Mathieu PUJOL wrote: > I'am writing a foreign data wrapper. To avoid returning data for a column that is not used, I parse 'targetlist' and 'qual' of the Plan. > I'am able to find Var nodes but I can't figure out how i could now if this node is related to a column my foreign table. For a Var v, v->varattno contains the attribute number of the column. That is the same as the attnum column in pg_attribute. If v->varattno == 0, it is a whole-row reference, like in SELECT mytab FROM mytab; Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com