Re: Parallel Aggregates for string_agg and array_agg

On 30 March 2018 at 02:00, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> On 03/29/2018 05:49 AM, David Rowley wrote:
>> Attached is v9, which is based on Tom's v8 but includes the new tests
>> and I think the required fix to disable use of the serial/deserial
>> function for array_agg().
>>
>
> I have only looked at the diff, but it seems fine to me (in the sense
> that it's doing the right checks to disable parallelism only when really
> needed).
>
> FWIW I wonder if we might simply fallback to input/output functions when
> the send/receive functions are not available. Not sure it's worth it.

I think it's a corner case to have a type without send/receive, but I
might just be lacking imagination.

I meant to mention earlier that I coded
agg_args_have_sendreceive_funcs() to only check for send/receive
functions. Really we could allow a byval types without send/receive
functions, since the serial/deserial just send the raw datums in that
case, but then the function becomes
agg_byref_args_have_sendreceive_funcs(), which seemed a bit obscure,
so I didn't do that. Maybe I should?

--
David Rowley http://www.2ndQuadrant.com/
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