Memory leak issue after restart of rails application in tomcat

Memory leak issue after restart of rails application in tomcat

Posted by Rakesh Arora (rakmoh)

on 2010-07-27 23:08

Hello,

I am debugging a memory leak issue after the restart of my rails 
application
in tomcat. I am using tomcat manager to stop and start the application.
Memory usage goes up after every restart and it becomes unusable after 
few
restarts. It is the only ruby/rails application that is deployed in 
tomcat.
When I used jstack to list java threads, I noticed that there are many 
jruby
threads running even after the application has been stopped. Number of
threads keeps growing after each restart.

I did try the following code to kill the threads:
at_exit do
  Thread.list.each { |t| Rails.logger.warn { "Thread Status is:
#{t.inspect}, #{t[:name]}, #{t.status}" } }
  Thread.list.each { |t| t.exit  unless t == Thread.current }
  Rails.logger.warn { "************EXITING**************" }
end

2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0x99dde9sleep>, synchronize_users, sleep
2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0x1b80d21sleep>, owner_audit, sleep
2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0x660d14run>, , run
2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0x1e4c027run>, , run
2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0x1036c7fsleep>, , sleep
2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0x1c814basleep>, flow_audit, sleep
2010-07-27 17:46:41,531 WARN  (            ?:?)     - Thread Status is:
#<Thread:0xc8e634run>, , run
2010-07-27 17:46:41,546 WARN  (            ?:?)     -
************EXITING**************

However, I still see lots of jruby threads in tomcat after stopping the
application and memory issue.

Here is my environment:
OS: Windows 2003
Jruby: 1.5.0
Tomcat: 6.0.18


Any idea how to resolve this issue?

Thanks,
-Rakesh

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Re: Memory leak issue after restart of rails application in tomcat

Posted by Rakesh Arora (rakmoh)

on 2010-07-29 06:41

I am still trying to figure out the root cause of the memory leak during
stop/restart/redeploy of application in tomcat.

I have very simple test rails application deployed in tomcat and 
analyzing
it using jconsole. I noticed that the number of classes goes up by about
3000 and memory usage goes up by about 40M for every restart. Also 
noticed
that every restart adds a new jruby runtime entry in jconsole
org.jruby->runtime (under MBean tab), so the jruby runtimes keeps 
growing. I
have the following in my application's web.xml file:
  <context-param>
    <param-name>jruby.max.runtimes</param-name>
    <param-value>1</param-value>
  </context-param>

  <context-param>
    <param-name>jruby.min.runtimes</param-name>
    <param-value>0</param-value>
  </context-param>

is this an issue? Any idea how I can fix this?

Thanks,
-Rakesh

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Re: Memory leak issue after restart of rails application in tomcat

Posted by Rakesh Arora (rakmoh)

on 2010-07-30 21:03

I am now using the latest jruby (snapshot) and trying to debug this 
issue.

- I have set jruby.max.runtimes and jruby.min.runtimes to 1 in web.xml.
However, I see two instances of runtime in jconsole. Is that an issue?
- After undeploying the app in tomcat, one instance of runtime is 
removed
but one instance remains. I confirmed that org.jruby.Ruby.tearDown is 
only
called once.
- If I don't set the jruby.max.runtimes and jruby.main.runtime in 
web.xml
the there is only instance of runtime. However, it remains there after
undeployment. I confimed that org.jruby.Ruby.tearDown is not called at 
all.

Is that Rack issue?

Thanks,
-Rakesh

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Re: Memory leak issue after restart of rails application in tomcat

Posted by Afterschool Carl (afterschoolcarl)

on 2010-07-31 00:25

Dude, let us absorb the first question before you ask 10 more.

Hope that helps!
Carl

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