On Sun, Jan 24, 2010 at 2:01 PM, Bernd Helmle <maili...@oopsware.de> wrote: > --On 24. Januar 2010 19:45:33 +0100 Bernd Helmle <maili...@oopsware.de> > wrote: >> I don't see where this should be related to the number of tables not >> part of the inheritance tree (or inheritance at all). > To answer that myself: it seems get_attname() introduces the overhead here > (forgot about that). Creating additional 16384 tables without any connection > to the inheritance increases the times on my Phenom-II Box to round about 2 > seconds: > > Current -HEAD > > bernd=# ALTER TABLE a1 RENAME COLUMN acol1 TO xyz; > ALTER TABLE > Time: 409,045 ms > > With KaiGai's recent patch: > > bernd=# ALTER TABLE a1 RENAME COLUMN acol1 TO xyz; > ALTER TABLE > Time: 2402,306 ms
Hmm, so adding those tables slowed down HEAD by <50%, but the time with KaiGai's patch more than trippled. So I think we definitely need KaiGai to try it the other way and see how that shakes out... ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
