Re: Automatic free space map filling
Bruce Momjian <pgman@candle.pha.pa.us>
From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@commandprompt.com>, Csaba Nagy <nagy@ecircle-ag.com>, "Matthew T. O'Connor" <matthew@zeut.net>, Christopher Browne <cbbrowne@acm.org>, postgres hackers <pgsql-hackers@postgresql.org>
Date: 2006-04-28T19:58:16Z
Lists: pgsql-hackers
Tom Lane wrote: > Alvaro Herrera <alvherre@commandprompt.com> writes: > > So for you it would certainly help a lot to be able to vacuum the first > > X pages of the big table, stop, release locks, create new transaction, > > continue with the next X pages, lather, rinse, repeat. > > > This is perfectly doable, it only needs enough motivation from a > > knowledgeable person. > > Bruce and I were discussing this the other day; it'd be pretty easy to > make plain VACUUM start a fresh transaction immediately after it > finishes a scan heap/clean indexes/clean heap cycle. The infrastructure > for this (in particular, session-level locks that won't be lost by > closing the xact) is all there. You'd have to figure out how often to > start a new xact ... every cycle is probably too often, at least for > smaller maintenance_work_mem settings ... but it'd not be hard or > involve any strange changes in system semantics. Should this be a TODO? One item of discussion was taht people should just increase their workmem so the job can be done faster in larger batches. -- Bruce Momjian http://candle.pha.pa.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +