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From Glenn Nielsen <>
Subject Re: socket errors in catalina.out and mod_jk.log
Date Thu, 27 Feb 2003 21:47:52 GMT
Henri Gomez wrote:
> Sven Köhler wrote:
> When Apache will be closing connections at a high rate, you make Tomcat
> spend precious cycle to catch exceptions, and so you'll slow tomcat also.
>>> FYI, Apache close ajp13 connections each time it recycle/kill a child
>>> and under heavy load on webserver, it happen very often.

I also dislike how mod_jk handles ajp socket connections.

There is another problem with how mod_jk handles the ajp connetor sockets.
That is the one to one mapping of apache child process to an ajp connector.
On an apache server that serves normal http requests you can end up with
many idle socket connections to Tomcat, and Tomcat will spawn many more
Connector threads than it needs to handle the request volume.

I have been toying with the idea of implementing a global worker socket
connection pool using APR for the Apache 2 version of mod_jk 1.2.
A global pool would allow the sockets to survive a child exit so they
don't have to be closed/reopened.  This would also reduce the number of
socket connections and Tomcat Connectors to the bare miniumum needed to
handle the request volume.

This would get rid of the "normal operation" exceptions and would not
require changing the AJP protocol.

This could also be done with mod_jk for Apache 1.3 if a dependency on
the APR were added.

In the end, I think this is the best solution.



>> that makes it even worse.
> Contact new-httpd team ;)
>>> If the webserver has closed a connection, tomcat detect it has close the
>>> connection silently....

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