Re: Query much slower when run from postgres function

From: Tom Lane
Subject: Re: Query much slower when run from postgres function
Date: ,
Msg-id: 355.1236705647@sss.pgh.pa.us
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In response to: Re: Query much slower when run from postgres function  ( (Frank Ch. Eigler))
Responses: Re: Query much slower when run from postgres function  (decibel)
List: pgsql-performance

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Query much slower when run from postgres function  (Mario Splivalo, )
 Re: Query much slower when run from postgres function  (Tom Lane, )
  Re: Query much slower when run from postgres function  (Guillaume Cottenceau, )
   Re: [JDBC] Query much slower when run from postgres function  (Guillaume Smet, )
    Re: [JDBC] Query much slower when run from postgres function  (Tom Lane, )
     Re: [JDBC] Query much slower when run from postgres function  (Andreas Wenk, )
     Re: [JDBC] Query much slower when run from postgres function  (Dave Cramer, )
      Re: [JDBC] Query much slower when run from postgres function  (James Mansion, )
    Re: [JDBC] Query much slower when run from postgres function  (Scott Carey, )
   Re: Query much slower when run from postgres function  (Mario Splivalo, )
  Re: Query much slower when run from postgres function  (Mario Splivalo, )
   Re: Query much slower when run from postgres function  (Tom Lane, )
    Re: Query much slower when run from postgres function  (Mario Splivalo, )
     Re: Query much slower when run from postgres function  (Tom Lane, )
  Re: Query much slower when run from postgres function  ( (Frank Ch. Eigler), )
   Re: Query much slower when run from postgres function  (Tom Lane, )
    Re: Query much slower when run from postgres function  (decibel, )
     Re: Query much slower when run from postgres function  (Віталій Тимчишин, )
 Re: Query much slower when run from postgres function  (decibel, )

 (Frank Ch. Eigler) writes:
> For a prepared statement, could the planner produce *several* plans,
> if it guesses great sensitivity to the parameter values?  Then it
> could choose amongst them at run time.

We've discussed that in the past.  "Choose at runtime" is a bit more
easily said than done though --- you can't readily flip between plan
choices part way through, if you've already emitted some result rows.

            regards, tom lane


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From: Scott Marlowe
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