Postgres Pro
Downloads
Home   >   mailing lists

Re: Increasing select max(datecol) from bilkaib where datecol<=date'2008-11-01' and (cr='00' or db='00') speed - Mailing list pgsql-performance

From Andrus
Subject Re: Increasing select max(datecol) from bilkaib where datecol<=date'2008-11-01' and (cr='00' or db='00') speed
Date
Msg-id 498EDF1308A1409E9CE994C83A345BA3@andrusnotebook
Whole thread Raw
In response to Re: Increasing select max(datecol) from bilkaib where datecol<=date'2008-11-01' and (cr='00' or db='00') speed  ("Vladimir Sitnikov" <sitnikov.vladimir@gmail.com>)
List pgsql-performance
Tree view 
Vladimir,

>I am afraid PostgreSQL is not smart enough to rewrite query with "or" into
>two separate index scans. There is no way to improve the query
>significantly without rewriting it.
>Note:  for this case indices on (datecol), (cr) and (db) are not very
>helpful.

Thank you very much.
I added you indexes to db and re-write query.
Now it runs fast.

Andrus.

pgsql-performance by date:

Previous
From: hubert depesz lubaczewski
Date:
Subject: Re: Increasing select max(datecol) from bilkaib where datecol<=date'2008-11-01' and (cr='00' or db='00') speed
Next
From: "Andrus"
Date:
Subject: Re: Increasing select max(datecol) from bilkaib wheredatecol<=date'2008-11-01' and (cr='00' or db='00') speed