am Wed, dem 04.04.2007, um 23:17:54 -0400 mailte Sumeet folgendes:
> sm=> explain analyze select * from ma limit 10;
> QUERY
> PLAN
> -------------------------------------------------------------------------------------------------------------------------------------
> Limit (cost=0.00..0.45 rows=10 width=76) (actual time=21985.292..22204.340
> rows=10 loops=1)
> -> Seq Scan on ma (cost=0.00..2181956.92 rows=48235392 width=76) (actual
> time=21985.285..22204.308 rows=10 loops=1)
> Total runtime: 22204.476 ms
> (3 rows)
which version?
I have 8.1 and on a table with 1.9 million records i got:
scholl=# explain analyse select * from bde_meldungen limit 10;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Limit (cost=0.00..0.34 rows=10 width=157) (actual time=19.570..19.660 rows=10
loops=1)
-> Seq Scan on bde_meldungen (cost=0.00..65748.33 rows=1957933 width=157)
(actual time=19.565..19.587 rows=10 loops=1)
Total runtime: 19.845 ms
(3 rows)
If I remember correctly, since 8.0 or 8.1 we have a massive improvement with
LIMIT.
Andreas
--
Andreas Kretschmer
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
