Re: Is it possible to create row-wise indexable condition for special case... - Mailing list pgsql-general

From François Beausoleil
Subject Re: Is it possible to create row-wise indexable condition for special case...
Date
Msg-id 8F808C79-81E1-4638-8C3A-B2D03541A705@teksol.info
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In response to Is it possible to create row-wise indexable condition for special case...  (Maxim Boguk <maxim.boguk@gmail.com>)
List pgsql-general

Le 2012-08-06 à 01:39, Maxim Boguk a écrit :

I know that for condition like   ((field1>value1) or (field1=value1 and field2>value2))  I could built index on (field1, field2) and use indexable condition like   (field1, field2) > (value1, value2).

However, I have very tricky query which requires an indexable condition like  (field1>value1) or (field1=value1 and field2<value2).
I guess that I could use index definition like ON(field1, field2 DESC) however,  I can not build query condition which would use that index effectively.

Is it possible and my mind just went black on simple task?

PS: field2 is varchar type so I couldn't using the negative values trick
build index ON(field1, (-field2))
and write something like WHERE (field1, -field2) > (value1, -value2).

--
Maxim Boguk
Senior Postgresql DBA
http://www.postgresql-consulting.ru/


Could you perhaps use bitmapped indexes? Such that you'd have two indexes, and the optimizer would AND the two indexes together?

Hope that helps!
François

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