Re: The planner chooses seqscan+sort when there is an

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От Tom Lane
Тема Re: The planner chooses seqscan+sort when there is an
Дата
Msg-id 18195.1146681248@sss.pgh.pa.us
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Ответ на Re: The planner chooses seqscan+sort when there is an  (Csaba Nagy <nagy@ecircle-ag.com>)
Ответы Re: The planner chooses seqscan+sort when there is an  (Scott Marlowe <smarlowe@g2switchworks.com>)
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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

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