specify whitch index to use - Mailing list pgsql-general

From pgsql-general@list.coretech.ro
Subject specify whitch index to use
Date
Msg-id 45574DA4.9090206@list.coretech.ro
Whole thread Raw
Responses Re: specify whitch index to use  (Andreas Kretschmer <akretschmer@spamfence.net>)
List pgsql-general
hello,

I have two indexes on a table on cols col1 and col2, the table has ~10M
rows on pg v8.1.4

when I use "where col1 = val1" the query is fast and returns 0 rows
when I use "where col2 > val2" the query is slow and returns ~1M rows

in both cases the corresponding indexes are used.
when I use "where col1 = val1 and col2 > val2" the query is slow and
returns 0 rows using the index on col2

is there any way for postgres to use both indexes when relevant columns
are present in a where clause ?
is it possible to specify which index to use in a query ?


thanks,
razvan radu



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