Re: Query Optimization

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Zach Calvert <zachcalvert(at)hemerasoftware(dot)com>
Cc: Sean Davis <sdavis2(at)mail(dot)nih(dot)gov>, Luiz Eduardo Cantanhede Neri <lecneri(at)gmail(dot)com>, pgsql-novice(at)postgresql(dot)org, Dan Scott <balancedtree(at)gmail(dot)com>
Subject: Re: Query Optimization
Date: 2009-05-27 19:53:05
Message-ID: 15817.1243453985@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-novice

Zach Calvert <zachcalvert(at)hemerasoftware(dot)com> writes:
> I've added the leaderboardid, score index and it still does the
> sequential scan. I'm going to try inserting a few hundred thousand
> rows and seeing if it switches to index scan.

You didn't answer the critical question, which is what fraction of the
table rows this query selects. If it's a large fraction then the
planner never will switch to indexscan, no matter what the table size
--- and it'll be doing the right thing. Indexscans aren't magic.

regards, tom lane

In response to

Responses

Browse pgsql-novice by date

  From Date Subject
Next Message Zach Calvert 2009-05-27 20:49:10 Re: Query Optimization
Previous Message Robert Schnabel 2009-05-27 19:03:33 table check constraint