Re: speed up query with max() and odd estimates - Mailing list pgsql-performance

From Steinar H. Gunderson
Subject Re: speed up query with max() and odd estimates
Date
Msg-id 20050426204853.GA29424@uio.no
Whole thread Raw
In response to speed up query with max() and odd estimates  (Matthew Nuzum <mattnuzum@gmail.com>)
Responses Re: speed up query with max() and odd estimates  (Matthew Nuzum <mattnuzum@gmail.com>)
Re: speed up query with max() and odd estimates  (Matthew Nuzum <mattnuzum@gmail.com>)
List pgsql-performance
On Tue, Apr 26, 2005 at 03:16:57PM -0500, Matthew Nuzum wrote:
>  Seq Scan on usage_access  (cost=0.00..1183396.40 rows=12713851
> width=116) (actual time=481796.22..481839.43 rows=3343 loops=1)

That's a gross misestimation -- four orders of magnitude off!

Have you considering doing this in two steps, first getting out whatever
comes from the subquery and then doing the query? Have you ANALYZEd recently?
Do you have an index on atime?

/* Steinar */
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