From: Simon Riggs <simon@2ndquadrant.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: pgsql-performance@postgresql.org
Subject: Re: Heavy write activity on first vacuum of fresh TOAST data
Date: Thu, 13 Dec 2007 21:40:10 +0000
Message-ID: <1197582010.4255.1912.camel@ebony.site> (raw)
In-Reply-To: <47614D86.EE98.0025.0@wicourts.gov>
References: <4760FF69.EE98.0025.0@wicourts.gov>
<1197562283.4255.1829.camel@ebony.site>
<47611B9D.EE98.0025.0@wicourts.gov>
<1197569564.4255.1855.camel@ebony.site>
<47614D86.EE98.0025.0@wicourts.gov>
On Thu, 2007-12-13 at 15:19 -0600, Kevin Grittner wrote:
> >>> On Thu, Dec 13, 2007 at 12:12 PM, in message
> <camel@ebony.site/">1197569564.4255.1855.camel@ebony.site>, Simon Riggs <simon@2ndquadrant.com>
> wrote:
> > On Thu, 2007-12-13 at 11:46 -0600, Kevin Grittner wrote:
> >> If the hint bit changes are written to the WAL ...
> >
> > They're not.
>
> So one would expect a write-intensive initial vacuum after a
> PITR-style recovery?
Very perceptive. I was just thinking about that myself. An interesting
issue when running with full_page_writes off.
> What impact would lack of the hint bits have until a vacuum?
Vacuum isn't important here. Its the first idiot to read the data that
gets hit.
--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com
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To: pgsql-performance@postgresql.org
Cc: simon@2ndquadrant.com, Kevin.Grittner@wicourts.gov
Subject: Re: Heavy write activity on first vacuum of fresh TOAST data
In-Reply-To: <1197582010.4255.1912.camel@ebony.site>
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