[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2481?page=all ]
Paul Malolepsy updated HHH-2481:
--------------------------------
Attachment: fix.diff
Here is a diff of the fix for this issue as well as a test case.
Just to give an idea of how potentially bad this leak was, making this change had a
dramatic impact on the the memory use and performance of our servlet based web
application. Before, we had to max out the Xmx of our servlets at 2gb, and even still
we'd get OOM errors after about 6 hours under heavy stress testing. Now they run fine
at 500mb. This has also translated to some astonishing performance gains in the overall
performance of our app. I'd be very interested to see if other people have a similar
experience.
Big memory leak in the use of CGLIB
-----------------------------------
Key: HHH-2481
URL:
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2481
Project: Hibernate3
Type: Bug
Components: core
Versions: 3.2.2
Environment: Hibernate 3.2.2
MySQL 5.1
Reporter: Paul Malolepsy
Priority: Critical
Attachments: fix.diff
Original Estimate: 5 minutes
Remaining: 5 minutes
The way CGLIBLazyInitializer is creating proxies is resulting in a potentially massive
memory leak.
In CGLIBLazyInitializer.getProxy() just before the proxy is instantiated, a call is made
to Enhancer.registerCallbacks() passing in the instance of CGLIBLazyInitializer that will
manage the proxy. This variable is stored in a static ThreadLocal on the CGLIB created
persistentClass so that any subsequent objects instantiated will get this callback class.
The problem is that once this ThreadLocal is set, it is never cleared, so it will stay
around (together with the object it's managing, and whatever object graph it may be
connected to) until the next time a proxy is created for that type on that thread.
For our application we have about 150 different proxy types, and our app can have over
100 threads. This results in potentially 15,000 proxy objects and their graphs stuck in
memory.
The fix for this is simple. Just make another call the Enhancer.registerCallbacks() with
a null callback arg, right after the proxy class is instantiated:
Enhancer.registerCallbacks(factory, null);
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://opensource.atlassian.com/projects/hibernate/secure/Administrators....
-
For more information on JIRA, see:
http://www.atlassian.com/software/jira