Bill,
> As a quick fix, since we're upgrading to 7.4.2 in a few weeks anyhow
> (which includes pg_autovacuum), I've simply set up an hourly vacuum on
> this table. It only takes ~4 seconds to execute when kept up on an
> hourly basis. Is there any penalty to vacuuming too frequently, other
> than the time wasted in an unnecessary vacuum operation?
Nope, no penalty other than the I/O and CPU load while vacuuming. If you
have a lot of transactions involving serial writes to many tables, sometimes
you can get into a deadlock situation, which is annoying, but I wouldn't
assume this to be a problem until it crops up.
--
-Josh Berkus
Aglio Database Solutions
San Francisco