Treat aggregate direct arguments as per-agg data not per-trans data.
There is no reason to insist that direct arguments must match before
we can merge transition states of two aggregate calls. They're only
used during the finalfn call, so we can treat them as like the finalfn
itself. This allows, eg, merging of
select
percentile_cont(0.25) within group (order by a),
percentile_disc(0.5) within group (order by a)
from ...
This didn't matter (and could not have been tested) before we allowed
state merging of OSAs otherwise.
projects / postgresql / commit