> I'm using a fake temporary table to hold lists of IDs. It has two fields :
> LISTID and ID.
> The common scenario is that I insert records in this table at the
> start of a
> tansaction and delete them all when committing, so that the table always
> "looks" empty.
>

Is there only one person sing this temp table? or one per user?
How long does this transaction stay open?

> I expect to insert and delete at most 300000 rows a day (10
> consecutive days
> per month).
>
> What kind of issues should I expect and how should I prevent them ?
>
> Some ideas ...
>
> Should I issue a "Select count(*)" every once in a while during the day to
> take care of GC, or should I leave that up the nightly SWEEP ?

oooooh, sweep every night eh? suck it in every night - blow it out every
day... seems like a waste of time to me. Let your databse server manage it's
own space requirements, i'll use what it's created very efficiently.

Alan