Re: Get access to the whole query in CustomScan path callback

I cannot find any information related to other relations in the query other
than the one which is being scanned in the root pointer. Is there any
function call which can be used to get access to it?

On Wed, Dec 21, 2022 at 9:46 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Amin <amin(dot)fallahi(at)gmail(dot)com> writes:
> > 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?
>
> Everything the planner knows is accessible via the "root" pointer.
>
> I very strongly question the idea that a custom scan provider should
> be doing what you say you want to do, but the info is there.
>
> regards, tom lane
>