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From David Blevins <>
Subject Re: DataSource configuration for production
Date Thu, 12 Jun 2008 06:46:42 GMT

On Jun 11, 2008, at 4:44 AM, jfjames wrote:

> We're back ... It seems we’ve identified the cause of the problem.  
> It is
> located in DBCP 1.3. In fact, the isClosed method of the
> DelegatingConnection class doesn’t really close the underlying JDBC
> connection  :
> * when called from the destroyObject method of the
> PoolableConnectionFactory, the _closed  variable is set to false,
> * therefore the test if ( _closed || _conn.isClosed() ) doesn’t  
> allow to
> propagate the close along the delegating chain (up to the JDBC  
> connection).
> According to us, it should be replaced by if ( _closed &&  
> _conn.isClosed()
> ). We’ve done some tests with this patch and it works fine :  
> maxActive is
> never exceeded and the number of connections to the database server is
> stable.
> Now, we have to check the impact on the DBCP jUnit tests before going
> further ...

Great work!  Going to be a fantastic contribution.

Once you're confident on the impact to the dbcp unit tests, craft up a  
patch file and open up a JIRA for the issue at
I can help you with instructions on creating patches if you need it  
(just an "svn diff > myPatch.txt" for the most part).  Then I can go  
tap those guys on the shoulder and let em know we're waiting on it and  
it's critical for us.

If we can get them to commit it we won't need to wait for a DBCP  
release and can just roll up a custom build that we can use in 3.0.1.


> jfjames wrote:
>> We've spent some time today investigating what actually happens in  
>> the
>> DataSource ... Not so easy since DBCP code is a little tricky !
>> We've observed that JDBC connections which are realeased from the  
>> pool by
>> the Evictor are not physically closed :
>> 1/ from the DataSource standpoint : the maximum size of the pool is  
>> never
>> exceeded (numActive is always inferior to maxActive),
>> 2/ but from the dataserver standpoint : the number of connections is
>> always increasing (up to the maximum allowed by the server).
>> We haven't identified the exact cause of this issue : for some  
>> unknown
>> reason the DelegatingConnection.close() method consider the JDBC
>> connection as already closed which is wrong.
>> Next step tomorrow ...
> -- 
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