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List:       turbine-torque-user
Subject:    Re: duplicate ID exception in cluster
From:       "Will Glass-Husain" <wglass () forio ! com>
Date:       2006-12-06 18:02:14
Message-ID: 2f8a5bd60612061002y75f1cdf7q9b680486cc515907 () mail ! gmail ! com
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Converted to AUTO_INCREMENT, I'm much happier.  Also solves the
problem of restarting Tomcat and suddenly having the db id's be out of
sync with ID_TABLE.  Always hated the ID Broker :-)

WILL

On 12/6/06, Henning Schmiedehausen <hps@intermeta.de> wrote:
> Ah, so it is an application cluster, not a db cluster (sorry, didn't saw
> that in your first mail).
>
> You get this behaviour when the two nodes refresh their Id Broker from
> the DB. Try
>
> torque.idbroker.cleverquantity=false
> torque.idbroker.prefetch=false
>
> Better yet, don't use the Id broker but use an AUTO_INCREMENT column.
>
>         Best regards
>                 Henning
>
>
>
> On Tue, 2006-12-05 at 14:42 -0800, Will Glass-Husain wrote:
> > Hi Henning!
> >
> > It's a real (Tomcat) cluster.  Two instances of Tomcat talking to a
> > single database.  (no database replication).  I use Apache/mod_jk to
> > split requests (based on session) between the two Tomcats.  Allows me
> > to run high number of users with a memory-heavy application.
> >
> > Thought briefly about database replication but since this is
> > write-heavy application it didn't seem to make sense.
> >
> > thanks,
> > WILL
> >
> > On 12/5/06, Henning P. Schmiedehausen <hps@intermeta.de> wrote:
> > > "Will Glass-Husain" <wglass@forio.com> writes:
> > >
> > > >Hi,
> > >
> > > >I just set up a new 2 server cluster with two instances of Tomcat both
> > > >reading/writing from a single database.  I'm using Torque 3.0, the
> > > >default ID Broker and MySQL 5. (InnoDB)
> > >
> > > Real cluster or just master/slave (or master/master with only one master
> > > active at a time)? The latter is just replication, not a real cluster.
> > >
> > > >My problem... Under heavy load, I notice that most write requests on
> > > >one of the servers fails with a duplicate ID error.  Typically, each
> > > >page request that fails does 10-20 insert statements.
> > >
> > > >Any tips as to how I might make this cluster work with simultaneous writes?
> > >
> > > a) in a master/master config, you can not write to both masters at the
> > >    same time. End of story. I had a summer project where we tested
> > >    exactly that *very* extensively. It does not work. No matter what you
> > >    google on the internet or what mysql.com wants to tell you. You will
> > >    get the described error sooner or later. If you want to have
> > >    master/master with failover, that is fine. Two active masters not.
> > >
> > > b) you probably run into the AUTO_INCREMENT problem. Make sure that you
> > >    have 5.0.20 at least. See http://dev.mysql.com/doc/refman/5.0/en/replication-features.html
> > >    for some docs.
> > >
> > >
> > >         Best regards
> > >                 Henning
> > >
> > > --
> > > Henning P. Schmiedehausen  -- hps@intermeta.de | J2EE, Linux,
> > > 91054 Buckenhof, Germany   -- +49 9131 506540 | Apache person
> > > Open Source Consulting, Development, Design | Velocity - Turbine guy
> > >
> > >           "Save the cheerleader. Save the world."
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> > > For additional commands, e-mail: torque-user-help@db.apache.org
> > >
> > >
> >
> >
> --
> Henning P. Schmiedehausen  -- hps@intermeta.de | J2EE, Linux,
> 91054 Buckenhof, Germany   -- +49 9131 506540 | Apache person
> Open Source Consulting, Development, Design | Velocity - Turbine guy
>
>           "Save the cheerleader. Save the world."
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> For additional commands, e-mail: torque-user-help@db.apache.org
>
>


-- 
Forio Business Simulations

Will Glass-Husain
wglass@forio.com
www.forio.com

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