Re: Automatic free space map filling

Tom Lane wrote:
> Alvaro Herrera <alvherre(at)commandprompt(dot)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.

Oh, reading the original posting, these are cases where
maintenance_work_mem is full and we are going to rescan the indexes
multiple times anyway for this table.

--
Bruce Momjian http://candle.pha.pa.us
SRA OSS, Inc. http://www.sraoss.com

+ If your life is a hard drive, Christ can be your backup. +