Re: Scrub one large table against another

Tom Lane wrote:
> Brendan Curran <brendan.curran@gmail.com> writes:
>> Tom Lane wrote:
>>> Have you tried doing EXPLAIN ANALYZE of each of the INSERT/DELETE steps?
>
>> FIRST INSERT (Just the select is explained):
>
> EXPLAIN ANALYZE, please, not just EXPLAIN.
>
>             regards, tom lane
>

Sorry, here is the EXPLAIN ANALYZE output of that first SELECT

EXPLAIN ANALYZE SELECT email_record_id from ONLY email_record er
    WHERE email_list_id = 13 AND email IN
    (select email from suppress);

Hash Join  (cost=8359220.68..9129843.00 rows=800912 width=8) (actual
time=2121601.603..2121601.603 rows=0 loops=1)
   Hash Cond: (("outer".email)::text = ("inner".email)::text)
   ->  Unique  (cost=4414093.19..4522324.49 rows=21646260 width=25)
(actual time=1165955.907..1434439.731 rows=21646261 loops=1)
         ->  Sort  (cost=4414093.19..4468208.84 rows=21646260 width=25)
(actual time=1165955.903..1384667.715 rows=21646261 loops=1)
               Sort Key: suppress.email
               ->  Seq Scan on suppress  (cost=0.00..393024.60
rows=21646260 width=25) (actual time=37.784..609848.551 rows=21646261
loops=1)
   ->  Hash  (cost=3899868.47..3899868.47 rows=4606808 width=32) (actual
time=554522.983..554522.983 rows=3245336 loops=1)
         ->  Bitmap Heap Scan on email_record er
(cost=38464.83..3899868.47 rows=4606808 width=32) (actual
time=275640.435..541342.727 rows=3245336 loops=1)
               Recheck Cond: (email_list_id = 13)
               ->  Bitmap Index Scan on list  (cost=0.00..38464.83
rows=4606808 width=0) (actual time=275102.037..275102.037 rows=5172979
loops=1)
                     Index Cond: (email_list_id = 13)
Total runtime: 2122693.864 ms


So much time is being spent in the Unique and Sort leaves... I would
think that it wouldn't need to do the unique portion, since there is no
DISTINCT clause...