Re: Replication

Craig Ringer wrote:
> On Mon, 2009-06-22 at 21:29 -0400, Gerry Reno wrote:
>
>
>> I don't know how it could guarantee that. That's really why row-based
>> is better.
>>
>
> Yep, especially in the face of things like user PL functions, C
> functions, etc.
>
> This page:
>
> http://dev.mysql.com/doc/refman/5.0/en/replication-features-functions.html
>
> is downright alarming, and (implicitly) says quite enough about how
> statement-based replication is a really, REALLY bad idea.
>
> Rather than replicating sets of changed rows, though, I suspect that
> block-level replication using the WAL is probably more efficient.
> Certainly it'll be easier on the slave in terms of the work required to
> keep up with the master.
>
> I guess block-level replication isn't much good for multi-master,
> though, since you'd be spending half your time finding out what the
> other masters were doing and what their state was, or telling them about
> yours. (I guess that's the case anyway to some extent, though, any time
> you have concurrent statements on different masters using the same data
> and one or more of them is altering it).
>
>
>> Sequences I deal with by setting up an offset and increment for each
>> replica so that there are no conflicts.
>>
>
> Ah, so you don't actually care if the replicas are identical - you
> expect things like different primary keys on master and replicas(s) ?
>
> How do your applications cope if they switch from one replica to another
> and suddenly primary key identifiers are different?
>
Here is a link that describes the technique:
http://www.onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html?page=1

<snip>

Regards,
Gerry