Re: Enabling Checksums
Bruce Momjian <bruce@momjian.us>
From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Greg Stark <stark@mit.edu>, Florian Pflug <fgp@phlo.org>, Ants Aasma <ants@cybertec.at>, Andres Freund <andres@2ndquadrant.com>, Jeff Davis <pgsql@j-davis.com>, Heikki Linnakangas <hlinnakangas@vmware.com>, Simon Riggs <simon@2ndquadrant.com>, Greg Smith <greg@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2013-04-17T17:24:42Z
Lists: pgsql-hackers
On Wed, Apr 17, 2013 at 01:22:01PM -0400, Tom Lane wrote: > Greg Stark <stark@mit.edu> writes: > > On Wed, Apr 17, 2013 at 4:28 PM, Florian Pflug <fgp@phlo.org> wrote: > >> Is there any way we can change the checksum algorithm in 9.4 > >> *without* breaking pg_upgrade? > > > Personally I think we're going to need a solution for page format > > changes someday eventually.... > > > What advantages are we postponing now to avoid it? > > Um, other than the ability to make a release? > > We aren't going to hold up 9.3 until that particular bit of pie in the > sky lands. Indeed I don't expect to see it available in the next couple > years either. When we were looking at that seriously, two or three > years ago, arbitrary page format changes looked *hard*. > > The idea of bumping the page format version number to signal a checksum > algorithm change might work though. Uh, not sure how pg_upgrade would detect that as the version number is not stored in pg_controldata, e.g.: Data page checksums: enabled/disabled Do we need to address this for 9.3? (Yuck) -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +