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https://issues.apache.org/jira/browse/DERBY-1781?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12535558
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Bryan Pendleton commented on DERBY-1781:
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> recap findings this far: 

Thomas, thanks very much for all the investigation and experimentation, it is 
very helpful!

I think you should assign this bug to yourself, to reflect that you are 
studying it.

Given the subject of the bug, and the fact that the behavior was markedly better
in recent code, I wonder if the fix for DERBY-47 is part of the behavior 
improvements?

I see that Mark Helkamp was monitoring the "handle count", while you have been 
looking
at Java object memory usage. Are these two things the same? I am not sure how to
observe "The handle count on the Derby process", but it would be nice if we 
could confirm
that this measurement, too, is substantially improved in the trunk prior to 
marking this
issue as resolved.

> Process handles appear to be leaking in queries using an IN clause during 
> concurrent DB access
> ----------------------------------------------------------------------------------------------
>
>                 Key: DERBY-1781
>                 URL: https://issues.apache.org/jira/browse/DERBY-1781
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 10.1.3.1
>         Environment: Windows XP, Java 1.5.0_05
>            Reporter: Mark Hellkamp
>         Attachments: SqlStressTest.java
>
>
> We are currently using Derby embedded in our web application running on 
> Windows. When processing multiple concurrent requests we have noticed that 
> the Java process handle count continues to increase until the machine becomes 
> unresponsive. I was able to isolate the problem to Derby by running the 
> database in network mode in another process. Further investigation showed 
> that the problem could be reproduced using a select statement that has an IN 
> clause with multiple entries on the primary key column. Spawning multiple 
> threads running the same query causes the handle count to increase 
> considerably on the Derby process. The problem occurs in version 10.1.3.1 and 
> 10.2.1.1 (even worse) in both embedded and network mode. The attached test 
> program duplicates the problem. Start Derby in network mode (using 
> startNetworkServer.bat) and run the enclosed test program. The handle count 
> on the Derby process will increase and never go down short of restarting 
> Derby. Using 10.2.1.1 the handle count for the Derby process goes somewhere 
> between 1400-1500 with just two threads in my environment. 

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