Re: Why performance improvement on converting subselect to a function ?

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От Tom Lane
Тема Re: Why performance improvement on converting subselect to a function ?
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Msg-id 4578.1059514334@sss.pgh.pa.us
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Ответ на Re: Why performance improvement on converting subselect  (Rajesh Kumar Mallah)
Ответы Re: Why performance improvement on converting subselect to a function ?  (Rajesh Kumar Mallah)
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Rajesh Kumar Mallah <> writes:
> Tom Lane wrote:
>> Odd.  Apparently the planner is picking a better plan in the function
>> context than in the subselect context --- which is strange since it
>> ought to have less information.

> [ verbose plan snipped ]

Well, that sure seems to be the same plan.  Curious that the runtime
wasn't about the same.  Perhaps the slow execution of the first query
was a caching effect?  If you alternate trying the query both ways,
does the speed difference persist?

            regards, tom lane

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