4 files changed, 95 insertions, 1 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 783e34b4fbc..c6095167e80 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -59,6 +59,8 @@ static Material *create_material_plan(PlannerInfo *root, MaterialPath *best_path
 static Plan *create_unique_plan(PlannerInfo *root, UniquePath *best_path);
 static SeqScan *create_seqscan_plan(PlannerInfo *root, Path *best_path,
 					List *tlist, List *scan_clauses);
+static SampleScan *create_samplescan_plan(PlannerInfo *root, Path *best_path,
+					List *tlist, List *scan_clauses);
 static Scan *create_indexscan_plan(PlannerInfo *root, IndexPath *best_path,
 					  List *tlist, List *scan_clauses, bool indexonly);
 static BitmapHeapScan *create_bitmap_scan_plan(PlannerInfo *root,
@@ -101,6 +103,7 @@ static List *order_qual_clauses(PlannerInfo *root, List *clauses);
 static void copy_path_costsize(Plan *dest, Path *src);
 static void copy_plan_costsize(Plan *dest, Plan *src);
 static SeqScan *make_seqscan(List *qptlist, List *qpqual, Index scanrelid);
+static SampleScan *make_samplescan(List *qptlist, List *qpqual, Index scanrelid);
 static IndexScan *make_indexscan(List *qptlist, List *qpqual, Index scanrelid,
 			   Oid indexid, List *indexqual, List *indexqualorig,
 			   List *indexorderby, List *indexorderbyorig, Oid *indexorderbyops,
@@ -229,6 +232,7 @@ create_plan_recurse(PlannerInfo *root, Path *best_path)
 	switch (best_path->pathtype)
 	{
 		case T_SeqScan:
+		case T_SampleScan:
 		case T_IndexScan:
 		case T_IndexOnlyScan:
 		case T_BitmapHeapScan:
@@ -344,6 +348,13 @@ create_scan_plan(PlannerInfo *root, Path *best_path)
 												scan_clauses);
 			break;
 
+		case T_SampleScan:
+			plan = (Plan *) create_samplescan_plan(root,
+												   best_path,
+												   tlist,
+												   scan_clauses);
+			break;
+
 		case T_IndexScan:
 			plan = (Plan *) create_indexscan_plan(root,
 												  (IndexPath *) best_path,
@@ -547,6 +558,7 @@ disuse_physical_tlist(PlannerInfo *root, Plan *plan, Path *path)
 	switch (path->pathtype)
 	{
 		case T_SeqScan:
+		case T_SampleScan:
 		case T_IndexScan:
 		case T_IndexOnlyScan:
 		case T_BitmapHeapScan:
@@ -1134,6 +1146,45 @@ create_seqscan_plan(PlannerInfo *root, Path *best_path,
 }
 
 /*
+ * create_samplescan_plan
+ *	 Returns a samplecan plan for the base relation scanned by 'best_path'
+ *	 with restriction clauses 'scan_clauses' and targetlist 'tlist'.
+ */
+static SampleScan *
+create_samplescan_plan(PlannerInfo *root, Path *best_path,
+					List *tlist, List *scan_clauses)
+{
+	SampleScan *scan_plan;
+	Index		scan_relid = best_path->parent->relid;
+
+	/* it should be a base rel with tablesample clause... */
+	Assert(scan_relid > 0);
+	Assert(best_path->parent->rtekind == RTE_RELATION);
+	Assert(best_path->pathtype == T_SampleScan);
+
+	/* Sort clauses into best execution order */
+	scan_clauses = order_qual_clauses(root, scan_clauses);
+
+	/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
+	scan_clauses = extract_actual_clauses(scan_clauses, false);
+
+	/* Replace any outer-relation variables with nestloop params */
+	if (best_path->param_info)
+	{
+		scan_clauses = (List *)
+			replace_nestloop_params(root, (Node *) scan_clauses);
+	}
+
+	scan_plan = make_samplescan(tlist,
+								scan_clauses,
+								scan_relid);
+
+	copy_path_costsize(&scan_plan->plan, best_path);
+
+	return scan_plan;
+}
+
+/*
  * create_indexscan_plan
  *	  Returns an indexscan plan for the base relation scanned by 'best_path'
  *	  with restriction clauses 'scan_clauses' and targetlist 'tlist'.
@@ -3378,6 +3429,24 @@ make_seqscan(List *qptlist,
 	return node;
 }
 
+static SampleScan *
+make_samplescan(List *qptlist,
+				List *qpqual,
+				Index scanrelid)
+{
+	SampleScan *node = makeNode(SampleScan);
+	Plan	   *plan = &node->plan;
+
+	/* cost should be inserted by caller */
+	plan->targetlist = qptlist;
+	plan->qual = qpqual;
+	plan->lefttree = NULL;
+	plan->righttree = NULL;
+	node->scanrelid = scanrelid;
+
+	return node;
+}
+
 static IndexScan *
 make_indexscan(List *qptlist,
 			   List *qpqual,
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 8de57c8e6bb..9ba10516bb2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -60,6 +60,7 @@ planner_hook_type planner_hook = NULL;
 #define EXPRKIND_LIMIT			6
 #define EXPRKIND_APPINFO		7
 #define EXPRKIND_PHV			8
+#define EXPRKIND_TABLESAMPLE    9
 
 /* Passthrough data for standard_qp_callback */
 typedef struct
@@ -486,7 +487,19 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
 		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 		int			kind;
 
-		if (rte->rtekind == RTE_SUBQUERY)
+		if (rte->rtekind == RTE_RELATION)
+		{
+			if (rte->tablesample)
+			{
+				rte->tablesample->args = (List *)
+					preprocess_expression(root, (Node *) rte->tablesample->args,
+										  EXPRKIND_TABLESAMPLE);
+				rte->tablesample->repeatable = (Node *)
+					preprocess_expression(root, rte->tablesample->repeatable,
+										  EXPRKIND_TABLESAMPLE);
+			}
+		}
+		else if (rte->rtekind == RTE_SUBQUERY)
 		{
 			/*
 			 * We don't want to do all preprocessing yet on the subquery's
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 517409d28a0..73b19888369 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -451,6 +451,17 @@ set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
 					fix_scan_list(root, splan->plan.qual, rtoffset);
 			}
 			break;
+		case T_SampleScan:
+			{
+				SampleScan	   *splan = (SampleScan *) plan;
+
+				splan->scanrelid += rtoffset;
+				splan->plan.targetlist =
+					fix_scan_list(root, splan->plan.targetlist, rtoffset);
+				splan->plan.qual =
+					fix_scan_list(root, splan->plan.qual, rtoffset);
+			}
+			break;
 		case T_IndexScan:
 			{
 				IndexScan  *splan = (IndexScan *) plan;
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index afccee53acf..2f7f5c0df0e 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -2167,6 +2167,7 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params,
 			break;
 
 		case T_SeqScan:
+		case T_SampleScan:
 			context.paramids = bms_add_members(context.paramids, scan_params);
 			break;