Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2 - Mailing list pgsql-performance

From Jignesh Shah
Subject Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2
Date
Msg-id 4642099C.3060504@sun.com
Whole thread Raw
In response to Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2  (david@lang.hm)
List pgsql-performance
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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