| From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
|---|---|
| To: | Emre Hasegeli <emre(at)hasegeli(dot)com> |
| Cc: | Petr Jediný <petr(dot)jediny(at)gmail(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: BRIN is missing in multicolumn indexes documentation |
| Date: | 2016-03-23 12:46:54 |
| Message-ID: | 20160323124654.GA566706@alvherre.pgsql |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
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
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Michael Paquier | 2016-03-23 12:51:37 | Re: Postgres_fdw join pushdown - getting server crash in left outer join of three table |
| Previous Message | Michael Paquier | 2016-03-23 12:46:08 | Re: pg_xlogdump fails to handle WAL file with multi-page XLP_FIRST_IS_CONTRECORD data |