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From "Bryan Pendleton (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-1781) Process handles appear to be leaking in queries using an IN clause during concurrent DB access
Date Wed, 17 Oct 2007 13:49:50 GMT

    [ https://issues.apache.org/jira/browse/DERBY-1781?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12535558
] 

Bryan Pendleton commented on DERBY-1781:
----------------------------------------

> 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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