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Re: crash-safe visibility map, take three

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: crash-safe visibility map, take three
Date: 2010-11-30 17:25:18
Message-ID: 4CF5337E.8000505@enterprisedb.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On 30.11.2010 19:22, Tom Lane wrote:
> But having said that, I wonder whether we need a full-page image for
> a WAL-logged action that is known to involve only setting a single bit
> and updating LSN.  Would omitting the FPI be any more risky than what
> happens now (ie, the page does get written back to disk at some point,
> without any image from which it can be rewritten if the write fails...)

You have to write a full-page image if you update the LSN, because 
otherwise the next update that comes along will not write a full page image.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com

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Subject: Re: crash-safe visibility map, take three
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