Re: Automatic free space map filling

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.
        regards, tom lane