Re: Optimizing Query

Ok, now I have another question... it doesn't seem to be accessing the index.

explain select k.kbid,k.title from knowledge k , kbwords w0 , kbwords w1
WHERE ((k.kbid=w0.kbid and w0.wordid=42743) AND (k.kbid=w1.kbid and
w1.wordid=85369))

NOTICE: QUERY PLAN:

Merge Join (cost=32339.30..35496.97 rows=19262538 width=24)
-> Merge Join (cost=16530.24..16668.77 rows=233274 width=20)
-> Sort (cost=15809.06..15809.06 rows=8257 width=4)
-> Seq Scan on kbwords w1 (cost=0.00..15271.85 rows=8257
width=4)
-> Sort (cost=721.18..721.18 rows=2825 width=16)
-> Seq Scan on knowledge k (cost=0.00..559.25 rows=2825
width=16)
-> Sort (cost=15809.06..15809.06 rows=8257 width=4)
-> Seq Scan on kbwords w0 (cost=0.00..15271.85 rows=8257 width=4)

Note the sequential scans... there is a wordindex where w0.wordid=42743...
why isn't it doing an indexscan? wouldn't that be more efficient?

Justin

At 04:45 PM 3/5/2001 -0500, you wrote:
>Yes.
>
> > On Mon, Mar 05, 2001 at 04:07:57PM -0500, Bruce Momjian allegedly wrote:
> > > Have you tried VACUUM ANALYZE and CLUSTER?
> >
> > I assume CLUSTER still drops all indexes except the one you're clustering
> > on?
> >
> > Mathijs
> > --
> > It's not that perl programmers are idiots, it's that the language
> > rewards idiotic behavior in a way that no other language or tool has
> > ever done.
> > Erik Naggum
> >
>
>
>--
> Bruce Momjian | http://candle.pha.pa.us
> pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
> + If your life is a hard drive, | 830 Blythe Avenue
> + Christ can be your backup. | Drexel Hill, Pennsylvania 19026

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