Assuming you are joining on "Table 1".id = "Table 2".id - do you have indexes on both columns? Have you analyzed your
tables+ indexes (are there statistics available?) If not those criterias are met, it is unlikely that postgres will
choosean index scan.
-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org]On Behalf Of Fernando
Lujan
Sent: den 21 mars 2006 19:08
To: pgsql-performance@postgresql.org
Subject: [PERFORM] Sequence Scan vs. Index scan
Hi guys,
I'm trying to figure out when Sequence Scan is better than Index Scan. I
just want to know this because I disabled the sequence scan in
postgresql and receive a better result. :)
Two tables.
Table 1 (1 million rows )
-----------
id
text
table2_id
Table 2 (300 thousand rows)
----------
id
text 2
When I join these two tables I have a sequence_scan. :(
Thanks in advance.
Fernando Lujan
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TIP 6: explain analyze is your friend
