Re: Using IN with subselect

That's what I wanted it to do I just did not understand how to read the
explain. So is it HashAggregate that means this already loaded?

On Thu, 2004-11-25 at 12:57, Tom Lane wrote:
> Dave Smith <dave.smith@candata.com> writes:
> > Well here is explain. I would guess that it is executed each time ..
> > function any different?
>
> > HashAggregate  (cost=288.32..288.32 rows=1 width=32)
> >    ->  Hash IN Join  (cost=288.18..288.31 rows=1 width=32)
> >          ->  Subquery Scan journal_all  (cost=282.36..282.45 rows=2 width=64)
> >          ->  Hash  (cost=5.83..5.83 rows=1 width=13)
> >                ->  Index Scan using glmast_index3 on glmast (cost=0.00..5.83 rows=1 width=13)
>
> No ... this plan says to scan glmast once, load the selected rows into
> an in-memory hash table, then scan journal_all once and probe the hash
> table for matches.  It looks like a pretty decent choice of plan to me.
>
>             regards, tom lane
--
Dave Smith
CANdata Systems Ltd
416-493-9020