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From "Knut Anders Hatlen (JIRA)" <derby-...@db.apache.org>
Subject [jira] Reopened: (DERBY-23) just booting jdbc driver and shutting down seem to leak memory
Date Thu, 06 Oct 2005 07:24:49 GMT
     [ http://issues.apache.org/jira/browse/DERBY-23?page=all ]
Knut Anders Hatlen reopened DERBY-23:

As I have mentioned on derby-dev earlier, there is a problem with the
current fix. After the fix was committed, store/encryptDatabase.sql
sometimes failed because one or more rawStoreDaemon threads printed a
NullPointerException to System.err.

For an example, see:

The reason for this is that the fix nulls out the reference from the
ContextService to the list of ContextManagers when the ContextService
is stopped. Some threads with references to the ContextService might
still be alive when the ContextService is stopped, and they get
NullPointerExceptions when accessing the stopped ContextService.

I have only been able to reproduce this behaviour with the
store/encryptDatabase.sql test on multi-cpu machines running with a
heavy background load. It seems like the threads that get
NullPointerExceptions are orphan threads (like the ones described in
DERBY-594) that have not yet been able to start because of the heavy
background load. The problem might go away when DERBY-594 is resolved,
but I think it needs further investigation.

> just booting jdbc driver and shutting down seem to leak memory
> --------------------------------------------------------------
>          Key: DERBY-23
>          URL: http://issues.apache.org/jira/browse/DERBY-23
>      Project: Derby
>         Type: Bug
>   Components: Services
>     Versions:
>     Reporter: Tulika Agrawal
>     Assignee: Knut Anders Hatlen
>     Priority: Minor
>      Fix For:
>  Attachments: DERBY-23-with_comments.diff, DERBY-23.diff, DERBY-23.stat
> Reporting for Daniel John Debrunner.
> Doing simple boot and shutdown of the driver in a loop
> seem to grow the heap forever:
> new org.apache.derby.jdbc.EmbeddedDriver(); //boot the driver
> DriverManager.getConnection("jdbc:derby:;shutdown=true"); 
> //shutdown the cloudscape instance completely
> after booting and shutting down 1516 times, memory used is  
> ~~41931056 bytes.
> Sample GC Output:
> 1931.93: [Full GC 43484K->43243K(65088K), 0.1779751 secs]
> 1933.13: [Full GC 43511K->43270K(65088K), 0.1914383 secs]
> 1934.47: [Full GC 43538K->43297K(65088K), 0.1808878 secs]
> 1935.68: [Full GC 43564K->43324K(65088K), 0.4461623 secs]
> 1937.43: [Full GC 43591K->43350K(65088K), 0.1842980 secs]
> 1938.63: [Full GC 43617K->43377K(65088K), 0.1873431 secs]
> 1939.85: [Full GC 43644K->43404K(65088K), 0.1948505 secs]
> 1941.07: [Full GC 43671K->43430K(65088K), 0.1790895 secs]

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