Re: Bug? Function with side effects not evaluated in CTE

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От
Tom Lane
Тема
Re: Bug? Function with side effects not evaluated in CTE
Дата
Msg-id
2651.1382381629@sss.pgh.pa.us
Ответ на
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Дерево обсуждения
Bug? Function with side effects not evaluated in CTE Moshe Jacobson <moshe@neadwerx.com>
Re: Bug? Function with side effects not evaluated in CTE Tom Lane <tgl@sss.pgh.pa.us>
Re: Bug? Function with side effects not evaluated in CTE Merlin Moncure <mmoncure@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE Rowan Collins <rowan.collins@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE Merlin Moncure <mmoncure@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Merlin Moncure <mmoncure@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Merlin Moncure <mmoncure@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Moshe Jacobson <moshe@neadwerx.com>
Re: Bug? Function with side effects not evaluated in CTE Tom Lane <tgl@sss.pgh.pa.us>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Tom Lane <tgl@sss.pgh.pa.us>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Moshe Jacobson <moshe@neadwerx.com>
Re: Bug? Function with side effects not evaluated in CTE Tom Lane <tgl@sss.pgh.pa.us>
Re: Bug? Function with side effects not evaluated in CTE Merlin Moncure <mmoncure@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE Rowan Collins <rowan.collins@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE BladeOfLight16 <bladeoflight16@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE John R Pierce <pierce@hogranch.com>
Re: Bug? Function with side effects not evaluated in CTE BladeOfLight16 <bladeoflight16@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Moshe Jacobson <moshe@neadwerx.com>
Re: Bug? Function with side effects not evaluated in CTE BladeOfLight16 <bladeoflight16@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE Adam Jelinek <ajelinek@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE David Johnston <polobo@yahoo.com>
Re: Bug? Function with side effects not evaluated in CTE Adam Jelinek <ajelinek@gmail.com>
Re: Bug? Function with side effects not evaluated in CTE Moshe Jacobson <moshe@neadwerx.com>
Moshe Jacobson  writes:
> I am of the belief that if the function in a CTE is volatile, that it
> should be executed unconditionally.

[ shrug... ]  Consider

	SELECT volatile_function(i) FROM generate_series(1, 10) i LIMIT 1;

How many times should the volatile function get executed?  If your answer
is not "10", how is this different from the CTE case?  This LIMIT clause
is restricting the number of times the function executes in pretty much
the same way that our definition of CTE evaluation does, AFAICS.

You could of course argue that our definition of LIMIT is wrong too,
but that's going to raise the bar for convincing people even higher,
because of the number of existing applications that such a redefinition
would break.

			regards, tom lane

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