Re: Force specific index disuse

Steve Crawford wrote:
> Is there a way to force a specific index to be removed from
> consideration in planning a single query?
>
> Specifically, on a 60-million-row table I have an index that is a
> candidate for removal. I have identified the sets of nightly queries
> that use the index but before dropping it I would like to run
> EXPLAIN and do timing tests on the queries to see the impact of not
> having that index available and rewrite the query to efficiently use
> other indexes if necessary.

If you can afford to lock the table for a while, the easiest is

BEGIN;
DROP INDEX bothersome_idx;
EXPLAIN your_query;
ROLLBACK;

--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services