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From Joe Baldwin <jfbald...@earthlink.net>
Subject Re: Connection Pool
Date Sun, 18 Apr 2010 01:04:43 GMT
Michael,

> I'm not saying it is definitely a MySQL issue, but it could be the JDBC driver or the
backend storage implementation.

True.  The production box is using a very old version of MySQL with documented innodb bugs,
so it could be anything from innodb to the connector that is causing the problem.

>  I'd be surprised if it was a direct Cayenne issue.

I agree, if there are no open Cayenne bugs, and you have personally deployed configured for
only 1-2 connections with no errors, that appears to rule out Cayenne.  My code is pretty
standard cayenne select queries and updates, and has been using Cayenne for over a year on
the development box without any such errors.

>   It would be good if you could test (locally) on a different setup and see if it still
happens.


These exceptions and 60sec load times only occur on the production machine and have never
occurred on the development machine. The only difference is the hardware and the version of
MySQL.

All the evidence seems to be pointing to MySQL and/or the JDBC connector.   In my opinion,
the unresolved innodb bug is the proverbial "elephant in the living room". How it is being
triggered is simple to understand, however the cascade effects are probably due to a combination
requests by the small number of concurrent users.

Thanks so much for your attention to this.  I think Cayenne has been ruled out.
Joe





On Apr 17, 2010, at 5:21 PM, Michael Gentry wrote:

> It should also be noted that I was running against Sybase, so a
> completely different JDBC driver and database.  I'm not saying it is
> definitely a MySQL issue, but it could be the JDBC driver or the
> backend storage implementation.  I'd be surprised if it was a direct
> Cayenne issue.  It would be good if you could test (locally) on a
> different setup and see if it still happens.
> 
> mrg
> 
> 
> On Sat, Apr 17, 2010 at 4:18 AM, Joe Baldwin <jfbaldwin@earthlink.net> wrote:
>> However Michael was able to run his app configured for only two connections.


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