Re: Need to run CLUSTER to keep performance

Rafael Martinez <r.m.guerrero@usit.uio.no> writes:
> Heikki Linnakangas wrote:
>> On a small table like that you could run VACUUM every few minutes
>> without much impact on performance. That should keep the table size in
>> check.

> Ok, we run VACUUM ANALYZE only one time a day, every night.

There's your problem.

Reading between the lines I gather that you think an update is "free"
in the sense of not creating a need for vacuum.  It's not --- it's
exactly equivalent to an insert + a delete, and it leaves behind a
dead row that needs to be vacuumed.  If you do a lot of updates, you
need to vacuum.

            regards, tom lane