On Sat, Dec 6, 2008 at 12:53 PM, hubert depesz lubaczewski <[EMAIL PROTECTED]> wrote: > First run - without visibility maps, timing of vacuums: > Time: 267844.822 ms > Time: 138854.592 ms > Time: 305467.950 ms > Time: 487133.179 ms > > Second run - on head: > > Time: 252218.609 ms > Time: 234388.763 ms > Time: 334016.413 ms > Time: 575698.750 ms > > Now - as I understand the change - visilibity maps should make second run > much faster?
If I understand correctly what Heikki explained, not if you run VACUUM only once (and you confirmed me on IRC you run it only once). It's the VACUUM which sets the PD_ALL_VISIBLE flag on the pages so the first VACUUM should be slower with HEAD than with 8.3 as it has far more work to do. The second VACUUM should then be faster. -- Guillaume -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
