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From Suresh Thalamati <tsur...@Source-Zone.org>
Subject Re: [jira] Commented: (DERBY-106) HashJoinStrategy leads to java.lang.OutOfMemoryError
Date Tue, 21 Dec 2004 02:20:40 GMT
Gerald Khin (JIRA) wrote:

>     [ http://nagoya.apache.org/jira/browse/DERBY-106?page=comments#action_56877 ]
>Gerald Khin commented on DERBY-106:
>The system property derby.language.maxMemoryPerTable is the system property I asked for.
Setting it to 0 works like a charm and turns the hash join strategy off. So I'm happy and
the bug can be closed. Perhaps this system property should be mentioned somewhere in the derby
tuning manual.

I don't think this bug should be closed.  Most probably  out of memory
error is coming because the whole hash table is stored  in memory;
current implementation of
Derby hash table does not have logic to  spill the hash table  entries 
to disk when lot of memory is required.  Although using the
maxMemoryPerTableflag is good work around.,  it would be good
to fix the optimizer to NOT  choose hash-table join when memory
requirements can not be estimated accurately.


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