Kevin Grittner wrote:
> Wouldn't we get substantially the same thing just by counting tuple
> inserts toward the autovacuum vacuum threshold? I mean, it unless
> the table is due for wraparound prevention autovacuum, it will only
> visit pages that don't have the all-visible bit set, right? And
> how much work would that do beyond what you're describing if none
> of the tuples are dead?
The problem is precisely what happens if there are some dead tuples, but
not enough to reach the 20% threshold: this vacuum now has to scan the
table twice and has to clean up indexes also.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
