Re: Condition pushdown: why (=) is pushed down into join, but BETWEEN or >= is not?

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От Robert Haas
Тема Re: Condition pushdown: why (=) is pushed down into join, but BETWEEN or >= is not?
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Msg-id CA+TgmoZSJpZY78Etvyc-xrZ+acjGWDCyr7mjLQbQWB2U_gyHZg@mail.gmail.com
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Ответ на Re: Condition pushdown: why (=) is pushed down into join, but BETWEEN or >= is not?  (Andy Fan <zhihui.fan1213@gmail.com>)
Ответы Re: Condition pushdown: why (=) is pushed down into join, but BETWEEN or >= is not?  (Tom Lane <tgl@sss.pgh.pa.us>)
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On Mon, Feb 21, 2022 at 2:31 AM Andy Fan <zhihui.fan1213@gmail.com> wrote:
> +1.  Just to be more precise,  are you also confused about why this
> should not be done at all.  IIUC, I get 3 reasons from Tom's reply.
> a). Planning cost. b). estimation error.  c)  extra qual execution is bad.

This topic has been discussed a number of times, and Tom has basically
always said that he thinks this would be expensive to plan (which I
think is true) and that we wouldn't get much benefit (which I think is
false).

-- 
Robert Haas
EDB: http://www.enterprisedb.com

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