Re: The planner chooses seqscan+sort when there is an - Mailing list pgsql-general

From Tom Lane
Subject Re: The planner chooses seqscan+sort when there is an
Date
Msg-id 18195.1146681248@sss.pgh.pa.us
Whole thread Raw
In response to Re: The planner chooses seqscan+sort when there is an  (Csaba Nagy <nagy@ecircle-ag.com>)
Responses Re: The planner chooses seqscan+sort when there is an  (Scott Marlowe <smarlowe@g2switchworks.com>)
List pgsql-general
Csaba Nagy <nagy@ecircle-ag.com> writes:
> OK, maybe that's the point... the "cost bust" given to the sequential
> scan by enable_seqscan=off is not enough in this case to exceed the cost
> of the index scan ?

Looks that way to me.  You could try setting enable_sort off as well,
which will penalize the seqscan+sort plan another 100million cost units.
And maybe try reducing random_page_cost to make the indexscan look
cheaper.  However, if there's a 100million delta between the two plans,
I suspect you really really don't want the indexscan anyway ;-)

            regards, tom lane

pgsql-general by date:

Previous
From: "Florian G. Pflug"
Date:
Subject: Re: The planner chooses seqscan+sort when there is an
Next
From: Scott Marlowe
Date:
Subject: Re: The planner chooses seqscan+sort when there is an