| From: | Jignesh Shah <J(dot)K(dot)Shah(at)Sun(dot)COM> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | ?? Ian Li <liyan82(at)gmail(dot)com>, PostgreSQL Performance <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: ZFS and Postgresql - WASRe: Best OS for Postgres 8.2 |
| Date: | 2007-05-09 17:49:16 |
| Message-ID: | 4642099C.3060504@sun.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | 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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