> I make a guess I've got this due to parallel running of a program making
> bulk INSERTs/UPDATEs into that table. Mmm...I need a way to avoid the big
> number of unused pages in such a case. LOCK TABLE?
Only UPDATEs and DELETEs (and rolled back INSERTs) cause unused pages.
The trick for other people was to run very frequent 'VACUUM goods;'
(like every 15 seconds) on tables when relatively few rows (in small tables)
where constantly beeing updated (e.g. counters/balances).
It might be sufficient in your case though to do the 'VACUUM goods;' after
every bulk UPDATE, like Christopher suggested. A concurrent vacuum won't
help if each bulk update is done in one single transaction.
Andreas