Disable shareinputscan with outer refs.

Currently shareinputscan doesn't handle rescan properly, and to fully
support it, there will be a lot of code changes. After some discussions,
we decide to disable shareinputscan with outer refs for now.

src/backend/optimizer/plan/planshare.c

@@ -134,6 +134,15 @@ static ShareInputScan *make_shareinputscan(PlannerInfo *root, Plan *inputplan)
 
 	Assert(IsA(inputplan, Material) || IsA(inputplan, Sort));
 
+	/*
+	 * Currently GPDB doesn't fully support shareinputscan referencing outer
+	 * rels.
+	 */
+	if (!bms_is_empty(inputplan->extParam))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("shareinputscan with outer refs is not supported by GPDB")));
+
 	sisc = makeNode(ShareInputScan);
 	incr_plan_nsharer(inputplan);
 
@@ -212,6 +221,8 @@ prepare_plan_for_sharing(PlannerInfo *root, Plan *common)
 		shared->plan_width = common->plan_width;
 		shared->dispatch = common->dispatch;
 		shared->flow = copyObject(common->flow); 
+		shared->extParam = bms_copy(common->extParam);
+		shared->allParam = bms_copy(common->allParam);
 
 		m->share_id = SHARE_ID_NOT_ASSIGNED;
 		m->share_type = SHARE_MATERIAL;

src/test/regress/expected/shared_scan.out

@@ -30,3 +30,10 @@ SELECT * FROM
 ---+---+---+---+---+---
 (0 rows)
 
+SELECT *,
+        (
+        WITH cte AS (SELECT * FROM jazz WHERE jazz.e = bar.c)
+        SELECT 1 FROM cte c1, cte c2
+        )
+        FROM bar;
+ERROR:  shareinputscan with outer refs is not supported by GPDB

src/test/regress/sql/shared_scan.sql

@@ -27,3 +27,10 @@ SELECT * FROM
         JOIN bar ON b = c
         ) AS XY
         JOIN jazz on c = e AND b = f;
+
+SELECT *,
+        (
+        WITH cte AS (SELECT * FROM jazz WHERE jazz.e = bar.c)
+        SELECT 1 FROM cte c1, cte c2
+        )
+        FROM bar;