Re: how to change the index chosen in plan?

From: Rural Hunter <ruralhunter(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: how to change the index chosen in plan?
Date: 2012-06-08 14:23:12
Message-ID: 4FD20AD0.3040902@gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

No, it's not the analyze problem. For some other values on b.bid such
as 9, 10, the plan is fine since there a a lot of rows in table b for
them. But for some specific values such as 8 I want the plan changed.

于2012年6月8日 22:10:58,Tom Lane写到:
> Rural Hunter <ruralhunter(at)gmail(dot)com> writes:
>> I have a query like this:
>> select a.* from a inner join b on a.aid=b.aid where a.col1=33 a.col2=44
>> and b.bid=8
>> postgresql selected the index on a.col1 then selected the index on
>> b.bid. But in my situation, I know that the query will be faster if it
>> chose the index on b.bid first since there are only a few rows with
>> value 8.
>
> If you know that and the planner doesn't, maybe ANALYZE is called for.
>
> regards, tom lane
>

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Cédric Villemain 2012-06-08 14:31:10 Re: non index use on LIKE on a non pattern string
Previous Message Tom Lane 2012-06-08 14:10:58 Re: how to change the index chosen in plan?