Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-06 Thread Merlin Moncure
On Wed, Oct 5, 2016 at 3:27 PM, Stephen Frost wrote: > Darren, > > * Darren Lafreniere (dlafreni...@onezero.com) wrote: >> Tom Lane wrote: >> > > Gavin Wahl wrote: >> > >> It seems trivial to accelerate a MAX or MIN query with a BRIN index. You >> > >> just find the page range with the largest/sm

Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-05 Thread Darren Lafreniere
Stephen Frost wrote: > For at least some of the common BRIN use-cases, where the rows are > inserted in-order and never/very-rarely modified or deleted, this > approach would work very well. > Thanks Stephen, this is exactly our use case.

Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-05 Thread Stephen Frost
Darren, * Darren Lafreniere (dlafreni...@onezero.com) wrote: > Tom Lane wrote: > > > Gavin Wahl wrote: > > >> It seems trivial to accelerate a MAX or MIN query with a BRIN index. You > > >> just find the page range with the largest/smallest value, and then only > > >> scan that one. Would that be

Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-05 Thread Darren Lafreniere
Tom Lane wrote: > > Gavin Wahl wrote: > >> It seems trivial to accelerate a MAX or MIN query with a BRIN index. You > >> just find the page range with the largest/smallest value, and then only > >> scan that one. Would that be hard to implement? I'm interested in > working > >> on it if someone c

Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-05 Thread Tom Lane
Alvaro Herrera writes: > Darren Lafreniere wrote: >> We found a pgsql-hackers thread from about a year ago about optimizing >> ORDER BY for BRIN indexes. Tom Lane suggested that he was working on it: >> https://www.postgresql.org/message-id/11881.1443393360%40sss.pgh.pa.us > Tom said he was worki

Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-05 Thread Darren Lafreniere
Ahh, yes. I misread that. Thank you for the clarification. On Wed, Oct 5, 2016 at 2:27 PM, Alvaro Herrera wrote: > Darren Lafreniere wrote: > > > "In addition to simply finding the rows to be returned by a query, an > index > > may be able to deliver them in a specific sorted order. This allows

Re: [GENERAL] BRIN indexes and ORDER BY

2016-10-05 Thread Alvaro Herrera
Darren Lafreniere wrote: > "In addition to simply finding the rows to be returned by a query, an index > may be able to deliver them in a specific sorted order. This allows a > query's ORDER BY specification to be honored without a separate sorting > step. Of the index types currently supported by

Re: [GENERAL] BRIN indexes

2016-01-30 Thread Alvaro Herrera
Felipe Santos wrote: > brin_db=# EXPLAIN ANALYSE SELECT count(*) FROM orders WHERE order_date > BETWEEN '2012-01-04 09:00:00' and '2014-01-04 14:30:00'; > > QUERY PLAN > > --

Re: [GENERAL] BRIN indexes

2016-01-30 Thread Igor Neyman
From: pgsql-general-ow...@postgresql.org [mailto:pgsql-general-ow...@postgresql.org] On Behalf Of Felipe Santos Sent: Thursday, January 28, 2016 1:17 PM To: Joshua D. Drake Cc: Melvin Davidson ; David Rowley ; pgsql-general@postgresql.org; Thomas Kellerer Subject: Re: [GENERAL] BRIN indexes

Re: [GENERAL] BRIN indexes

2016-01-29 Thread Alvaro Herrera
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

Re: [GENERAL] BRIN indexes

2016-01-29 Thread Emre Hasegeli
>> 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

Re: [GENERAL] BRIN indexes

2016-01-29 Thread Felipe Santos
Rowley < > david.row...@2ndquadrant.com>; pgsql-general@postgresql.org; Thomas > Kellerer > *Subject:* Re: [GENERAL] BRIN indexes > > > > "Further to the point, it is self defeating to have more than one BRIN > index on the table if the columns involved would have mutual

Re: [GENERAL] BRIN indexes

2016-01-28 Thread Felipe Santos
2016-01-28 16:03 GMT-02:00 Joshua D. Drake : > On 01/28/2016 09:41 AM, Melvin Davidson wrote: > >> So, IOW, and the answer to my question is yes, it should be insured that >> all pages involved are physically adjacent (by design or by pre-sort) >> before creating a BRIN on them. >> Further to the

Re: [GENERAL] BRIN indexes

2016-01-28 Thread Joshua D. Drake
On 01/28/2016 09:41 AM, Melvin Davidson wrote: So, IOW, and the answer to my question is yes, it should be insured that all pages involved are physically adjacent (by design or by pre-sort) before creating a BRIN on them. Further to the point, it is self defeating to have more than one BRIN index

Re: [GENERAL] BRIN indexes

2016-01-28 Thread Melvin Davidson
So, IOW, and the answer to my question is yes, it should be insured that all pages involved are physically adjacent (by design or by pre-sort) before creating a BRIN on them. Further to the point, it is self defeating to have more than one BRIN index on the table if the columns involved would have

Re: [GENERAL] BRIN indexes

2016-01-28 Thread David Rowley
On 29 January 2016 at 06:10, Melvin Davidson wrote: > With regard to BRIN indexes: > > http://www.postgresql.org/docs/9.5/interactive/brin-intro.html > > 62.1. Introduction > > "A block range is a group of pages that are physically adjacent in the > table; for each block range, some summar

Re: [GENERAL] BRIN indexes

2016-01-28 Thread Alvaro Herrera
Melvin Davidson wrote: > With regard to BRIN indexes: > > http://www.postgresql.org/docs/9.5/interactive/brin-intro.html > > 62.1. Introduction > > "A block range is a group of pages that are physically adjacent in the > table; for each block range, some summary info is stored by the inde