Re: VACUUM and 24/7 database operation

Thomas.Favier@accelance.fr writes:
> - Is 2 minutes a standard time for vacuuming a 500.000 rows table ?
> - Can it be reduced ?
> - In a far future, what are the problems we can run into not vacuuming
> that table ? We have already seen that after a month, some transactions
> involving where id >= some_value take forever, so we supressed them.

If it takes a month before query performance gets bad, then perhaps you
could vacuum the table only once a month.  However, that vacuum would
probably take longer than two minutes, so it's a tradeoff...

We have plans for 7.2 to reduce the need for periodic vacuums, but that
won't help you much now.

There are patches available for a "lazy vacuum" process on 7.0.3,
which can be a win if vacuum only needs to get rid of a few rows.
But they're not very thoroughly tested IMHO.  See
http://people.freebsd.org/~alfred/vacfix/

            regards, tom lane