HarmeekSingh Bedi <harmeeksingh@gmail.com> writes:
> In a plan where Node 1 is parent {say join) and Node 2 is child
> (say scan) . If node 1 has a expression say foo(column) then scan
> will project 'column' for sure and join will
> evaluate foo(column). Now if the node above join does not need
> column ? how does postgress remove the column from join's projection
> list .
See build_joinrel_tlist() in relnode.c.
> I am seeing that it does not in many
> cases specially when sort appears above.
Please show a concrete example.
regards, tom lane