We have a partitioned table structure where the partitions are created
on a daily basis. One of the inserts into the daily partition failed
(crashed) ..the partition was empty after the crash. We did a vacuum
of the partition and it takes very long (over 30 minutes).
Postgres 8.1.2 ... vacuum_cost_delay = 0.
2 cpu...dual core with raid 10 6x300Gb disks.
the load during vacuum was normal (about 50% cpu util with a similar IO wait).
What is vacuum doing that takes so long on an empty table?