From: | Peter Geoghegan <pg(at)heroku(dot)com> |
---|---|
To: | Andres Freund <andres(at)anarazel(dot)de> |
Cc: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Improving executor performance - tidbitmap |
Date: | 2016-07-15 03:41:21 |
Message-ID: | CAM3SWZQpu0GHrfNNnP3Sk35-24HJyoMirJxD9e_Dkm2CgH2PKA@mail.gmail.com |
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On Wed, Jul 13, 2016 at 8:06 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> I've quickly hacked up an alternative linear addressing hashtable
> implementation. And the improvements are quite remarkable.
>
> Example Query:
> EXPLAIN ANALYZE SELECT SUM(l_extendedprice) FROM lineitem WHERE (l_shipdate >= '1995-01-01'::date) AND (l_shipdate <= '1996-12-31'::date);
> timing without analyze: 4136.425 4101.873 4177.441
>
> after:
> timing without analyze: 2647.364 2674.456 2680.197
>
> as you can see the the time for the bitmap index scan goes from 2461.622
> to 952.161.
That's pretty great. I wonder what this would look like with a BRIN
index, since l_shipdate looks like a good candidate for BRIN indexing.
--
Peter Geoghegan
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