_util_lib.h"
+#include "psycstore.h"
+#include "gnunet_pq_lib.h"
+
+/**
+ * After how many ms "busy" should a DB operation fail for good?  A
+ * low value makes sure that we are more responsive to requests
+ * (especially PUTs).  A high value guarantees a higher success rate
+ * (SELECTs in iterate can take several seconds despite LIMIT=1).
+ *
+ * The default value of 1s should ensure that users do not experience
+ * huge latencies while at the same time allowing operations to
+ * succeed with reasonable probability.
+ */
+#define BUSY_TIMEOUT_MS 1000
+
+#define DEBUG_PSYCSTORE GNUNET_EXTRA_LOGGING
+
+#define LOG(kind,...) GNUNET_log_from (kind, "psycstore-postgres", __VA_ARGS__)
+
+enum Transactions {
+  TRANSACTION_NONE = 0,
+  TRANSACTION_STATE_MODIFY,
+  TRANSACTION_STATE_SYNC,
+};
+
+/**
+ * Context for all functions in this plugin.
+ */
+struct Plugin
+{
+
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Native Postgres database handle.
+   */
+  PGconn *dbh;
+
+  enum Transactions transaction;
+
+  void *cls;
+};
+
+
+/**
+ * Initialize the database connections and associated
+ * data structures (create tables and indices
+ * as needed as well).
+ *
+ * @param plugin the plugin context (state for this module)
+ * @return #GNUNET_OK on success
+ */
+static int
+database_setup (struct Plugin *plugin)
+{
+  struct GNUNET_PQ_ExecuteStatement es[] = {
+    GNUNET_PQ_make_execute ("CREATE TABLE IF NOT EXISTS channels (\n"
+                            " id SERIAL,\n"
+                            " pub_key BYTEA NOT NULL CHECK (LENGTH(pub_key)=32),\n"
+                            " max_state_message_id BIGINT,\n"
+                            " state_hash_message_id BIGINT,\n"
+                            " PRIMARY KEY(id)\n"
+                            ")"
+                            "WITH OIDS"),
+    GNUNET_PQ_make_execute ("CREATE UNIQUE INDEX IF NOT EXISTS channel_pub_key_idx \n"
+                            " ON channels (pub_key)"),
+    GNUNET_PQ_make_execute ("CREATE OR REPLACE FUNCTION get_chan_id(BYTEA) RETURNS INTEGER AS \n"
+                            " 'SELECT id FROM channels WHERE pub_key=$1;' LANGUAGE SQL STABLE \n"
+                            "RETURNS NULL ON NULL INPUT"),
+    GNUNET_PQ_make_execute ("CREATE TABLE IF NOT EXISTS slaves (\n"
+                            " id SERIAL,\n"
+                            " pub_key BYTEA NOT NULL CHECK (LENGTH(pub_key)=32),\n"
+                            " PRIMARY KEY(id)\n"
+                            ")"
+                            "WITH OIDS"),
+    GNUNET_PQ_make_execute ("CREATE UNIQUE INDEX IF NOT EXISTS slaves_pub_key_idx \n"
+                            " ON slaves (pub_key)"),
+    GNUNET_PQ_make_execute ("CREATE OR REPLACE FUNCTION get_slave_id(BYTEA) RETURNS INTEGER AS \n"
+                            " 'SELECT id FROM slaves WHERE pub_key=$1;' LANGUAGE SQL STABLE \n"
+                            "RETURNS NULL ON NULL INPUT"),
+    GNUNET_PQ_make_execute ("CREATE TABLE IF NOT EXISTS membership (\n"
+                            "  channel_id BIGINT NOT NULL REFERENCES channels(id),\n"
+                            "  slave_id BIGINT NOT NULL REFERENCES slaves(id),\n"
+                            "  did_join INT NOT NULL,\n"
+                            "  announced_at BIGINT NOT NULL,\n"
+                            "  effective_since BIGINT NOT NULL,\n"
+                            "  group_generation BIGINT NOT NULL\n"
+                            ")"
+                            "WITH OIDS"),
+    GNUNET_PQ_make_execute ("CREATE INDEX IF NOT EXISTS idx_membership_channel_id_slave_id "
+                            "ON membership (channel_id, slave_id)"),
+    /** @todo messages table: add method_name column */
+    GNUNET_PQ_make_execute ("CREATE TABLE IF NOT EXISTS messages (\n"
+                            "  channel_id BIGINT NOT NULL REFERENCES channels(id),\n"
+                            "  hop_counter INT NOT NULL,\n"
+                            "  signature BYTEA CHECK (LENGTH(signature)=64),\n"
+                            "  purpose BYTEA CHECK (LENGTH(purpose)=8),\n"
+                            "  fragment_id BIGINT NOT NULL,\n"
+                            "  fragment_offset BIGINT NOT NULL,\n"
+                            "  message_id BIGINT NOT NULL,\n"
+                            "  group_generation BIGINT NOT NULL,\n"
+                            "  multicast_flags INT NOT NULL,\n"
+                            "  psycstore_flags INT NOT NULL,\n"
+                            "  data BYTEA,\n"
+                            "  PRIMARY KEY (channel_id, fragment_id),\n"
+                            "  UNIQUE (channel_id, message_id, fragment_offset)\n"
+                            ")"
+                            "WITH OIDS"),
+    GNUNET_PQ_make_execute ("CREATE TABLE IF NOT EXISTS state (\n"
+                            "  channel_id BIGINT NOT NULL REFERENCES channels(id),\n"
+                            "  name TEXT NOT NULL,\n"
+                            "  value_current BYTEA,\n"
+                            "  value_signed BYTEA,\n"
+                            "  PRIMARY KEY (channel_id, name)\n"
+                            ")"
+                            "WITH OIDS"),
+    GNUNET_PQ_make_execute ("CREATE TABLE IF NOT EXISTS state_sync (\n"
+                            "  channel_id BIGINT NOT NULL REFERENCES channels(id),\n"
+                            "  name TEXT NOT NULL,\n"
+                            "  value BYTEA,\n"
+                            "  PRIMARY KEY (channel_id, name)\n"
+                            ")"
+                            "WITH OIDS"),
+    GNUNET_PQ_EXECUTE_STATEMENT_END
+  };
+
+  /* Open database and precompile statements */
+  plugin->dbh = GNUNET_PQ_connect_with_cfg (plugin->cfg,
+                                            "psycstore-postgres");
+  if (NULL == plugin->dbh)
+    return GNUNET_SYSERR;
+  if (GNUNET_OK !=
+      GNUNET_PQ_exec_statements (plugin->dbh,
+                                 es))
+  {
+    PQfinish (plugin->dbh);
+    plugin->dbh = NULL;
+    return GNUNET_SYSERR;
+  }
+
+  /* Prepare statements */
+  {
+    struct GNUNET_PQ_PreparedStatement ps[] = {
+      GNUNET_PQ_make_prepare ("transaction_begin",
+                              "BEGIN", 0),
+      GNUNET_PQ_make_prepare ("transaction_commit",
+                              "COMMIT", 0),
+      GNUNET_PQ_make_prepare ("transaction_rollback",
+                              "ROLLBACK", 0),
+      GNUNET_PQ_make_prepare ("insert_channel_key",
+                              "INSERT INTO channels (pub_key) VALUES ($1)"
+                              " ON CONFLICT DO NOTHING", 1),
+      GNUNET_PQ_make_prepare ("insert_slave_key",
+                              "INSERT INTO slaves (pub_key) VALUES ($1)"
+                              " ON CONFLICT DO NOTHING", 1),
+      GNUNET_PQ_make_prepare ("insert_membership",
+                              "INSERT INTO membership\n"
+                              " (channel_id, slave_id, did_join, announced_at,\n"
+                              "  effective_since, group_generation)\n"
+                              "VALUES (get_chan_id($1),\n"
+                              "        get_slave_id($2),\n"
+                              "        $3, $4, $5, $6)", 6),
+      GNUNET_PQ_make_prepare ("select_membership",
+                              "SELECT did_join FROM membership\n"
+                              "WHERE channel_id = get_chan_id($1)\n"
+                              "      AND slave_id = get_slave_id($2)\n"
+                              "      AND effective_since <= $3 AND did_join = 1\n"
+                              "ORDER BY announced_at DESC LIMIT 1", 3),
+      GNUNET_PQ_make_prepare ("insert_fragment",
+                              "INSERT INTO messages\n"
+                              " (channel_id, hop_counter, signature, purpose,\n"
+                              "  fragment_id, fragment_offset, message_id,\n"
+                              "  group_generation, multicast_flags, psycstore_flags, data)\n"
+                              "VALUES (get_chan_id($1),\n"
+                              "        $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)"
+                              "ON CONFLICT DO NOTHING", 11),
+      GNUNET_PQ_make_prepare ("update_message_flags",
+                              "UPDATE messages\n"
+                              "SET psycstore_flags = psycstore_flags | $1\n"
+                              "WHERE channel_id = get_chan_id($2) \n"
+                              "      AND message_id = $3 AND fragment_offset = 0", 3),
+      GNUNET_PQ_make_prepare ("select_fragments",
+                              "SELECT hop_counter, signature, purpose, fragment_id,\n"
+                              "       fragment_offset, message_id, group_generation,\n"
+                              "       multicast_flags, psycstore_flags, data\n"
+                              "FROM messages\n"
+                              "WHERE channel_id = get_chan_id($1) \n"
+                              "      AND $2 <= fragment_id AND fragment_id <= $3", 3),
+      /** @todo select_messages: add method_prefix filter */
+      GNUNET_PQ_make_prepare ("select_messages",
+                              "SELECT hop_counter, signature, purpose, fragment_id,\n"
+                              "       fragment_offset, message_id, group_generation,\n"
+                              "       multicast_flags, psycstore_flags, data\n"
+                              "FROM messages\n"
+                              "WHERE channel_id = get_chan_id($1) \n"
+                              "      AND $2 <= message_id AND message_id <= $3\n"
+                              "LIMIT $4;", 4),
+      /** @todo select_latest_messages: add method_prefix filter */
+      GNUNET_PQ_make_prepare ("select_latest_fragments",
+                              "SELECT  rev.hop_counter AS hop_counter,\n"
+                              "        rev.signature AS signature,\n"
+                              "        rev.purpose AS purpose,\n"
+                              "        rev.fragment_id AS fragment_id,\n"
+                              "        rev.fragment_offset AS fragment_offset,\n"
+                              "        rev.message_id AS message_id,\n"
+                              "        rev.group_generation AS group_generation,\n"
+                              "        rev.multicast_flags AS multicast_flags,\n"
+                              "        rev.psycstore_flags AS psycstore_flags,\n"
+                              "        rev.data AS data\n"
+                              " FROM\n"
+                              " (SELECT hop_counter, signature, purpose, fragment_id,\n"
+                              "        fragment_offset, message_id, group_generation,\n"
+                              "        multicast_flags, psycstore_flags, data \n"
+                              "  FROM messages\n"
+                              "  WHERE channel_id = get_chan_id($1) \n"
+                              "  ORDER BY fragment_id DESC\n"
+                              "  LIMIT $2) AS rev\n"
+                              " ORDER BY rev.fragment_id;", 2),
+      GNUNET_PQ_make_prepare ("select_latest_messages",
+                              "SELECT hop_counter, signature, purpose, fragment_id,\n"
+                              "       fragment_offset, message_id, group_generation,\n"
+                              "        multicast_flags, psycstore_flags, data\n"
+                              "FROM messages\n"
+                              "WHERE channel_id = get_chan_id($1)\n"
+                              "      AND message_id IN\n"
+                              "      (SELECT message_id\n"
+                              "       FROM messages\n"
+                              "       WHERE channel_id = get_chan_id($2) \n"
+                              "       GROUP BY message_id\n"
+                              "       ORDER BY message_id\n"
+                              "       DESC LIMIT $3)\n"
+                              "ORDER BY fragment_id", 3),
+      GNUNET_PQ_make_prepare ("select_message_fragment",
+                              "SELECT hop_counter, signature, purpose, fragment_id,\n"
+                              "       fragment_offset, message_id, group_generation,\n"
+                              "       multicast_flags, psycstore_flags, data\n"
+                              "FROM messages\n"
+                              "WHERE channel_id = get_chan_id($1) \n"
+                              "      AND message_id = $2 AND fragment_offset = $3", 3),
+      GNUNET_PQ_make_prepare ("select_counters_message",
+                              "SELECT fragment_id, message_id, group_generation\n"
+                              "FROM messages\n"
+                              "WHERE channel_id = get_chan_id($1)\n"
+                              "ORDER BY fragment_id DESC LIMIT 1", 1),
+      GNUNET_PQ_make_prepare ("select_counters_state",
+                              "SELECT max_state_message_id\n"
+                              "FROM channels\n"
+                              "WHERE pub_key = $1 AND max_state_message_id IS NOT NULL", 1),
+      GNUNET_PQ_make_prepare ("update_max_state_message_id",
+                              "UPDATE channels\n"
+                              "SET max_state_message_id = $1\n"
+                              "WHERE pub_key = $2", 2),
+
+      GNUNET_PQ_make_prepare ("update_state_hash_message_id",
+                              "UPDATE channels\n"
+                              "SET state_hash_message_id = $1\n"
+                              "WHERE pub_key = $2", 2),
+      GNUNET_PQ_make_prepare ("insert_state_current",
+                              "INSERT INTO state\n"
+                              "  (channel_id, name, value_current, value_signed)\n"
+                              "SELECT new.channel_id, new.name,\n"
+                              "       new.value_current, old.value_signed\n"
+                              "FROM (SELECT get_chan_id($1) AS channel_id,\n"
+                              "             $2::TEXT AS name, $3::BYTEA AS value_current) AS new\n"
+                              "LEFT JOIN (SELECT channel_id, name, value_signed\n"
+                              "           FROM state) AS old\n"
+                              "ON new.channel_id = old.channel_id AND new.name = old.name\n"
+                              "ON CONFLICT (channel_id, name)\n"
+                              "   DO UPDATE SET value_current = EXCLUDED.value_current,\n"
+                              "                 value_signed = EXCLUDED.value_signed", 3),
+      GNUNET_PQ_make_prepare ("delete_state_empty",
+                              "DELETE FROM state\n"
+                              "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = $1)\n"
+                              "      AND (value_current IS NULL OR length(value_current) = 0)\n"
+                              "      AND (value_signed IS NULL OR length(value_signed) = 0)", 1),
+      GNUNET_PQ_make_prepare ("update_state_signed",
+                              "UPDATE state\n"
+                              "SET value_signed = value_current\n"
+                              "WHERE channel_id = get_chan_id($1) ", 1),
+      GNUNET_PQ_make_prepare ("delete_state",
+                              "DELETE FROM state\n"
+                              "WHERE channel_id = get_chan_id($1) ", 1),
+      GNUNET_PQ_make_prepare ("insert_state_sync",
+                              "INSERT INTO state_sync (channel_id, name, value)\n"
+                              "VALUES (get_chan_id($1), $2, $3)", 3),
+      GNUNET_PQ_make_prepare ("insert_state_from_sync",
+                              "INSERT INTO state\n"
+                              " (channel_id, name, value_current, value_signed)\n"
+                              "SELECT channel_id, name, value, value\n"
+                              "FROM state_sync\n"
+                              "WHERE channel_id = get_chan_id($1)", 1),
+      GNUNET_PQ_make_prepare ("delete_state_sync",
+                              "DELETE FROM state_sync\n"
+                              "WHERE channel_id = get_chan_id($1)", 1),
+      GNUNET_PQ_make_prepare ("select_state_one",
+                              "SELECT value_current\n"
+                              "FROM state\n"
+                              "WHERE channel_id = get_chan_id($1)\n"
+                              "      AND name = $2", 2),
+      GNUNET_PQ_make_prepare ("select_state_prefix",
+                              "SELECT name, value_current\n"
+                              "FROM state\n"
+                              "WHERE channel_id = get_chan_id($1)\n"
+                              "      AND (name = $2 OR substr(name, 1, $3) = $4)", 4),
+      GNUNET_PQ_make_prepare ("select_state_signed",
+                              "SELECT name, value_signed\n"
+                              "FROM state\n"
+                              "WHERE channel_id = get_chan_id($1)\n"
+                              "      AND value_signed IS NOT NULL", 1),
+      GNUNET_PQ_PREPARED_STATEMENT_END
+    };
+
+    if (GNUNET_OK !=
+        GNUNET_PQ_prepare_statements (plugin->dbh,
+                                      ps))
+    {
+      PQfinish (plugin->dbh);
+      plugin->dbh = NULL;
+      return GNUNET_SYSERR;
+    }
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Shutdown database connection and associate data
+ * structures.
+ * @param plugin the plugin context (state for this module)
+ */
+static void
+database_shutdown (struct Plugin *plugin)
+{
+  PQfinish (plugin->dbh);
+  plugin->dbh = NULL;
+}
+
+
+/**
+ * Execute a prepared statement with a @a channel_key argument.
+ *
+ * @param plugin Plugin handle.
+ * @param stmt Statement to execute.
+ * @param channel_key Public key of the channel.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+exec_channel (struct Plugin *plugin, const char *stmt,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, stmt, params))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Begin a transaction.
+ */
+static int
+transaction_begin (struct Plugin *plugin, enum Transactions transaction)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, "transaction_begin", params))
+    return GNUNET_SYSERR;
+
+  plugin->transaction = transaction;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Commit current transaction.
+ */
+static int
+transaction_commit (struct Plugin *plugin)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, "transaction_commit", params))
+    return GNUNET_SYSERR;
+
+  plugin->transaction = TRANSACTION_NONE;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Roll back current transaction.
+ */
+static int
+transaction_rollback (struct Plugin *plugin)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, "transaction_rollback", params))
+    return GNUNET_SYSERR;
+
+  plugin->transaction = TRANSACTION_NONE;
+  return GNUNET_OK;
+}
+
+
+static int
+channel_key_store (struct Plugin *plugin,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh,
+					  "insert_channel_key",
+					  params))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+static int
+slave_key_store (struct Plugin *plugin,
+                 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_auto_from_type (slave_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, "insert_slave_key", params))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Store join/leave events for a PSYC channel in order to be able to answer
+ * membership test queries later.
+ *
+ * @see GNUNET_PSYCSTORE_membership_store()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+postgres_membership_store (void *cls,
+                           const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                           const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                           int did_join,
+                           uint64_t announced_at,
+                           uint64_t effective_since,
+                           uint64_t group_generation)
+{
+  struct Plugin *plugin = cls;
+  uint32_t idid_join = (uint32_t) did_join;
+
+  GNUNET_assert (TRANSACTION_NONE == plugin->transaction);
+
+  if ( (announced_at > INT64_MAX) ||
+       (effective_since > INT64_MAX) ||
+       (group_generation > INT64_MAX) )
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if ( (GNUNET_OK !=
+	channel_key_store (plugin, channel_key)) ||
+       (GNUNET_OK !=
+	slave_key_store (plugin, slave_key)) )
+    return GNUNET_SYSERR;
+
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_auto_from_type (slave_key),
+    GNUNET_PQ_query_param_uint32 (&idid_join),
+    GNUNET_PQ_query_param_uint64 (&announced_at),
+    GNUNET_PQ_query_param_uint64 (&effective_since),
+    GNUNET_PQ_query_param_uint64 (&group_generation),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh,
+					  "insert_membership",
+					  params))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+/**
+ * Test if a member was admitted to the channel at the given message ID.
+ *
+ * @see GNUNET_PSYCSTORE_membership_test()
+ *
+ * @return #GNUNET_YES if the member was admitted, #GNUNET_NO if not,
+ *         #GNUNET_SYSERR if there was en error.
+ */
+static int
+membership_test (void *cls,
+                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                 uint64_t message_id)
+{
+  struct Plugin *plugin = cls;
+
+  uint32_t did_join = 0;
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_auto_from_type (slave_key),
+    GNUNET_PQ_query_param_uint64 (&message_id),
+    GNUNET_PQ_query_param_end
+  };
+
+  struct GNUNET_PQ_ResultSpec results_select[] = {
+    GNUNET_PQ_result_spec_uint32 ("did_join", &did_join),
+    GNUNET_PQ_result_spec_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_singleton_select (plugin->dbh, "select_membership", 
+                                                params_select, results_select))
+     return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+/**
+ * Store a message fragment sent to a channel.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_store()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_store (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                const struct GNUNET_MULTICAST_MessageHeader *msg,
+                uint32_t psycstore_flags)
+{
+  struct Plugin *plugin = cls;
+
+  GNUNET_assert (TRANSACTION_NONE == plugin->transaction);
+
+  uint64_t fragment_id = GNUNET_ntohll (msg->fragment_id);
+
+  uint64_t fragment_offset = GNUNET_ntohll (msg->fragment_offset);
+  uint64_t message_id = GNUNET_ntohll (msg->message_id);
+  uint64_t group_generation = GNUNET_ntohll (msg->group_generation);
+
+  uint32_t hop_counter = ntohl(msg->hop_counter);
+  uint32_t flags = ntohl(msg->flags);
+
+  if (fragment_id > INT64_MAX || fragment_offset > INT64_MAX ||
+      message_id > INT64_MAX || group_generation > INT64_MAX)
+  {
+    LOG(GNUNET_ERROR_TYPE_ERROR,
+         "Tried to store fragment with a field > INT64_MAX: "
+         "%lu, %lu, %lu, %lu\n", fragment_id, fragment_offset,
+         message_id, group_generation);
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != channel_key_store (plugin, channel_key))
+    return GNUNET_SYSERR;
+
+  struct GNUNET_PQ_QueryParam params_insert[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint32 (&hop_counter),
+    GNUNET_PQ_query_param_auto_from_type (&msg->signature),
+    GNUNET_PQ_query_param_auto_from_type (&msg->purpose),
+    GNUNET_PQ_query_param_uint64 (&fragment_id),
+    GNUNET_PQ_query_param_uint64 (&fragment_offset),
+    GNUNET_PQ_query_param_uint64 (&message_id),
+    GNUNET_PQ_query_param_uint64 (&group_generation),
+    GNUNET_PQ_query_param_uint32 (&flags),
+    GNUNET_PQ_query_param_uint32 (&psycstore_flags),
+    GNUNET_PQ_query_param_fixed_size (&msg[1], ntohs (msg->header.size) - sizeof (*msg)),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, "insert_fragment", params_insert))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+/**
+ * Set additional flags for a given message.
+ *
+ * They are OR'd with any existing flags set.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_add_flags (void *cls,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                   uint64_t message_id,
+                   uint32_t psycstore_flags)
+{
+  struct Plugin *plugin = cls;
+
+  struct GNUNET_PQ_QueryParam params_update[] = {
+    GNUNET_PQ_query_param_uint32 (&psycstore_flags),
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint64 (&message_id),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, "update_message_flags", params_update))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Closure for #fragment_rows.
+ */
+struct FragmentRowsContext {
+  GNUNET_PSYCSTORE_FragmentCallback cb;
+  void *cb_cls;
+
+  uint64_t *returned_fragments;
+
+  /* I preserved this but I do not see the point since
+   * it cannot stop the loop early and gets overwritten ?? */
+  int ret;
+};
+
+
+/**
+ * Callback that retrieves the results of a SELECT statement
+ * reading form the messages table.
+ *
+ * Only passed to GNUNET_PQ_eval_prepared_multi_select and
+ * has type GNUNET_PQ_PostgresResultHandler.
+ *
+ * @param cls closure
+ * @param result the postgres result
+ * @param num_result the number of results in @a result
+ */
+void fragment_rows (void *cls,
+                    PGresult *res,
+                    unsigned int num_results)
+{
+  struct FragmentRowsContext *c = cls;
+
+  for (unsigned int i=0;i<num_results;i++)
+  {
+    uint32_t hop_counter;
+    void *signature = NULL;
+    void *purpose = NULL;
+    size_t signature_size;
+    size_t purpose_size;
+    uint64_t fragment_id;
+    uint64_t fragment_offset;
+    uint64_t message_id;
+    uint64_t group_generation;
+    uint32_t flags;
+    void *buf;
+    size_t buf_size;
+    uint32_t msg_flags;
+    struct GNUNET_PQ_ResultSpec results[] = {
+      GNUNET_PQ_result_spec_uint32 ("hop_counter", &hop_counter),
+      GNUNET_PQ_result_spec_variable_size ("signature", &signature, &signature_size),
+      GNUNET_PQ_result_spec_variable_size ("purpose", &purpose, &purpose_size),
+      GNUNET_PQ_result_spec_uint64 ("fragment_id", &fragment_id),
+      GNUNET_PQ_result_spec_uint64 ("fragment_offset", &fragment_offset),
+      GNUNET_PQ_result_spec_uint64 ("message_id", &message_id),
+      GNUNET_PQ_result_spec_uint64 ("group_generation", &group_generation),
+      GNUNET_PQ_result_spec_uint32 ("multicast_flags", &msg_flags),
+      GNUNET_PQ_result_spec_uint32 ("psycstore_flags", &flags),
+      GNUNET_PQ_result_spec_variable_size ("data", &buf, &buf_size),
+      GNUNET_PQ_result_spec_end
+    };
+    struct GNUNET_MULTICAST_MessageHeader *mp;
+
+    if (GNUNET_YES != GNUNET_PQ_extract_result (res, results, i))
+    {
+      GNUNET_PQ_cleanup_result(results);  /* missing previously, a memory leak?? */
+      break;  /* nothing more?? */
+    }
+
+    mp = GNUNET_malloc (sizeof (*mp) + buf_size);
+
+    mp->header.size = htons (sizeof (*mp) + buf_size);
+    mp->header.type = htons (GNUNET_MESSAGE_TYPE_MULTICAST_MESSAGE);
+    mp->hop_counter = htonl (hop_counter);
+    GNUNET_memcpy (&mp->signature,
+                   signature, signature_size);
+    GNUNET_memcpy (&mp->purpose,
+                   purpose, purpose_size);
+    mp->fragment_id = GNUNET_htonll (fragment_id);
+    mp->fragment_offset = GNUNET_htonll (fragment_offset);
+    mp->message_id = GNUNET_htonll (message_id);
+    mp->group_generation = GNUNET_htonll (group_generation);
+    mp->flags = htonl(msg_flags);
+
+    GNUNET_memcpy (&mp[1],
+                   buf, buf_size);
+    GNUNET_PQ_cleanup_result(results);
+    c->ret = c->cb (c->cb_cls, mp, (enum GNUNET_PSYCSTORE_MessageFlags) flags);
+    if (NULL != c->returned_fragments)
+      (*c->returned_fragments)++;
+  }
+}
+
+
+static int
+fragment_select (struct Plugin *plugin,
+                 const char *stmt,
+                 struct GNUNET_PQ_QueryParam *params,
+                 uint64_t *returned_fragments,
+                 GNUNET_PSYCSTORE_FragmentCallback cb,
+                 void *cb_cls)
+{
+  /* Stack based closure */
+  struct FragmentRowsContext frc = {
+    .cb = cb,
+    .cb_cls = cb_cls,
+    .returned_fragments = returned_fragments,
+    .ret = GNUNET_SYSERR
+  };
+
+  if (0 > GNUNET_PQ_eval_prepared_multi_select (plugin->dbh,
+                                                stmt, params,
+                                                &fragment_rows, &frc))
+    return GNUNET_SYSERR;
+  return frc.ret;  /* GNUNET_OK ?? */
+}
+
+/**
+ * Retrieve a message fragment range by fragment ID.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_get (void *cls,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+              uint64_t first_fragment_id,
+              uint64_t last_fragment_id,
+              uint64_t *returned_fragments,
+              GNUNET_PSYCSTORE_FragmentCallback cb,
+              void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint64 (&first_fragment_id),
+    GNUNET_PQ_query_param_uint64 (&last_fragment_id),
+    GNUNET_PQ_query_param_end
+  };
+
+  *returned_fragments = 0;
+  return fragment_select (plugin,
+                          "select_fragments",
+                          params_select,
+                          returned_fragments,
+                          cb, cb_cls);
+}
+
+
+/**
+ * Retrieve a message fragment range by fragment ID.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_get_latest()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_get_latest (void *cls,
+                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                     uint64_t fragment_limit,
+                     uint64_t *returned_fragments,
+                     GNUNET_PSYCSTORE_FragmentCallback cb,
+                     void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+
+  *returned_fragments = 0;
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint64 (&fragment_limit),
+    GNUNET_PQ_query_param_end
+  };
+
+  return fragment_select (plugin,
+                          "select_latest_fragments",
+                          params_select,
+                          returned_fragments,
+                          cb, cb_cls);
+}
+
+
+/**
+ * Retrieve all fragments of a message ID range.
+ *
+ * @see GNUNET_PSYCSTORE_message_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get (void *cls,
+             const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+             uint64_t first_message_id,
+             uint64_t last_message_id,
+             uint64_t fragment_limit,
+             uint64_t *returned_fragments,
+             GNUNET_PSYCSTORE_FragmentCallback cb,
+             void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint64 (&first_message_id),
+    GNUNET_PQ_query_param_uint64 (&last_message_id),
+    GNUNET_PQ_query_param_uint64 (&fragment_limit),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (0 == fragment_limit)
+    fragment_limit = INT64_MAX;
+  *returned_fragments = 0;
+  return fragment_select (plugin,
+                          "select_messages",
+                          params_select,
+                          returned_fragments,
+                          cb, cb_cls);
+}
+
+
+/**
+ * Retrieve all fragments of the latest messages.
+ *
+ * @see GNUNET_PSYCSTORE_message_get_latest()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get_latest (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t message_limit,
+                    uint64_t *returned_fragments,
+                    GNUNET_PSYCSTORE_FragmentCallback cb,
+                    void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint64 (&message_limit),
+    GNUNET_PQ_query_param_end
+  };
+
+  *returned_fragments = 0;
+  return fragment_select (plugin,
+                          "select_latest_messages",
+                          params_select,
+                          returned_fragments,
+                          cb, cb_cls);
+}
+
+
+/**
+ * Retrieve a fragment of message specified by its message ID and fragment
+ * offset.
+ *
+ * @see GNUNET_PSYCSTORE_message_get_fragment()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get_fragment (void *cls,
+                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                      uint64_t message_id,
+                      uint64_t fragment_offset,
+                      GNUNET_PSYCSTORE_FragmentCallback cb,
+                      void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  const char *stmt = "select_message_fragment";
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_uint64 (&message_id),
+    GNUNET_PQ_query_param_uint64 (&fragment_offset),
+    GNUNET_PQ_query_param_end
+  };
+
+  /* Stack based closure */
+  struct FragmentRowsContext frc = {
+    .cb = cb,
+    .cb_cls = cb_cls,
+    .returned_fragments = NULL,
+    .ret = GNUNET_SYSERR
+  };
+
+  if (0 > GNUNET_PQ_eval_prepared_multi_select (plugin->dbh,
+                                                stmt, params_select,
+                                                &fragment_rows, &frc))
+    return GNUNET_SYSERR;
+  return frc.ret;  /* GNUNET_OK ?? */
+}
+
+/**
+ * Retrieve the max. values of message counters for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+counters_message_get (void *cls,
+                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                      uint64_t *max_fragment_id,
+                      uint64_t *max_message_id,
+                      uint64_t *max_group_generation)
+{
+  struct Plugin *plugin = cls;
+
+  const char *stmt = "select_counters_message";
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  struct GNUNET_PQ_ResultSpec results_select[] = {
+    GNUNET_PQ_result_spec_uint64 ("fragment_id", max_fragment_id),
+    GNUNET_PQ_result_spec_uint64 ("message_id", max_message_id),
+    GNUNET_PQ_result_spec_uint64 ("group_generation", max_group_generation),
+    GNUNET_PQ_result_spec_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_singleton_select (plugin->dbh, stmt, 
+                                                params_select, results_select))
+     return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+/**
+ * Retrieve the max. values of state counters for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+counters_state_get (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t *max_state_message_id)
+{
+  struct Plugin *plugin = cls;
+
+  const char *stmt = "select_counters_state";
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  struct GNUNET_PQ_ResultSpec results_select[] = {
+    GNUNET_PQ_result_spec_uint64 ("max_state_message_id", max_state_message_id),
+    GNUNET_PQ_result_spec_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_singleton_select (plugin->dbh, stmt, 
+                                                params_select, results_select))
+     return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Assign a value to a state variable.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_assign (struct Plugin *plugin, const char *stmt,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+              const char *name, const void *value, size_t value_size)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_string (name),
+    GNUNET_PQ_query_param_fixed_size (value, value_size),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, stmt, params))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+static int
+update_message_id (struct Plugin *plugin,
+                   const char *stmt,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                   uint64_t message_id)
+{
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_uint64 (&message_id),
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS !=
+      GNUNET_PQ_eval_prepared_non_select (plugin->dbh, stmt, params))
+    return GNUNET_SYSERR;
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Begin modifying current state.
+ */
+static int
+state_modify_begin (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t message_id, uint64_t state_delta)
+{
+  struct Plugin *plugin = cls;
+
+  if (state_delta > 0)
+  {
+    /**
+     * We can only apply state modifiers in the current message if modifiers in
+     * the previous stateful message (message_id - state_delta) were already
+     * applied.
+     */
+
+    uint64_t max_state_message_id = 0;
+    int ret = counters_state_get (plugin, channel_key, &max_state_message_id);
+    switch (ret)
+    {
+    case GNUNET_OK:
+    case GNUNET_NO: // no state yet
+      ret = GNUNET_OK;
+      break;
+
+    default:
+      return ret;
+    }
+
+    if (max_state_message_id < message_id - state_delta)
+      return GNUNET_NO; /* some stateful messages not yet applied */
+    else if (message_id - state_delta < max_state_message_id)
+      return GNUNET_NO; /* changes already applied */
+  }
+
+  if (TRANSACTION_NONE != plugin->transaction)
+  {
+    /** @todo FIXME: wait for other transaction to finish  */
+    return GNUNET_SYSERR;
+  }
+  return transaction_begin (plugin, TRANSACTION_STATE_MODIFY);
+}
+
+
+/**
+ * Set the current value of state variable.
+ *
+ * @see GNUNET_PSYCSTORE_state_modify()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_modify_op (void *cls,
+                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                 enum GNUNET_PSYC_Operator op,
+                 const char *name, const void *value, size_t value_size)
+{
+  struct Plugin *plugin = cls;
+  GNUNET_assert (TRANSACTION_STATE_MODIFY == plugin->transaction);
+
+  switch (op)
+  {
+  case GNUNET_PSYC_OP_ASSIGN:
+    return state_assign (plugin, "insert_state_current",
+                         channel_key, name, value, value_size);
+
+  default: /** @todo implement more state operations */
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * End modifying current state.
+ */
+static int
+state_modify_end (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  uint64_t message_id)
+{
+  struct Plugin *plugin = cls;
+  GNUNET_assert (TRANSACTION_STATE_MODIFY == plugin->transaction);
+
+  return
+    GNUNET_OK == exec_channel (plugin, "delete_state_empty", channel_key)
+    && GNUNET_OK == update_message_id (plugin,
+                                       "update_max_state_message_id",
+                                       channel_key, message_id)
+    && GNUNET_OK == transaction_commit (plugin)
+    ? GNUNET_OK : GNUNET_SYSERR;
+}
+
+
+/**
+ * Begin state synchronization.
+ */
+static int
+state_sync_begin (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, "delete_state_sync", channel_key);
+}
+
+
+/**
+ * Assign current value of a state variable.
+ *
+ * @see GNUNET_PSYCSTORE_state_modify()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_sync_assign (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                const char *name, const void *value, size_t value_size)
+{
+  struct Plugin *plugin = cls;
+  return state_assign (plugin, "insert_state_sync",
+                       channel_key, name, value, value_size);
+}
+
+
+/**
+ * End modifying current state.
+ */
+static int
+state_sync_end (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                uint64_t max_state_message_id,
+                uint64_t state_hash_message_id)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  if (TRANSACTION_NONE != plugin->transaction)
+  {
+    /** @todo FIXME: wait for other transaction to finish  */
+    return GNUNET_SYSERR;
+  }
+
+  GNUNET_OK == transaction_begin (plugin, TRANSACTION_STATE_SYNC)
+    && GNUNET_OK == exec_channel (plugin, "delete_state", channel_key)
+    && GNUNET_OK == exec_channel (plugin, "insert_state_from_sync",
+                                  channel_key)
+    && GNUNET_OK == exec_channel (plugin, "delete_state_sync",
+                                  channel_key)
+    && GNUNET_OK == update_message_id (plugin,
+                                       "update_state_hash_message_id",
+                                       channel_key, state_hash_message_id)
+    && GNUNET_OK == update_message_id (plugin,
+                                       "update_max_state_message_id",
+                                       channel_key, max_state_message_id)
+    && GNUNET_OK == transaction_commit (plugin)
+    ? ret = GNUNET_OK
+    : transaction_rollback (plugin);
+  return ret;
+}
+
+
+/**
+ * Delete the whole state.
+ *
+ * @see GNUNET_PSYCSTORE_state_reset()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_reset (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, "delete_state", channel_key);
+}
+
+
+/**
+ * Update signed values of state variables in the state store.
+ *
+ * @see GNUNET_PSYCSTORE_state_hash_update()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_update_signed (void *cls,
+                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, "update_state_signed", channel_key);
+}
+
+
+/**
+ * Retrieve a state variable by name.
+ *
+ * @see GNUNET_PSYCSTORE_state_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+           const char *name, GNUNET_PSYCSTORE_StateCallback cb, void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+
+  const char *stmt = "select_state_one";
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_string (name),
+    GNUNET_PQ_query_param_end
+  };
+
+  void *value_current = NULL;
+  size_t value_size = 0;
+
+  struct GNUNET_PQ_ResultSpec results_select[] = {
+    GNUNET_PQ_result_spec_variable_size ("value_current", &value_current, &value_size),
+    GNUNET_PQ_result_spec_end
+  };
+
+  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
+      GNUNET_PQ_eval_prepared_singleton_select (plugin->dbh, stmt, 
+                                                params_select, results_select))
+     return GNUNET_SYSERR;
+
+  return cb (cb_cls, name, value_current,
+            value_size);
+}
+
+
+
+/**
+ * Closure for #get_state_cb.
+ */
+struct GetStateContext {
+  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key;
+  // const char *name,
+  GNUNET_PSYCSTORE_StateCallback cb;
+  void *cb_cls;
+
+  const char *value_id;
+
+  /* I preserved this but I do not see the point since
+   * it cannot stop the loop early and gets overwritten ?? */
+  int ret;
+};
+
+
+/**
+ * Callback that retrieves the results of a SELECT statement
+ * reading form the state table.
+ *
+ * Only passed to GNUNET_PQ_eval_prepared_multi_select and
+ * has type GNUNET_PQ_PostgresResultHandler.
+ *
+ * @param cls closure
+ * @param result the postgres result
+ * @param num_result the number of results in @a result
+ */
+static void 
+get_state_cb (void *cls,
+                PGresult *res,
+                unsigned int num_results)
+{
+  struct GetStateContext *c = cls;
+
+  for (unsigned int i=0;i<num_results;i++)
+  {
+    char *name = "";
+    void *value = NULL;
+    size_t value_size = 0;
+
+    struct GNUNET_PQ_ResultSpec results[] = {
+      GNUNET_PQ_result_spec_string ("name", &name),
+      GNUNET_PQ_result_spec_variable_size (c->value_id, &value, &value_size),
+      GNUNET_PQ_result_spec_end
+    };
+
+    if (GNUNET_YES != GNUNET_PQ_extract_result (res, results, i))
+    {
+      GNUNET_PQ_cleanup_result(results);  /* previously invoked via PQclear?? */
+      break;  /* nothing more?? */
+    }
+
+    c->ret = c->cb (c->cb_cls, (const char *) name, value, value_size);
+    GNUNET_PQ_cleanup_result(results);
+  }
+}
+
+/**
+ * Retrieve all state variables for a channel with the given prefix.
+ *
+ * @see GNUNET_PSYCSTORE_state_get_prefix()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get_prefix (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  const char *name, GNUNET_PSYCSTORE_StateCallback cb,
+                  void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+
+  const char *stmt = "select_state_prefix";
+
+  uint32_t name_len = (uint32_t) strlen (name);
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_string (name),
+    GNUNET_PQ_query_param_uint32 (&name_len),
+    GNUNET_PQ_query_param_string (name),
+    GNUNET_PQ_query_param_end
+  };
+
+  struct GetStateContext gsc = {
+    .cb = cb,
+    .cb_cls = cb_cls,
+    .value_id = "value_current",
+    .ret = GNUNET_NO
+  };
+
+  if (0 > GNUNET_PQ_eval_prepared_multi_select (plugin->dbh,
+                                                stmt, params_select,
+                                                &get_state_cb, &gsc))
+    return GNUNET_SYSERR;
+  return gsc.ret;  /* GNUNET_OK ?? */
+}
+
+
+/**
+ * Retrieve all signed state variables for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_state_get_signed()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get_signed (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  GNUNET_PSYCSTORE_StateCallback cb, void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+
+  const char *stmt = "select_state_signed";
+
+  struct GNUNET_PQ_QueryParam params_select[] = {
+    GNUNET_PQ_query_param_auto_from_type (channel_key),
+    GNUNET_PQ_query_param_end
+  };
+
+  struct GetStateContext gsc = {
+    .cb = cb,
+    .cb_cls = cb_cls,
+    .value_id = "value_signed",
+    .ret = GNUNET_NO
+  };
+
+  if (0 > GNUNET_PQ_eval_prepared_multi_select (plugin->dbh,
+                                                stmt, params_select,
+                                                &get_state_cb, &gsc))
+    return GNUNET_SYSERR;
+  return gsc.ret;  /* GNUNET_OK ?? */
+}
+
+
+/**
+ * Entry point for the plugin.
+ *
+ * @param cls The struct GNUNET_CONFIGURATION_Handle.
+ * @return NULL on error, otherwise the plugin context
+ */
+void *
+libgnunet_plugin_psycstore_postgres_init (void *cls)
+{
+  static struct Plugin plugin;
+  const struct GNUNET_CONFIGURATION_Handle *cfg = cls;
+  struct GNUNET_PSYCSTORE_PluginFunctions *api;
+
+  if (NULL != plugin.cfg)
+    return NULL;                /* can only initialize once! */
+  memset (&plugin, 0, sizeof (struct Plugin));
+  plugin.cfg = cfg;
+  if (GNUNET_OK != database_setup (&plugin))
+  {
+    database_shutdown (&plugin);
+    return NULL;
+  }
+  api = GNUNET_new (struct GNUNET_PSYCSTORE_PluginFunctions);
+  api->cls = &plugin;
+  api->membership_store = &postgres_membership_store;
+  api->membership_test = &membership_test;
+  api->fragment_store = &fragment_store;
+  api->message_add_flags = &message_add_flags;
+  api->fragment_get = &fragment_get;
+  api->fragment_get_latest = &fragment_get_latest;
+  api->message_get = &message_get;
+  api->message_get_latest = &message_get_latest;
+  api->message_get_fragment = &message_get_fragment;
+  api->counters_message_get = &counters_message_get;
+  api->counters_state_get = &counters_state_get;
+  api->state_modify_begin = &state_modify_begin;
+  api->state_modify_op = &state_modify_op;
+  api->state_modify_end = &state_modify_end;
+  api->state_sync_begin = &state_sync_begin;
+  api->state_sync_assign = &state_sync_assign;
+  api->state_sync_end = &state_sync_end;
+  api->state_reset = &state_reset;
+  api->state_update_signed = &state_update_signed;
+  api->state_get = &state_get;
+  api->state_get_prefix = &state_get_prefix;
+  api->state_get_signed = &state_get_signed;
+
+  LOG (GNUNET_ERROR_TYPE_INFO, _("Postgres database running\n"));
+  return api;
+}
+
+
+/**
+ * Exit point from the plugin.
+ *
+ * @param cls The plugin context (as returned by "init")
+ * @return Always NULL
+ */
+void *
+libgnunet_plugin_psycstore_postgres_done (void *cls)
+{
+  struct GNUNET_PSYCSTORE_PluginFunctions *api = cls;
+  struct Plugin *plugin = api->cls;
+
+  database_shutdown (plugin);
+  plugin->cfg = NULL;
+  GNUNET_free (api);
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Postgres plugin has finished\n");
+  return NULL;
+}
+
+/* end of plugin_psycstore_postgres.c */
diff --git a/src/psycstore/plugin_psycstore_sqlite.c b/src/psycstore/plugin_psycstore_sqlite.c
new file mode 100644
index 0000000..24de383
--- /dev/null
+++ b/src/psycstore/plugin_psycstore_sqlite.c
@@ -0,0 +1,1948 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/plugin_psycstore_sqlite.c
+ * @brief sqlite-based psycstore backend
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ */
+
+/*
+ * FIXME: SQLite3 only supports signed 64-bit integers natively,
+ *        thus it can only store 63 bits of the uint64_t's.
+ */
+
+#include "platform.h"
+#include "gnunet_psycstore_plugin.h"
+#include "gnunet_psycstore_service.h"
+#include "gnunet_multicast_service.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_psyc_util_lib.h"
+#include "psycstore.h"
+#include <sqlite3.h>
+
+/**
+ * After how many ms "busy" should a DB operation fail for good?  A
+ * low value makes sure that we are more responsive to requests
+ * (especially PUTs).  A high value guarantees a higher success rate
+ * (SELECTs in iterate can take several seconds despite LIMIT=1).
+ *
+ * The default value of 1s should ensure that users do not experience
+ * huge latencies while at the same time allowing operations to
+ * succeed with reasonable probability.
+ */
+#define BUSY_TIMEOUT_MS 1000
+
+#define DEBUG_PSYCSTORE GNUNET_EXTRA_LOGGING
+
+/**
+ * Log an error message at log-level 'level' that indicates
+ * a failure of the command 'cmd' on file 'filename'
+ * with the message given by strerror(errno).
+ */
+#define LOG_SQLITE(db, level, cmd) do { GNUNET_log_from (level, "psycstore-sqlite", _("`%s' failed at %s:%d with error: %s (%d)\n"), cmd, __FILE__, __LINE__, sqlite3_errmsg(db->dbh), sqlite3_errcode(db->dbh)); } while(0)
+
+#define LOG(kind,...) GNUNET_log_from (kind, "psycstore-sqlite", __VA_ARGS__)
+
+enum Transactions {
+  TRANSACTION_NONE = 0,
+  TRANSACTION_STATE_MODIFY,
+  TRANSACTION_STATE_SYNC,
+};
+
+/**
+ * Context for all functions in this plugin.
+ */
+struct Plugin
+{
+
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Database filename.
+   */
+  char *fn;
+
+  /**
+   * Native SQLite database handle.
+   */
+  sqlite3 *dbh;
+
+  /**
+   * Current transaction.
+   */
+  enum Transactions transaction;
+
+  sqlite3_stmt *transaction_begin;
+
+  sqlite3_stmt *transaction_commit;
+
+  sqlite3_stmt *transaction_rollback;
+
+  /**
+   * Precompiled SQL for channel_key_store()
+   */
+  sqlite3_stmt *insert_channel_key;
+
+  /**
+   * Precompiled SQL for slave_key_store()
+   */
+  sqlite3_stmt *insert_slave_key;
+
+
+  /**
+   * Precompiled SQL for membership_store()
+   */
+  sqlite3_stmt *insert_membership;
+
+  /**
+   * Precompiled SQL for membership_test()
+   */
+  sqlite3_stmt *select_membership;
+
+
+  /**
+   * Precompiled SQL for fragment_store()
+   */
+  sqlite3_stmt *insert_fragment;
+
+  /**
+   * Precompiled SQL for message_add_flags()
+   */
+  sqlite3_stmt *update_message_flags;
+
+  /**
+   * Precompiled SQL for fragment_get()
+   */
+  sqlite3_stmt *select_fragments;
+
+  /**
+   * Precompiled SQL for fragment_get()
+   */
+  sqlite3_stmt *select_latest_fragments;
+
+  /**
+   * Precompiled SQL for message_get()
+   */
+  sqlite3_stmt *select_messages;
+
+  /**
+   * Precompiled SQL for message_get()
+   */
+  sqlite3_stmt *select_latest_messages;
+
+  /**
+   * Precompiled SQL for message_get_fragment()
+   */
+  sqlite3_stmt *select_message_fragment;
+
+  /**
+   * Precompiled SQL for counters_get_message()
+   */
+  sqlite3_stmt *select_counters_message;
+
+  /**
+   * Precompiled SQL for counters_get_state()
+   */
+  sqlite3_stmt *select_counters_state;
+
+  /**
+   * Precompiled SQL for state_modify_end()
+   */
+  sqlite3_stmt *update_state_hash_message_id;
+
+  /**
+   * Precompiled SQL for state_sync_end()
+   */
+  sqlite3_stmt *update_max_state_message_id;
+
+  /**
+   * Precompiled SQL for state_modify_op()
+   */
+  sqlite3_stmt *insert_state_current;
+
+  /**
+   * Precompiled SQL for state_modify_end()
+   */
+  sqlite3_stmt *delete_state_empty;
+
+  /**
+   * Precompiled SQL for state_set_signed()
+   */
+  sqlite3_stmt *update_state_signed;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  sqlite3_stmt *insert_state_sync;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  sqlite3_stmt *delete_state;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  sqlite3_stmt *insert_state_from_sync;
+
+  /**
+   * Precompiled SQL for state_sync()
+   */
+  sqlite3_stmt *delete_state_sync;
+
+  /**
+   * Precompiled SQL for state_get_signed()
+   */
+  sqlite3_stmt *select_state_signed;
+
+  /**
+   * Precompiled SQL for state_get()
+   */
+  sqlite3_stmt *select_state_one;
+
+  /**
+   * Precompiled SQL for state_get_prefix()
+   */
+  sqlite3_stmt *select_state_prefix;
+
+};
+
+#if DEBUG_PSYCSTORE
+
+static void
+sql_trace (void *cls, const char *sql)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "SQL query:\n%s\n", sql);
+}
+
+#endif
+
+/**
+ * @brief Prepare a SQL statement
+ *
+ * @param dbh handle to the database
+ * @param sql SQL statement, UTF-8 encoded
+ * @param stmt set to the prepared statement
+ * @return 0 on success
+ */
+static int
+sql_prepare (sqlite3 *dbh, const char *sql, sqlite3_stmt **stmt)
+{
+  char *tail;
+  int result;
+
+  result = sqlite3_prepare_v2 (dbh, sql, strlen (sql), stmt,
+                               (const char **) &tail);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Prepared `%s' / %p: %d\n", sql, *stmt, result);
+  if (result != SQLITE_OK)
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+	 _("Error preparing SQL query: %s\n  %s\n"),
+	 sqlite3_errmsg (dbh), sql);
+  return result;
+}
+
+
+/**
+ * @brief Prepare a SQL statement
+ *
+ * @param dbh handle to the database
+ * @param sql SQL statement, UTF-8 encoded
+ * @return 0 on success
+ */
+static int
+sql_exec (sqlite3 *dbh, const char *sql)
+{
+  int result;
+
+  result = sqlite3_exec (dbh, sql, NULL, NULL, NULL);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Executed `%s' / %d\n", sql, result);
+  if (result != SQLITE_OK)
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+	 _("Error executing SQL query: %s\n  %s\n"),
+	 sqlite3_errmsg (dbh), sql);
+  return result;
+}
+
+
+/**
+ * Initialize the database connections and associated
+ * data structures (create tables and indices
+ * as needed as well).
+ *
+ * @param plugin the plugin context (state for this module)
+ * @return GNUNET_OK on success
+ */
+static int
+database_setup (struct Plugin *plugin)
+{
+  char *filename;
+
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_filename (plugin->cfg, "psycstore-sqlite",
+                                               "FILENAME", &filename))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+			       "psycstore-sqlite", "FILENAME");
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_OK != GNUNET_DISK_file_test (filename))
+  {
+    if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (filename))
+    {
+      GNUNET_break (0);
+      GNUNET_free (filename);
+      return GNUNET_SYSERR;
+    }
+  }
+  /* filename should be UTF-8-encoded. If it isn't, it's a bug */
+  plugin->fn = filename;
+
+  /* Open database and precompile statements */
+  if (SQLITE_OK != sqlite3_open (plugin->fn, &plugin->dbh))
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+	 _("Unable to initialize SQLite: %s.\n"),
+	 sqlite3_errmsg (plugin->dbh));
+    return GNUNET_SYSERR;
+  }
+
+#if DEBUG_PSYCSTORE
+  sqlite3_trace (plugin->dbh, &sql_trace, NULL);
+#endif
+
+  sql_exec (plugin->dbh, "PRAGMA temp_store=MEMORY");
+  sql_exec (plugin->dbh, "PRAGMA synchronous=NORMAL");
+  sql_exec (plugin->dbh, "PRAGMA legacy_file_format=OFF");
+  sql_exec (plugin->dbh, "PRAGMA auto_vacuum=INCREMENTAL");
+  sql_exec (plugin->dbh, "PRAGMA encoding=\"UTF-8\"");
+#if ! DEBUG_PSYCSTORE
+  sql_exec (plugin->dbh, "PRAGMA locking_mode=EXCLUSIVE");
+#endif
+  sql_exec (plugin->dbh, "PRAGMA page_size=4096");
+
+  sqlite3_busy_timeout (plugin->dbh, BUSY_TIMEOUT_MS);
+
+  /* Create tables */
+
+  sql_exec (plugin->dbh,
+            "CREATE TABLE IF NOT EXISTS channels (\n"
+            "  id INTEGER PRIMARY KEY,\n"
+            "  pub_key BLOB(32) UNIQUE,\n"
+            "  max_state_message_id INTEGER,\n" // last applied state message ID
+            "  state_hash_message_id INTEGER\n" // last message ID with a state hash
+            ");");
+
+  sql_exec (plugin->dbh,
+            "CREATE TABLE IF NOT EXISTS slaves (\n"
+            "  id INTEGER PRIMARY KEY,\n"
+            "  pub_key BLOB(32) UNIQUE\n"
+            ");");
+
+  sql_exec (plugin->dbh,
+            "CREATE TABLE IF NOT EXISTS membership (\n"
+            "  channel_id INTEGER NOT NULL REFERENCES channels(id),\n"
+            "  slave_id INTEGER NOT NULL REFERENCES slaves(id),\n"
+            "  did_join INTEGER NOT NULL,\n"
+            "  announced_at INTEGER NOT NULL,\n"
+            "  effective_since INTEGER NOT NULL,\n"
+            "  group_generation INTEGER NOT NULL\n"
+            ");");
+  sql_exec (plugin->dbh,
+            "CREATE INDEX IF NOT EXISTS idx_membership_channel_id_slave_id "
+            "ON membership (channel_id, slave_id);");
+
+  /** @todo messages table: add method_name column */
+  sql_exec (plugin->dbh,
+            "CREATE TABLE IF NOT EXISTS messages (\n"
+            "  channel_id INTEGER NOT NULL REFERENCES channels(id),\n"
+            "  hop_counter INTEGER NOT NULL,\n"
+            "  signature BLOB,\n"
+            "  purpose BLOB,\n"
+            "  fragment_id INTEGER NOT NULL,\n"
+            "  fragment_offset INTEGER NOT NULL,\n"
+            "  message_id INTEGER NOT NULL,\n"
+            "  group_generation INTEGER NOT NULL,\n"
+            "  multicast_flags INTEGER NOT NULL,\n"
+            "  psycstore_flags INTEGER NOT NULL,\n"
+            "  data BLOB,\n"
+            "  PRIMARY KEY (channel_id, fragment_id),\n"
+            "  UNIQUE (channel_id, message_id, fragment_offset)\n"
+            ");");
+
+  sql_exec (plugin->dbh,
+            "CREATE TABLE IF NOT EXISTS state (\n"
+            "  channel_id INTEGER NOT NULL REFERENCES channels(id),\n"
+            "  name TEXT NOT NULL,\n"
+            "  value_current BLOB,\n"
+            "  value_signed BLOB,\n"
+            "  PRIMARY KEY (channel_id, name)\n"
+            ");");
+
+  sql_exec (plugin->dbh,
+            "CREATE TABLE IF NOT EXISTS state_sync (\n"
+            "  channel_id INTEGER NOT NULL REFERENCES channels(id),\n"
+            "  name TEXT NOT NULL,\n"
+            "  value BLOB,\n"
+            "  PRIMARY KEY (channel_id, name)\n"
+            ");");
+
+  /* Prepare statements */
+
+  sql_prepare (plugin->dbh, "BEGIN;", &plugin->transaction_begin);
+
+  sql_prepare (plugin->dbh, "COMMIT;", &plugin->transaction_commit);
+
+  sql_prepare (plugin->dbh, "ROLLBACK;", &plugin->transaction_rollback);
+
+  sql_prepare (plugin->dbh,
+               "INSERT OR IGNORE INTO channels (pub_key) VALUES (?);",
+               &plugin->insert_channel_key);
+
+  sql_prepare (plugin->dbh,
+               "INSERT OR IGNORE INTO slaves (pub_key) VALUES (?);",
+               &plugin->insert_slave_key);
+
+  sql_prepare (plugin->dbh,
+               "INSERT INTO membership\n"
+               " (channel_id, slave_id, did_join, announced_at,\n"
+               "  effective_since, group_generation)\n"
+               "VALUES ((SELECT id FROM channels WHERE pub_key = ?),\n"
+               "        (SELECT id FROM slaves WHERE pub_key = ?),\n"
+               "        ?, ?, ?, ?);",
+               &plugin->insert_membership);
+
+  sql_prepare (plugin->dbh,
+               "SELECT did_join FROM membership\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND slave_id = (SELECT id FROM slaves WHERE pub_key = ?)\n"
+               "      AND effective_since <= ? AND did_join = 1\n"
+               "ORDER BY announced_at DESC LIMIT 1;",
+               &plugin->select_membership);
+
+  sql_prepare (plugin->dbh,
+               "INSERT OR IGNORE INTO messages\n"
+               " (channel_id, hop_counter, signature, purpose,\n"
+               "  fragment_id, fragment_offset, message_id,\n"
+               "  group_generation, multicast_flags, psycstore_flags, data)\n"
+               "VALUES ((SELECT id FROM channels WHERE pub_key = ?),\n"
+               "        ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);",
+               &plugin->insert_fragment);
+
+  sql_prepare (plugin->dbh,
+               "UPDATE messages\n"
+               "SET psycstore_flags = psycstore_flags | ?\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND message_id = ? AND fragment_offset = 0;",
+               &plugin->update_message_flags);
+
+  sql_prepare (plugin->dbh,
+               "SELECT hop_counter, signature, purpose, fragment_id,\n"
+               "       fragment_offset, message_id, group_generation,\n"
+               "       multicast_flags, psycstore_flags, data\n"
+               "FROM messages\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND ? <= fragment_id AND fragment_id <= ?;",
+               &plugin->select_fragments);
+
+  /** @todo select_messages: add method_prefix filter */
+  sql_prepare (plugin->dbh,
+               "SELECT hop_counter, signature, purpose, fragment_id,\n"
+               "       fragment_offset, message_id, group_generation,\n"
+               "       multicast_flags, psycstore_flags, data\n"
+               "FROM messages\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND ? <= message_id AND message_id <= ?"
+               "LIMIT ?;",
+               &plugin->select_messages);
+
+  sql_prepare (plugin->dbh,
+               "SELECT * FROM\n"
+               "(SELECT hop_counter, signature, purpose, fragment_id,\n"
+               "        fragment_offset, message_id, group_generation,\n"
+               "        multicast_flags, psycstore_flags, data\n"
+               " FROM messages\n"
+               " WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               " ORDER BY fragment_id DESC\n"
+               " LIMIT ?)\n"
+               "ORDER BY fragment_id;",
+               &plugin->select_latest_fragments);
+
+  /** @todo select_latest_messages: add method_prefix filter */
+  sql_prepare (plugin->dbh,
+               "SELECT hop_counter, signature, purpose, fragment_id,\n"
+               "       fragment_offset, message_id, group_generation,\n"
+               "        multicast_flags, psycstore_flags, data\n"
+               "FROM messages\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND message_id IN\n"
+               "      (SELECT message_id\n"
+               "       FROM messages\n"
+               "       WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "       GROUP BY message_id\n"
+               "       ORDER BY message_id\n"
+               "       DESC LIMIT ?)\n"
+               "ORDER BY fragment_id;",
+               &plugin->select_latest_messages);
+
+  sql_prepare (plugin->dbh,
+               "SELECT hop_counter, signature, purpose, fragment_id,\n"
+               "       fragment_offset, message_id, group_generation,\n"
+               "       multicast_flags, psycstore_flags, data\n"
+               "FROM messages\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND message_id = ? AND fragment_offset = ?;",
+               &plugin->select_message_fragment);
+
+  sql_prepare (plugin->dbh,
+               "SELECT fragment_id, message_id, group_generation\n"
+               "FROM messages\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "ORDER BY fragment_id DESC LIMIT 1;",
+               &plugin->select_counters_message);
+
+  sql_prepare (plugin->dbh,
+               "SELECT max_state_message_id\n"
+               "FROM channels\n"
+               "WHERE pub_key = ? AND max_state_message_id IS NOT NULL;",
+               &plugin->select_counters_state);
+
+  sql_prepare (plugin->dbh,
+               "UPDATE channels\n"
+               "SET max_state_message_id = ?\n"
+               "WHERE pub_key = ?;",
+               &plugin->update_max_state_message_id);
+
+  sql_prepare (plugin->dbh,
+               "UPDATE channels\n"
+               "SET state_hash_message_id = ?\n"
+               "WHERE pub_key = ?;",
+               &plugin->update_state_hash_message_id);
+
+  sql_prepare (plugin->dbh,
+               "INSERT OR REPLACE INTO state\n"
+               "  (channel_id, name, value_current, value_signed)\n"
+               "SELECT new.channel_id, new.name,\n"
+               "       new.value_current, old.value_signed\n"
+               "FROM (SELECT (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "             AS channel_id,\n"
+               "             ? AS name, ? AS value_current) AS new\n"
+               "LEFT JOIN (SELECT channel_id, name, value_signed\n"
+               "           FROM state) AS old\n"
+               "ON new.channel_id = old.channel_id AND new.name = old.name;",
+               &plugin->insert_state_current);
+
+  sql_prepare (plugin->dbh,
+               "DELETE FROM state\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND (value_current IS NULL OR length(value_current) = 0)\n"
+               "      AND (value_signed IS NULL OR length(value_signed) = 0);",
+               &plugin->delete_state_empty);
+
+  sql_prepare (plugin->dbh,
+               "UPDATE state\n"
+               "SET value_signed = value_current\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+               &plugin->update_state_signed);
+
+  sql_prepare (plugin->dbh,
+               "DELETE FROM state\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+               &plugin->delete_state);
+
+  sql_prepare (plugin->dbh,
+               "INSERT INTO state_sync (channel_id, name, value)\n"
+               "VALUES ((SELECT id FROM channels WHERE pub_key = ?), ?, ?);",
+               &plugin->insert_state_sync);
+
+  sql_prepare (plugin->dbh,
+               "INSERT INTO state\n"
+               " (channel_id, name, value_current, value_signed)\n"
+               "SELECT channel_id, name, value, value\n"
+               "FROM state_sync\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+               &plugin->insert_state_from_sync);
+
+  sql_prepare (plugin->dbh,
+               "DELETE FROM state_sync\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?);",
+               &plugin->delete_state_sync);
+
+  sql_prepare (plugin->dbh,
+               "SELECT value_current\n"
+               "FROM state\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND name = ?;",
+               &plugin->select_state_one);
+
+  sql_prepare (plugin->dbh,
+               "SELECT name, value_current\n"
+               "FROM state\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)\n"
+               "      AND (name = ? OR substr(name, 1, ?) = ?);",
+               &plugin->select_state_prefix);
+
+  sql_prepare (plugin->dbh,
+               "SELECT name, value_signed\n"
+               "FROM state\n"
+               "WHERE channel_id = (SELECT id FROM channels WHERE pub_key = ?)"
+               "      AND value_signed IS NOT NULL;",
+               &plugin->select_state_signed);
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Shutdown database connection and associate data
+ * structures.
+ * @param plugin the plugin context (state for this module)
+ */
+static void
+database_shutdown (struct Plugin *plugin)
+{
+  int result;
+  sqlite3_stmt *stmt;
+  while (NULL != (stmt = sqlite3_next_stmt (plugin->dbh, NULL)))
+  {
+    result = sqlite3_finalize (stmt);
+    if (SQLITE_OK != result)
+      LOG (GNUNET_ERROR_TYPE_WARNING,
+           "Failed to close statement %p: %d\n", stmt, result);
+  }
+  if (SQLITE_OK != sqlite3_close (plugin->dbh))
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR, "sqlite3_close");
+
+  GNUNET_free_non_null (plugin->fn);
+}
+
+/**
+ * Execute a prepared statement with a @a channel_key argument.
+ *
+ * @param plugin Plugin handle.
+ * @param stmt Statement to execute.
+ * @param channel_key Public key of the channel.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+exec_channel (struct Plugin *plugin, sqlite3_stmt *stmt,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+/**
+ * Begin a transaction.
+ */
+static int
+transaction_begin (struct Plugin *plugin, enum Transactions transaction)
+{
+  sqlite3_stmt *stmt = plugin->transaction_begin;
+
+  if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  plugin->transaction = transaction;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Commit current transaction.
+ */
+static int
+transaction_commit (struct Plugin *plugin)
+{
+  sqlite3_stmt *stmt = plugin->transaction_commit;
+
+  if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  plugin->transaction = TRANSACTION_NONE;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Roll back current transaction.
+ */
+static int
+transaction_rollback (struct Plugin *plugin)
+{
+  sqlite3_stmt *stmt = plugin->transaction_rollback;
+
+  if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+  plugin->transaction = TRANSACTION_NONE;
+  return GNUNET_OK;
+}
+
+
+static int
+channel_key_store (struct Plugin *plugin,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  sqlite3_stmt *stmt = plugin->insert_channel_key;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+static int
+slave_key_store (struct Plugin *plugin,
+                 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key)
+{
+  sqlite3_stmt *stmt = plugin->insert_slave_key;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, slave_key,
+                                      sizeof (*slave_key), SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Store join/leave events for a PSYC channel in order to be able to answer
+ * membership test queries later.
+ *
+ * @see GNUNET_PSYCSTORE_membership_store()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+sqlite_membership_store (void *cls,
+                         const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                         const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                         int did_join,
+                         uint64_t announced_at,
+                         uint64_t effective_since,
+                         uint64_t group_generation)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->insert_membership;
+
+  GNUNET_assert (TRANSACTION_NONE == plugin->transaction);
+
+  if (announced_at > INT64_MAX ||
+      effective_since > INT64_MAX ||
+      group_generation > INT64_MAX)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != channel_key_store (plugin, channel_key)
+      || GNUNET_OK != slave_key_store (plugin, slave_key))
+    return GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 2, slave_key,
+                                         sizeof (*slave_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int (stmt, 3, did_join)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 4, announced_at)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 5, effective_since)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 6, group_generation))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+/**
+ * Test if a member was admitted to the channel at the given message ID.
+ *
+ * @see GNUNET_PSYCSTORE_membership_test()
+ *
+ * @return #GNUNET_YES if the member was admitted, #GNUNET_NO if not,
+ *         #GNUNET_SYSERR if there was en error.
+ */
+static int
+membership_test (void *cls,
+                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                 uint64_t message_id)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_membership;
+  int ret = GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 2, slave_key,
+                                         sizeof (*slave_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 3, message_id))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = GNUNET_NO;
+      break;
+    case SQLITE_ROW:
+      ret = GNUNET_YES;
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+/**
+ * Store a message fragment sent to a channel.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_store()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_store (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                const struct GNUNET_MULTICAST_MessageHeader *msg,
+                uint32_t psycstore_flags)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->insert_fragment;
+
+  GNUNET_assert (TRANSACTION_NONE == plugin->transaction);
+
+  uint64_t fragment_id = GNUNET_ntohll (msg->fragment_id);
+  uint64_t fragment_offset = GNUNET_ntohll (msg->fragment_offset);
+  uint64_t message_id = GNUNET_ntohll (msg->message_id);
+  uint64_t group_generation = GNUNET_ntohll (msg->group_generation);
+
+  if (fragment_id > INT64_MAX || fragment_offset > INT64_MAX ||
+      message_id > INT64_MAX || group_generation > INT64_MAX)
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         "Tried to store fragment with a field > INT64_MAX: "
+         "%lu, %lu, %lu, %lu\n", fragment_id, fragment_offset,
+         message_id, group_generation);
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != channel_key_store (plugin, channel_key))
+    return GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 2, ntohl (msg->hop_counter) )
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 3, (const void *) &msg->signature,
+                                         sizeof (msg->signature), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 4, (const void *) &msg->purpose,
+                                         sizeof (msg->purpose), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 5, fragment_id)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 6, fragment_offset)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 7, message_id)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 8, group_generation)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 9, ntohl (msg->flags))
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 10, psycstore_flags)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 11, (const void *) &msg[1],
+                                         ntohs (msg->header.size)
+                                         - sizeof (*msg), SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+/**
+ * Set additional flags for a given message.
+ *
+ * They are OR'd with any existing flags set.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_add_flags (void *cls,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                   uint64_t message_id,
+                   uint32_t psycstore_flags)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->update_message_flags;
+  int ret = GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_int64 (stmt, 1, psycstore_flags)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 2, channel_key,
+                                         sizeof (*channel_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 3, message_id))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = sqlite3_total_changes (plugin->dbh) > 0 ? GNUNET_OK : GNUNET_NO;
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+static int
+fragment_row (sqlite3_stmt *stmt, GNUNET_PSYCSTORE_FragmentCallback cb,
+              void *cb_cls)
+{
+  int data_size = sqlite3_column_bytes (stmt, 9);
+  struct GNUNET_MULTICAST_MessageHeader *msg
+    = GNUNET_malloc (sizeof (*msg) + data_size);
+
+  msg->header.size = htons (sizeof (*msg) + data_size);
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_MULTICAST_MESSAGE);
+  msg->hop_counter = htonl ((uint32_t) sqlite3_column_int64 (stmt, 0));
+  GNUNET_memcpy (&msg->signature,
+          sqlite3_column_blob (stmt, 1),
+          sqlite3_column_bytes (stmt, 1));
+  GNUNET_memcpy (&msg->purpose,
+          sqlite3_column_blob (stmt, 2),
+          sqlite3_column_bytes (stmt, 2));
+  msg->fragment_id = GNUNET_htonll (sqlite3_column_int64 (stmt, 3));
+  msg->fragment_offset = GNUNET_htonll (sqlite3_column_int64 (stmt, 4));
+  msg->message_id = GNUNET_htonll (sqlite3_column_int64 (stmt, 5));
+  msg->group_generation = GNUNET_htonll (sqlite3_column_int64 (stmt, 6));
+  msg->flags = htonl (sqlite3_column_int64 (stmt, 7));
+  GNUNET_memcpy (&msg[1], sqlite3_column_blob (stmt, 9), data_size);
+
+  return cb (cb_cls, (void *) msg, sqlite3_column_int64 (stmt, 8));
+}
+
+
+static int
+fragment_select (struct Plugin *plugin, sqlite3_stmt *stmt,
+                 uint64_t *returned_fragments,
+                 GNUNET_PSYCSTORE_FragmentCallback cb, void *cb_cls)
+{
+  int ret = GNUNET_SYSERR;
+  int sql_ret;
+
+  do
+  {
+    sql_ret = sqlite3_step (stmt);
+    switch (sql_ret)
+    {
+    case SQLITE_DONE:
+      if (ret != GNUNET_OK)
+        ret = GNUNET_NO;
+      break;
+    case SQLITE_ROW:
+      ret = fragment_row (stmt, cb, cb_cls);
+      (*returned_fragments)++;
+      if (ret != GNUNET_YES)
+        sql_ret = SQLITE_DONE;
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+  while (sql_ret == SQLITE_ROW);
+
+  return ret;
+}
+
+/**
+ * Retrieve a message fragment range by fragment ID.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_get (void *cls,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+              uint64_t first_fragment_id,
+              uint64_t last_fragment_id,
+              uint64_t *returned_fragments,
+              GNUNET_PSYCSTORE_FragmentCallback cb,
+              void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_fragments;
+  int ret = GNUNET_SYSERR;
+  *returned_fragments = 0;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 2, first_fragment_id)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 3, last_fragment_id))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    ret = fragment_select (plugin, stmt, returned_fragments, cb, cb_cls);
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve a message fragment range by fragment ID.
+ *
+ * @see GNUNET_PSYCSTORE_fragment_get_latest()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+fragment_get_latest (void *cls,
+                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                     uint64_t fragment_limit,
+                     uint64_t *returned_fragments,
+                     GNUNET_PSYCSTORE_FragmentCallback cb,
+                     void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_latest_fragments;
+  int ret = GNUNET_SYSERR;
+  *returned_fragments = 0;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 2, fragment_limit))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    ret = fragment_select (plugin, stmt, returned_fragments, cb, cb_cls);
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all fragments of a message ID range.
+ *
+ * @see GNUNET_PSYCSTORE_message_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get (void *cls,
+             const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+             uint64_t first_message_id,
+             uint64_t last_message_id,
+             uint64_t fragment_limit,
+             uint64_t *returned_fragments,
+             GNUNET_PSYCSTORE_FragmentCallback cb,
+             void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_messages;
+  int ret = GNUNET_SYSERR;
+  *returned_fragments = 0;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 2, first_message_id)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 3, last_message_id)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 4,
+                                          (0 != fragment_limit)
+                                          ? fragment_limit
+                                          : INT64_MAX))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    ret = fragment_select (plugin, stmt, returned_fragments, cb, cb_cls);
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all fragments of the latest messages.
+ *
+ * @see GNUNET_PSYCSTORE_message_get_latest()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get_latest (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t message_limit,
+                    uint64_t *returned_fragments,
+                    GNUNET_PSYCSTORE_FragmentCallback cb,
+                    void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_latest_messages;
+  int ret = GNUNET_SYSERR;
+  *returned_fragments = 0;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 2, channel_key,
+                                         sizeof (*channel_key),
+                                         SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 3, message_limit))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    ret = fragment_select (plugin, stmt, returned_fragments, cb, cb_cls);
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve a fragment of message specified by its message ID and fragment
+ * offset.
+ *
+ * @see GNUNET_PSYCSTORE_message_get_fragment()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+message_get_fragment (void *cls,
+                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                      uint64_t message_id,
+                      uint64_t fragment_offset,
+                      GNUNET_PSYCSTORE_FragmentCallback cb,
+                      void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_message_fragment;
+  int ret = GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 2, message_id)
+      || SQLITE_OK != sqlite3_bind_int64 (stmt, 3, fragment_offset))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = GNUNET_NO;
+      break;
+    case SQLITE_ROW:
+      ret = fragment_row (stmt, cb, cb_cls);
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+/**
+ * Retrieve the max. values of message counters for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+counters_message_get (void *cls,
+                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                      uint64_t *max_fragment_id,
+                      uint64_t *max_message_id,
+                      uint64_t *max_group_generation)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_counters_message;
+  int ret = GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = GNUNET_NO;
+      break;
+    case SQLITE_ROW:
+      *max_fragment_id = sqlite3_column_int64 (stmt, 0);
+      *max_message_id = sqlite3_column_int64 (stmt, 1);
+      *max_group_generation = sqlite3_column_int64 (stmt, 2);
+      ret = GNUNET_OK;
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+/**
+ * Retrieve the max. values of state counters for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+counters_state_get (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t *max_state_message_id)
+{
+  struct Plugin *plugin = cls;
+  sqlite3_stmt *stmt = plugin->select_counters_state;
+  int ret = GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = GNUNET_NO;
+      break;
+    case SQLITE_ROW:
+      *max_state_message_id = sqlite3_column_int64 (stmt, 0);
+      ret = GNUNET_OK;
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Assign a value to a state variable.
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_assign (struct Plugin *plugin, sqlite3_stmt *stmt,
+              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+              const char *name, const void *value, size_t value_size)
+{
+  int ret = GNUNET_SYSERR;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_text (stmt, 2, name, -1, SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 3, value, value_size,
+                                         SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = 0 < sqlite3_total_changes (plugin->dbh) ? GNUNET_OK : GNUNET_NO;
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+
+  return ret;
+}
+
+
+static int
+update_message_id (struct Plugin *plugin, sqlite3_stmt *stmt,
+                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                   uint64_t message_id)
+{
+  if (SQLITE_OK != sqlite3_bind_int64 (stmt, 1, message_id)
+      || SQLITE_OK != sqlite3_bind_blob (stmt, 2, channel_key,
+                                         sizeof (*channel_key), SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else if (SQLITE_DONE != sqlite3_step (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_step");
+  }
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Begin modifying current state.
+ */
+static int
+state_modify_begin (void *cls,
+                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                    uint64_t message_id, uint64_t state_delta)
+{
+  struct Plugin *plugin = cls;
+
+  if (state_delta > 0)
+  {
+    /**
+     * We can only apply state modifiers in the current message if modifiers in
+     * the previous stateful message (message_id - state_delta) were already
+     * applied.
+     */
+
+    uint64_t max_state_message_id = 0;
+    int ret = counters_state_get (plugin, channel_key, &max_state_message_id);
+    switch (ret)
+    {
+    case GNUNET_OK:
+    case GNUNET_NO: // no state yet
+      ret = GNUNET_OK;
+      break;
+    default:
+      return ret;
+    }
+
+    if (max_state_message_id < message_id - state_delta)
+      return GNUNET_NO; /* some stateful messages not yet applied */
+    else if (message_id - state_delta < max_state_message_id)
+      return GNUNET_NO; /* changes already applied */
+  }
+
+  if (TRANSACTION_NONE != plugin->transaction)
+  {
+    /** @todo FIXME: wait for other transaction to finish  */
+    return GNUNET_SYSERR;
+  }
+  return transaction_begin (plugin, TRANSACTION_STATE_MODIFY);
+}
+
+
+/**
+ * Set the current value of state variable.
+ *
+ * @see GNUNET_PSYCSTORE_state_modify()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_modify_op (void *cls,
+                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                 enum GNUNET_PSYC_Operator op,
+                 const char *name, const void *value, size_t value_size)
+{
+  struct Plugin *plugin = cls;
+  GNUNET_assert (TRANSACTION_STATE_MODIFY == plugin->transaction);
+
+  switch (op)
+  {
+  case GNUNET_PSYC_OP_ASSIGN:
+    return state_assign (plugin, plugin->insert_state_current, channel_key,
+                         name, value, value_size);
+
+  default: /** @todo implement more state operations */
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * End modifying current state.
+ */
+static int
+state_modify_end (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  uint64_t message_id)
+{
+  struct Plugin *plugin = cls;
+  GNUNET_assert (TRANSACTION_STATE_MODIFY == plugin->transaction);
+
+  return
+    GNUNET_OK == exec_channel (plugin, plugin->delete_state_empty, channel_key)
+    && GNUNET_OK == update_message_id (plugin,
+                                       plugin->update_max_state_message_id,
+                                       channel_key, message_id)
+    && GNUNET_OK == transaction_commit (plugin)
+    ? GNUNET_OK : GNUNET_SYSERR;
+}
+
+
+/**
+ * Begin state synchronization.
+ */
+static int
+state_sync_begin (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, plugin->delete_state_sync, channel_key);
+}
+
+
+/**
+ * Assign current value of a state variable.
+ *
+ * @see GNUNET_PSYCSTORE_state_modify()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_sync_assign (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                const char *name, const void *value, size_t value_size)
+{
+  struct Plugin *plugin = cls;
+  return state_assign (cls, plugin->insert_state_sync, channel_key,
+                       name, value, value_size);
+}
+
+
+/**
+ * End modifying current state.
+ */
+static int
+state_sync_end (void *cls,
+                const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                uint64_t max_state_message_id,
+                uint64_t state_hash_message_id)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  if (TRANSACTION_NONE != plugin->transaction)
+  {
+    /** @todo FIXME: wait for other transaction to finish  */
+    return GNUNET_SYSERR;
+  }
+
+  GNUNET_OK == transaction_begin (plugin, TRANSACTION_STATE_SYNC)
+    && GNUNET_OK == exec_channel (plugin, plugin->delete_state, channel_key)
+    && GNUNET_OK == exec_channel (plugin, plugin->insert_state_from_sync,
+                                  channel_key)
+    && GNUNET_OK == exec_channel (plugin, plugin->delete_state_sync,
+                                  channel_key)
+    && GNUNET_OK == update_message_id (plugin,
+                                       plugin->update_state_hash_message_id,
+                                       channel_key, state_hash_message_id)
+    && GNUNET_OK == update_message_id (plugin,
+                                       plugin->update_max_state_message_id,
+                                       channel_key, max_state_message_id)
+    && GNUNET_OK == transaction_commit (plugin)
+    ? ret = GNUNET_OK
+    : transaction_rollback (plugin);
+  return ret;
+}
+
+
+/**
+ * Delete the whole state.
+ *
+ * @see GNUNET_PSYCSTORE_state_reset()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_reset (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, plugin->delete_state, channel_key);
+}
+
+
+/**
+ * Update signed values of state variables in the state store.
+ *
+ * @see GNUNET_PSYCSTORE_state_hash_update()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_update_signed (void *cls,
+                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key)
+{
+  struct Plugin *plugin = cls;
+  return exec_channel (plugin, plugin->update_state_signed, channel_key);
+}
+
+
+/**
+ * Retrieve a state variable by name.
+ *
+ * @see GNUNET_PSYCSTORE_state_get()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+           const char *name, GNUNET_PSYCSTORE_StateCallback cb, void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  sqlite3_stmt *stmt = plugin->select_state_one;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key),
+                                      SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_text (stmt, 2, name, -1, SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    switch (sqlite3_step (stmt))
+    {
+    case SQLITE_DONE:
+      ret = GNUNET_NO;
+      break;
+    case SQLITE_ROW:
+      ret = cb (cb_cls, name, sqlite3_column_blob (stmt, 0),
+                sqlite3_column_bytes (stmt, 0));
+      break;
+    default:
+      LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "sqlite3_step");
+    }
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Retrieve all state variables for a channel with the given prefix.
+ *
+ * @see GNUNET_PSYCSTORE_state_get_prefix()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get_prefix (void *cls, const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  const char *name, GNUNET_PSYCSTORE_StateCallback cb,
+                  void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+  sqlite3_stmt *stmt = plugin->select_state_prefix;
+  size_t name_len = strlen (name);
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_text (stmt, 2, name, name_len, SQLITE_STATIC)
+      || SQLITE_OK != sqlite3_bind_int (stmt, 3, name_len)
+      || SQLITE_OK != sqlite3_bind_text (stmt, 4, name, name_len, SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    int sql_ret;
+    do
+    {
+      sql_ret = sqlite3_step (stmt);
+      switch (sql_ret)
+      {
+      case SQLITE_DONE:
+        if (ret != GNUNET_OK)
+          ret = GNUNET_NO;
+        break;
+      case SQLITE_ROW:
+        ret = cb (cb_cls, (const char *) sqlite3_column_text (stmt, 0),
+                  sqlite3_column_blob (stmt, 1),
+                  sqlite3_column_bytes (stmt, 1));
+        if (ret != GNUNET_YES)
+          sql_ret = SQLITE_DONE;
+        break;
+      default:
+        LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                    "sqlite3_step");
+      }
+    }
+    while (sql_ret == SQLITE_ROW);
+  }
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+  return ret;
+}
+
+
+/**
+ * Retrieve all signed state variables for a channel.
+ *
+ * @see GNUNET_PSYCSTORE_state_get_signed()
+ *
+ * @return #GNUNET_OK on success, else #GNUNET_SYSERR
+ */
+static int
+state_get_signed (void *cls,
+                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                  GNUNET_PSYCSTORE_StateCallback cb, void *cb_cls)
+{
+  struct Plugin *plugin = cls;
+  int ret = GNUNET_SYSERR;
+
+  sqlite3_stmt *stmt = plugin->select_state_signed;
+
+  if (SQLITE_OK != sqlite3_bind_blob (stmt, 1, channel_key,
+                                      sizeof (*channel_key), SQLITE_STATIC))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_bind");
+  }
+  else
+  {
+    int sql_ret;
+    do
+    {
+      sql_ret = sqlite3_step (stmt);
+      switch (sql_ret)
+      {
+      case SQLITE_DONE:
+        if (ret != GNUNET_OK)
+          ret = GNUNET_NO;
+        break;
+      case SQLITE_ROW:
+        ret = cb (cb_cls, (const char *) sqlite3_column_text (stmt, 0),
+                  sqlite3_column_blob (stmt, 1),
+                  sqlite3_column_bytes (stmt, 1));
+        if (ret != GNUNET_YES)
+          sql_ret = SQLITE_DONE;
+        break;
+      default:
+        LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                    "sqlite3_step");
+      }
+    }
+    while (sql_ret == SQLITE_ROW);
+  }
+
+  if (SQLITE_OK != sqlite3_reset (stmt))
+  {
+    LOG_SQLITE (plugin, GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                "sqlite3_reset");
+  }
+
+  return ret;
+}
+
+
+/**
+ * Entry point for the plugin.
+ *
+ * @param cls The struct GNUNET_CONFIGURATION_Handle.
+ * @return NULL on error, otherwise the plugin context
+ */
+void *
+libgnunet_plugin_psycstore_sqlite_init (void *cls)
+{
+  static struct Plugin plugin;
+  const struct GNUNET_CONFIGURATION_Handle *cfg = cls;
+  struct GNUNET_PSYCSTORE_PluginFunctions *api;
+
+  if (NULL != plugin.cfg)
+    return NULL;                /* can only initialize once! */
+  memset (&plugin, 0, sizeof (struct Plugin));
+  plugin.cfg = cfg;
+  if (GNUNET_OK != database_setup (&plugin))
+  {
+    database_shutdown (&plugin);
+    return NULL;
+  }
+  api = GNUNET_new (struct GNUNET_PSYCSTORE_PluginFunctions);
+  api->cls = &plugin;
+  api->membership_store = &sqlite_membership_store;
+  api->membership_test = &membership_test;
+  api->fragment_store = &fragment_store;
+  api->message_add_flags = &message_add_flags;
+  api->fragment_get = &fragment_get;
+  api->fragment_get_latest = &fragment_get_latest;
+  api->message_get = &message_get;
+  api->message_get_latest = &message_get_latest;
+  api->message_get_fragment = &message_get_fragment;
+  api->counters_message_get = &counters_message_get;
+  api->counters_state_get = &counters_state_get;
+  api->state_modify_begin = &state_modify_begin;
+  api->state_modify_op = &state_modify_op;
+  api->state_modify_end = &state_modify_end;
+  api->state_sync_begin = &state_sync_begin;
+  api->state_sync_assign = &state_sync_assign;
+  api->state_sync_end = &state_sync_end;
+  api->state_reset = &state_reset;
+  api->state_update_signed = &state_update_signed;
+  api->state_get = &state_get;
+  api->state_get_prefix = &state_get_prefix;
+  api->state_get_signed = &state_get_signed;
+
+  LOG (GNUNET_ERROR_TYPE_INFO, _("SQLite database running\n"));
+  return api;
+}
+
+
+/**
+ * Exit point from the plugin.
+ *
+ * @param cls The plugin context (as returned by "init")
+ * @return Always NULL
+ */
+void *
+libgnunet_plugin_psycstore_sqlite_done (void *cls)
+{
+  struct GNUNET_PSYCSTORE_PluginFunctions *api = cls;
+  struct Plugin *plugin = api->cls;
+
+  database_shutdown (plugin);
+  plugin->cfg = NULL;
+  GNUNET_free (api);
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "SQLite plugin is finished\n");
+  return NULL;
+}
+
+/* end of plugin_psycstore_sqlite.c */
diff --git a/src/psycstore/psycstore.conf.in b/src/psycstore/psycstore.conf.in
new file mode 100644
index 0000000..3905db1
--- /dev/null
+++ b/src/psycstore/psycstore.conf.in
@@ -0,0 +1,28 @@
+[psycstore]
+START_ON_DEMAND = @START_ON_DEMAND@
+BINARY = gnunet-service-psycstore
+
+UNIXPATH = $GNUNET_RUNTIME_DIR/gnunet-service-psycstore.sock
+UNIX_MATCH_UID = YES
+UNIX_MATCH_GID = YES
+
+@UNIXONLY@PORT = 2111
+HOSTNAME = localhost
+ACCEPT_FROM = 127.0.0.1;
+ACCEPT_FROM6 = ::1;
+
+DATABASE = sqlite
+
+[psycstore-sqlite]
+FILENAME = $GNUNET_DATA_HOME/psycstore/sqlite.db
+
+[psycstore-mysql]
+DATABASE = gnunet
+CONFIG = ~/.my.cnf
+# USER = gnunet
+# PASSWORD =
+# HOST = localhost
+# PORT = 3306
+
+[psycstore-postgres]
+CONFIG = connect_timeout=10; dbname=gnunet
diff --git a/src/psycstore/psycstore.h b/src/psycstore/psycstore.h
new file mode 100644
index 0000000..9a1c06a
--- /dev/null
+++ b/src/psycstore/psycstore.h
@@ -0,0 +1,520 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/psycstore.h
+ * @brief Common type definitions for the PSYCstore service and API.
+ * @author Gabor X Toth
+ */
+
+#ifndef GNUNET_PSYCSTORE_H
+#define GNUNET_PSYCSTORE_H
+
+#include "gnunet_common.h"
+
+
+GNUNET_NETWORK_STRUCT_BEGIN
+
+/**
+ * Answer from service to client about last operation.
+ */
+struct OperationResult
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_CODE
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**lowed by
+   * Status code for the operation.
+   */
+  uint64_t result_code GNUNET_PACKED;
+
+  /* followed by 0-terminated error message (on error) */
+
+};
+
+
+/**
+ * Answer from service to client about master counters.
+ *
+ * @see GNUNET_PSYCSTORE_counters_get()
+ */
+struct CountersResult
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_COUNTERS
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Status code for the operation:
+   * #GNUNET_OK: success, counter values are returned.
+   * #GNUNET_NO: no message has been sent to the channel yet.
+   * #GNUNET_SYSERR: an error occurred.
+   */
+  uint32_t result_code GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  uint64_t max_fragment_id GNUNET_PACKED;
+
+  uint64_t max_message_id GNUNET_PACKED;
+
+  uint64_t max_group_generation GNUNET_PACKED;
+
+  uint64_t max_state_message_id GNUNET_PACKED;
+};
+
+
+/**
+ * Answer from service to client containing a message fragment.
+ */
+struct FragmentResult
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_CODE
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t psycstore_flags GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /* Followed by GNUNET_MULTICAST_MessageHeader */
+};
+
+
+/**
+ * Answer from service to client containing a state variable.
+ */
+struct StateResult
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_CODE
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint16_t name_size GNUNET_PACKED;
+
+  uint16_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /* Followed by name and value */
+};
+
+
+/**
+ * Generic operation request.
+ */
+struct OperationRequest
+{
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_membership_store()
+ */
+struct MembershipStoreRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_MEMBERSHIP_STORE
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Slave's public key.
+   */
+  struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
+
+  uint64_t announced_at GNUNET_PACKED;
+  uint64_t effective_since GNUNET_PACKED;
+  uint64_t group_generation GNUNET_PACKED;
+  uint8_t did_join;
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_membership_test()
+ */
+struct MembershipTestRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_MEMBERSHIP_TEST
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Slave's public key.
+   */
+  struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
+
+  uint64_t message_id GNUNET_PACKED;
+
+  uint64_t group_generation GNUNET_PACKED;
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_fragment_store()
+ */
+struct FragmentStoreRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_STORE
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * enum GNUNET_PSYCSTORE_MessageFlags
+   */
+  uint32_t psycstore_flags GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id;
+
+  /* Followed by fragment */
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_fragment_get()
+ */
+struct FragmentGetRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_GET
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Slave's public key.
+   */
+  struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
+
+  /**
+   * First fragment ID to request.
+   */
+  uint64_t first_fragment_id GNUNET_PACKED;
+
+  /**
+   * Last fragment ID to request.
+   */
+  uint64_t last_fragment_id GNUNET_PACKED;
+
+  /**
+   * Maximum number of fragments to retrieve.
+   */
+  uint64_t fragment_limit GNUNET_PACKED;
+
+  /**
+   * Do membership test with @a slave_key before returning fragment?
+   * #GNUNET_YES or #GNUNET_NO
+   */
+  uint8_t do_membership_test;
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_message_get()
+ */
+struct MessageGetRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_GET
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Slave's public key.
+   */
+  struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
+
+  /**
+   * First message ID to request.
+   */
+  uint64_t first_message_id GNUNET_PACKED;
+
+  /**
+   * Last message ID to request.
+   */
+  uint64_t last_message_id GNUNET_PACKED;
+
+  /**
+   * Maximum number of messages to retrieve.
+   */
+  uint64_t message_limit GNUNET_PACKED;
+
+  /**
+   * Maximum number of fragments to retrieve.
+   */
+  uint64_t fragment_limit GNUNET_PACKED;
+
+  /**
+   * Do membership test with @a slave_key before returning fragment?
+   * #GNUNET_YES or #GNUNET_NO
+   */
+  uint8_t do_membership_test;
+
+  /* Followed by method_prefix */
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_message_get_fragment()
+ */
+struct MessageGetFragmentRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_FRAGMENT_GET
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /**
+   * Slave's public key.
+   */
+  struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
+
+  /**
+   * Requested message ID.
+   */
+  uint64_t message_id GNUNET_PACKED;
+
+  /**
+   * Requested fragment offset.
+   */
+  uint64_t fragment_offset GNUNET_PACKED;
+
+  /**
+   * Do membership test with @a slave_key before returning fragment?
+   * #GNUNET_YES or #GNUNET_NO
+   */
+  uint8_t do_membership_test;
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_state_hash_update()
+ */
+struct StateHashUpdateRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_HASH_UPDATE
+   */
+  struct GNUNET_MessageHeader header;
+
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  struct GNUNET_HashCode hash;
+};
+
+
+enum StateOpFlags
+{
+  STATE_OP_FIRST = 1 << 0,
+  STATE_OP_LAST = 1 << 1
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_state_modify()
+ */
+struct StateModifyRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_MODIFY
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * ID of the message to apply the state changes in.
+   */
+  uint64_t message_id GNUNET_PACKED;
+
+  /**
+   * State delta of the message with ID @a message_id.
+   */
+  uint64_t state_delta GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+};
+
+
+/**
+ * @see GNUNET_PSYCSTORE_state_sync()
+ */
+struct StateSyncRequest
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_SYNC
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Size of name, including NUL terminator.
+   */
+  uint16_t name_size GNUNET_PACKED;
+
+  /**
+   * OR'd StateOpFlags
+   */
+  uint8_t flags;
+
+  uint8_t reserved;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id GNUNET_PACKED;
+
+  /**
+   * ID of the message that contains the state_hash PSYC header variable.
+   */
+  uint64_t state_hash_message_id GNUNET_PACKED;
+
+  /**
+   * ID of the last stateful message before @a state_hash_message_id.
+   */
+  uint64_t max_state_message_id GNUNET_PACKED;
+
+  /**
+   * Channel's public key.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey channel_key;
+
+  /* Followed by NUL-terminated name, then the value. */
+};
+
+
+GNUNET_NETWORK_STRUCT_END
+
+#endif
diff --git a/src/psycstore/psycstore_api.c b/src/psycstore/psycstore_api.c
new file mode 100644
index 0000000..ab4cd0f
--- /dev/null
+++ b/src/psycstore/psycstore_api.c
@@ -0,0 +1,1285 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/psycstore_api.c
+ * @brief API to interact with the PSYCstore service
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ */
+
+#include <inttypes.h>
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_constants.h"
+#include "gnunet_protocols.h"
+#include "gnunet_psycstore_service.h"
+#include "gnunet_multicast_service.h"
+#include "psycstore.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "psycstore-api",__VA_ARGS__)
+
+/**
+ * Handle for an operation with the PSYCstore service.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle
+{
+
+  /**
+   * Main PSYCstore handle.
+   */
+  struct GNUNET_PSYCSTORE_Handle *h;
+
+  /**
+   * Data callbacks.
+   */
+  union {
+    GNUNET_PSYCSTORE_FragmentCallback fragment_cb;
+    GNUNET_PSYCSTORE_CountersCallback counters_cb;
+    GNUNET_PSYCSTORE_StateCallback state_cb;
+  };
+
+  /**
+   * Closure for callbacks.
+   */
+  void *cls;
+
+  /**
+   * Message envelope.
+   */
+  struct GNUNET_MQ_Envelope *env;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id;
+};
+
+
+/**
+ * Handle for the service.
+ */
+struct GNUNET_PSYCSTORE_Handle
+{
+  /**
+   * Configuration to use.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Client connection.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Async operations.
+   */
+  struct GNUNET_OP_Handle *op;
+
+  /**
+   * Task doing exponential back-off trying to reconnect.
+   */
+  struct GNUNET_SCHEDULER_Task *reconnect_task;
+
+  /**
+   * Delay for next connect retry.
+   */
+  struct GNUNET_TIME_Relative reconnect_delay;
+
+
+  GNUNET_PSYCSTORE_FragmentCallback *fragment_cb;
+
+  GNUNET_PSYCSTORE_CountersCallback *counters_cb;
+
+  GNUNET_PSYCSTORE_StateCallback *state_cb;
+  /**
+   * Closure for callbacks.
+   */
+  void *cb_cls;
+};
+
+
+static int
+check_result_code (void *cls, const struct OperationResult *opres)
+{
+  uint16_t size = ntohs (opres->header.size);
+  const char *str = (const char *) &opres[1];
+  if ( (sizeof (*opres) < size) &&
+       ('\0' != str[size - sizeof (*opres) - 1]) )
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+static void
+handle_result_code (void *cls, const struct OperationResult *opres)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = cls;
+  struct GNUNET_PSYCSTORE_OperationHandle *op = NULL;
+  uint16_t size = ntohs (opres->header.size);
+
+  const char *
+    str = (sizeof (*opres) < size) ? (const char *) &opres[1] : "";
+
+  if (GNUNET_YES == GNUNET_OP_result (h->op, GNUNET_ntohll (opres->op_id),
+                                      GNUNET_ntohll (opres->result_code) + INT64_MIN,
+                                      str, size - sizeof (*opres), (void **) &op))
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "handle_result_code: Received result message with OP ID: %" PRIu64 "\n",
+         GNUNET_ntohll (opres->op_id));
+    GNUNET_free (op);
+  }
+  else
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "handle_result_code: No callback registered for OP ID %" PRIu64 ".\n",
+         GNUNET_ntohll (opres->op_id));
+  }
+  h->reconnect_delay = GNUNET_TIME_UNIT_MILLISECONDS;
+}
+
+
+static void
+handle_result_counters (void *cls, const struct CountersResult *cres)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = cls;
+  struct GNUNET_PSYCSTORE_OperationHandle *op = NULL;
+
+  if (GNUNET_YES == GNUNET_OP_get (h->op, GNUNET_ntohll (cres->op_id),
+                                   NULL, NULL, (void **) &op))
+  {
+    GNUNET_assert (NULL != op);
+    if (NULL != op->counters_cb)
+    {
+      op->counters_cb (op->cls,
+                       ntohl (cres->result_code),
+                       GNUNET_ntohll (cres->max_fragment_id),
+                       GNUNET_ntohll (cres->max_message_id),
+                       GNUNET_ntohll (cres->max_group_generation),
+                       GNUNET_ntohll (cres->max_state_message_id));
+    }
+    GNUNET_OP_remove (h->op, GNUNET_ntohll (cres->op_id));
+    GNUNET_free (op);
+  }
+  else
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "handle_result_counters: No callback registered for OP ID %" PRIu64 ".\n",
+         GNUNET_ntohll (cres->op_id));
+  }
+  h->reconnect_delay = GNUNET_TIME_UNIT_MILLISECONDS;
+}
+
+
+static int
+check_result_fragment (void *cls, const struct FragmentResult *fres)
+{
+  uint16_t size = ntohs (fres->header.size);
+  struct GNUNET_MULTICAST_MessageHeader *mmsg =
+    (struct GNUNET_MULTICAST_MessageHeader *) &fres[1];
+  if (sizeof (*fres) + sizeof (*mmsg) < size
+      && sizeof (*fres) + ntohs (mmsg->header.size) != size)
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         "check_result_fragment: Received message with invalid length %lu bytes.\n",
+         size, sizeof (*fres));
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+static void
+handle_result_fragment (void *cls, const struct FragmentResult *fres)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = cls;
+  struct GNUNET_PSYCSTORE_OperationHandle *op = NULL;
+
+  if (GNUNET_YES == GNUNET_OP_get (h->op, GNUNET_ntohll (fres->op_id),
+                                   NULL, NULL, (void **) &op))
+  {
+    GNUNET_assert (NULL != op);
+    if (NULL != op->fragment_cb)
+      op->fragment_cb (op->cls,
+                       (struct GNUNET_MULTICAST_MessageHeader *) &fres[1],
+                       ntohl (fres->psycstore_flags));
+    //GNUNET_OP_remove (h->op, GNUNET_ntohll (fres->op_id));
+    //GNUNET_free (op);
+  }
+  else
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "handle_result_fragment: No callback registered for OP ID %" PRIu64 ".\n",
+         GNUNET_ntohll (fres->op_id));
+  }
+  h->reconnect_delay = GNUNET_TIME_UNIT_MILLISECONDS;
+}
+
+
+static int
+check_result_state (void *cls, const struct StateResult *sres)
+{
+  const char *name = (const char *) &sres[1];
+  uint16_t size = ntohs (sres->header.size);
+  uint16_t name_size = ntohs (sres->name_size);
+
+  if (name_size <= 2
+      || size - sizeof (*sres) < name_size
+      || '\0' != name[name_size - 1])
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         "check_result_state: Received state result message with invalid name.\n");
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+static void
+handle_result_state (void *cls, const struct StateResult *sres)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = cls;
+  struct GNUNET_PSYCSTORE_OperationHandle *op = NULL;
+
+  const char *name = (const char *) &sres[1];
+  uint16_t name_size = ntohs (sres->name_size);
+
+  if (GNUNET_YES == GNUNET_OP_get (h->op, GNUNET_ntohll (sres->op_id),
+                                   NULL, NULL, (void **) &op))
+  {
+    GNUNET_assert (NULL != op);
+    if (NULL != op->state_cb)
+       op->state_cb (op->cls, name, (char *) &sres[1] + name_size,
+                     ntohs (sres->header.size) - sizeof (*sres) - name_size);
+    //GNUNET_OP_remove (h->op, GNUNET_ntohll (sres->op_id));
+    //GNUNET_free (op);
+  }
+  else
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "handle_result_state: No callback registered for OP ID %" PRIu64 ".\n",
+         GNUNET_ntohll (sres->op_id));
+  }
+  h->reconnect_delay = GNUNET_TIME_UNIT_MILLISECONDS;
+}
+
+
+static void
+reconnect (void *cls);
+
+
+/**
+ * Client disconnected from service.
+ *
+ * Reconnect after backoff period.=
+ */
+static void
+disconnected (void *cls, enum GNUNET_MQ_Error error)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = cls;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Origin client disconnected (%d), re-connecting\n",
+       (int) error);
+  if (NULL != h->mq)
+  {
+    GNUNET_MQ_destroy (h->mq);
+    GNUNET_OP_destroy (h->op);
+    h->mq = NULL;
+    h->op = NULL;
+  }
+
+  h->reconnect_task = GNUNET_SCHEDULER_add_delayed (h->reconnect_delay,
+                                                    &reconnect, h);
+  h->reconnect_delay = GNUNET_TIME_STD_BACKOFF (h->reconnect_delay);
+}
+
+
+static void
+do_connect (struct GNUNET_PSYCSTORE_Handle *h)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Connecting to PSYCstore service.\n");
+
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    GNUNET_MQ_hd_var_size (result_code,
+                           GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_CODE,
+                           struct OperationResult,
+                           h),
+    GNUNET_MQ_hd_fixed_size (result_counters,
+                             GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_COUNTERS,
+                             struct CountersResult,
+                             h),
+    GNUNET_MQ_hd_var_size (result_fragment,
+                           GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_FRAGMENT,
+                           struct FragmentResult,
+                           h),
+    GNUNET_MQ_hd_var_size (result_state,
+                           GNUNET_MESSAGE_TYPE_PSYCSTORE_RESULT_STATE,
+                           struct StateResult,
+                           h),
+    GNUNET_MQ_handler_end ()
+  };
+
+  h->op = GNUNET_OP_create ();
+  GNUNET_assert (NULL == h->mq);
+  h->mq = GNUNET_CLIENT_connect (h->cfg, "psycstore",
+                                 handlers, disconnected, h);
+  GNUNET_assert (NULL != h->mq);
+}
+
+
+/**
+ * Try again to connect to the PSYCstore service.
+ *
+ * @param cls Handle to the PSYCstore service.
+ */
+static void
+reconnect (void *cls)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = cls;
+
+  h->reconnect_task = NULL;
+  do_connect (cls);
+}
+
+
+/**
+ * Connect to the PSYCstore service.
+ *
+ * @param cfg The configuration to use
+ * @return Handle to use
+ */
+struct GNUNET_PSYCSTORE_Handle *
+GNUNET_PSYCSTORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  struct GNUNET_PSYCSTORE_Handle *h
+    = GNUNET_new (struct GNUNET_PSYCSTORE_Handle);
+  h->cfg = cfg;
+  h->reconnect_delay = GNUNET_TIME_UNIT_MILLISECONDS;
+  do_connect (h);
+  return h;
+}
+
+
+/**
+ * Disconnect from PSYCstore service
+ *
+ * @param h Handle to destroy
+ */
+void
+GNUNET_PSYCSTORE_disconnect (struct GNUNET_PSYCSTORE_Handle *h)
+{
+  GNUNET_assert (NULL != h);
+  if (h->reconnect_task != NULL)
+  {
+    GNUNET_SCHEDULER_cancel (h->reconnect_task);
+    h->reconnect_task = NULL;
+  }
+  if (NULL != h->mq)
+  {
+    // FIXME: free data structures for pending operations
+    GNUNET_MQ_destroy (h->mq);
+    h->mq = NULL;
+  }
+  GNUNET_free (h);
+}
+
+
+/**
+ * Message sent notification.
+ *
+ * Remove invalidated envelope pointer.
+ */
+static void
+message_sent (void *cls)
+{
+  struct GNUNET_PSYCSTORE_OperationHandle *op = cls;
+  op->env = NULL;
+}
+
+
+/**
+ * Create a new operation.
+ */
+static struct GNUNET_PSYCSTORE_OperationHandle *
+op_create (struct GNUNET_PSYCSTORE_Handle *h,
+           struct GNUNET_OP_Handle *hop,
+           GNUNET_PSYCSTORE_ResultCallback result_cb,
+           void *cls)
+{
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = GNUNET_malloc (sizeof (*op));
+  op->h = h;
+  op->op_id = GNUNET_OP_add (hop,
+                             (GNUNET_ResultCallback) result_cb,
+                             cls, op);
+  return op;
+}
+
+
+/**
+ * Send a message associated with an operation.
+ *
+ * @param h
+ *        PSYCstore handle.
+ * @param op
+ *        Operation handle.
+ * @param env
+ *        Message envelope to send.
+ * @param[out] op_id
+ *        Operation ID to write in network byte order. NULL if not needed.
+ *
+ * @return Operation handle.
+ *
+ */
+static struct GNUNET_PSYCSTORE_OperationHandle *
+op_send (struct GNUNET_PSYCSTORE_Handle *h,
+         struct GNUNET_PSYCSTORE_OperationHandle *op,
+         struct GNUNET_MQ_Envelope *env,
+         uint64_t *op_id)
+{
+  op->env = env;
+  if (NULL != op_id)
+    *op_id = GNUNET_htonll (op->op_id);
+
+  GNUNET_MQ_notify_sent (env, message_sent, op);
+  GNUNET_MQ_send (h->mq, env);
+  return op;
+}
+
+
+/**
+ * Cancel a PSYCstore operation. Note that the operation MAY still
+ * be executed; this merely cancels the continuation; if the request
+ * was already transmitted, the service may still choose to complete
+ * the operation.
+ *
+ * @param op Operation to cancel.
+ *
+ * @return #GNUNET_YES if message was not sent yet and got discarded,
+ *         #GNUNET_NO  if it was already sent, and only the callbacks got cancelled.
+ */
+int
+GNUNET_PSYCSTORE_operation_cancel (struct GNUNET_PSYCSTORE_OperationHandle *op)
+{
+  struct GNUNET_PSYCSTORE_Handle *h = op->h;
+  int ret = GNUNET_NO;
+
+  if (NULL != op->env)
+  {
+    GNUNET_MQ_send_cancel (op->env);
+    ret = GNUNET_YES;
+  }
+
+  GNUNET_OP_remove (h->op, op->op_id);
+  GNUNET_free (op);
+
+  return ret;
+}
+
+
+/**
+ * Store join/leave events for a PSYC channel in order to be able to answer
+ * membership test queries later.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel where the event happened.
+ * @param slave_key
+ *        Public key of joining/leaving slave.
+ * @param did_join
+ *        #GNUNET_YES on join, #GNUNET_NO on part.
+ * @param announced_at
+ *        ID of the message that announced the membership change.
+ * @param effective_since
+ *        Message ID this membership change is in effect since.
+ *        For joins it is <= announced_at, for parts it is always 0.
+ * @param group_generation
+ *        In case of a part, the last group generation the slave has access to.
+ *        It has relevance when a larger message have fragments with different
+ *        group generations.
+ * @param result_cb
+ *        Callback to call with the result of the storage operation.
+ * @param cls
+ *        Closure for the callback.
+ *
+ * @return Operation handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_membership_store (struct GNUNET_PSYCSTORE_Handle *h,
+                                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                   const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                                   int did_join,
+                                   uint64_t announced_at,
+                                   uint64_t effective_since,
+                                   uint64_t group_generation,
+                                   GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                   void *cls)
+{
+  GNUNET_assert (NULL != h);
+  GNUNET_assert (NULL != channel_key);
+  GNUNET_assert (NULL != slave_key);
+  GNUNET_assert (GNUNET_YES == did_join || GNUNET_NO == did_join);
+  GNUNET_assert (did_join
+                 ? effective_since <= announced_at
+                 : effective_since == 0);
+
+  struct MembershipStoreRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_MEMBERSHIP_STORE);
+  req->channel_key = *channel_key;
+  req->slave_key = *slave_key;
+  req->did_join = did_join;
+  req->announced_at = GNUNET_htonll (announced_at);
+  req->effective_since = GNUNET_htonll (effective_since);
+  req->group_generation = GNUNET_htonll (group_generation);
+
+  return
+    op_send (h, op_create (h, h->op, result_cb, cls),
+             env, &req->op_id);
+}
+
+
+/**
+ * Test if a member was admitted to the channel at the given message ID.
+ *
+ * This is useful when relaying and replaying messages to check if a particular
+ * slave has access to the message fragment with a given group generation.  It
+ * is also used when handling join requests to determine whether the slave is
+ * currently admitted to the channel.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param slave_key
+ *        Public key of slave whose membership to check.
+ * @param message_id
+ *        Message ID for which to do the membership test.
+ * @param group_generation
+ *        Group generation of the fragment of the message to test.
+ *        It has relevance if the message consists of multiple fragments with
+ *        different group generations.
+ * @param result_cb
+ *        Callback to call with the test result.
+ * @param cls
+ *        Closure for the callback.
+ *
+ * @return Operation handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_membership_test (struct GNUNET_PSYCSTORE_Handle *h,
+                                  const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                  const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                                  uint64_t message_id,
+                                  uint64_t group_generation,
+                                  GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                  void *cls)
+{
+  struct MembershipTestRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_MEMBERSHIP_TEST);
+  req->channel_key = *channel_key;
+  req->slave_key = *slave_key;
+  req->message_id = GNUNET_htonll (message_id);
+  req->group_generation = GNUNET_htonll (group_generation);
+
+  return
+    op_send (h, op_create (h, h->op, result_cb, cls),
+             env, &req->op_id);
+}
+
+
+/**
+ * Store a message fragment sent to a channel.
+ *
+ * @param h Handle for the PSYCstore.
+ * @param channel_key The channel the message belongs to.
+ * @param message Message to store.
+ * @param psycstore_flags Flags indicating whether the PSYC message contains
+ *        state modifiers.
+ * @param result_cb Callback to call with the result of the operation.
+ * @param cls Closure for the callback.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_fragment_store (struct GNUNET_PSYCSTORE_Handle *h,
+                                 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                 const struct GNUNET_MULTICAST_MessageHeader *msg,
+                                 enum GNUNET_PSYCSTORE_MessageFlags psycstore_flags,
+                                 GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                 void *cls)
+{
+  uint16_t size = ntohs (msg->header.size);
+  struct FragmentStoreRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (req, size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_STORE);
+  req->channel_key = *channel_key;
+  req->psycstore_flags = htonl (psycstore_flags);
+  GNUNET_memcpy (&req[1], msg, size);
+
+  return
+    op_send (h, op_create (h, h->op, result_cb, cls),
+             env, &req->op_id);
+}
+
+
+/**
+ * Retrieve message fragments by fragment ID range.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param slave_key
+ *        The slave requesting the fragment.  If not NULL, a membership test is
+ *        performed first and the fragment is only returned if the slave has
+ *        access to it.
+ * @param first_fragment_id
+ *        First fragment ID to retrieve.
+ *        Use 0 to get the latest message fragment.
+ * @param last_fragment_id
+ *        Last consecutive fragment ID to retrieve.
+ *        Use 0 to get the latest message fragment.
+ * @param fragment_limit
+ *        Maximum number of fragments to retrieve.
+ * @param fragment_cb
+ *        Callback to call with the retrieved fragments.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_fragment_get (struct GNUNET_PSYCSTORE_Handle *h,
+                               const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                               const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                               uint64_t first_fragment_id,
+                               uint64_t last_fragment_id,
+                               GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+                               GNUNET_PSYCSTORE_ResultCallback result_cb,
+                               void *cls)
+{
+  struct FragmentGetRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_GET);
+  req->channel_key = *channel_key;
+  req->first_fragment_id = GNUNET_htonll (first_fragment_id);
+  req->last_fragment_id = GNUNET_htonll (last_fragment_id);
+  if (NULL != slave_key)
+  {
+    req->slave_key = *slave_key;
+    req->do_membership_test = GNUNET_YES;
+  }
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->fragment_cb = fragment_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Retrieve latest message fragments.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param slave_key
+ *        The slave requesting the fragment.  If not NULL, a membership test is
+ *        performed first and the fragment is only returned if the slave has
+ *        access to it.
+ * @param first_fragment_id
+ *        First fragment ID to retrieve.
+ *        Use 0 to get the latest message fragment.
+ * @param last_fragment_id
+ *        Last consecutive fragment ID to retrieve.
+ *        Use 0 to get the latest message fragment.
+ * @param fragment_limit
+ *        Maximum number of fragments to retrieve.
+ * @param fragment_cb
+ *        Callback to call with the retrieved fragments.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_fragment_get_latest (struct GNUNET_PSYCSTORE_Handle *h,
+                                      const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                      const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                                      uint64_t fragment_limit,
+                                      GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+                                      GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                      void *cls)
+{
+  struct FragmentGetRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_FRAGMENT_GET);
+  req->channel_key = *channel_key;
+  req->fragment_limit = GNUNET_ntohll (fragment_limit);
+  if (NULL != slave_key)
+  {
+    req->slave_key = *slave_key;
+    req->do_membership_test = GNUNET_YES;
+  }
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->fragment_cb = fragment_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Retrieve all fragments of messages in a message ID range.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param slave_key
+ *        The slave requesting the message.
+ *        If not NULL, a membership test is performed first
+ *        and the message is only returned if the slave has access to it.
+ * @param first_message_id
+ *        First message ID to retrieve.
+ * @param last_message_id
+ *        Last consecutive message ID to retrieve.
+ * @param fragment_limit
+ *        Maximum number of fragments to retrieve.
+ * @param method_prefix
+ *        Retrieve only messages with a matching method prefix.
+ * @todo Implement method_prefix query.
+ * @param fragment_cb
+ *        Callback to call with the retrieved fragments.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_message_get (struct GNUNET_PSYCSTORE_Handle *h,
+                              const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                              const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                              uint64_t first_message_id,
+                              uint64_t last_message_id,
+                              uint64_t fragment_limit,
+                              const char *method_prefix,
+                              GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+                              GNUNET_PSYCSTORE_ResultCallback result_cb,
+                              void *cls)
+{
+  struct MessageGetRequest *req;
+  if (NULL == method_prefix)
+    method_prefix = "";
+  uint16_t method_size = strnlen (method_prefix,
+                                  GNUNET_MAX_MESSAGE_SIZE
+                                  - sizeof (*req)) + 1;
+
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (req, method_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_GET);
+  req->channel_key = *channel_key;
+  req->first_message_id = GNUNET_htonll (first_message_id);
+  req->last_message_id = GNUNET_htonll (last_message_id);
+  req->fragment_limit = GNUNET_htonll (fragment_limit);
+  if (NULL != slave_key)
+  {
+    req->slave_key = *slave_key;
+    req->do_membership_test = GNUNET_YES;
+  }
+  GNUNET_memcpy (&req[1], method_prefix, method_size);
+  ((char *) &req[1])[method_size - 1] = '\0';
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->fragment_cb = fragment_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Retrieve all fragments of the latest messages.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param slave_key
+ *        The slave requesting the message.
+ *        If not NULL, a membership test is performed first
+ *        and the message is only returned if the slave has access to it.
+ * @param message_limit
+ *        Maximum number of messages to retrieve.
+ * @param method_prefix
+ *        Retrieve only messages with a matching method prefix.
+ * @todo Implement method_prefix query.
+ * @param fragment_cb
+ *        Callback to call with the retrieved fragments.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_message_get_latest (struct GNUNET_PSYCSTORE_Handle *h,
+                                     const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                     const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                                     uint64_t message_limit,
+                                     const char *method_prefix,
+                                     GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+                                     GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                     void *cls)
+{
+  struct MessageGetRequest *req;
+
+  if (NULL == method_prefix)
+    method_prefix = "";
+  uint16_t method_size = strnlen (method_prefix,
+                                  GNUNET_MAX_MESSAGE_SIZE
+                                  - sizeof (*req)) + 1;
+  GNUNET_assert ('\0' == method_prefix[method_size - 1]);
+
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (req, method_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_GET);
+  req->channel_key = *channel_key;
+  req->message_limit = GNUNET_ntohll (message_limit);
+  if (NULL != slave_key)
+  {
+    req->slave_key = *slave_key;
+    req->do_membership_test = GNUNET_YES;
+  }
+  GNUNET_memcpy (&req[1], method_prefix, method_size);
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->fragment_cb = fragment_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Retrieve a fragment of message specified by its message ID and fragment
+ * offset.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param slave_key
+ *        The slave requesting the message fragment.  If not NULL, a membership
+ *        test is performed first and the message fragment is only returned
+ *        if the slave has access to it.
+ * @param message_id
+ *        Message ID to retrieve.  Use 0 to get the latest message.
+ * @param fragment_offset
+ *        Offset of the fragment to retrieve.
+ * @param fragment_cb
+ *        Callback to call with the retrieved fragments.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_message_get_fragment (struct GNUNET_PSYCSTORE_Handle *h,
+                                       const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                       const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+                                       uint64_t message_id,
+                                       uint64_t fragment_offset,
+                                       GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+                                       GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                       void *cls)
+{
+  struct MessageGetFragmentRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_MESSAGE_GET_FRAGMENT);
+
+  req->channel_key = *channel_key;
+  req->message_id = GNUNET_htonll (message_id);
+  req->fragment_offset = GNUNET_htonll (fragment_offset);
+  if (NULL != slave_key)
+  {
+    req->slave_key = *slave_key;
+    req->do_membership_test = GNUNET_YES;
+  }
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->fragment_cb = fragment_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Retrieve latest values of counters for a channel master.
+ *
+ * The current value of counters are needed when a channel master is restarted,
+ * so that it can continue incrementing the counters from their last value.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        Public key that identifies the channel.
+ * @param ccb
+ *        Callback to call with the result.
+ * @param ccb_cls
+ *        Closure for the @a ccb callback.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_counters_get (struct GNUNET_PSYCSTORE_Handle *h,
+                               struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                               GNUNET_PSYCSTORE_CountersCallback counters_cb,
+                               void *cls)
+{
+  struct OperationRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_COUNTERS_GET);
+  req->channel_key = *channel_key;
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, NULL, NULL);
+  op->counters_cb = counters_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Apply modifiers of a message to the current channel state.
+ *
+ * An error is returned if there are missing messages containing state
+ * operations before the current one.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param message_id
+ *        ID of the message that contains the @a modifiers.
+ * @param state_delta
+ *        Value of the _state_delta PSYC header variable of the message.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for @a result_cb.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_state_modify (struct GNUNET_PSYCSTORE_Handle *h,
+                               const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                               uint64_t message_id,
+                               uint64_t state_delta,
+                               GNUNET_PSYCSTORE_ResultCallback result_cb,
+                               void *cls)
+{
+  struct StateModifyRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_MODIFY);
+  req->channel_key = *channel_key;
+  req->message_id = GNUNET_htonll (message_id);
+  req->state_delta = GNUNET_htonll (state_delta);
+
+  return op_send (h, op_create (h, h->op, result_cb, cls),
+                  env, &req->op_id);
+}
+
+
+struct StateSyncClosure
+{
+  GNUNET_PSYCSTORE_ResultCallback result_cb;
+  void *cls;
+  uint8_t last;
+};
+
+
+static void
+state_sync_result (void *cls, int64_t result,
+                   const char *err_msg, uint16_t err_msg_size)
+{
+  struct StateSyncClosure *ssc = cls;
+  if (GNUNET_OK != result || ssc->last)
+    ssc->result_cb (ssc->cls, result, err_msg, err_msg_size);
+  GNUNET_free (ssc);
+}
+
+
+/**
+ * Store synchronized state.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param max_state_message_id
+ *        ID of the last stateful message before @a state_hash_message_id.
+ * @param state_hash_message_id
+ *        ID of the message that contains the state_hash PSYC header variable.
+ * @param modifier_count
+ *        Number of elements in the @a modifiers array.
+ * @param modifiers
+ *        Full state to store.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callback.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_state_sync (struct GNUNET_PSYCSTORE_Handle *h,
+                             const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                             uint64_t max_state_message_id,
+                             uint64_t state_hash_message_id,
+                             size_t modifier_count,
+                             const struct GNUNET_PSYC_Modifier *modifiers,
+                             GNUNET_PSYCSTORE_ResultCallback result_cb,
+                             void *cls)
+{
+  struct GNUNET_PSYCSTORE_OperationHandle *op = NULL;
+  size_t i;
+
+  for (i = 0; i < modifier_count; i++) {
+    struct StateSyncRequest *req;
+    uint16_t name_size = strlen (modifiers[i].name) + 1;
+
+    struct GNUNET_MQ_Envelope *
+      env = GNUNET_MQ_msg_extra (req,
+                                 sizeof (*req) + name_size + modifiers[i].value_size,
+                                 GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_SYNC);
+
+    req->header.type = htons (GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_SYNC);
+    req->header.size = htons (sizeof (*req) + name_size
+                              + modifiers[i].value_size);
+    req->channel_key = *channel_key;
+    req->max_state_message_id = GNUNET_htonll (max_state_message_id);
+    req->state_hash_message_id = GNUNET_htonll (state_hash_message_id);
+    req->name_size = htons (name_size);
+    req->flags
+      = (0 == i)
+      ? STATE_OP_FIRST
+      : (modifier_count - 1 == i)
+      ? STATE_OP_LAST
+      : 0;
+
+    GNUNET_memcpy (&req[1], modifiers[i].name, name_size);
+    GNUNET_memcpy ((char *) &req[1] + name_size, modifiers[i].value, modifiers[i].value_size);
+
+    struct StateSyncClosure *ssc = GNUNET_malloc (sizeof (*ssc));
+    ssc->last = (req->flags & STATE_OP_LAST);
+    ssc->result_cb = result_cb;
+    ssc->cls = cls;
+
+    op_send (h, op_create (h, h->op, state_sync_result, ssc),
+             env, &req->op_id);
+  }
+  // FIXME: only one operation is returned,
+  //        add pointers to other operations and make all cancellable.
+  return op;
+}
+
+
+/**
+ * Reset the state of a channel.
+ *
+ * Delete all state variables stored for the given channel.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callback.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_state_reset (struct GNUNET_PSYCSTORE_Handle *h,
+                              const struct GNUNET_CRYPTO_EddsaPublicKey
+                              *channel_key,
+                              GNUNET_PSYCSTORE_ResultCallback result_cb,
+                              void *cls)
+{
+  struct OperationRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_RESET);
+  req->channel_key = *channel_key;
+
+  return
+    op_send (h, op_create (h, h->op, result_cb, cls),
+             env, &req->op_id);
+}
+
+
+/**
+ * Update signed values of state variables in the state store.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param message_id
+ *        Message ID that contained the state @a hash.
+ * @param hash
+ *        Hash of the serialized full state.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callback.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_state_hash_update (struct GNUNET_PSYCSTORE_Handle *h,
+                                    const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                    uint64_t message_id,
+                                    const struct GNUNET_HashCode *hash,
+                                    GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                    void *cls)
+{
+  struct StateHashUpdateRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg (req, GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_HASH_UPDATE);
+  req->channel_key = *channel_key;
+  req->hash = *hash;
+
+  return
+    op_send (h, op_create (h, h->op, result_cb, cls),
+             env, &req->op_id);
+}
+
+
+/**
+ * Retrieve the best matching state variable.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param name
+ *        Name of variable to match, the returned variable might be less specific.
+ * @param state_cb
+ *        Callback to return the matching state variable.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_state_get (struct GNUNET_PSYCSTORE_Handle *h,
+                            const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                            const char *name,
+                            GNUNET_PSYCSTORE_StateCallback state_cb,
+                            GNUNET_PSYCSTORE_ResultCallback result_cb,
+                            void *cls)
+{
+  size_t name_size = strlen (name) + 1;
+  struct OperationRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (req, name_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_GET);
+  req->channel_key = *channel_key;
+  GNUNET_memcpy (&req[1], name, name_size);
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->state_cb = state_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+
+/**
+ * Retrieve all state variables for a channel with the given prefix.
+ *
+ * @param h
+ *        Handle for the PSYCstore.
+ * @param channel_key
+ *        The channel we are interested in.
+ * @param name_prefix
+ *        Prefix of state variable names to match.
+ * @param state_cb
+ *        Callback to return matching state variables.
+ * @param result_cb
+ *        Callback to call with the result of the operation.
+ * @param cls
+ *        Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_state_get_prefix (struct GNUNET_PSYCSTORE_Handle *h,
+                                   const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+                                   const char *name_prefix,
+                                   GNUNET_PSYCSTORE_StateCallback state_cb,
+                                   GNUNET_PSYCSTORE_ResultCallback result_cb,
+                                   void *cls)
+{
+  size_t name_size = strlen (name_prefix) + 1;
+  struct OperationRequest *req;
+  struct GNUNET_MQ_Envelope *
+    env = GNUNET_MQ_msg_extra (req, name_size,
+                               GNUNET_MESSAGE_TYPE_PSYCSTORE_STATE_GET_PREFIX);
+  req->channel_key = *channel_key;
+  GNUNET_memcpy (&req[1], name_prefix, name_size);
+
+  struct GNUNET_PSYCSTORE_OperationHandle *
+    op = op_create (h, h->op, result_cb, cls);
+  op->state_cb = state_cb;
+  op->cls = cls;
+  return op_send (h, op, env, &req->op_id);
+}
+
+/* end of psycstore_api.c */
diff --git a/src/psycstore/test_plugin_psycstore.c b/src/psycstore/test_plugin_psycstore.c
new file mode 100644
index 0000000..ff4eac8
--- /dev/null
+++ b/src/psycstore/test_plugin_psycstore.c
@@ -0,0 +1,532 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ *
+ * @file
+ * Test for the PSYCstore plugins.
+ */
+
+#include <inttypes.h>
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_testing_lib.h"
+#include "gnunet_psycstore_plugin.h"
+#include "gnunet_psycstore_service.h"
+#include "gnunet_multicast_service.h"
+
+#define DEBUG_PSYCSTORE GNUNET_EXTRA_LOGGING
+#if DEBUG_PSYCSTORE
+# define LOG_LEVEL "DEBUG"
+#else
+# define LOG_LEVEL "WARNING"
+#endif
+
+#define C2ARG(str) str, (sizeof (str) - 1)
+
+#define LOG(kind,...)                                                          \
+  GNUNET_log_from (kind, "test-plugin-psycstore", __VA_ARGS__)
+
+static int ok;
+
+/**
+ * Name of plugin under test.
+ */
+static const char *plugin_name;
+
+static struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key;
+static struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key;
+
+static struct GNUNET_CRYPTO_EddsaPublicKey channel_pub_key;
+static struct GNUNET_CRYPTO_EcdsaPublicKey slave_pub_key;
+
+/**
+ * Function called when the service shuts down.  Unloads our psycstore
+ * plugin.
+ *
+ * @param api api to unload
+ */
+static void
+unload_plugin (struct GNUNET_PSYCSTORE_PluginFunctions *api)
+{
+  char *libname;
+
+  GNUNET_asprintf (&libname, "libgnunet_plugin_psycstore_%s", plugin_name);
+  GNUNET_break (NULL == GNUNET_PLUGIN_unload (libname, api));
+  GNUNET_free (libname);
+}
+
+
+/**
+ * Load the psycstore plugin.
+ *
+ * @param cfg configuration to pass
+ * @return NULL on error
+ */
+static struct GNUNET_PSYCSTORE_PluginFunctions *
+load_plugin (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  struct GNUNET_PSYCSTORE_PluginFunctions *ret;
+  char *libname;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Loading `%s' psycstore plugin\n"),
+              plugin_name);
+  GNUNET_asprintf (&libname, "libgnunet_plugin_psycstore_%s", plugin_name);
+  if (NULL == (ret = GNUNET_PLUGIN_load (libname, (void*) cfg)))
+  {
+    FPRINTF (stderr, "Failed to load plugin `%s'!\n", plugin_name);
+    return NULL;
+  }
+  GNUNET_free (libname);
+  return ret;
+}
+
+
+#define MAX_MSG 16
+
+struct FragmentClosure
+{
+  uint8_t n;
+  uint64_t flags[MAX_MSG];
+  struct GNUNET_MULTICAST_MessageHeader *msg[MAX_MSG];
+};
+
+static int
+fragment_cb (void *cls, struct GNUNET_MULTICAST_MessageHeader *msg2,
+             enum GNUNET_PSYCSTORE_MessageFlags flags)
+{
+  struct FragmentClosure *fcls = cls;
+  struct GNUNET_MULTICAST_MessageHeader *msg1;
+  uint64_t flags1;
+  int ret;
+
+  if (fcls->n >= MAX_MSG)
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+  msg1 = fcls->msg[fcls->n];
+  flags1 = fcls->flags[fcls->n++];
+  if (NULL == msg1)
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+
+  if (flags1 == flags && msg1->header.size == msg2->header.size
+      && 0 == memcmp (msg1, msg2, ntohs (msg1->header.size)))
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Fragment %llu matches\n",
+         GNUNET_ntohll (msg1->fragment_id));
+    ret = GNUNET_YES;
+  }
+  else
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR, "Fragment %llu differs\n",
+         GNUNET_ntohll (msg1->fragment_id));
+    ret = GNUNET_SYSERR;
+  }
+
+  GNUNET_free (msg2);
+  return ret;
+}
+
+
+struct StateClosure {
+  size_t n;
+  char *name[16];
+  void *value[16];
+  size_t value_size[16];
+};
+
+static int
+state_cb (void *cls, const char *name, const void *value, uint32_t value_size)
+{
+  struct StateClosure *scls = cls;
+  const void *val = scls->value[scls->n]; // FIXME: check for n out-of-bounds FIRST!
+  size_t val_size = scls->value_size[scls->n++];
+
+  /* FIXME: check name */
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "  name = %s, value_size = %u\n",
+       name, value_size);
+
+  return GNUNET_YES;
+  return value_size == val_size && 0 == memcmp (value, val, val_size)
+    ? GNUNET_YES
+    : GNUNET_SYSERR;
+}
+
+
+static void
+run (void *cls, char *const *args, const char *cfgfile,
+     const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  struct GNUNET_PSYCSTORE_PluginFunctions *db;
+
+  ok = 1;
+  db = load_plugin (cfg);
+  if (NULL == db)
+  {
+    FPRINTF (stderr,
+             "%s",
+	     "Failed to initialize PSYCstore.  "
+             "Database likely not setup, skipping test.\n");
+    ok = 77;
+    return;
+  }
+
+  /* Store & test membership */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "MEMBERSHIP\n");
+
+  channel_key = GNUNET_CRYPTO_eddsa_key_create ();
+  slave_key = GNUNET_CRYPTO_ecdsa_key_create ();
+
+  GNUNET_CRYPTO_eddsa_key_get_public (channel_key,
+                                                  &channel_pub_key);
+  GNUNET_CRYPTO_ecdsa_key_get_public (slave_key, &slave_pub_key);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "membership_store()\n");
+
+  GNUNET_assert (GNUNET_OK == db->membership_store (db->cls, &channel_pub_key,
+                                                    &slave_pub_key, GNUNET_YES,
+                                                    4, 2, 1));
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "membership_test()\n");
+
+  GNUNET_assert (GNUNET_YES == db->membership_test (db->cls, &channel_pub_key,
+                                                    &slave_pub_key, 4));
+
+  GNUNET_assert (GNUNET_YES == db->membership_test (db->cls, &channel_pub_key,
+                                                    &slave_pub_key, 2));
+
+  GNUNET_assert (GNUNET_NO == db->membership_test (db->cls, &channel_pub_key,
+                                                   &slave_pub_key, 1));
+
+  /* Store & get messages */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "MESSAGES\n");
+
+  struct GNUNET_MULTICAST_MessageHeader *msg
+    = GNUNET_malloc (sizeof (*msg) + sizeof (channel_pub_key));
+  GNUNET_assert (msg != NULL);
+
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_MULTICAST_MESSAGE);
+  msg->header.size = htons (sizeof (*msg) + sizeof (channel_pub_key));
+
+  uint64_t fragment_id = INT64_MAX - 1;
+  msg->fragment_id = GNUNET_htonll (fragment_id);
+
+  uint64_t message_id = INT64_MAX - 10;
+  msg->message_id = GNUNET_htonll (message_id);
+
+  uint64_t group_generation = INT64_MAX - 3;
+  msg->group_generation = GNUNET_htonll (group_generation);
+
+  msg->hop_counter = htonl (9);
+  msg->fragment_offset = GNUNET_htonll (0);
+  msg->flags = htonl (GNUNET_MULTICAST_MESSAGE_LAST_FRAGMENT);
+
+  GNUNET_memcpy (&msg[1], &channel_pub_key, sizeof (channel_pub_key));
+
+  msg->purpose.size = htonl (ntohs (msg->header.size)
+                             - sizeof (msg->header)
+                             - sizeof (msg->hop_counter)
+                             - sizeof (msg->signature));
+  msg->purpose.purpose = htonl (234);
+  GNUNET_assert (GNUNET_OK ==
+                 GNUNET_CRYPTO_eddsa_sign (channel_key, &msg->purpose, &msg->signature));
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "fragment_store()\n");
+
+  struct FragmentClosure fcls = { 0 };
+  fcls.n = 0;
+  fcls.msg[0] = msg;
+  fcls.flags[0] = GNUNET_PSYCSTORE_MESSAGE_STATE;
+
+  GNUNET_assert (
+    GNUNET_OK == db->fragment_store (db->cls, &channel_pub_key, msg,
+                                     fcls.flags[0]));
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "fragment_get(%" PRIu64 ")\n", fragment_id);
+
+  uint64_t ret_frags = 0;
+  GNUNET_assert (
+    GNUNET_OK == db->fragment_get (db->cls, &channel_pub_key,
+                                   fragment_id, fragment_id,
+                                   &ret_frags, fragment_cb, &fcls));
+  GNUNET_assert (fcls.n == 1);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "message_get_fragment()\n");
+
+  fcls.n = 0;
+  GNUNET_assert (
+    GNUNET_OK == db->message_get_fragment (db->cls, &channel_pub_key,
+                                           GNUNET_ntohll (msg->message_id),
+                                           GNUNET_ntohll (msg->fragment_offset),
+                                           fragment_cb, &fcls));
+  GNUNET_assert (fcls.n == 1);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "message_add_flags()\n");
+  GNUNET_assert (
+    GNUNET_OK == db->message_add_flags (db->cls, &channel_pub_key,
+                                        GNUNET_ntohll (msg->message_id),
+                                        GNUNET_PSYCSTORE_MESSAGE_STATE_APPLIED));
+  LOG (GNUNET_ERROR_TYPE_INFO, "fragment_get(%" PRIu64 ")\n", fragment_id);
+
+  fcls.n = 0;
+  fcls.flags[0] |= GNUNET_PSYCSTORE_MESSAGE_STATE_APPLIED;
+
+  GNUNET_assert (
+    GNUNET_OK == db->fragment_get (db->cls, &channel_pub_key,
+                                   fragment_id, fragment_id,
+                                   &ret_frags, fragment_cb, &fcls));
+
+  GNUNET_assert (fcls.n == 1);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "fragment_store()\n");
+
+  struct GNUNET_MULTICAST_MessageHeader *msg1
+    = GNUNET_malloc (sizeof (*msg1) + sizeof (channel_pub_key));
+
+  GNUNET_memcpy (msg1, msg, sizeof (*msg1) + sizeof (channel_pub_key));
+
+  msg1->fragment_id = GNUNET_htonll (INT64_MAX);
+  msg1->fragment_offset = GNUNET_htonll (32768);
+
+  fcls.n = 0;
+  fcls.msg[1] = msg1;
+  fcls.flags[1] = GNUNET_PSYCSTORE_MESSAGE_STATE_HASH;
+
+  GNUNET_assert (GNUNET_OK == db->fragment_store (db->cls, &channel_pub_key, msg1,
+                                                  fcls.flags[1]));
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "message_get()\n");
+
+  GNUNET_assert (
+    GNUNET_OK == db->message_get (db->cls, &channel_pub_key,
+                                  message_id, message_id, 0,
+                                  &ret_frags, fragment_cb, &fcls));
+  GNUNET_assert (fcls.n == 2 && ret_frags == 2);
+
+  /* Message counters */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "counters_message_get()\n");
+
+  fragment_id = 0;
+  message_id = 0;
+  group_generation = 0;
+  GNUNET_assert (
+    GNUNET_OK == db->counters_message_get (db->cls, &channel_pub_key,
+                                           &fragment_id, &message_id,
+                                           &group_generation)
+    && fragment_id == GNUNET_ntohll (msg1->fragment_id)
+    && message_id == GNUNET_ntohll (msg1->message_id)
+    && group_generation == GNUNET_ntohll (msg1->group_generation));
+
+  /* Modify state */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "STATE\n");
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_modify_*()\n");
+
+  message_id = GNUNET_ntohll (fcls.msg[0]->message_id) + 1;
+  GNUNET_assert (GNUNET_OK == db->state_modify_begin (db->cls, &channel_pub_key,
+                                                      message_id, 0));
+
+  GNUNET_assert (GNUNET_OK == db->state_modify_op (db->cls, &channel_pub_key,
+                                                   GNUNET_PSYC_OP_ASSIGN,
+                                                   "_foo",
+                                                   C2ARG("one two three")));
+
+  GNUNET_assert (GNUNET_OK == db->state_modify_op (db->cls, &channel_pub_key,
+                                                   GNUNET_PSYC_OP_ASSIGN,
+                                                   "_foo_bar", slave_key,
+                                                   sizeof (*slave_key)));
+
+  GNUNET_assert (GNUNET_OK == db->state_modify_end (db->cls, &channel_pub_key,
+                                                    message_id));
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_get()\n");
+
+  struct StateClosure scls = { 0 };
+  scls.n = 0;
+  scls.value[0] = "one two three";
+  scls.value_size[0] = strlen ("one two three");
+
+  GNUNET_assert (GNUNET_OK == db->state_get (db->cls, &channel_pub_key, "_foo",
+                                             state_cb, &scls));
+  GNUNET_assert (scls.n == 1);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_get_prefix()\n");
+
+  scls.n = 0;
+  scls.value[1] = slave_key;
+  scls.value_size[1] = sizeof (*slave_key);
+
+  GNUNET_assert (GNUNET_OK == db->state_get_prefix (db->cls, &channel_pub_key,
+                                                    "_foo", state_cb, &scls));
+  GNUNET_assert (scls.n == 2);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_get_signed()\n");
+
+  scls.n = 0;
+  GNUNET_assert (GNUNET_NO == db->state_get_signed (db->cls, &channel_pub_key,
+                                                    state_cb, &scls));
+  GNUNET_assert (scls.n == 0);
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_update_signed()\n");
+
+  GNUNET_assert (GNUNET_OK == db->state_update_signed (db->cls,
+                                                       &channel_pub_key));
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_get_signed()\n");
+
+  scls.n = 0;
+  GNUNET_assert (GNUNET_YES == db->state_get_signed (db->cls, &channel_pub_key,
+                                                     state_cb, &scls));
+  GNUNET_assert (scls.n == 2);
+
+  /* State counters */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "counters_state_get()\n");
+
+  uint64_t max_state_msg_id = 0;
+  GNUNET_assert (GNUNET_OK == db->counters_state_get (db->cls, &channel_pub_key,
+                                                      &max_state_msg_id)
+                 && max_state_msg_id == message_id);
+
+  /* State sync */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_sync_*()\n");
+
+  scls.n = 0;
+  scls.value[0] = channel_key;
+  scls.value_size[0] = sizeof (*channel_key);
+  scls.value[1] = "three two one";
+  scls.value_size[1] = strlen ("three two one");
+
+  GNUNET_assert (GNUNET_OK == db->state_sync_begin (db->cls, &channel_pub_key));
+
+  GNUNET_assert (GNUNET_OK == db->state_sync_assign (db->cls, &channel_pub_key,
+                                                     "_sync_bar", scls.value[0],
+                                                     scls.value_size[0]));
+
+  GNUNET_assert (GNUNET_OK == db->state_sync_assign (db->cls, &channel_pub_key,
+                                                     "_sync_foo", scls.value[1],
+                                                     scls.value_size[1]));
+
+  GNUNET_assert (GNUNET_OK == db->state_sync_end (db->cls, &channel_pub_key,
+                                                  max_state_msg_id,
+                                                  INT64_MAX - 5));
+
+  GNUNET_assert (GNUNET_NO == db->state_get_prefix (db->cls, &channel_pub_key,
+                                                    "_foo", state_cb, &scls));
+  GNUNET_assert (scls.n == 0);
+
+  GNUNET_assert (GNUNET_OK == db->state_get_prefix (db->cls, &channel_pub_key,
+                                                    "_sync", state_cb, &scls));
+  GNUNET_assert (scls.n == 2);
+
+  scls.n = 0;
+  GNUNET_assert (GNUNET_OK == db->state_get_signed (db->cls, &channel_pub_key,
+                                                    state_cb, &scls));
+  GNUNET_assert (scls.n == 2);
+
+  /* Modify state after sync */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_modify_*()\n");
+
+  message_id = GNUNET_ntohll (fcls.msg[0]->message_id) + 6;
+  GNUNET_assert (GNUNET_OK == db->state_modify_begin (db->cls, &channel_pub_key,
+                                                      message_id,
+                                                      message_id - max_state_msg_id));
+
+  GNUNET_assert (GNUNET_OK == db->state_modify_op (db->cls, &channel_pub_key,
+                                                   GNUNET_PSYC_OP_ASSIGN,
+                                                   "_sync_foo",
+                                                   C2ARG("five six seven")));
+
+  GNUNET_assert (GNUNET_OK == db->state_modify_end (db->cls, &channel_pub_key,
+                                                    message_id));
+
+  /* Reset state */
+
+  LOG (GNUNET_ERROR_TYPE_INFO, "state_reset()\n");
+
+  scls.n = 0;
+  GNUNET_assert (GNUNET_OK == db->state_reset (db->cls, &channel_pub_key));
+  GNUNET_assert (scls.n == 0);
+
+  ok = 0;
+
+  if (NULL != channel_key)
+  {
+    GNUNET_free (channel_key);
+    channel_key = NULL;
+  }
+  if (NULL != slave_key)
+  {
+    GNUNET_free (slave_key);
+    slave_key = NULL;
+  }
+
+  unload_plugin (db);
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  char cfg_name[128];
+  char *const xargv[] = {
+    "test-plugin-psycstore",
+    "-c", cfg_name,
+    "-L", LOG_LEVEL,
+    NULL
+  };
+  struct GNUNET_GETOPT_CommandLineOption options[] = {
+    GNUNET_GETOPT_OPTION_END
+  };
+  GNUNET_DISK_directory_remove ("/tmp/gnunet-test-plugin-psycstore-sqlite");
+  GNUNET_log_setup ("test-plugin-psycstore", LOG_LEVEL, NULL);
+  plugin_name = GNUNET_TESTING_get_testname_from_underscore (argv[0]);
+  GNUNET_snprintf (cfg_name, sizeof (cfg_name), "test_plugin_psycstore_%s.conf",
+                   plugin_name);
+  GNUNET_PROGRAM_run ((sizeof (xargv) / sizeof (char *)) - 1, xargv,
+                      "test-plugin-psycstore", "nohelp", options, &run, NULL);
+
+  if ( (0 != ok) &&
+       (77 != ok) )
+    FPRINTF (stderr, "Missed some testcases: %d\n", ok);
+
+#if ! DEBUG_PSYCSTORE
+  GNUNET_DISK_directory_remove ("/tmp/gnunet-test-plugin-psycstore-sqlite");
+#endif
+
+  return ok;
+}
+
+/* end of test_plugin_psycstore.c */
diff --git a/src/psycstore/test_plugin_psycstore_mysql.conf b/src/psycstore/test_plugin_psycstore_mysql.conf
new file mode 100644
index 0000000..e15b3fd
--- /dev/null
+++ b/src/psycstore/test_plugin_psycstore_mysql.conf
@@ -0,0 +1,7 @@
+[psycstore-mysql]
+DATABASE = test
+# CONFIG = ~/.my.cnf
+# USER = gnunet
+# PASSWORD =
+# HOST = localhost
+# PORT = 3306
diff --git a/src/psycstore/test_plugin_psycstore_postgres.conf b/src/psycstore/test_plugin_psycstore_postgres.conf
new file mode 100644
index 0000000..4b870dd
--- /dev/null
+++ b/src/psycstore/test_plugin_psycstore_postgres.conf
@@ -0,0 +1,2 @@
+[psycstore-postgres]
+CONFIG = connect_timeout=10; dbname=template1
diff --git a/src/psycstore/test_plugin_psycstore_sqlite.conf b/src/psycstore/test_plugin_psycstore_sqlite.conf
new file mode 100644
index 0000000..498b1d0
--- /dev/null
+++ b/src/psycstore/test_plugin_psycstore_sqlite.conf
@@ -0,0 +1,2 @@
+[psycstore-sqlite]
+FILENAME = $GNUNET_TMP/gnunet-test-plugin-psycstore-sqlite/sqlite.db
diff --git a/src/psycstore/test_psycstore.c b/src/psycstore/test_psycstore.c
new file mode 100644
index 0000000..ca50904
--- /dev/null
+++ b/src/psycstore/test_psycstore.c
@@ -0,0 +1,586 @@
+/*
+ * This file is part of GNUnet
+ * Copyright (C) 2013 GNUnet e.V.
+ *
+ * GNUnet is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * GNUnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file psycstore/test_psycstore.c
+ * @brief Test for the PSYCstore service.
+ * @author Gabor X Toth
+ * @author Christian Grothoff
+ */
+
+#include <inttypes.h>
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_common.h"
+#include "gnunet_testing_lib.h"
+#include "gnunet_psycstore_service.h"
+
+#define TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)
+
+
+/**
+ * Return value from 'main'.
+ */
+static int res;
+
+/**
+ * Handle to PSYCstore service.
+ */
+static struct GNUNET_PSYCSTORE_Handle *h;
+
+/**
+ * Handle to PSYCstore operation.
+ */
+static struct GNUNET_PSYCSTORE_OperationHandle *op;
+
+/**
+ * Handle for task for timeout termination.
+ */
+static struct GNUNET_SCHEDULER_Task *end_badly_task;
+
+static struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key;
+static struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key;
+
+static struct GNUNET_CRYPTO_EddsaPublicKey channel_pub_key;
+static struct GNUNET_CRYPTO_EcdsaPublicKey slave_pub_key;
+
+static struct FragmentClosure
+{
+  uint8_t n;
+  uint8_t n_expected;
+  uint64_t flags[16];
+  struct GNUNET_MULTICAST_MessageHeader *msg[16];
+} fcls;
+
+struct StateClosure {
+  size_t n;
+  char *name[16];
+  void *value[16];
+  size_t value_size[16];
+} scls;
+
+static struct GNUNET_PSYC_Modifier modifiers[16];
+
+/**
+ * Clean up all resources used.
+ */
+static void
+cleanup ()
+{
+  if (NULL != op)
+  {
+    GNUNET_PSYCSTORE_operation_cancel (op);
+    op = NULL;
+  }
+  if (NULL != h)
+  {
+    GNUNET_PSYCSTORE_disconnect (h);
+    h = NULL;
+  }
+  if (NULL != channel_key)
+  {
+    GNUNET_free (channel_key);
+    channel_key = NULL;
+  }
+  if (NULL != slave_key)
+  {
+    GNUNET_free (slave_key);
+    slave_key = NULL;
+  }
+  GNUNET_SCHEDULER_shutdown ();
+}
+
+
+/**
+ * Terminate the testcase (failure).
+ *
+ * @param cls NULL
+ */
+static void
+end_badly (void *cls)
+{
+  res = 1;
+  cleanup ();
+}
+
+
+/**
+ * Terminate the testcase (success).
+ *
+ * @param cls NULL
+ */
+static void
+end_normally (void *cls)
+{
+  res = 0;
+  cleanup ();
+}
+
+
+/**
+ * Finish the testcase (successfully).
+ */
+static void
+end ()
+{
+  if (NULL != end_badly_task)
+  {
+    GNUNET_SCHEDULER_cancel (end_badly_task);
+    end_badly_task = NULL;
+  }
+  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS,
+				&end_normally, NULL);
+}
+
+
+static void
+state_reset_result (void *cls,
+                    int64_t result,
+                    const char *err_msg,
+                    uint16_t err_msg_size)
+{
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+              "state_reset_result:\t%d\n",
+              (int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  op = GNUNET_PSYCSTORE_state_reset (h, &channel_pub_key,
+                                     &state_reset_result, cls);
+  GNUNET_PSYCSTORE_operation_cancel (op);
+  op = NULL;
+  end ();
+}
+
+
+static int
+state_result (void *cls,
+              const char *name,
+              const void *value,
+              uint32_t value_size)
+{
+  struct StateClosure *scls = cls;
+  const char *nam = scls->name[scls->n];
+  const void *val = scls->value[scls->n];
+  size_t val_size = scls->value_size[scls->n++];
+
+  if (value_size == val_size
+      && 0 == memcmp (value, val, val_size)
+      && 0 == strcmp (name, nam))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "  variable %s matches\n",
+                name);
+    return GNUNET_YES;
+  }
+  else
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "  variable %s differs\nReceived: %.*s\nExpected: %.*s\n",
+                name, (int) value_size, (char*) value, (int) val_size, (char*) val);
+    GNUNET_assert (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+static void
+state_get_prefix_result (void *cls, int64_t result,
+                         const char *err_msg, uint16_t err_msg_size)
+{
+  struct StateClosure *scls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "state_get_prefix_result:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result && 2 == scls->n);
+
+  op = GNUNET_PSYCSTORE_state_reset (h, &channel_pub_key,
+                                     &state_reset_result, cls);
+}
+
+
+static void
+state_get_result (void *cls, int64_t result,
+                  const char *err_msg, uint16_t err_msg_size)
+{
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "state_get_result:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  scls.n = 0;
+
+  scls.name[0] = "_sync_bar";
+  scls.value[0] = "ten eleven twelve";
+  scls.value_size[0] = sizeof ("ten eleven twelve") - 1;
+
+  scls.name[1] = "_sync_foo";
+  scls.value[1] = "three two one";
+  scls.value_size[1] = sizeof ("three two one") - 1;
+
+  op = GNUNET_PSYCSTORE_state_get_prefix (h, &channel_pub_key, "_sync",
+                                          &state_result,
+                                          &state_get_prefix_result, &scls);
+}
+
+
+static void
+counters_result (void *cls, int status, uint64_t max_fragment_id,
+                 uint64_t max_message_id, uint64_t max_group_generation,
+                 uint64_t max_state_message_id)
+{
+  struct FragmentClosure *fcls = cls;
+  int result = 0;
+  op = NULL;
+
+  if (GNUNET_OK == status
+      && max_fragment_id == GNUNET_ntohll (fcls->msg[2]->fragment_id)
+      && max_message_id == GNUNET_ntohll (fcls->msg[2]->message_id)
+      && max_group_generation == GNUNET_ntohll (fcls->msg[2]->group_generation)
+      && max_state_message_id == GNUNET_ntohll (fcls->msg[0]->message_id))
+    result = 1;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "counters_get:\t%d\n", result);
+  GNUNET_assert (result == 1);
+
+  scls.n = 0;
+  scls.name[0] = "_sync_bar";
+  scls.value[0] = "ten eleven twelve";
+  scls.value_size[0] = sizeof ("ten eleven twelve") - 1;
+
+  op = GNUNET_PSYCSTORE_state_get (h, &channel_pub_key, "_sync_bar_x_yy_zzz",
+                                   &state_result, &state_get_result, &scls);
+}
+
+
+static void
+state_modify_result (void *cls, int64_t result,
+                     const char *err_msg, uint16_t err_msg_size)
+{
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "state_modify_result:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  op = GNUNET_PSYCSTORE_counters_get (h, &channel_pub_key,
+                                      &counters_result, cls);
+}
+
+
+static void
+state_sync_result (void *cls, int64_t result,
+                   const char *err_msg, uint16_t err_msg_size)
+{
+  struct FragmentClosure *fcls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "state_sync_result:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  op = GNUNET_PSYCSTORE_state_modify (h, &channel_pub_key,
+                                      GNUNET_ntohll (fcls->msg[0]->message_id),
+                                      0, state_modify_result, fcls);
+}
+
+
+static int
+fragment_result (void *cls,
+                 struct GNUNET_MULTICAST_MessageHeader *msg,
+                 enum GNUNET_PSYCSTORE_MessageFlags flags)
+{
+  struct FragmentClosure *fcls = cls;
+  GNUNET_assert (fcls->n < fcls->n_expected);
+  struct GNUNET_MULTICAST_MessageHeader *msg0 = fcls->msg[fcls->n];
+  uint64_t flags0 = fcls->flags[fcls->n++];
+
+  if (flags == flags0 && msg->header.size == msg0->header.size
+      && 0 == memcmp (msg, msg0, ntohs (msg->header.size)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "  fragment %" PRIu64 " matches\n",
+                GNUNET_ntohll (msg->fragment_id));
+    return GNUNET_YES;
+  }
+  else
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "  fragment differs: expected %" PRIu64 ", got %" PRIu64 "\n",
+                GNUNET_ntohll (msg0->fragment_id),
+                GNUNET_ntohll (msg->fragment_id));
+    GNUNET_assert (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+static void
+message_get_latest_result (void *cls, int64_t result,
+                           const char *err_msg, uint16_t err_msg_size)
+{
+  struct FragmentClosure *fcls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "message_get_latest:\t%ld\n", (long int) result);
+  GNUNET_assert (0 < result && fcls->n == fcls->n_expected);
+
+  modifiers[0] = (struct GNUNET_PSYC_Modifier) {
+    .oper = '=',
+    .name = "_sync_foo",
+    .value = "three two one",
+    .value_size = sizeof ("three two one") - 1
+  };
+  modifiers[1] = (struct GNUNET_PSYC_Modifier) {
+    .oper = '=',
+    .name = "_sync_bar",
+    .value = "ten eleven twelve",
+    .value_size = sizeof ("ten eleven twelve") - 1
+  };
+
+  op = GNUNET_PSYCSTORE_state_sync (h, &channel_pub_key,
+                                    GNUNET_ntohll (fcls->msg[0]->message_id) + 1,
+                                    GNUNET_ntohll (fcls->msg[0]->message_id) + 2,
+                                    2, modifiers, state_sync_result, fcls);
+}
+
+
+static void
+message_get_result (void *cls, int64_t result,
+                    const char *err_msg, uint16_t err_msg_size)
+{
+  struct FragmentClosure *fcls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "message_get:\t%ld\n", (long int) result);
+  GNUNET_assert (0 < result && fcls->n == fcls->n_expected);
+
+  fcls->n = 0;
+  fcls->n_expected = 3;
+  op = GNUNET_PSYCSTORE_message_get_latest (h, &channel_pub_key, &slave_pub_key,
+                                            1, "", &fragment_result,
+                                            &message_get_latest_result, fcls);
+}
+
+
+static void
+message_get_fragment_result (void *cls, int64_t result,
+                             const char *err_msg, uint16_t err_msg_size)
+{
+  struct FragmentClosure *fcls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "message_get_fragment:\t%ld\n", (long int) result);
+  GNUNET_assert (0 < result && fcls->n == fcls->n_expected);
+
+  fcls->n = 0;
+  fcls->n_expected = 3;
+  uint64_t message_id = GNUNET_ntohll (fcls->msg[0]->message_id);
+  op = GNUNET_PSYCSTORE_message_get (h, &channel_pub_key, &slave_pub_key,
+                                     message_id, message_id, 0, "",
+                                     &fragment_result,
+                                     &message_get_result, fcls);
+}
+
+
+static void
+fragment_get_latest_result (void *cls, int64_t result,
+                            const char *err_msg, uint16_t err_msg_size)
+{
+  struct FragmentClosure *fcls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "fragment_get_latest:\t%ld\n", (long int) result);
+  GNUNET_assert (0 < result && fcls->n == fcls->n_expected);
+
+  fcls->n = 1;
+  fcls->n_expected = 2;
+  op = GNUNET_PSYCSTORE_message_get_fragment (h, &channel_pub_key, &slave_pub_key,
+                                              GNUNET_ntohll (fcls->msg[1]->message_id),
+                                              GNUNET_ntohll (fcls->msg[1]->fragment_offset),
+                                              &fragment_result,
+                                              &message_get_fragment_result, fcls);
+}
+
+
+static void
+fragment_get_result (void *cls, int64_t result,
+                     const char *err_msg, uint16_t err_msg_size)
+{
+  struct FragmentClosure *fcls = cls;
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+              "fragment_get:\t%d\n",
+              (int) result);
+  GNUNET_assert (0 < result && fcls->n == fcls->n_expected);
+
+  fcls->n = 0;
+  fcls->n_expected = 3;
+  op = GNUNET_PSYCSTORE_fragment_get_latest (h, &channel_pub_key,
+                                             &slave_pub_key, fcls->n_expected,
+                                             &fragment_result,
+                                             &fragment_get_latest_result, fcls);
+}
+
+
+static void
+fragment_store_result (void *cls, int64_t result,
+                       const char *err_msg, uint16_t err_msg_size)
+{
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "fragment_store:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  if ((intptr_t) cls == GNUNET_YES)
+  { /* last fragment */
+    fcls.n = 0;
+    fcls.n_expected = 1;
+    uint64_t fragment_id = GNUNET_ntohll (fcls.msg[0]->fragment_id);
+    op = GNUNET_PSYCSTORE_fragment_get (h, &channel_pub_key, &slave_pub_key,
+                                        fragment_id, fragment_id,
+                                        &fragment_result,
+                                        &fragment_get_result, &fcls);
+  }
+}
+
+
+static void
+fragment_store ()
+{
+  struct GNUNET_MULTICAST_MessageHeader *msg;
+  fcls.flags[0] = GNUNET_PSYCSTORE_MESSAGE_STATE;
+  fcls.msg[0] = msg = GNUNET_malloc (sizeof (*msg) + sizeof (channel_pub_key));
+  GNUNET_assert (msg != NULL);
+
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_MULTICAST_MESSAGE);
+  msg->header.size = htons (sizeof (*msg) + sizeof (channel_pub_key));
+
+  msg->hop_counter = htonl (9);
+  msg->fragment_id = GNUNET_htonll (INT64_MAX - 8);
+  msg->fragment_offset = GNUNET_htonll (0);
+  msg->message_id = GNUNET_htonll (INT64_MAX - 10);
+  msg->group_generation = GNUNET_htonll (INT64_MAX - 3);
+  msg->flags = htonl (GNUNET_MULTICAST_MESSAGE_LAST_FRAGMENT);
+
+  GNUNET_memcpy (&msg[1], &channel_pub_key, sizeof (channel_pub_key));
+
+  msg->purpose.size = htonl (ntohs (msg->header.size)
+                             - sizeof (msg->header)
+                             - sizeof (msg->hop_counter)
+                             - sizeof (msg->signature));
+  msg->purpose.purpose = htonl (234);
+  GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_eddsa_sign (channel_key, &msg->purpose,
+                                                        &msg->signature));
+
+  op = GNUNET_PSYCSTORE_fragment_store (h, &channel_pub_key, msg, fcls.flags[0],
+                                        &fragment_store_result, GNUNET_NO);
+
+  fcls.flags[1] = GNUNET_PSYCSTORE_MESSAGE_STATE_APPLIED;
+  fcls.msg[1] = msg = GNUNET_malloc (sizeof (*msg) + sizeof (channel_pub_key));
+  GNUNET_memcpy (msg, fcls.msg[0], sizeof (*msg) + sizeof (channel_pub_key));
+  msg->fragment_id = GNUNET_htonll (INT64_MAX - 4);
+  msg->fragment_offset = GNUNET_htonll (1024);
+
+  op = GNUNET_PSYCSTORE_fragment_store (h, &channel_pub_key, msg, fcls.flags[1],
+                                        &fragment_store_result, GNUNET_NO);
+
+  fcls.flags[2] = GNUNET_PSYCSTORE_MESSAGE_STATE_HASH;
+  fcls.msg[2] = msg = GNUNET_malloc (sizeof (*msg) + sizeof (channel_pub_key));
+  GNUNET_memcpy (msg, fcls.msg[1], sizeof (*msg) + sizeof (channel_pub_key));
+  msg->fragment_id = GNUNET_htonll (INT64_MAX);
+  msg->fragment_offset = GNUNET_htonll (16384);
+
+  op = GNUNET_PSYCSTORE_fragment_store (h, &channel_pub_key, msg, fcls.flags[2],
+                                        &fragment_store_result, (void *) GNUNET_YES);
+}
+
+
+static void
+membership_test_result (void *cls, int64_t result,
+                        const char *err_msg, uint16_t err_msg_size)
+{
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "membership_test:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  fragment_store ();
+}
+
+
+static void
+membership_store_result (void *cls, int64_t result,
+                         const char *err_msg, uint16_t err_msg_size)
+{
+  op = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "membership_store:\t%ld\n", (long int) result);
+  GNUNET_assert (GNUNET_OK == result);
+
+  op = GNUNET_PSYCSTORE_membership_test (h, &channel_pub_key, &slave_pub_key,
+                                         INT64_MAX - 10, 2,
+                                         &membership_test_result, NULL);
+}
+
+
+/**
+ * Main function of the test, run from scheduler.
+ *
+ * @param cls NULL
+ * @param cfg configuration we use (also to connect to PSYCstore service)
+ * @param peer handle to access more of the peer (not used)
+ */
+static void
+#if DEBUG_TEST_PSYCSTORE
+run (void *cls, char *const *args, const char *cfgfile,
+     const struct GNUNET_CONFIGURATION_Handle *cfg)
+#else
+run (void *cls,
+     const struct GNUNET_CONFIGURATION_Handle *cfg,
+     struct GNUNET_TESTING_Peer *peer)
+#endif
+{
+  end_badly_task = GNUNET_SCHEDULER_add_delayed (TIMEOUT, &end_badly, NULL);
+
+  h = GNUNET_PSYCSTORE_connect (cfg);
+  GNUNET_assert (NULL != h);
+
+  channel_key = GNUNET_CRYPTO_eddsa_key_create ();
+  slave_key = GNUNET_CRYPTO_ecdsa_key_create ();
+
+  GNUNET_CRYPTO_eddsa_key_get_public (channel_key, &channel_pub_key);
+  GNUNET_CRYPTO_ecdsa_key_get_public (slave_key, &slave_pub_key);
+
+  op = GNUNET_PSYCSTORE_membership_store (h, &channel_pub_key, &slave_pub_key,
+                                          GNUNET_YES, INT64_MAX - 5,
+                                          INT64_MAX - 10, 2,
+                                          &membership_store_result, NULL);
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  res = 1;
+#if DEBUG_TEST_PSYCSTORE
+  const struct GNUNET_GETOPT_CommandLineOption opts[] = {
+    GNUNET_GETOPT_OPTION_END
+  };
+  if (GNUNET_OK != GNUNET_PROGRAM_run (argc, argv, "test-psycstore",
+                                       "test-psycstore [options]",
+                                       opts, &run, NULL))
+    return 1;
+#else
+  if (0 != GNUNET_TESTING_service_run ("test-psycstore", "psycstore",
+                                       "test_psycstore.conf", &run, NULL))
+    return 1;
+#endif
+  return res;
+}
+
+/* end of test_psycstore.c */
diff --git a/src/psycstore/test_psycstore.conf b/src/psycstore/test_psycstore.conf
new file mode 100644
index 0000000..fa7c2d0
--- /dev/null
+++ b/src/psycstore/test_psycstore.conf
@@ -0,0 +1,8 @@
+[PATHS]
+GNUNET_TEST_HOME = $GNUNET_TMP/test-gnunet-psycstore/
+
+[psycstore]
+DATABASE = sqlite
+
+[psycstore-sqlite]
+FILENAME = $GNUNET_TEST_HOME/psycstore/sqlite.db