Date: Thu, 27 Oct 2005 11:51:35 -0400
From: Andrew Sullivan <ajs@crankycanuck.ca>
To: Mario Splivalo <mario.splivalo@mobart.hr>
Cc: Andrew Sullivan <ajs@crankycanuck.ca>, pgsql-sql@postgresql.org
Subject: Re: why vacuum
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On Thu, Oct 27, 2005 at 02:34:13PM +0200, Mario Splivalo wrote:
> 
> Postgres itself offers no replication. You could achive some sort of
> replication by restoring the parts of WAL files, but that's rather
> inconvinient. Then, if you want to replicate your data in any way, you

Well, AFAIK Oracle itself offers no replication, either.  If you want
it, you have to buy a license for it.  Which means it's an add-on. 
Heck, most Linux distributions' kernels don't offer support for
network cards: they're an add-on.  We call them modules.  (In case
it's not clear, I don't buy the "itself/add-on" distinction.  The
point is that the whole system works together.  PostgreSQL most
definitely offers replication.  In fact, you can get warm-standby with
WAL shipping, or read-only capabilities with Slony or some other
tools.)

> like that :) I am sorry. I was just addressing the issue where
> replication to one means 'just move my data here', and at others it
> means 'merge my data'.

Yes: this multiple-meaning "replication" word causes a great deal of
confusion.  But just because one person has need A does not mean that
need B isn't a real one.  My employer, Afilias, sponsors the Slony
work, in the direction of our needs.  We did not initially have a
many-write-nodes scenario in mind, and we had a pressing need for a
"single master" system.  So that's the itch we scratched.

> I'll be glad to, I'm just not that familiar (in fact, i'm not familiar
> at all) with the 'proof-of-cocept' or 'General Bits' terms, so if you
> could http-redirect me, I'll be  most thankfull.

Proof of concept is just a description of what you did, how it
worked, design and limitations, &c.  Post it to the lists (uh,
-general or maybe -hackers, I suppose), or put it on a web page or
whatever.  General Bits is a fairly regular column that Elein Mustain
puts out.  I bet she'd include a submission on this topic, although
you'd have to ask her.  You can find GB at
<http://varlena.com/varlena/GeneralBits/>.

> Mentioning the 2PC, is it available in pg8.1beta4?

Should be.

A
-- 
Andrew Sullivan  | ajs@crankycanuck.ca
The whole tendency of modern prose is away from concreteness.
		--George Orwell