1 files changed, 49 insertions, 0 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index fb8cd37fb68..3b0145207b0 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5308,6 +5308,55 @@ add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel,
 
 	useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel);
 
+	/*
+	 * Before creating sorted paths, arrange for the passed-in EPQ path, if
+	 * any, to return columns needed by the parent ForeignScan node so that
+	 * they will propagate up through Sort nodes injected below, if necessary.
+	 */
+	if (epq_path != NULL && useful_pathkeys_list != NIL)
+	{
+		PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
+		PathTarget *target = copy_pathtarget(epq_path->pathtarget);
+
+		/* Include columns required for evaluating PHVs in the tlist. */
+		add_new_columns_to_pathtarget(target,
+									  pull_var_clause((Node *) target->exprs,
+													  PVC_RECURSE_PLACEHOLDERS));
+
+		/* Include columns required for evaluating the local conditions. */
+		foreach(lc, fpinfo->local_conds)
+		{
+			RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
+
+			add_new_columns_to_pathtarget(target,
+										  pull_var_clause((Node *) rinfo->clause,
+														  PVC_RECURSE_PLACEHOLDERS));
+		}
+
+		/*
+		 * If we have added any new columns, adjust the tlist of the EPQ path.
+		 *
+		 * Note: the plan created using this path will only be used to execute
+		 * EPQ checks, where accuracy of the plan cost and width estimates
+		 * would not be important, so we do not do set_pathtarget_cost_width()
+		 * for the new pathtarget here.  See also postgresGetForeignPlan().
+		 */
+		if (list_length(target->exprs) > list_length(epq_path->pathtarget->exprs))
+		{
+			/* The EPQ path is a join path, so it is projection-capable. */
+			Assert(is_projection_capable_path(epq_path));
+
+			/*
+			 * Use create_projection_path() here, so as to avoid modifying it
+			 * in place.
+			 */
+			epq_path = (Path *) create_projection_path(root,
+													   rel,
+													   epq_path,
+													   target);
+		}
+	}
+
 	/* Create one path for each set of pathkeys we found above. */
 	foreach(lc, useful_pathkeys_list)
 	{