Re: ALTER TABLE SET STATISTICS requires AccessExclusiveLock
Simon Riggs <simon@2ndquadrant.com>
From: Simon Riggs <simon@2ndQuadrant.com>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Peter Eisentraut <peter_e@gmx.net>, pgsql-hackers@postgresql.org
Date: 2009-10-19T16:00:37Z
Lists: pgsql-hackers
On Mon, 2009-10-19 at 12:56 -0300, Alvaro Herrera wrote: > Simon Riggs wrote: > > > > On Fri, 2009-08-07 at 15:58 -0400, Alvaro Herrera wrote: > > > Tom Lane wrote: > > > > Peter Eisentraut <peter_e@gmx.net> writes: > > > > > Is there a good reason for $subject, other than that the code is entangled > > > > > with other ALTER TABLE code? > > > > > > > > I think it could be lower, but it would take nontrivial restructuring of > > > > the ALTER TABLE support. In particular, consider what happens when you > > > > have a list of subcommands that don't all require the same lock level. > > > > I think you'd need to scan the list and find the highest required lock > > > > level before starting ... > > > > > > IIRC there was a patch from Simon to address this issue, but it had some > > > holes which he didn't have time to close, so it sank. Maybe this can be > > > resurrected and fixed. > > > > I was intending to finish that patch in this release cycle. > > Since you're busy with Hot Standby, any chance you could pass it on? If you'd like. It's mostly finished, just one last thing to finish: atomic changes to pg_class via an already agreed API. -- Simon Riggs www.2ndQuadrant.com