Horton

Re: Wrong aggregate result when sorting by a NULL value

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Ondřej Bouda <obouda@email.cz>, pgsql-bugs@postgresql.org
Date: 2018-11-03T05:57:00Z
Lists: pgsql-bugs 
Hi,

On 2018-11-02 17:34:43 +0000, Andrew Gierth wrote:
> >>>>> "Andres" == Andres Freund <andres@anarazel.de> writes:
> 
>  >> Andres, do you have time to look at this right now?
> 
>  Andres> Thanks for bisecting.  I'll take a look later today.
> 
> Looks like this:
> 
> +           scratch.d.agg_strict_input_check.nargs = numInputs;
> 
> should have been pertrans->numTransInputs instead?

That looks like it's precisely the reason. I'll push something tomorrow
PST morning, crediting both you (diagnosis) and Tom (bisecting)
obviously, unless you prefer to do so yourself.

It's a bit sad that we don't have any tests that test this :/. I'll add
something for the specific case, but that'll obviously not be
exhaustive.

Greetings,

Andres Freund

Commits

  1. Fix unused-variable warning.

  2. Prevent generating EEOP_AGG_STRICT_INPUT_CHECK operations when nargs == 0.

  3. Fix STRICT check for strict aggregates with NULL ORDER BY columns.

  4. Expression evaluation based aggregate transition invocation.