Re: BLCKSZ - Mailing list pgsql-performance

From Steinar H. Gunderson
Subject Re: BLCKSZ
Date
Msg-id 20051206105935.GA21823@uio.no
Whole thread Raw
In response to Re: BLCKSZ  (Olleg <olleg_s@mail.ru>)
Responses Re: BLCKSZ  (David Lang <dlang@invendra.net>)
List pgsql-performance
On Tue, Dec 06, 2005 at 01:40:47PM +0300, Olleg wrote:
> I can't undestand why "bigger is better". For instance in search by
> index. Index point to page and I need load page to get one row. Thus I
> load 8kb from disk for every raw. And keep it then in cache. You
> recommend 64kb. With your recomendation I'll get 8 times more IO
> throughput, 8 time more head seek on disk, 8 time more memory cache (OS
> cache and postgresql) become busy.

Hopefully, you won't have eight times the seeking; a single block ought to be
in one chunk on disk. You're of course at your filesystem's mercy, though.

/* Steinar */
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Homepage: http://www.sesse.net/

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