Re: Ordering behavior for aggregates

Ronan Dunklau <ronan.dunklau@aiven.io> writes:
> Le mardi 13 décembre 2022, 16:13:34 CET Tom Lane a écrit :
>> Accordingly, I find nothing at all attractive in this proposal.
>> I think the main thing it'd accomplish is to drive users back to
>> the bad old days of ordering-by-subquery, if they have a requirement
>> we failed to account for.

> I think the ability to mark certain aggregates as being able to completely
> ignore the ordering because they produce exactly the same results is still a
> useful optimization.

That is *exactly* the position I do not accept.

I think it's fairly unlikely that a user would trouble to write ORDER BY
within an aggregate call if they didn't need it.  So my opinion of this
proposal is that it's a lot of work to create an optimization effect that
will be useless to nearly all users, and might actively break the queries
of some.

            regards, tom lane