| 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 |
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| 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
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