Message-ID: <4540E001.5030201@commandprompt.com>
Date: Thu, 26 Oct 2006 09:19:13 -0700
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
User-Agent: Thunderbird 1.5.0.7 (X11/20060918)
MIME-Version: 1.0
To: Bruce Momjian <bruce@momjian.us>
CC: "Jim C. Nasby" <jim@nasby.net>, Dawid Kuroczko <qnex42@gmail.com>,
	pgsql-docs@postgresql.org, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Replication documentation addition
References: <200610261559.k9QFxv129610@momjian.us>
In-Reply-To: <200610261559.k9QFxv129610@momjian.us>
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Bruce Momjian wrote:
> Jim C. Nasby wrote:
>> On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote:
>>> Jim C. Nasby wrote:
>>>> Something else worth doing though is to have a paragraph explaining why
>>>> there's no built-in replication. I don't have time to write something
>>>> right now, but I can do it later tonight if no one beats me to it.
>>> I thought that was implied in the early paragraph about why there are
>>> many solutions.
>> I think we should explicitely spell it out, especially considering how
>> many times people ask about it. How about...
>>
>>  This multitude of choices is why PostgreSQL does not ship with a
>>  replication solution by default; any bundled solution would only
>>  satisfy a subset of replication needs.
> 
> The problem is that we do have some solutions in our code, like doing
> data partitioning in the application, warm standby, or using a shared
> disk for failover, so how do we spell that out?  I say there are
> multiple solutions, but I don't see how I can say that all are external
> and not included.

None of those are replication solutions. So I would have to agree with
Jim here.

This isn't about what people do with their app, so that is not relevant.

Warm standby is PITR which is a backup and recovery solution. It does
not include a failover solution and is *not* replication. It technically
does not provide an HA solution either as it will be almost always
farther behind than a replication solution.

Shared disk for failover could be used by anything it isn't special to a
replication scenario it is standard for many HA.

Sincerely,

Joshua D. Drake


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