Horton
Menu

Re: Enabling Checksums

Jeff Davis <pgsql@j-davis.com>

View thread
From: Jeff Davis <pgsql@j-davis.com>
To: Greg Smith <greg@2ndQuadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Ants Aasma <ants@cybertec.at>, Florian Pflug <fgp@phlo.org>, Andres Freund <andres@2ndquadrant.com>, Bruce Momjian <bruce@momjian.us>, Heikki Linnakangas <hlinnakangas@vmware.com>, Simon Riggs <simon@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2013-04-18T17:04:08Z
Lists: pgsql-hackers 
On Wed, 2013-04-17 at 20:21 -0400, Greg Smith wrote:
> -Original checksum feature used Fletcher checksums.  Its main problems, 
> to quote wikipedia, include that it "cannot distinguish between blocks 
> of all 0 bits and blocks of all 1 bits".

That is fairly easy to fix by using a different modulus: 251 vs 255.

Regards,
	Jeff Davis