On 02/27/2012 08:53 AM, Andrew Dunstan wrote:
If he has autovacuum on he could well be just fine with his proposed strategy. Or he could have tables partitioned by time and do the delete by just dropping partitions. There are numerous way he could get this to work.
He isn't using partitions though. That's the whole reason for this thread. Having autovacuum turned on (which should be the case for 8.4 and above anyway) will not magically remove the old rows. VACUUM marks rows as dead/reusable, so INSERT and UPDATE statements will take the dead spots instead of creating new extents.
Like I said, this will stop his tables from growing further so long as he keeps his maintenance functions running regularly from now on, but the existing rows he's trying to delete will never go away until he runs a CLUSTER or some other system of actually purging the dead rows.
Notice how I don't suggest using VACUUM FULL. :) -- Shaun Thomas OptionsHouse | 141 W. Jackson Blvd. | Suite 500 | Chicago IL, 60604 312-444-8534 sthomas@xxxxxxxxx ______________________________________________ See http://www.peak6.com/email_disclaimer/ for terms and conditions related to this email -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
