On 10/02/2010 20:11, Jordan Michaels wrote:
Hey Joseph,
Honestly I'm not sure about the code. We didn't write the code for it
and I haven't dug around in that part of it because the first few
requests seem to go through without a hitch.
If you've not checked the code then how can you tell whether you've able
to see any exceptions?
...
}
catch (Exception e) {
// TODO log errors later, when I remember
}
(It does happen)
You might check to see if the connection, etc is being properly closed.
You may be using up the maximum number of connections that the database
can handle. Depends on what the SQL query actually does.
p
We doubled the Xmx value from 512 to 1024 and added the MaxPermSize so
I've been going under the impression that if those were part of the
problem that I should be able to pull at least a few more hits out of
the page, right?
Warm regards,
Jordan Michaels
Vivio Technologies
http://www.viviotech.net/
Open BlueDragon Steering Committee
Railo Community Distributions
Joseph Morgan wrote:
Jordan,
It sounds to me like a memory issue as well, but you should see an
OutOfMemory error in the logs, or so I would think.
Is the page (or the actions within it) caching anything in the context
or session?
Joe
-----Original Message-----
From: Jordan Michaels [mailto:jor...@viviotech.net] Sent: Wednesday,
February 10, 2010 1:53 PM
To: users@tomcat.apache.org
Subject: JSP Page "hangs"... clues?
We have an interesting situation and I'm wondering if anyone has any
ideas on where we could look for possible solutions.
We have a JSP page that performs a large mysql query of product titles
(just the names). The list is then spit out on the page with
drill-down links. Pretty simple really. The problem is that just after
a tomcat restart, the first and occasionally the second and third
requests will process all the way just fine, but most subsequent
requests will "hang" on a random record. Occasionally one will go all
the way through, but most will hang.
Let me clarify, we restart tomcat, hit the page, and the page loads
fine. We hit refresh once or twice, and the page will fail to load
fully. The page will hang after a random product title and just stop
responding. You can click on any other page on the site, but this one
page with the large product listing query hangs in random spots.
We've studied this intently. The server this is running on is a CentOS
4, 32-bit box with 1.5 GB RAM, Apache 2, and mod_jk.
Our first thought was memory issues. We increased Tomcat's memory
using the setenv.sh file, which now contains the following line:
JAVA_OPTS="-Xms128m -Xmx1024m -Xss256m -XX:MaxPermSize=256m "; export
JAVA_OPTS
We've verified that the settings are in place by using the "ps ax"
command and making sure the java process includes the updated
settings. Unfortunately, this seems to have no effect at all.
We then reviewed the logs: catalina.out, mod_jk.log, and apache's
error_log, among others. We monitored these logs using "tail" so we
could see if any errors were thrown as we hit the page. No errors were
thrown if the request went through good or it failed. The logs were
completely quiet.
We've updated Tomcat, mod_jk, the JVM, and the MySQL driver to the
absolute latest versions available as of this writing.
Does anyone have any clues as to where we might look for what is
happening to make this one page hang? It still feels like a memory
issue, but with nothing in the logs and no indicators other then the
problem itself, we'd appreciate any suggestions on what to look for at
this point.
Thank you in advance!
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