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Re: PG 8.3 and large shared buffer settings

From: Aidan Van Dyk <aidan(at)highrise(dot)ca>
To: Scott Carey <scott(at)richrelevance(dot)com>
Cc: Dan Sugalski <dan(at)sidhe(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,"pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: PG 8.3 and large shared buffer settings
Date: 2009-09-25 16:15:42
Message-ID: 20090925161542.GK586@oak.highrise.ca (view raw or flat)
Thread:
Lists: pgsql-performance
* Scott Carey <scott(at)richrelevance(dot)com> [090925 11:57]:
> That won't work well anyway because the postgres shared_buffers dos not cache things that are sequentially scanned (it uses a ring buffer for each scan).  So, for any data that is only accessed by sequential scan, you're relying on the OS and the disks.  If you access a table via index scan though, all its pages will go through shared_buffers.

In older version too, or only since synchronized scans got in?

a.


-- 
Aidan Van Dyk                                             Create like a god,
aidan(at)highrise(dot)ca                                       command like a king,
http://www.highrise.ca/                                   work like a slave.

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