Yesterday, I indeed upgraded another server box to Apache 2.0.59, mod_jk
1.2.20, Tomcat 5.5.17, and also set the connection_pool_timeout=600 (is that
value 600 seconds, or milliseconds?). I then subjected this server to a
brief stresstest (roughly 50 simultanious HTTP sessions on Tomcat's end) and
noticed the following:

Of the two 'Apache.exe' processes running under the Apache2 NT service, one
grew in memory usage quickly from an initial 12MB to nearly 65MB, and stayed
at that level overnight, even though there were no further requests made to
that server since yesterday. I also noticed that a simple 'netstat -a'
reported 35 established connections:

<<
TCP   DAOHPRW2:1682       DAOHPRW2.essex.ac.uk:8009 ESTABLISHED
TCP   DAOHPRW2:4240       DAOHPRW2.essex.ac.uk:8009 ESTABLISHED
TCP   DAOHPRW2:4241       DAOHPRW2.essex.ac.uk:8009 ESTABLISHED
.....
>>

and another 35 established connection the opposite direction:

<<
TCP   DAOHPRW2:8009       DAOHPRW2.essex.ac.uk:1682 ESTABLISHED
TCP   DAOHPRW2:8009       DAOHPRW2.essex.ac.uk:4240 ESTABLISHED
TCP   DAOHPRW2:8009       DAOHPRW2.essex.ac.uk:4241 ESTABLISHED
....
>>

So, are the connections managed by mod_jk between Apache2 and Tomcat not
released from the connection pool, despite the connection_pool_timeout=600?

Ideally I'd like to set an upper limit of lets say 200 concurrent HTTP
Sessions for Tomcat, but I am not sure how exactly to configure the various
timeout values and limits for mod_jk and Apache accordingly. Our Tomcat
service makes MySQL queries and it can take at times a few seconds for
generating a response. Does Apache2 use just one child process handling all
requests or connections?

J.Neuhoff




P.S.
At the moment our server is configured like that:

httpd.conf:

<<
....
Timeout 300
KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 15
# WinNT MPM
# ThreadsPerChild: constant number of worker threads in the server process
# MaxRequestsPerChild: maximum number of requests a server process serves
<IfModule mpm_winnt.c>
ThreadsPerChild 250
MaxRequestsPerChild 0
</IfModule>
....
### mod_jk 1.x configuration for connecting to Tomcat 5.5
LoadModule   jk_module modules/mod_jk.so
JkWorkersFile "C:/Program Files/Apache Software Foundation/Tomcat
5.5/conf/workers.properties"
JkLogFile   "C:/Program Files/Apache Software Foundation/Tomcat
5.5/logs/mod_jk.log"
JkLogLevel   info
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
JkOptions   +ForwardKeySize +ForwardURICompat -ForwardDirectories
JkRequestLogFormat   "%w %V %T %r %s"
JkMount /jsp-examples/* ajp13
JkMount /servletsp-examples/* ajp13
JkMount /manager/* ajp13
JkMount /ohpr/* ajp13
JkMount /demo-b/* ajp13
....
>>

workers.properties:

<<
# Define 1 real worker using ajp13
worker.list=ajp13
# Set properties for worker1 (ajp13)
worker.ajp13.type=ajp13
worker.ajp13.host=localhost
worker.ajp13.port=8009
worker.ajp13.connection_pool_timeout=600
>>

--
Sent from the Tomcat - User mailing list archive at Nabble.com.


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