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Re: WAL logging of SELECT ... INTO command

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
Cc: Qingqing Zhou <zhouqq(at)cs(dot)toronto(dot)edu>, pgsql-performance(at)postgresql(dot)org
Subject: Re: WAL logging of SELECT ... INTO command
Date: 2006-03-24 12:39:02
Message-ID: 20060324123902.GA14217@surnet.cl (view raw or flat)
Thread:
Lists: pgsql-patchespgsql-performance
Jim C. Nasby wrote:

> Why would the content of the old_table be unreliable? If we've replayed
> logs up to the point of the CTAS then any data that would be visible to
> the CTAS should be fine, no?
> 
> Though, the way Tom put it in one of his replies it sounds like WAL
> doesn't do any kind of statement logging, only data logging. If that's
> the case I'm not sure that the CTAS would actually get replayed. But I
> suspect I'm just misunderstanding...

The CTAS doesn't get logged (nor replayed obviously).  What happens is
that the involved files are fsync'ed before transaction commit, AFAIR.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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