commit 7a60acb3457388c22ae5dfdcbf100f197537618b
parent 37351b1556d577d2e0c5e58da583d3b8eab9c2ff
Author: Christian Grothoff <christian@grothoff.org>
Date: Mon, 16 Aug 2010 12:33:19 +0000
document problem DV had
Diffstat:
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/doc/microhttpd.texi b/doc/microhttpd.texi
@@ -311,7 +311,28 @@ Maximum number of concurrenct connections to accept (followed by an
@code{unsigned int}). The default is @code{FD_SETSIZE - 4} (the
maximum number of file descriptors supported by @code{select} minus
four for @code{stdin}, @code{stdout}, @code{stderr} and the server
-socket). In other words, the default is as large as possible.
+socket). In other words, the default is as large as possible.
+
+Note that if you set a low connection limit, you can easily get into
+trouble with browsers doing request pipelining. For example, if your
+connection limit is ``1'', a browser may open a first connection to
+access your ``index.html'' file, keep it open but use a second
+connection to retrieve CSS files, images and the like. In fact, modern
+browsers are typically by default configured for up to 15 parallel
+connections to a single server. If this happens, MHD will refuse to
+even accept the second connection until the first connection is
+closed --- which does not happen until timeout. As a result, the
+browser will fail to render the page and seem to hang. If you expect
+your server to operate close to the connection limit, you should
+first consider using a lower timeout value and also possibly add
+a ``Connection: close'' header to your response to ensure that
+request pipelining is not used and connections are closed immediately
+after the request has completed:
+@example
+MHD_add_response_header (response,
+ MHD_HTTP_HEADER_CONNECTION,
+ "close");
+@end example
@item MHD_OPTION_CONNECTION_TIMEOUT
@cindex timeout
