Chris Browne wrote:
> It strikes me as a slick idea for autovacuum to take on that
> behaviour. If the daily backup runs for 2h, then it is quite futile
> to bother vacuuming a table multiple times during that 2h period when
> none of the tuples obsoleted during the 2h period will be able to be
> cleaned out until the end.
Hmm, yeah, sounds useful. There's one implementation issue to notice
however, and it's that the autovacuum process dies and restarts for each
iteration, so there's no way for it to remember previous state unless
it's saved somewhere permanent, as the stats info is.
However this seems at least slightly redundant with the "maintenance
window" feature -- you could set a high barrier to vacuum during the
daily backup period instead. (Anybody up for doing this job?)
--
Alvaro Herrera http://www.amazon.com/gp/registry/5ZYLFMCVHXC
"No single strategy is always right (Unless the boss says so)"
(Larry Wall)