On Tue, Jun 26, 2012 at 05:05:27PM -0500, Kevin Grittner wrote: > David Fetter <da...@fetter.org> wrote: > > On Mon, Jun 25, 2012 at 01:50:54PM -0500, Kevin Grittner wrote: > > >> One fine point regarding before and after images -- if a value > >> doesn't change in an UPDATE, there's no reason to include it in > >> both the BEFORE and AFTER tuple images, as long as we have the > >> null column bitmaps -- or some other way of distinguishing > >> unchanged from NULL. (This could be especially important when > >> the unchanged column was a 50 MB bytea.) > > > > How about two bitmaps: one telling which columns are actually > > there, the other with NULLs? > > There are quite a few ways that could be done, but I suspect > Álvaro's idea is best: > > http://archives.postgresql.org/message-id/1340654533-sup-5...@alvh.no-ip.org
Looks great (or at least way better than mine) to me :) > In any event, it sounds like Andres wants to keep it as simple as > possible for the moment, and just include both tuples in their > entirety. Hopefully that is something which can be revisited before > the last CF. I hope so, too... Cheers, David. -- David Fetter <da...@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fet...@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
