On Wed, Jun 25, 2008 at 02:43:29PM -0700, Dane Miller wrote:

> which makes perfect sense, thanks for the clue bat Bill.  But I *think* I
> also want to avoid having to constantly vacuum this table during
> frequent UPDATEs (see #3 below for why this is couched in 'I think').

You shouldn't need to worry about constant vacuuming.  See below.

> 3) use UPDATE statements 
>   UPDATE transcation_log set tid=DEFAULT;
>   -- autovacuum will clean up dead tuples as needed
>   -- Heap-Only Tuples (Postgresql 8.3) reclaim space and reduce need to
> vacuum

Yes.  If you're on 8.3, then if you set the table with a suitable fill
factor and put no index on the field that contains the value, you'll be in
fine shape.  HOT works, I have seen it in action, and I'm a believer.  Note
that this means you need a dummy primary key on this table.

A