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Subject: AW: duplicate ID exception in cluster
Date: Wed, 6 Dec 2006 09:32:02 +0100
Message-ID: 
 <F1EF69E69C1EED4FA3BB295B07664EEE523922@srv-master.cadooz-ag.intern>
Thread-Topic: duplicate ID exception in cluster
Thread-Index: AccYvsmfeuM4vwwlS3m7qDg4KajAsgAUVlpQ
From: "Thoralf Rickert" <thoralf.rickert@cadooz.de>
To: "Apache Torque Users List" <torque-user@db.apache.org>

It's a little bit off-topic but have a look at "How to set up a =
load-balanced MySQL cluster" =
(http://www.howtoforge.com/loadbalanced_mysql_cluster_debian). If you =
use a load-balancing server in front of the mysql cluster you don't have =
to change your application. The HowTo uses UltraMonkey to wrap the =
cluster behind a virtual IP that you have to use in your application. It =
works fine.

> -----Urspr=FCngliche Nachricht-----
> Von: wglasshusain@gmail.com [mailto:wglasshusain@gmail.com]=20
> Im Auftrag von Will Glass-Husain
> Gesendet: Dienstag, 5. Dezember 2006 23:43
> An: Apache Torque Users List; hps@intermeta.de
> Betreff: Re: duplicate ID exception in cluster
>=20
>=20
> Hi Henning!
>=20
> It's a real (Tomcat) cluster.  Two instances of Tomcat=20
> talking to a single database.  (no database replication).  I=20
> use Apache/mod_jk to split requests (based on session)=20
> between the two Tomcats.  Allows me to run high number of=20
> users with a memory-heavy application.
>=20
> Thought briefly about database replication but since this is=20
> write-heavy application it didn't seem to make sense.
>=20
> thanks,
> WILL
>=20
> 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=20
> > >both reading/writing from a single database.  I'm using=20
> Torque 3.0,=20
> > >the default ID Broker and MySQL 5. (InnoDB)
> >
> > Real cluster or just master/slave (or master/master with only one=20
> > master active at a time)? The latter is just replication,=20
> not a real=20
> > cluster.
> >
> > >My problem... Under heavy load, I notice that most write=20
> requests on=20
> > >one of the servers fails with a duplicate ID error. =20
> Typically, each=20
> > >page request that fails does 10-20 insert statements.
> >
> > >Any tips as to how I might make this cluster work with=20
> simultaneous=20
> > >writes?
> >
> > a) in a master/master config, you can not write to both=20
> 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=20
> matter what you
> >    google on the internet or what mysql.com wants to tell=20
> you. You will
> >    get the described error sooner or later. If you want to have
> >    master/master with failover, that is fine. Two active=20
> masters not.
> >
> > b) you probably run into the AUTO_INCREMENT problem. Make=20
> sure that you
> >    have 5.0.20 at least. See=20
> 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."
> >
> >=20
> ---------------------------------------------------------------------
> > To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> > For additional commands, e-mail: torque-user-help@db.apache.org
> >
> >
>=20
>=20
> --=20
> Forio Business Simulations
>=20
> Will Glass-Husain
> wglass@forio.com
> www.forio.com
>=20
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> For additional commands, e-mail: torque-user-help@db.apache.org
>=20
>=20


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