| From: | "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com> |
|---|---|
| To: | boinger <boinger(at)gmail(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Performance woes relating to DISTINCT (I think) |
| Date: | 2005-09-29 20:49:00 |
| Message-ID: | 20050929204900.GM30974@pervasive.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
On Tue, Sep 27, 2005 at 09:07:41AM -0500, boinger wrote:
> -> Index Scan using strafe_group on tasks_applied
> (cost=0.00..6.02 rows=1 width=22) (actual time=0.042..0.043 rows=0
> loops=1188)
>
> Index Cond: ((("outer".modcode)::text =
> (tasks_applied.modcode)::text) AND (tasks_applied.yearcode =
> "outer".yearcode) AND (tasks_applied.seid = 500001))
>
> Filter: (cid = 0)
>
> Total runtime: 80.764 ms
Compare that to the index scan it had to do before. Now that you gave
the database the exact info it needs to answer your real question, it
can use a much, much more selective index scan.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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