[ http://issues.apache.org/jira/browse/DERBY-106?page=all ]
Rick Hillegas updated DERBY-106:
--------------------------------
Component: SQL
Assigning to SQL component.
> HashJoinStrategy leads to java.lang.OutOfMemoryError
> ----------------------------------------------------
>
> Key: DERBY-106
> URL: http://issues.apache.org/jira/browse/DERBY-106
> Project: Derby
> Type: Bug
> Components: SQL
> Reporter: Gerald Khin
> Fix For: 10.1.1.0
>
> My application is running out of memory: I encounterd a
> java.lang.OutOfMemoryError. I used -Xmx256M. Unfortunatley, I cannot spend an
> arbitrary amount of JVM memory.
> Then, I commented out the line in class OptimizerFactoryImpl which was adding
> the HashJoinStrategy to the set of Join strategies:
> if (joinStrategySet == null)
> {
> // JoinStrategy[] jss = new JoinStrategy[2];
> JoinStrategy[] jss = new JoinStrategy[1];
> jss[0] = new NestedLoopJoinStrategy();
> // jss[1] = new HashJoinStrategy();
> joinStrategySet = jss;
> }
> And with these changes the OutOfMemoryError has gone away! And it works even
> with -Xmx128M!!!
> So I guess that there is a major memory issue with this HashJoin strategy
> implementation.
> If it turns out to be too complicated to make the memory consumption more
> predicatble or even bounded to some configurable limit, then I need at least
> as a workaround a way to turn off the HashJoin strategy completely: I did it
> by patching and building my own derby.jar, but if there would be an official
> solution with some kind of switch like a system property, it would be great!
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