Re: Postgres Optimizer is not smart enough?

Litao Wu wrote:
> Hi All,
>
> Here is my test comparison between Postgres (7.3.2)
> optimizer vs Oracle (10g) optimizer.
>
> It seems to me that Postgres optimizer is not smart
> enough.
>
> Did I miss anything?

Yeah, 7.4.

7.3.2 is *ancient*. Here's output from 7.4:

[test@ferrari] explain analyze
test-# SELECT module,  sum(action_deny)
test-# FROM test
test-# WHERE  created >= ('now'::timestamptz - '1
test'# day'::interval) AND customer_id='100'
test-#   AND  domain='100'
test-# GROUP BY module;

  QUERY PLAN


-----------------------------------------------------------------------------------------------------------------------------------------------------------
  HashAggregate  (cost=5.69..5.69 rows=1 width=13) (actual
time=715.058..715.060 rows=1 loops=1)
    ->  Index Scan using test_id1 on test  (cost=0.00..5.68 rows=1
width=13) (actual time=0.688..690.459 rows=1 loops=1)
          Index Cond: ((customer_id = 100) AND (created >= '2005-01-11
17:52:22.364145-05'::timestamp with time zone) AND (("domain")::text =
'100'::text))
  Total runtime: 717.546 ms
(4 rows)

[test@ferrari] create index test_id2 on test(domain);
CREATE INDEX
[test@ferrari] analyze test;
ANALYZE
[test@ferrari]
[test@ferrari] explain analyze
test-# SELECT module,  sum(action_deny)
test-# FROM test
test-# WHERE  created >= ('now'::timestamptz - '1
test'# day'::interval) AND customer_id='100'
test-#   AND  domain='100'
test-# GROUP BY module;
                                                        QUERY PLAN


------------------------------------------------------------------------------------------------------------------------
  HashAggregate  (cost=5.68..5.69 rows=1 width=13) (actual
time=10.778..10.780 rows=1 loops=1)
    ->  Index Scan using test_id2 on test  (cost=0.00..5.68 rows=1
width=13) (actual time=10.702..10.721 rows=1 loops=1)
          Index Cond: (("domain")::text = '100'::text)
          Filter: ((created >= '2005-01-11
17:53:16.720749-05'::timestamp with time zone) AND (customer_id = 100))
  Total runtime: 11.039 ms
(5 rows)

[test@ferrari] select version();
  PostgreSQL 7.4.5 on i686-pc-linux-gnu, compiled by GCC
i686-pc-linux-gnu-gcc (GCC) 3.4.0 20040204 (prerelease)
(1 row)

Hope that helps,

Mike Mascari