Re: Replication and PITR

On Monday 25 September 2006 07:48, Bo Lorentsen wrote:
> Jeff Davis wrote:
> > Standby mode means that the database is kept almost up to date with the
> > master, but is not "up". When the master goes down, you can bring the
> > standby machine up. Until then, you unfortunately can't even do read
> > queries on that machine.
>
> Do you know if this will change in the future ?
>
> > If you want more of a master/slave setup for performance, you should
> > take a second look at Slony. A PITR standby doesn't help you with
> > performance at all.
>
> Ok, I can see that ... so PITR is for a standby backup DB, with at the
> best ... manual fail over ?
>
> > Why don't you like the fact that Slony is trigger-based? Does that cause
> > you a problem?
>
> Hmm, well i guess i dislike the idea of having a high level mechanism to
> collect data, not a rational argument, sorry. The PITR just seemed so
> right as it has a more prober low level approach, but it sound to me
> like Slony is the only real choice at the moment, and it will do the job
> with a relatively low overhead.
>
> > And missing DDL is mainly a problem when you want to provide postgresql
> > to many people, and you have no idea how they will use it. If that's the
> > case, standby PITR might be a better solution for you. Slony has nice
> > "execute script" functionality that is useful for making DDL changes on
> > all machines.
>
> Ok, I think that the only thing I really need to do is to try to work
> more with Slony and learn to understand it. And the DDL problem is more
> when others need to maintain the system, and I then have to explain how
> to do this and that, and I think I am a bit spoiled by the easy working
> of the mysql replication :-)
>

Hmm.... almost sounds like what you really want is mammoth replicator... lower
level than slony, built into the db, can handle ddl (iirc).... not oss
though.

--
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL