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Message-ID: <4A40EDDD.2000305@hanik.com>
Date: Tue, 23 Jun 2009 08:59:41 -0600
From: Filip Hanik - Dev Lists <devlists@hanik.com>
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To: Tomcat Developers List <dev@tomcat.apache.org>
Subject: Re: dbcp pool evictor deadlock?
References: <h1oprn$ur4$1@ger.gmane.org>
 <6a79aa8f0906230700u6ce54da3y4d36eca15e17a358@mail.gmail.com>
 <4A40E12C.2070504@apache.org> <h1qnv7$251$1@ger.gmane.org>
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first, sorry for bringing this thread to dev, that should have never 
happened. I fat fingered the keyboard.

Eric B. wrote:
> "Mark Thomas" <markt@apache.org> wrote in message 
> news:4A40E12C.2070504@apache.org...
>   
>> 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?
>   
its a different package all together. Similar features, different 
implementation.
> 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?
>   
if the issue is fixed in 1.5.1, you should upgrade to 1.5.1 if that's 
what you want.

> Thanks,
>
> Eric
>
>
>
>
>
>
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