29 May
2008
29 May
'08
9:02 p.m.
Notice that PermGen space is not java heap.
Therefore I suppose it is unlikely to have anything to do with attachment.
Not in this case.
You may want to check if other web applications are deployed to your tomcat
instance - and if they use many classes/libs.
Then you may want to increase the "-XX:MaxPermSize" or undeploy some
webapps.
Pavel
On Thu, May 29, 2008 at 9:16 PM, Richard V. <xgcom(a)hotmail.com> wrote:
Thanks for the prompt response.
The answer regarding to large attachments is no. I don't have any large
attachments in any of my pages.
The "out-of-memory" error happens without any page in common, but when that
happens, any other page that I want to access will result with the same
error. It is like once memory has run out, it is unrecoverable.
You may be right regarding to the DB connections threads not receiving the
shutdown message, but that does not explain why i can't properly shutdown
tomcat with XWiki deployed. Again, Tomcat shutdows smoothly when XWiki is
not present. I don't mind not being able to gracefully shutdown tomcat,
since i can always do "kill -9 <pid>", but what annoys me is the
out-of-memory error after certain time.
What could be the problem? This is happening on my development machine, but
I am going to build another Linux machine right now and try if I can
replicate the problem.
Richard
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Date: Thu, 29 May 2008 19:46:20 +0200
From: sergiu(a)xwiki.com
To: users(a)xwiki.org
Subject: Re: [xwiki-users] Xwiki memory leak?
Richard V. wrote:
>
> Hi XWiki users,
>
> I have encountered a problem where after running XWiki on my tomcat
server
for a week, i get an java.lang.OutOfMemoryError: PermGen space error.
It appears that xwiki consumed all the java heap space. I believe the
problem may be related to unreleased DB connections because, I noticed that
everytime I try to shutdown tomcat, it hangs with xwiki deployed, also by
running "ps aux" i see the postgresql connection processes belonging to
xwiki still running. I tried deploying another application that uses
hibernate + postgresql on the same tomcat running xwiki, and upon shutting
down the server, all db connection processes from the other application
gracefully terminate but not the ones from xwiki.
>
> My question is does anyone ever had this problem before? If so what is
the
solution?
Solutions
that I have tried but did NOT work:
1- Increase java heap with -Xmx512m
2- Reduce the maximum and minimum idle DB connections
My system specs:
OS: Linux ubuntu kernel 2.6.20
Java: 1.6.0_05-13
Xwiki: 1.4 (binary distribution)
Posgresql: 8.2.6
Total RAM: 1Gb
AFAIK, there isn't a leak, but a somewhat "normal" behavior caused by
the cache settings. The cache is configured to be a fixed size LRU
cache, so if you store large entries in the cache, they will be kept
there. The OOM error appears mostly when there are large attachments in
the database. You should either reduce the size of the attachment cache
or increase the memory.
The shutdown problem is a different thing, it doesn't have anything to
do with the database connections. I think it is because of some threads
we're spawning that don't receive the shutdown message (the quartz
scheduler for example). A memory leak regarding DB connections would
mean there are thousands of open connections to the database, but I am
pretty sure that's not the case, right?
So, the main question is: Are there many & pretty large attachments in
the wiki?
--
Sergiu Dumitriu
http://purl.org/net/sergiu/
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