Redesign PlanForeignScan API to allow multiple paths for a foreign table.

The original API specification only allowed an FDW to create a single
access path, which doesn't seem like a terribly good idea in hindsight.
Instead, move the responsibility for building the Path node and calling
add_path() into the FDW's PlanForeignScan function.  Now, it can do that
more than once if appropriate.  There is no longer any need for the
transient FdwPlan struct, so get rid of that.

Etsuro Fujita, Shigeru Hanada, Tom Lane

1 files changed, 2 insertions, 19 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 7fec4dbf7b5..868fb7130a8 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -23,7 +23,8 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
-#include "foreign/fdwapi.h"
+#include "nodes/plannodes.h"
+#include "nodes/relation.h"
 #include "utils/datum.h"
 
 
@@ -591,21 +592,6 @@ _copyForeignScan(const ForeignScan *from)
 	 * copy remainder of node
 	 */
 	COPY_SCALAR_FIELD(fsSystemCol);
-	COPY_NODE_FIELD(fdwplan);
-
-	return newnode;
-}
-
-/*
- * _copyFdwPlan
- */
-static FdwPlan *
-_copyFdwPlan(const FdwPlan *from)
-{
-	FdwPlan    *newnode = makeNode(FdwPlan);
-
-	COPY_SCALAR_FIELD(startup_cost);
-	COPY_SCALAR_FIELD(total_cost);
 	COPY_NODE_FIELD(fdw_private);
 
 	return newnode;
@@ -3842,9 +3828,6 @@ copyObject(const void *from)
 		case T_ForeignScan:
 			retval = _copyForeignScan(from);
 			break;
-		case T_FdwPlan:
-			retval = _copyFdwPlan(from);
-			break;
 		case T_Join:
 			retval = _copyJoin(from);
 			break;