5 files changed, 89 insertions, 0 deletions
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index bdc7e250456..12f58e0ffd0 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -24,6 +24,7 @@
 #include "optimizer/optimizer.h"
 #include "nodes/nodes.h"
 #include "nodes/pathnodes.h"
+#include "parser/parsetree.h"
 #include "statistics/extended_stats_internal.h"
 #include "statistics/statistics.h"
 #include "utils/bytea.h"
@@ -963,6 +964,14 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
 	MVDependencies *dependencies;
 	Bitmapset **list_attnums;
 	int			listidx;
+	RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
+
+	/*
+	 * When dealing with inheritance trees, ignore extended stats (which were
+	 * built without data from child rels, and thus do not represent them).
+	 */
+	if (rte->inh)
+		return 1.0;
 
 	/* check if there's any stats that might be useful for us. */
 	if (!has_stats_of_kind(rel->statlist, STATS_EXT_DEPENDENCIES))
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index e0aece6b51d..6593eb6c2de 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -28,6 +28,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/clauses.h"
 #include "optimizer/optimizer.h"
+#include "parser/parsetree.h"
 #include "postmaster/autovacuum.h"
 #include "statistics/extended_stats_internal.h"
 #include "statistics/statistics.h"
@@ -1075,6 +1076,14 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
 				mcv_totalsel,
 				other_sel,
 				sel;
+	RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
+
+	/*
+	 * When dealing with inheritance trees, ignore extended stats (which were
+	 * built without data from child rels, and thus do not represent them).
+	 */
+	if (rte->inh)
+		return 1.0;
 
 	/* check if there's any stats that might be useful for us. */
 	if (!has_stats_of_kind(rel->statlist, STATS_EXT_MCV))
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 1ce5eb268b7..10a83e27ea0 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -3641,6 +3641,14 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
 	Oid			statOid = InvalidOid;
 	MVNDistinct *stats;
 	Bitmapset  *matched = NULL;
+	RangeTblEntry		*rte = planner_rt_fetch(rel->relid, root);
+
+	/*
+	 * When dealing with inheritance trees, ignore extended stats (which were
+	 * built without data from child rels, and thus do not represent them).
+	 */
+	if (rte->inh)
+		return false;
 
 	/* bail out immediately if the table has no extended statistics */
 	if (!rel->statlist)
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 06521a426a3..3ad21567947 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -124,6 +124,47 @@ CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
 ANALYZE ab1;
 DROP TABLE ab1 CASCADE;
 NOTICE:  drop cascades to table ab1c
+-- Tests for stats with inheritance
+CREATE TABLE stxdinh(a int, b int);
+CREATE TABLE stxdinh1() INHERITS(stxdinh);
+CREATE TABLE stxdinh2() INHERITS(stxdinh);
+INSERT INTO stxdinh SELECT mod(a,50), mod(a,100) FROM generate_series(0, 1999) a;
+INSERT INTO stxdinh1 SELECT mod(a,100), mod(a,100) FROM generate_series(0, 999) a;
+INSERT INTO stxdinh2 SELECT mod(a,100), mod(a,100) FROM generate_series(0, 999) a;
+VACUUM ANALYZE stxdinh, stxdinh1, stxdinh2;
+-- Ensure non-inherited stats are not applied to inherited query
+-- Without stats object, it looks like this
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* GROUP BY 1, 2');
+ estimated | actual 
+-----------+--------
+       400 |    150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* WHERE a = 0 AND b = 0');
+ estimated | actual 
+-----------+--------
+         3 |     40
+(1 row)
+
+CREATE STATISTICS stxdinh ON a, b FROM stxdinh;
+VACUUM ANALYZE stxdinh, stxdinh1, stxdinh2;
+-- Since the stats object does not include inherited stats, it should not
+-- affect the estimates
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* GROUP BY 1, 2');
+ estimated | actual 
+-----------+--------
+       400 |    150
+(1 row)
+
+-- Dependencies are applied at individual relations (within append), so
+-- this estimate changes a bit because we improve estimates for the parent
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* WHERE a = 0 AND b = 0');
+ estimated | actual 
+-----------+--------
+        22 |     40
+(1 row)
+
+DROP TABLE stxdinh, stxdinh1, stxdinh2;
 -- Verify supported object types for extended statistics
 CREATE schema tststats;
 CREATE TABLE tststats.t (a int, b int, c text);
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 06a2caff7ba..4fd7ed1b814 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -92,6 +92,28 @@ CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
 ANALYZE ab1;
 DROP TABLE ab1 CASCADE;
 
+-- Tests for stats with inheritance
+CREATE TABLE stxdinh(a int, b int);
+CREATE TABLE stxdinh1() INHERITS(stxdinh);
+CREATE TABLE stxdinh2() INHERITS(stxdinh);
+INSERT INTO stxdinh SELECT mod(a,50), mod(a,100) FROM generate_series(0, 1999) a;
+INSERT INTO stxdinh1 SELECT mod(a,100), mod(a,100) FROM generate_series(0, 999) a;
+INSERT INTO stxdinh2 SELECT mod(a,100), mod(a,100) FROM generate_series(0, 999) a;
+VACUUM ANALYZE stxdinh, stxdinh1, stxdinh2;
+-- Ensure non-inherited stats are not applied to inherited query
+-- Without stats object, it looks like this
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* GROUP BY 1, 2');
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* WHERE a = 0 AND b = 0');
+CREATE STATISTICS stxdinh ON a, b FROM stxdinh;
+VACUUM ANALYZE stxdinh, stxdinh1, stxdinh2;
+-- Since the stats object does not include inherited stats, it should not
+-- affect the estimates
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* GROUP BY 1, 2');
+-- Dependencies are applied at individual relations (within append), so
+-- this estimate changes a bit because we improve estimates for the parent
+SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* WHERE a = 0 AND b = 0');
+DROP TABLE stxdinh, stxdinh1, stxdinh2;
+
 -- Verify supported object types for extended statistics
 CREATE schema tststats;