Re: Post-mature optimization...

Hey Jeff,
Jeff Frost wrote:
> What does the explain output look like for this select:
>
> SELECT * FROM foo WHERE service_account NOT IN
> (SELECT service_account FROM existing_data);
I'll change the actual table names to match my earlier example for
consistency. Note that I left out the inner WHERE clause, originally,
to try to keep the example simple. Here's the EXPLAIN:
=> EXPLAIN
-> SELECT * FROM foo
-> WHERE service_account NOT IN
-> (SELECT service_account FROM existing_data
(> WHERE ut_id = 1 AND account_type = 'c');
QUERY PLAN

------------------------------------------------------------------------------------------
Seq Scan on foo (cost=0.00..479764255675.94 rows=1137108 width=181)
Filter: (NOT (subplan))
SubPlan
-> Seq Scan on existing_data (cost=0.00..413623.32 rows=3317084
width=13)
Filter: ((ut_id = 1) AND ((account_type)::text = 'c'::text))
(5 rows)

> Also, how many service accounts are there in your real data?
=> SELECT COUNT(id) FROM uv2_serviceaddresses WHERE ut_id = 1 and
account_type='c';
count
---------
2274214
(1 row)

uv2=> SELECT COUNT(id) FROM uv2_serviceaddresses;
count
---------
8004888
(1 row)

Thanks for taking the time to respond,

Eric.