2010/1/5 Milan Zamazal <pdm@brailcom.org>:
>>>>>> "PS" == Pavel Stehule <pavel.stehule@gmail.com> writes:
>
> PS> please EXPLAIN ANALYZE Pavel
>
> I see, I'm sorry. Here are the results:
Have you original values random_page_cost and seq_page_cost in postgres.conf?
it is strange.
Pavel
>
> set enable_seqscan = on;
> explain analyze declare c cursor for select * from foo2 order by value;
> QUERY PLAN
>
-------------------------------------------------------------------------------------------------------------------------
> Sort (cost=1829429.20..1854429.20 rows=9999999 width=10) (actual time=43432.727..49303.902 rows=9999999 loops=1)
> Sort Key: value
> Sort Method: external merge Disk: 204208kB
> -> Seq Scan on foo2 (cost=0.00..154049.99 rows=9999999 width=10) (actual time=0.058..1775.928 rows=9999999
loops=1)
> Total runtime: 53693.012 ms
> (5 rows)
>
> set enable_seqscan = off;
> explain analyze declare c cursor for select * from foo2 order by value;
>
> QUERY PLAN
>
---------------------------------------------------------------------------------------------------------------------------------------------
> Index Scan using foo2_value_idx on foo2 (cost=0.00..32220140.73 rows=9999999 width=10) (actual
time=0.225..55055.583rows=9999999 loops=1)
> Total runtime: 56394.283 ms
> (2 rows)
>
>