Do it in two ways (a) re-use the rte list as much as possible instead of
re-calculating over and over again (b) Limit the recursion to the relevant
parts of the query tree
Since flattening query may flatten outer joins' columns into coalesce expr that is
in the USING part, and that was not expected before this commit, these queries were
erroring out. It is fixed by this commit with considering coalesce expression as well.
We used to error out if there is a reference table
in the query participating a union. This has caused
pushdownable queries to be evaluated in coordinator.
Now we let reference tables inside union queries as long
as there is a distributed table in from clause.
Existing join checks (reference table on the outer part)
sufficient enought that we do not need check the join relation
of reference tables.
Marco Slot
velioglu
Murat Tuncer
Hanefi Onaldi