From: Olleg <olleg_s@mail.ru>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: BLCKSZ
Date: Tue, 06 Dec 2005 00:32:03 +0300
Message-ID: <4394B1D3.7000304@mail.ru> (raw)
In-Reply-To: <29518.1133794958@sss.pgh.pa.us>
References: <dn1gdd$19kg$1@news.hub.org>
<29518.1133794958@sss.pgh.pa.us>
Tom Lane wrote:
> Olleg Samoylov <olleg_s@mail.ru> writes:
>
>>I try to test this. Linux, memory page 4kb, disk page 4kb. I set BLCKSZ
>>to 4kb. I get some performance improve, but not big, may be because I
>>have 4Gb on test server (amd64).
>
> It's highly unlikely that reducing BLCKSZ is a good idea. There are bad
> side-effects on the maximum index entry size, maximum number of tuple
> fields, etc.
Yes, when I set BLCKSZ=512, database dont' work. With BLCKSZ=1024
database very slow. (This was surprise me. I expect increase performance
in 8 times with 1024 BLCKSZ. :) ) As I already see in this maillist,
increase of BLCKSZ reduce performace too. May be exist optimum value?
Theoretically BLCKSZ equal memory/disk page/block size may reduce
defragmentation drawback of memory and disk.
> In any case, when you didn't say *what* you tested, it's
> impossible to judge the usefulness of the change.
> regards, tom lane
I test performace on database test server. This is copy of working
billing system to test new features and experiments. Test task was one
day traffic log. Average time of a one test was 260 minutes. Postgresql
7.4.8. Server dual Opteron 240, 4Gb RAM.
--
Olleg
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To: pgsql-performance@postgresql.org
Cc: olleg_s@mail.ru, tgl@sss.pgh.pa.us
Subject: Re: BLCKSZ
In-Reply-To: <4394B1D3.7000304@mail.ru>
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