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