Amin <amin(dot)fallahi(at)gmail(dot)com> writes:
> To simplify: Can CustomScan scan multiple relations in the same query or it
> will always be assigned to one or zero relations?
There's barely any code in the core planner that is specific to custom
scans. Almost certainly this misbehavior is the fault of your
custom-path-creation code. Maybe you're labeling the paths with the
wrong parent relation, or forgetting to submit them to add_path,
or assigning them costs that are high enough to get them rejected?
regards, tom lane