On Tue, Mar 31, 2015 at 1:09 PM, Heikki Linnakangas <hlinn...@iki.fi> wrote: > I'm pretty sceptical of that. ISTM you'll need to do modify the page twice > for each insertion, first to insert the promise tuple, and then to turn the > promise tuple into a real tuple. And WAL-log both updates. That's going to > hurt performance.
Andres' wish to do things that way is at least partially motivated by having logical decoding just work. The co-ordination I'm currently doing across changes within transaction reassembly is pretty ugly. Andres has strongly suggested that it's broken, too, since a snapshot change could occur between a speculative insertion and its super deletion within transaction resassembly, thus invalidating the assumption that the next change not being a super deletion means there is no such super deletion change (i.e. the insert should be treated as "real"). Anyway, if we don't do this, we'll need to make sure my changes to transaction reassembly are sound. Hopefully that's an easy fix. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
