Re: Enabling Checksums

Simon Riggs <simon@2ndquadrant.com>

From: Simon Riggs <simon@2ndQuadrant.com>

To: Jeff Davis <pgsql@j-davis.com>

Cc: Daniel Farina <daniel@heroku.com>, Greg Smith <greg@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@2ndquadrant.com>, Ants Aasma <ants@cybertec.at>, Heikki Linnakangas <hlinnakangas@vmware.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2013-03-18T19:25:55Z

Lists: pgsql-hackers

On 18 March 2013 19:02, Jeff Davis <pgsql@j-davis.com> wrote:
> On Sun, 2013-03-17 at 22:26 -0700, Daniel Farina wrote:
>> as long as I am able to turn them off easily
>
> To be clear: you don't get the performance back by doing
> "ignore_checksum_failure = on". You only get around the error itself,
> which allows you to dump/reload the good data.

Given that the worst pain point comes from setting hint bits during a
large SELECT, it makes sense to offer an option to simply skip hint
bit setting when we are reading data (SELECT, not
INSERT/UPDATE/DELETE). That seems like a useful option even without
checksums. I know I have seen cases across many releases where setting
that would have been good, since it puts the cleanup back onto
VACUUM/writers, rather than occasional SELECTs.

-- 
 Simon Riggs                   http://www.2ndQuadrant.com/
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