From: Date: March 8 2010 9:36pm
Subject: Re: Addutional slave to a master-to-master replication
List-Archive: http://lists.mysql.org/replication/1825
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Database System wrote:
> Hi,
> 
> I have one master A , and two slaves B and C both replicate A.
> 
> Now I want to change A and B as master to master replication. I know how to setup A and B. I'm not sure if I need to do any change on C, in order it execute all statements once and won't miss any statements. For example, updates on A, and updates original done on B, but replicated/executed on A.

Hi Lisa,

I'm not sure what problem you're trying to solve, but replication
between A and B will work since A will prune any events tagged with
its server ID. For events that originate from C you have to be careful
since those events will not be pruned by any server if they get into
the loop between A and B.

Note that you cannot replicate from two masters at the same time
(unless you resort to various tricks), so you have to re-direct the A
and B server to each others. If you are too quick in re-directing the
A and B servers, it might be that there are C events in the binlog for
either A or B, and they will then circle forever, and being executed a
lot of times.

Just my few cents,
Mats Kindahl

> 
> Thanks,
> Lisa
> 
> 
>       
> 

-- 
Mats Kindahl
Senior Software Engineer
Database Technology Group
Sun Microsystems