Function finalize_agg_primnode

src/backend/optimizer/plan/subselect.c:3475–3491

* finalize_agg_primnode: find all Aggref nodes in the given expression tree, * and add IDs of all PARAM_EXEC params appearing within their aggregated * arguments to the result set. */

 * arguments to the result set.
 */
static bool
finalize_agg_primnode(Node *node, finalize_primnode_context *context)
{
	if (node == NULL)
		return false;
	if (IsA(node, Aggref))
	{
		Aggref	   *agg = (Aggref *) node;

		/* we should not consider the direct arguments, if any */
		finalize_primnode((Node *) agg->args, context);
		finalize_primnode((Node *) agg->aggfilter, context);
		return false;			/* there can't be any Aggrefs below here */
	}
	return expression_tree_walker(node, finalize_agg_primnode,
								  (void *) context);
}

/*
 * SS_make_initplan_output_param - make a Param for an initPlan's output