Re: Duplicate Key Problem

From: Christian Mittendorf (christian.mittendor..reenet.de)
Date: Fri Jul 21 2006 - 11:08:45 EDT

  • Next message: Gentry, Michael \(Contractor\): "RE: Duplicate Key Problem"

    Am 21.07.2006 um 16:14 schrieb Gentry, Michael ((Contractor)):

    > 4.0.12 of MySQL. I think autoReconnect=false is a good thing to try,
    > since Cayenne will catch connection exceptions and try to reconnect on
    > its own.

     From what I can see so far, after we updated all apps some hours
    ago, it
    seems to be working fine.

    How would Cayenne handle a lost connection? Would that result into an
    Exception or would Cayenne take care, try to reconnect and try to
    work as
    expected?

    Is there some documentation available or do I have to play "Read the
    source, Luke", as Obi-Wan liked to say ;-)

    Thanks and have a nice weekend!

    Christian

    >
    > Thanks,
    >
    > /dev/mrg
    >
    >
    >
    > -----Original Message-----
    > From: Christian Mittendorf [mailto:christian.mittendor..reenet.de]
    > Sent: Friday, July 21, 2006 9:56 AM
    > To: cayenne-use..ncubator.apache.org
    > Subject: Re: Duplicate Key Problem
    >
    >
    > Am 13.07.2006 um 20:35 schrieb Andrus Adamchik:
    >
    >> BTW, I tried to reproduce PK generator getting an incorrect PK
    >> range on MySQL by emulating some load via JMeter. It never happens
    >> (at least on a single VM instance). I wrote a test case that throws
    >> an exception randomly on committing the user transaction. Still the
    >> application was able to recover from failed transactions and carry
    >> on processing other requests.
    >
    > May it be that the version of MySQL has some affects on what we
    > experience? We are currently using 5.0.18.
    >
    >
    >> I am curious what Michael finds in his tests.
    >
    > Me too, are there any results available?
    >
    >
    >> Anyways, I went ahead and added an explicit commit to the PK
    >> generator (that code, although I couldn't make it fail, still
    >> looked suspect) and posted new jars here:
    >>
    >> http://dev.objectstyle.org/~andrus/cayenne-07132006/
    >>
    >> Christian, I would appreciate if you could try this in your
    >> application and see if you still get those errors.
    >
    > We will update some applications in the next week, we haven't found
    > the time to do so this week.
    >
    > But there was some other idea we had discussed recently. At the
    > moment all of our apps use the "autoReconnect=true" feature of the
    > jdbc driver and after some discussions with colleagues we updated the
    > config to use "autoReconnect=false". If our problem is related to
    > MySQL loosing the connection I would expect to get some kind of "Lost
    > connection" errors instead of duplicate key messages.
    >
    >
    > Christian
    >
    >



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