Re: Force specific index disuse

From: Seamus Abshere <seamus(at)abshere(dot)net>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Force specific index disuse
Date: 2014-05-20 16:44:49
Message-ID: 537B8681.3020109@abshere.net
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On 5/20/14, 1:38 PM, Steve Crawford wrote:
> Is there a way to force a specific index to be removed from
> consideration in planning a single query?

hi Steve,

What is the query? Or at least a sanitized but complete version?

Thanks,
Seamus

PS. I've had luck "hinting" with OFFSET 0 but it might not help in your
use case.
http://seamusabshere.github.io/2013/03/29/hinting-postgres-and-mysql-with-offset-and-limit/

> 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.

--
Seamus Abshere, SCEA
+598 99 54 99 54
https://github.com/seamusabshere

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