2010/3/3 Bruce Momjian <br...@momjian.us>: > Peter Eisentraut wrote: >> On m?n, 2010-02-22 at 10:32 -0500, Bruce Momjian wrote: >> > Simon Riggs wrote: >> > > 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 <pete...@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. >> > >> > I assume this did not get done for 9.0. Do we want a TODO item? >> >> Yes. > > Added: > > Reduce locking required for ALTER commands
I just faced production issue where it is impossible to alter table to adjust autovacuum settings in a pg8.4. (5K tps, 260M rows table, lock too much) Can we add some mechanism to prevent that situation also in the TODO item ? (alternative is actualy to alter other tables and adjust the postgresql.conf for biggest tables, but not an ideal solution anyway) > > * http://archives.postgresql.org/pgsql-hackers/2009-08/msg00533.php > * http://archives.postgresql.org/pgsql-hackers/2009-10/msg01083.php > * http://archives.postgresql.org/pgsql-hackers/2010-01/msg02349.php > > -- > Bruce Momjian <br...@momjian.us> http://momjian.us > EnterpriseDB http://enterprisedb.com > > PG East: http://www.enterprisedb.com/community/nav-pg-east-2010.do > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers > -- Cédric Villemain 2ndQuadrant http://2ndQuadrant.fr/ PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
