Get access to the whole query in CustomScan path callback

Hi,

The goal is to have access to all the tables that are being scanned or will be scanned as a part of the query. Basically, the callback looks like this:

typedef void (*set_rel_pathlist_hook_type) (PlannerInfo *root,                                            RelOptInfo *rel,                                            Index rti,                                            RangeTblEntry *rte);

Now, the problem is when there is a nested query, the function will be called once for the parent query and once for the subquery. However, I need access to the whole query in this function. There seems to be no CustomScan callback before this that has the whole query passed to it. Is there any way I can get access to the complete query (or all the relations in the query) by using the parameters passed to this function? Or any other workaround?

Thank you and happy holidays!