Scott Marlowe escribió: > On Tue, Mar 23, 2010 at 5:28 PM, Bhella Paramjeet-PFCW67 > <pbhe...@motorola.com> wrote: > > Hi Scott, > > > > Thanks for replying. > > Can you explain what you mean by increase the number of threads or how I > > can increase the number of threads? I just have 2 tables that are very > > active. I am using postgres version 8.2.7 and 3510 storagetek array with 10 > > disks in raid 1+0. > > Sure, if you psql into your db and do: > > show autovac > > and hit tab a couple times you'll see a list of all these > configuration options. The one we're looking for is > autovacuum_max_workers. Setting this to something higher will allow > that many threads to run at once. While 6 or 8 threads at 5 or 10 > milliseconds delay is ok on a bigger RAID array, it'll kill the perf > of a machine with a pair of disks in a RAID-1. As you drop the > cost_delay, you can no longer run as many threads without starving > your machine of IO. It's a good idea to keep track of how many vacuum > threads you're usually running and how long they run for > (pg_stat_activity can shed some light there).
Hmm, keep in mind that having more workers means that each one of them increments its cost_delay so that the total is roughly what you configured. Also, keep in mind that max_workers is a new setting in 8.3. Since the OP is running 8.2, he can only get one "worker". Presumable he needs to disable autovac for those two very active tables and setup a cron job to process them in their own schedule. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
