Re: Parallel Aggregates for string_agg and array_agg - Mailing list pgsql-hackers

Hi,

On 2018-05-01 14:09:39 -0700, Mark Dilger wrote:
> I don't care which order the data is in, as long as x[i] and y[i] are
> matched correctly.  It sounds like this patch would force me to write
> that as, for example:
> 
> select array_agg(a order by a, b) AS x, array_agg(b order by a, b) AS y
>   from generate_a_b_func(foo);
> 
> which I did not need to do before.

Why would it require that? Rows are still processed row-by-row even if
there's parallelism, no?

Greetings,

Andres Freund