On Wed, Feb 11, 2009 at 7:11 PM, Guillaume Cottenceau <gc@xxxxxx> wrote: > Rajesh Kumar Mallah <mallah.rajesh 'at' gmail.com> writes: > >> Hi, >> >> Is it possible to configure autovacuum to run only >> during certain hours ? We are forced to keep >> it off because it pops up during the peak >> query hours. > > You'd rather configure the delaying process to not alter too much > performance. Autovacuum is really not targeted at running once a > day - I think it is partly because the old vacuuming was too weak > (because too seldom in many cases) that autovaccum was added. > > A delaying configuration that works nicely for us without > impacting performance much (tested at the time of 8.2 to cause a > +40% response time during autovacuuming, compared to +300% with > more default values): > > vacuum_cost_delay = 150 > vacuum_cost_page_hit = 1 > vacuum_cost_page_miss = 10 > vacuum_cost_page_dirty = 20 > vacuum_cost_limit = 1000 > autovacuum_vacuum_cost_delay = 300 why is it not a good idea to give end users control over when they want to run it ? > > (Disclaimer: IIRC, Alvaro doesn't like these figures at all) > > Of course, these are good for us (bloat is very, very low and > performance impact is not experienced in production), not > necessarily for you. You should conduct your own tests. > > Be sure to also consider http://developer.postgresql.org/~wieck/vacuum_cost/ > > -- > Guillaume Cottenceau > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
