Gayathri TK <gtambar@ncsu.edu> writes:
> How do i efficiently retrieve this information?
You don't, because the planner doesn't actually calculate all possible
join trees --- it wouldn't run in a reasonable amount of time if it
tried. It only considers trees that are built from subtrees that appear
optimal for their subset of the relations.
If that's enough for your purpose, you could hack the planner to save
aside the info somewhere. Note that the representation is not a
finished Plan tree, only a Path tree.
regards, tom lane