From: Brendan Curran <brendan.curran@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Pg Performance list <pgsql-performance@postgresql.org>
Subject: Re: Scrub one large table against another
Date: Tue, 10 Oct 2006 17:46:18 -0600
Message-ID: <452C30CA.2070801@gmail.com> (raw)
In-Reply-To: <13912.1160520427@sss.pgh.pa.us>
References: <452C1437.9040709@gmail.com>
<13451.1160518445@sss.pgh.pa.us>
<452C208C.5010603@gmail.com>
<13912.1160520427@sss.pgh.pa.us>
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...
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To: pgsql-performance@postgresql.org
Cc: brendan.curran@gmail.com, tgl@sss.pgh.pa.us
Subject: Re: Scrub one large table against another
In-Reply-To: <452C30CA.2070801@gmail.com>
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