Re: BRIN is missing in multicolumn indexes documentation

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От Alvaro Herrera
Тема Re: BRIN is missing in multicolumn indexes documentation
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Msg-id 20160323124654.GA566706@alvherre.pgsql
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Ответ на Re: BRIN is missing in multicolumn indexes documentation  (Emre Hasegeli <emre@hasegeli.com>)
Ответы Re: BRIN is missing in multicolumn indexes documentation  (Petr Jediný <petr.jediny@gmail.com>)
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Emre Hasegeli wrote:
> > I guess multicolumn BRIN behaves similarly to B-tree or GiST. But I'm
> > no expert, so I need someone knowledgeable to confirm this. If the
> > following wording is OK, I will update the patch.
> 
> Multicolumn BRIN is like GIN.  Every column is indexed separately.
> The order of the columns doesn't matter.

Right.  You can use one index to cover all columns; the position of the
column in the index won't matter for a query that uses one column.  The
only reason to have multiple BRIN indexes on a single table is to have
a different pages_per_range.

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



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