Re: array_agg(DISTINCT) caused a segmentation fault

On 2023/02/13 16:44, David Rowley wrote:
> On Mon, 13 Feb 2023 at 18:29, Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>> =# SELECT array_agg(distinct val) FROM (SELECT NULL AS val FROM generate_series(1, 2)) hoge;
>> LOG: server process (PID 76507) was terminated by signal 11: Segmentation fault: 11
>> DETAIL: Failed process was running: SELECT array_agg(distinct val) FROM (SELECT NULL AS val FROM generate_series(1, 2)) hoge;
>
> This was a fairly trivial logic bug in
> ExecEvalPreOrderedDistinctSingle(). The JIT code calls that same
> function and ExecEvalPreOrderedDistinctMulti() uses the standard
> expression evaluation logic. So looks like the problem is just
> isolated to ExecEvalPreOrderedDistinctSingle().
>
> I've now pushed a fix for it and included your test. To get it to
> crash it needed to be a byref aggregate without a strict transition
> function. There are not too many of those, which is probably why
> nobody noticed this before.

Thanks for the fix!

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION