Re: Forcing seq_scan off for large table joined with tiny table yeilds improved performance

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: Mario Splivalo <mario(dot)splivalo(at)megafon(dot)hr>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Forcing seq_scan off for large table joined with tiny table yeilds improved performance
Date: 2009-04-06 13:58:05
Message-ID: dcc563d10904060658v621cbd3drbb75b6428d770b04@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

On Mon, Apr 6, 2009 at 6:20 AM, Mario Splivalo
<mario(dot)splivalo(at)megafon(dot)hr> wrote:
> Scott Marlowe wrote:
>>
>> It's not really solved, it's just a happy coincidence that the current
>> plan runs well.  In order to keep the query planner making good
>> choices you need to increase stats target for the field in the index
>> above.  The easiest way to do so is to do this:
>>
>> alter database mydb set default_statistics_target=100;
>>
>> and run analyze again:
>>
>> analyze;
>
> So, i removed the index on field_name, set default_default_statistics_target
> to 100, analyzed, and the results are the same:

Why did you remove the index?

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Robert Haas 2009-04-06 14:36:50 Re: plpgsql arrays
Previous Message Tom Lane 2009-04-06 13:54:00 Re: probelm with alter table add constraint......