From: Jignesh Shah <J.K.Shah@Sun.COM>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: ?? Ian Li <liyan82@gmail.com>
Cc: PostgreSQL Performance <pgsql-performance@postgresql.org>
Subject: Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2
Date: Wed, 09 May 2007 18:49:16 +0100
Message-ID: <4642099C.3060504@sun.com> (raw)
In-Reply-To: <20070509170145.GS4504@alvh.no-ip.org>
References: <1178574927.533849.90730@e51g2000hsg.googlegroups.com>
<B699315F-9D8D-40E7-9C42-DD0C9E7DEA4F@blighty.com>
<463FFF76.5070108@gmail.com>
<4641F672.6090508@sun.com>
<20070509170145.GS4504@alvh.no-ip.org>
But we still pay the penalty on WAL while writing them in the first
place I guess .. Is there an option to disable it.. I can test how much
is the impact I guess couple of %s but good to verify :-) )
Regards,
Jignesh
Alvaro Herrera wrote:
> Jignesh Shah escribió:
>
>
>> Now comes the thing that I am still exploring
>> * Do we do checksum in WAL ? I guess we do .. Which means that we are
>> now doing double checksumming on the data. One in ZFS and one in
>> postgresql. ZFS does allow checksumming to be turned off (but on new
>> blocks allocated). But of course the philosophy is where should it be
>> done (ZFS or PostgreSQL).
>>
>
> Checksums on WAL are not optional in Postgres, because AFAIR they are
> used to determine when it should stop recovering.
>
>
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To: pgsql-performance@postgresql.org
Cc: J.K.Shah@Sun.COM, alvherre@commandprompt.com, liyan82@gmail.com
Subject: Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2
In-Reply-To: <4642099C.3060504@sun.com>
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