Re: BRIN indexes

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От Alvaro Herrera
Тема Re: BRIN indexes
Дата
Msg-id 20160129132155.GA767307@alvherre.pgsql
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Ответ на Re: BRIN indexes  (Emre Hasegeli <emre@hasegeli.com>)
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Emre Hasegeli wrote:
> >> From the above, may I presume that it is best to cluster (or sort), the
> >> table based on the intended
> >> BRIN column(s) before actually creating the index to insure the pages are
> >> adjacent? If so, should
> >>  that not be included in the documentation, instead of implied?
>
> The same question is asked to me at PGConf.DE.  I think it would be
> nice to address it in the documentation somehow.  Maybe, we should
> also explain how the table is physically organised.  It is not clear
> to users what kind of operations would make BRIN more useful.

Grumble.

> > I don't have faith in CLUSTER anyway.  Taking exclusive locks and all.
>
> It also requires a btree index.  If you can afford to have btree, you
> probably don't need BRIN anyway.  Something lighter than CLUSTER which
> can use BRIN would be useful.

What I think would be useful is a way for the BRIN index to guide
location of a new tuple, so that it's put in the right spot right from
the start, instead of having it be moved later.

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


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