Re: The type int8 and the use of indexes - Mailing list pgsql-general

From Tom Lane
Subject Re: The type int8 and the use of indexes
Date
Msg-id 29644.980522417@sss.pgh.pa.us
Whole thread Raw
In response to Re: The type int8 and the use of indexes  ("Igor V. Rafienko" <igorr@ifi.uio.no>)
Responses Re: The type int8 and the use of indexes  ("Igor V. Rafienko" <igorr@ifi.uio.no>)
List pgsql-general
"Igor V. Rafienko" <igorr@ifi.uio.no> writes:
> on Jan 25, 2001, 15:14, Stephan Szabo std::cout'ed:
> | select * from table where pk=1::int8 should use the index if pk is an
> | int8 column.

> Would that work for other operators (such as <, >, etc.) as well?

It's a necessary prerequisite, anyway.

> Last time I tried something similar on Postgres-7.0.2, the index was
> used on equality but not on "less-than" (the number of rows in the
> result was very small).

It won't use an index unless the optimizer knows that the number of
rows to be selected is small, which for a one-sided "<" query would
depend on where the endpoints of the data range are.  Had you done
a VACUUM ANALYZE recently?

            regards, tom lane

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