Re: Replication Docs

Markus Schiltknecht wrote:
> Hi,
>
> Bruce Momjian wrote:
> > OK, it is two separate entries now:
> >
> > http://momjian.us/main/writings/pgsql/sgml/high-availability.html
>
> Yes, that's fine with me.

Good.

> > Uh, good point. The title is now "Statement-Based Replication
> > Middleware". That doesn't say multi-master, but it doesn't say
> > master/slave either. The Sequoia PDF you sent me is very detailed:
> >
> > http://www.continuent.org/uploads/sequoia/Resources/2006-08-15Cecchet_ApacheConAsia2006.pdf
> >
> > I think we are back to the issue of classification. We have traditional
> > master/slave as slony, and multi-master as perhaps pgcluster, and lots
> > in between. I am thinking pgpool and sequoia fit in there. I have
> > added Sequoia to the Statement-Based Replication Middleware section.
>
> I'll look into that shortly, but I think Emmanuel can better categorize
> sequoia, I've CCed him. I'd certainly categorize it as Multi Master
> Replication (like pgpool, only that it's a poor implementation).

OK, let's see what they say. Right now, middleware is a separate
section.

> Good, that sounds better for me.
>
> There's only a typo at the very end:
>
> "..conflict resolution rules. rules."

OK, fixed, thanks.

> > Uh, if the data isn't partitioned, what value is there to hitting
> > multiple servers, for single query? I am confused.
>
> Right, makes only sense for complex queries, i.e. when having multiple
> seq scans and/or joins. The executor would have to be super clever for
> such things to happen. Just forget about my comment.

Oh, I see, splitting I/O load even with multiple copies --- interesting,
but seems too far out for this documentation, as you suggested above.

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

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