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From Wernke zur Borg <>
Subject Performance question
Date Tue, 24 Jan 2012 16:11:59 GMT

Dear list,

I have another question. My application converts a huge MS Access 
database to a set of XML files by traversing some really big tables with 
Select queries and also querying related tables to collect the 
information needed for the output. Performance is horribly bad, so I did 
some profiling and found that it spends 75% of its CPU time in 
org.apache.cayenne.access.ExternalTransaction.close() and another 21% in 
org.apache.cayenne.conn.DriverDataSource.getConnection(). Only 2% are 
spent in SelectAction.performAction().

So it appears that it opens and closes a new connection for every single 
select query. I must be doing something wrong here! Where can I tell it 
to re-use connections? Or make one big transaction as it is read-only 
anyway? Any other hints? I hope I can reduce the processing time to 4% 
of what it is now...


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