Re: planner not using index for like operator - Mailing list pgsql-performance

From Jim C. Nasby
Subject Re: planner not using index for like operator
Date
Msg-id 20060425182444.GK97354@pervasive.com
Whole thread Raw
In response to planner not using index for like operator  ("Sriram Dandapani" <sdandapani@counterpane.com>)
List pgsql-performance
On Tue, Apr 25, 2006 at 10:08:02AM -0700, Sriram Dandapani wrote:
Here's the key:

> "  Filter: ((col1)::text ~~ '172.%'::text)"

In order to do a like comparison, it has to convert col1 (which I'm
guessing is of type 'inet') to text, so there's no way it can use an
index on col1 (maybe a function index, but that's a different story).

Is there some reason you're not doing

WHERE col1 <<= '172/8'::inet

?
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461

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