On 5 June 2015 at 11:02, Andres Freund <and...@anarazel.de> wrote: > On 2015-06-05 10:45:09 +0100, Simon Riggs wrote: > > On 1 June 2015 at 20:53, Thomas Munro <thomas.mu...@enterprisedb.com> > wrote: > > > > > On Tue, May 12, 2015 at 9:20 AM, Heikki Linnakangas <hlinn...@iki.fi> > > > wrote: > > > > The beauty of this would be that the TED entries can be zapped at > > > restart, > > > > just like pg_subtrans, and pg_multixact before 9.3. It doesn't need > to be > > > > WAL-logged, and we are free to change its on-disk layout even in a > minor > > > > release. > > > > > > What about prepared transactions? They can lock rows FOR SHARE that > > > survive server restarts. > > > > > > > Interesting comment. I'm not aware that we do. > > > > If we do support row locking that survives server restart, how did it > work > > before 9.3? > > Multixacts were persistent before 9.3 as well. A good number of the bugs > existed then as well, but their effect was much more limited. The > difference is that now multixacts don't just have to survive till the > last locker isn't running anymore (which was determined by a horizon), > but that they have to live till they're vacuumed away, since xmax might > be stored in the multixact. >
Phew! Had me worried for a minute. -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
