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From "Eric B." <>
Subject Re: dbcp pool evictor deadlock?
Date Tue, 23 Jun 2009 14:13:50 GMT
"Mark Thomas" <> wrote in message
> Narendra Sarkar wrote:
>> Hi,
>> We have a multi threaded environment. We have noticed that thread blocks 
>> for
>> 10 to 20 minutes due DBCP getConnection method call. Then, we 
>> investigated
>> the source code of DBCP(commons-dbcp-1.2.1-PII.jar) and noticed that
>> createConnection method is synchronized. This problem occur more 
>> frequently
>> when we have lower value of MaxIdleConnection parameter. After increasing
>> the value of MaxIdleConnection parameter, frequency of blocking get 
>> reduced.
>> We then replaced DBCP connection pooling with Oracle Connection pooling
>> (ojdbc14.jar) and never encountered blocking issue.
>> I think the issue is with that createConnection method of DBCP
>> synchronization. We have taken Thread dump to do above analysis.
> Yep, known issues with commons-pool. Should be fixed in 1.5.1. Trunk has
> been updated. Proposed for 6.0.x and 5.5.x. Alternatively, there is the
> new JDBC pool module.

I'm a little confused now.   Filip pointed me to the jdbp-1.0.5 package.  Is 
that just repackaged versions of dbcp 1.2.2/pool 1.5?  If not, what versions 
of dbcp/pool are contained within there?

If the fix in commons-pool is in 1.5.1, am I still expecting concurrency 
problems if upgrading 1.5?  What would be the best move?



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