Re: Cube Index Size

From: Teodor Sigaev <teodor(at)sigaev(dot)ru>
To: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: Nick Raj <nickrajjain(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Cube Index Size
Date: 2011-06-01 12:38:08
Message-ID: 4DE632B0.5030603@sigaev.ru
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> Ok, I can reproduce the issue with that. The index is only 4MB in size
> when I populate it with random data (vs. 15 MB with your data). The
> command I used is:
>
> INSERT INTO cubtest SELECT cube(random(), random()) FROM
> generate_series(1,20000);
>
> My guess is that the picksplit algorithm performs poorly with that data.
> Unfortunately, I have no idea how to improve that.

One of idea is add sorting of Datums to be splitted by cost of insertion. It's
implemented in intarray/tsearch GiST indexes.

Although I'm not sure that it will help but our researches on Guttman's
picksplit algorimth show significant improvements.
--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/

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