Re: Replication

Thanks for all who replied.

There are certain cases where multi-master rep are very implementable such as where
the datasets being rep are fairly disjointed but need to be replicated for completeness in
terms of reporting. But you are absolutely 110% correct. Multimaster synchro is a nightmare.

-----Original Message-----
From: Christopher Browne [mailto:cbbrowne(at)acm(dot)org]
Sent: Sat 8/30/2003 4:47 PM
To: pgsql-admin(at)postgresql(dot)org
Cc:
Subject: Re: [ADMIN] Replication

Martha Stewart called it a Good Thing whenianh(at)hubspan(dot)com ("Ian Huynh")wrote:
> Seems that there are a number of simultaneous project in trying to implement replication
> for postgres.
>
> Is anyone out there using this feature currently? If so , which package & OS environment.
>
> the latest news was eRServer v1.0. Is this the same as the v1.2 that Postgres INC announced
> early this year ?
>
> Is there a master-master capability or only master-multi-slave ?

The version of eRServer recently released as free software is not the
latest "production" release, but it is a direct predecessor.

Its operational model is that of "master/possible multiple slaves,"
NOT multimaster.

Multimaster involves some thorny issues surrounding synchronization,
as it is possible for one master to receive a set of changes
concurrently with another master receiving _incompatible_ changes.

PalmOS users see this if they change a particular record on both
desktop and palmtop; the next time they sync, the conflicting record
normally gets duplicated and the user gets to decide how to fix it.

Doing that in a big production database context may not be
possible/acceptable. You only should do multimaster if you REALLY
know what you're doing.
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