>
> Perhaps this is what you mean by "deterministic", but isn't it
> possible for some collations to treat multiple byte sequences as equal
> values? And those multiple byte sequences wouldn't necessarily occur
> sequentially in C collation, so it wouldn't be possible to work around
> that by having the grouping node use one collation but the sorting
> node use the C one.
>
> If my memory is incorrect, then this sounds like an intriguing idea.
>
>
I could see the value in a hash aggregate on C-collation that then passes
itself as a partial aggregate up to another step which applies the
collation and then finalizes the aggregation before sorting
