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Re: Bug: Buffer cache is not scan resistant

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, Luke Lonergan <LLonergan(at)greenplum(dot)com>, Sherry Moore <sherry(dot)moore(at)sun(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Mark Kirkwood <markir(at)paradise(dot)net(dot)nz>, Pavan Deolasee <pavan(at)enterprisedb(dot)com>, Gavin Sherry <swm(at)alcove(dot)com(dot)au>, PGSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Doug Rady <drady(at)greenplum(dot)com>
Subject: Re: Bug: Buffer cache is not scan resistant
Date: 2007-04-02 23:15:44
Message-ID: 200704022315.l32NFiP18580@momjian.us (view raw or flat)
Thread:
Lists: pgsql-hackers
"test" version, but I am putting in the queue so we can track it there.

Your patch has been added to the PostgreSQL unapplied patches list at:

	http://momjian.postgresql.org/cgi-bin/pgpatches

It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.

---------------------------------------------------------------------------


Simon Riggs wrote:
> On Mon, 2007-03-12 at 09:14 +0000, Simon Riggs wrote:
> > On Mon, 2007-03-12 at 16:21 +0900, ITAGAKI Takahiro wrote:
> 
> > > With the default
> > > value of scan_recycle_buffers(=0), VACUUM seems to use all of buffers in pool,
> > > just like existing sequential scans. Is this intended?
> > 
> > Yes, but its not very useful for testing to have done that. I'll do
> > another version within the hour that sets N=0 (only) back to current
> > behaviour for VACUUM.
> 
> New test version enclosed, where scan_recycle_buffers = 0 doesn't change
> existing VACUUM behaviour.
> 
> -- 
>   Simon Riggs             
>   EnterpriseDB   http://www.enterprisedb.com
> 

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-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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