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Re: Working around, or with, bitmap heap scan? - Mailing list pgsql-general

From Laurenz Albe
Subject Re: Working around, or with, bitmap heap scan?
Date
Msg-id 44fa6ec751eb8473583edfbf56d51fb7c229bab9.camel@cybertec.at
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In response to Working around, or with, bitmap heap scan?  ("James A. Robinson" <jim.robinson@gmail.com>)
Responses Re: Working around, or with, bitmap heap scan?
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James A. Robinson wrote:
> I'm newly exposed to a Postgres 9.4 database system, and am
> trying to understand how I might optimize a query that is taking
> a long time to return.
> 
> What I'm observing is an uncached query that takes much much
> longer to complete, sometimes minutes longer, when
> enable_bitmapscan is true.  Even after the query result is
> cached, it seems to consistently be 300 ms slower when
> enable_bitmapscan is true (so taking 900 ms to return instead of
> 600 ms).

It would be helpful to have EXPLAIN (ANALYZE, BUFFERS) output for
both queries.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com

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