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From "Marinko, Jeff" <>
Subject RE: Checking Tomcat's Memory
Date Thu, 15 Aug 2002 17:43:57 GMT
Heh, the answer to that is "kind of".  I can actually do roughly 250 TPS (at
least according to a tool I'm using) for about 10-20 thousand requests, but
I think this memory problem is giving me trouble after that.  I thought it
was a connections problem (I was getting connection errors from the tool),
then I thought I had screwed something up in my code (and I've tried
different versions, nothing seems to affect performance), then I noticed the
memory never went above ~154 MB, so now I'm examining memory issues.

My problem is still the same, after so many requests (and thus some amount
of information stored in memory), Tomcat starts to use up a whole lot of CPU
time.  I think I hit the memory limit (as I get out of memory errors), so
I'm trying to increase the memory Tomcat has, without much luck.

I set the environment variable (as I mentioned before), but it does not
appear to be working.  I stopped and restarted Tomcat after doing this
(although I have not restarted Windows) and the results were the same, no
change in memory.... I'm still working on it though, still have a couple
more things to try, if anyone has a good suggestions, feel free to chime in!


-----Original Message-----
From: Sexton, George []
Sent: Thursday, August 15, 2002 10:34 AM
To: Tomcat Users List
Subject: RE: Checking Tomcat's Memory

So, did you get past to your 200 TPS limit goal?

-----Original Message-----
From: Marinko, Jeff []
Sent: 15 August, 2002 10:49 AM
To: Tomcat Users List
Subject: Checking Tomcat's Memory


I'm running Tomcat 4.0.4 (w/ JDK 1.4, WinNT/2K) and would like to know how
to check Tomcat's memory settings.  I've defined an environment variable (in
Windows) like so:

CATALINA_OPTS=-server -Xms1g -Xmx3g

and from reading previous e-mails on this list, this should set the JVM min
and max heap size, yet how can I verify this?

I'm currently testing a program that takes a considerable amount of memory,
and after getting so many thousand requests (and storing a considerable
amount of data in memory), the performance becomes horrible (3 to 4 times
CPU usage, possibly due to gc looking for more memory?).  I suspect the
memory settings because when the CPU usage starts to spike, the memory usage
tops off and does not appear to go up at all (when it most likely should
continue to go up).

Suggestions appreciated!

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