20 files changed, 267 insertions, 1 deletions
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index c9c9a187774..b8fa18ae2ea 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201703241
+#define CATALOG_VERSION_NO	201703242
 
 #endif
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 10759c7c58d..9effbce2f11 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -147,6 +147,7 @@ typedef enum ObjectClass
 	OCLASS_REWRITE,				/* pg_rewrite */
 	OCLASS_TRIGGER,				/* pg_trigger */
 	OCLASS_SCHEMA,				/* pg_namespace */
+	OCLASS_STATISTIC_EXT,		/* pg_statistic_ext */
 	OCLASS_TSPARSER,			/* pg_ts_parser */
 	OCLASS_TSDICT,				/* pg_ts_dict */
 	OCLASS_TSTEMPLATE,			/* pg_ts_template */
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index 1187797fd9e..473fe177ba4 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -119,6 +119,7 @@ extern void RemoveAttrDefault(Oid relid, AttrNumber attnum,
 				  DropBehavior behavior, bool complain, bool internal);
 extern void RemoveAttrDefaultById(Oid attrdefId);
 extern void RemoveStatistics(Oid relid, AttrNumber attnum);
+extern void RemoveStatisticsExt(Oid relid, AttrNumber attnum);
 
 extern Form_pg_attribute SystemAttributeDefinition(AttrNumber attno,
 						  bool relhasoids);
diff --git a/src/include/catalog/indexing.h b/src/include/catalog/indexing.h
index 5d4190c05eb..a7266860ceb 100644
--- a/src/include/catalog/indexing.h
+++ b/src/include/catalog/indexing.h
@@ -182,6 +182,13 @@ DECLARE_UNIQUE_INDEX(pg_largeobject_loid_pn_index, 2683, on pg_largeobject using
 DECLARE_UNIQUE_INDEX(pg_largeobject_metadata_oid_index, 2996, on pg_largeobject_metadata using btree(oid oid_ops));
 #define LargeObjectMetadataOidIndexId	2996
 
+DECLARE_UNIQUE_INDEX(pg_statistic_ext_oid_index, 3380, on pg_statistic_ext using btree(oid oid_ops));
+#define StatisticExtOidIndexId	3380
+DECLARE_UNIQUE_INDEX(pg_statistic_ext_name_index, 3997, on pg_statistic_ext using btree(staname name_ops, stanamespace oid_ops));
+#define StatisticExtNameIndexId 3997
+DECLARE_INDEX(pg_statistic_ext_relid_index, 3379, on pg_statistic_ext using btree(starelid oid_ops));
+#define StatisticExtRelidIndexId 3379
+
 DECLARE_UNIQUE_INDEX(pg_namespace_nspname_index, 2684, on pg_namespace using btree(nspname name_ops));
 #define NamespaceNameIndexId  2684
 DECLARE_UNIQUE_INDEX(pg_namespace_oid_index, 2685, on pg_namespace using btree(oid oid_ops));
diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h
index dbeb25b1ac1..35e0e2b089b 100644
--- a/src/include/catalog/namespace.h
+++ b/src/include/catalog/namespace.h
@@ -141,6 +141,8 @@ extern Oid	get_collation_oid(List *collname, bool missing_ok);
 extern Oid	get_conversion_oid(List *conname, bool missing_ok);
 extern Oid	FindDefaultConversionProc(int32 for_encoding, int32 to_encoding);
 
+extern Oid	get_statistics_oid(List *names, bool missing_ok);
+
 /* initialization & transaction cleanup code */
 extern void InitializeSearchPath(void);
 extern void AtEOXact_Namespace(bool isCommit, bool parallel);
diff --git a/src/include/catalog/pg_cast.h b/src/include/catalog/pg_cast.h
index ce8dc59e5af..bc5d28a4fac 100644
--- a/src/include/catalog/pg_cast.h
+++ b/src/include/catalog/pg_cast.h
@@ -254,6 +254,10 @@ DATA(insert (	23	 18   78 e f ));
 /* pg_node_tree can be coerced to, but not from, text */
 DATA(insert (  194	 25    0 i b ));
 
+/* pg_ndistinct can be coerced to, but not from, bytea and text */
+DATA(insert (  3361  17    0 i b ));
+DATA(insert (  3361  25    0 i i ));
+
 /*
  * Datetime category
  */
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index a66d0451003..ee67459c32e 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1983,6 +1983,8 @@ DESCR("select statement of a view");
 DATA(insert OID = 1642 (  pg_get_userbyid	   PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 19 "26" _null_ _null_ _null_ _null_ _null_ pg_get_userbyid _null_ _null_ _null_ ));
 DESCR("role name by OID (with fallback)");
 DATA(insert OID = 1643 (  pg_get_indexdef	   PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 25 "26" _null_ _null_ _null_ _null_ _null_ pg_get_indexdef _null_ _null_ _null_ ));
+DESCR("extended statistics description");
+DATA(insert OID = 3415 (  pg_get_statisticsextdef	   PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 25 "26" _null_ _null_ _null_ _null_ _null_ pg_get_statisticsextdef _null_ _null_ _null_ ));
 DESCR("index description");
 DATA(insert OID = 3352 (  pg_get_partkeydef    PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 25 "26" _null_ _null_ _null_ _null_ _null_ pg_get_partkeydef _null_ _null_ _null_ ));
 DESCR("partition key description");
@@ -2758,6 +2760,15 @@ DESCR("current user privilege on any column by rel name");
 DATA(insert OID = 3029 (  has_any_column_privilege	   PGNSP PGUID 12 10 0 0 0 f f f f t f s s 2 0 16 "26 25" _null_ _null_ _null_ _null_ _null_ has_any_column_privilege_id _null_ _null_ _null_ ));
 DESCR("current user privilege on any column by rel oid");
 
+DATA(insert OID = 3355 (  pg_ndistinct_in	PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 3361 "2275" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_in _null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3356 (  pg_ndistinct_out	PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 2275 "3361" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_out _null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3357 (  pg_ndistinct_recv PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 3361 "2281" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_recv _null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3358 (  pg_ndistinct_send PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 17 "3361" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_send _null_ _null_ _null_ ));
+DESCR("I/O");
+
 DATA(insert OID = 1928 (  pg_stat_get_numscans			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_numscans _null_ _null_ _null_ ));
 DESCR("statistics: number of scans done for table/index");
 DATA(insert OID = 1929 (  pg_stat_get_tuples_returned	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_tuples_returned _null_ _null_ _null_ ));
diff --git a/src/include/catalog/pg_statistic_ext.h b/src/include/catalog/pg_statistic_ext.h
new file mode 100644
index 00000000000..5f67fe7fc84
--- /dev/null
+++ b/src/include/catalog/pg_statistic_ext.h
@@ -0,0 +1,75 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_statistic_ext.h
+ *	  definition of the system "extended statistic" relation (pg_statistic_ext)
+ *	  along with the relation's initial contents.
+ *
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/catalog/pg_statistic_ext.h
+ *
+ * NOTES
+ *	  the genbki.pl script reads this file and generates .bki
+ *	  information from the DATA() statements.
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_STATISTIC_EXT_H
+#define PG_STATISTIC_EXT_H
+
+#include "catalog/genbki.h"
+
+/* ----------------
+ *		pg_statistic_ext definition.  cpp turns this into
+ *		typedef struct FormData_pg_statistic_ext
+ * ----------------
+ */
+#define StatisticExtRelationId	3381
+
+CATALOG(pg_statistic_ext,3381)
+{
+	/* These fields form the unique key for the entry: */
+	Oid			starelid;		/* relation containing attributes */
+	NameData	staname;		/* statistics name */
+	Oid			stanamespace;	/* OID of namespace containing this statistics */
+	Oid			staowner;		/* statistics owner */
+
+	/*
+	 * variable-length fields start here, but we allow direct access to
+	 * stakeys
+	 */
+	int2vector	stakeys;		/* array of column keys */
+
+#ifdef CATALOG_VARLEN
+	char		staenabled[1] BKI_FORCE_NOT_NULL;	/* statistic types
+													 * requested to build */
+	pg_ndistinct standistinct;	/* ndistinct coefficients (serialized) */
+#endif
+
+} FormData_pg_statistic_ext;
+
+/* ----------------
+ *		Form_pg_statistic_ext corresponds to a pointer to a tuple with
+ *		the format of pg_statistic_ext relation.
+ * ----------------
+ */
+typedef FormData_pg_statistic_ext *Form_pg_statistic_ext;
+
+/* ----------------
+ *		compiler constants for pg_statistic_ext
+ * ----------------
+ */
+#define Natts_pg_statistic_ext					7
+#define Anum_pg_statistic_ext_starelid			1
+#define Anum_pg_statistic_ext_staname			2
+#define Anum_pg_statistic_ext_stanamespace		3
+#define Anum_pg_statistic_ext_staowner			4
+#define Anum_pg_statistic_ext_stakeys			5
+#define Anum_pg_statistic_ext_staenabled		6
+#define Anum_pg_statistic_ext_standistinct		7
+
+#define STATS_EXT_NDISTINCT		'd'
+
+#endif   /* PG_STATISTIC_EXT_H */
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 9f61238179b..9ad67258fef 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -364,6 +364,10 @@ DATA(insert OID = 194 ( pg_node_tree	PGNSP PGUID -1 f b S f t \054 0 0 0 pg_node
 DESCR("string representing an internal node tree");
 #define PGNODETREEOID	194
 
+DATA(insert OID = 3361 ( pg_ndistinct		PGNSP PGUID -1 f b S f t \054 0 0 0 pg_ndistinct_in pg_ndistinct_out pg_ndistinct_recv pg_ndistinct_send - - - i x f 0 -1 0 100 _null_ _null_ _null_ ));
+DESCR("multivariate ndistinct coefficients");
+#define PGNDISTINCTOID	3361
+
 DATA(insert OID = 32 ( pg_ddl_command	PGNSP PGUID SIZEOF_POINTER t p P f t \054 0 0 0 pg_ddl_command_in pg_ddl_command_out pg_ddl_command_recv pg_ddl_command_send - - - ALIGNOF_POINTER p f 0 -1 0 0 _null_ _null_ _null_ ));
 DESCR("internal type for passing CollectedCommand");
 #define PGDDLCOMMANDOID 32
diff --git a/src/include/catalog/toasting.h b/src/include/catalog/toasting.h
index db7f145b5f3..00d0a8326f3 100644
--- a/src/include/catalog/toasting.h
+++ b/src/include/catalog/toasting.h
@@ -53,6 +53,7 @@ DECLARE_TOAST(pg_proc, 2836, 2837);
 DECLARE_TOAST(pg_rewrite, 2838, 2839);
 DECLARE_TOAST(pg_seclabel, 3598, 3599);
 DECLARE_TOAST(pg_statistic, 2840, 2841);
+DECLARE_TOAST(pg_statistic_ext, 3439, 3440);
 DECLARE_TOAST(pg_trigger, 2336, 2337);
 
 /* shared catalogs */
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 8740cee9440..c323e81e6c5 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -77,6 +77,10 @@ extern ObjectAddress DefineOperator(List *names, List *parameters);
 extern void RemoveOperatorById(Oid operOid);
 extern ObjectAddress AlterOperator(AlterOperatorStmt *stmt);
 
+/* commands/statscmds.c */
+extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt);
+extern void RemoveStatisticsById(Oid statsOid);
+
 /* commands/aggregatecmds.c */
 extern ObjectAddress DefineAggregate(ParseState *pstate, List *name, List *args, bool oldstyle,
 				List *parameters);
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index b2d8514f895..fc883a6f3ec 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -279,6 +279,7 @@ typedef enum NodeTag
 	T_PlaceHolderInfo,
 	T_MinMaxAggInfo,
 	T_PlannerParamItem,
+	T_StatisticExtInfo,
 
 	/*
 	 * TAGS FOR MEMORY NODES (memnodes.h)
@@ -424,6 +425,7 @@ typedef enum NodeTag
 	T_CreateSubscriptionStmt,
 	T_AlterSubscriptionStmt,
 	T_DropSubscriptionStmt,
+	T_CreateStatsStmt,
 	T_AlterCollationStmt,
 
 	/*
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3773ca9294..3a71dd5b37d 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1593,6 +1593,7 @@ typedef enum ObjectType
 	OBJECT_SCHEMA,
 	OBJECT_SEQUENCE,
 	OBJECT_SUBSCRIPTION,
+	OBJECT_STATISTIC_EXT,
 	OBJECT_TABCONSTRAINT,
 	OBJECT_TABLE,
 	OBJECT_TABLESPACE,
@@ -2657,6 +2658,20 @@ typedef struct IndexStmt
 } IndexStmt;
 
 /* ----------------------
+ *		Create Statistics Statement
+ * ----------------------
+ */
+typedef struct CreateStatsStmt
+{
+	NodeTag		type;
+	List	   *defnames;		/* qualified name (list of Value strings) */
+	RangeVar   *relation;		/* relation to build statistics on */
+	List	   *keys;			/* String nodes naming referenced columns */
+	List	   *options;		/* list of DefElem */
+	bool		if_not_exists;	/* do nothing if statistics already exists */
+} CreateStatsStmt;
+
+/* ----------------------
  *		Create Function Statement
  * ----------------------
  */
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 1c88a79a217..0a5187cef3b 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -529,6 +529,7 @@ typedef struct RelOptInfo
 	List	   *lateral_vars;	/* LATERAL Vars and PHVs referenced by rel */
 	Relids		lateral_referencers;	/* rels that reference me laterally */
 	List	   *indexlist;		/* list of IndexOptInfo */
+	List	   *statlist;		/* list of StatisticExtInfo */
 	BlockNumber pages;			/* size estimates derived from pg_class */
 	double		tuples;
 	double		allvisfrac;
@@ -668,6 +669,24 @@ typedef struct ForeignKeyOptInfo
 	List	   *rinfos[INDEX_MAX_KEYS];
 } ForeignKeyOptInfo;
 
+/*
+ * StatisticExtInfo
+ *		Information about extended statistics for planning/optimization
+ *
+ * This contains information about which columns are covered by the
+ * statistics (stakeys), which options were requested while adding the
+ * statistics (*_enabled), and which kinds of statistics were actually
+ * built and are available for the optimizer (*_built).
+ */
+typedef struct StatisticExtInfo
+{
+	NodeTag		type;
+
+	Oid			statOid;		/* OID of the statistics row */
+	RelOptInfo *rel;			/* back-link to index's table */
+	char		kind;			/* statistic kind of this entry */
+	Bitmapset  *keys;			/* attnums of the columns covered */
+} StatisticExtInfo;
 
 /*
  * EquivalenceClasses
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
new file mode 100644
index 00000000000..961f1f78c08
--- /dev/null
+++ b/src/include/statistics/extended_stats_internal.h
@@ -0,0 +1,64 @@
+/*-------------------------------------------------------------------------
+ *
+ * extended_stats_internal.h
+ *	  POSTGRES extended statistics internal declarations
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/include/statistics/extended_stats_internal.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EXTENDED_STATS_INTERNAL_H
+#define EXTENDED_STATS_INTERNAL_H
+
+#include "utils/sortsupport.h"
+#include "statistics/statistics.h"
+
+
+typedef struct
+{
+	Oid			eqopr;			/* '=' operator for datatype, if any */
+	Oid			eqfunc;			/* and associated function */
+	Oid			ltopr;			/* '<' operator for datatype, if any */
+} StdAnalyzeData;
+
+typedef struct
+{
+	Datum		value;			/* a data value */
+	int			tupno;			/* position index for tuple it came from */
+} ScalarItem;
+
+/* multi-sort */
+typedef struct MultiSortSupportData
+{
+	int			ndims;			/* number of dimensions supported by the */
+	SortSupportData ssup[1];	/* sort support data for each dimension */
+} MultiSortSupportData;
+
+typedef MultiSortSupportData *MultiSortSupport;
+
+typedef struct SortItem
+{
+	Datum	   *values;
+	bool	   *isnull;
+} SortItem;
+
+extern MVNDistinct *statext_ndistinct_build(double totalrows,
+						int numrows, HeapTuple *rows,
+						Bitmapset *attrs, VacAttrStats **stats);
+extern bytea *statext_ndistinct_serialize(MVNDistinct *ndistinct);
+extern MVNDistinct *statext_ndistinct_deserialize(bytea *data);
+
+extern MultiSortSupport multi_sort_init(int ndims);
+extern void multi_sort_add_dimension(MultiSortSupport mss, int sortdim,
+						 Oid oper);
+extern int	multi_sort_compare(const void *a, const void *b, void *arg);
+extern int multi_sort_compare_dim(int dim, const SortItem * a,
+					   const SortItem * b, MultiSortSupport mss);
+extern int multi_sort_compare_dims(int start, int end, const SortItem * a,
+						const SortItem * b, MultiSortSupport mss);
+
+#endif   /* EXTENDED_STATS_INTERNAL_H */
diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h
new file mode 100644
index 00000000000..a15e39e1a30
--- /dev/null
+++ b/src/include/statistics/statistics.h
@@ -0,0 +1,47 @@
+/*-------------------------------------------------------------------------
+ *
+ * statistics.h
+ *	  Extended statistics and selectivity estimation functions.
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/statistics/statistics.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STATISTICS_H
+#define STATISTICS_H
+
+#include "commands/vacuum.h"
+
+#define STATS_MAX_DIMENSIONS	8		/* max number of attributes */
+
+/* Multivariate distinct coefficients */
+#define STATS_NDISTINCT_MAGIC		0xA352BFA4	/* struct identifier */
+#define STATS_NDISTINCT_TYPE_BASIC	1	/* struct version */
+
+/* MVDistinctItem represents a single combination of columns */
+typedef struct MVNDistinctItem
+{
+	double		ndistinct;		/* ndistinct value for this combination */
+	Bitmapset  *attrs;			/* attr numbers of items */
+} MVNDistinctItem;
+
+/* A MVNDistinct object, comprising all possible combinations of columns */
+typedef struct MVNDistinct
+{
+	uint32		magic;			/* magic constant marker */
+	uint32		type;			/* type of ndistinct (BASIC) */
+	uint32		nitems;			/* number of items in the statistic */
+	MVNDistinctItem items[FLEXIBLE_ARRAY_MEMBER];
+} MVNDistinct;
+
+extern MVNDistinct *statext_ndistinct_load(Oid mvoid);
+
+extern void BuildRelationExtStatistics(Relation onerel, double totalrows,
+						   int numrows, HeapTuple *rows,
+						   int natts, VacAttrStats **vacattrstats);
+extern bool statext_is_kind_built(HeapTuple htup, char kind);
+
+#endif   /* STATISTICS_H */
diff --git a/src/include/utils/acl.h b/src/include/utils/acl.h
index 0d118525c9c..c957d8e1701 100644
--- a/src/include/utils/acl.h
+++ b/src/include/utils/acl.h
@@ -192,6 +192,7 @@ typedef enum AclObjectKind
 	ACL_KIND_OPFAMILY,			/* pg_opfamily */
 	ACL_KIND_COLLATION,			/* pg_collation */
 	ACL_KIND_CONVERSION,		/* pg_conversion */
+	ACL_KIND_STATISTICS,		/* pg_statistic_ext */
 	ACL_KIND_TABLESPACE,		/* pg_tablespace */
 	ACL_KIND_TSDICTIONARY,		/* pg_ts_dict */
 	ACL_KIND_TSCONFIGURATION,	/* pg_ts_config */
@@ -326,6 +327,7 @@ extern bool pg_event_trigger_ownercheck(Oid et_oid, Oid roleid);
 extern bool pg_extension_ownercheck(Oid ext_oid, Oid roleid);
 extern bool pg_publication_ownercheck(Oid pub_oid, Oid roleid);
 extern bool pg_subscription_ownercheck(Oid sub_oid, Oid roleid);
+extern bool pg_statistics_ownercheck(Oid stat_oid, Oid roleid);
 extern bool has_createrole_privilege(Oid roleid);
 extern bool has_bypassrls_privilege(Oid roleid);
 
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index a617a7cf566..ab875bb9d77 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -92,6 +92,7 @@ typedef struct RelationData
 	bool		rd_isvalid;		/* relcache entry is valid */
 	char		rd_indexvalid;	/* state of rd_indexlist: 0 = not valid, 1 =
 								 * valid, 2 = temporarily forced */
+	bool		rd_statvalid;	/* is rd_statlist valid? */
 
 	/*
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
@@ -136,6 +137,9 @@ typedef struct RelationData
 	Oid			rd_pkindex;		/* OID of primary key, if any */
 	Oid			rd_replidindex; /* OID of replica identity index, if any */
 
+	/* data managed by RelationGetStatExtList: */
+	List	   *rd_statlist;	/* list of OIDs of extended stats */
+
 	/* data managed by RelationGetIndexAttrBitmap: */
 	Bitmapset  *rd_indexattr;	/* identifies columns used in indexes */
 	Bitmapset  *rd_keyattr;		/* cols that can be ref'd by foreign keys */
diff --git a/src/include/utils/relcache.h b/src/include/utils/relcache.h
index da36b6774fc..81af3aebb8d 100644
--- a/src/include/utils/relcache.h
+++ b/src/include/utils/relcache.h
@@ -39,6 +39,7 @@ extern void RelationClose(Relation relation);
  */
 extern List *RelationGetFKeyList(Relation relation);
 extern List *RelationGetIndexList(Relation relation);
+extern List *RelationGetStatExtList(Relation relation);
 extern Oid	RelationGetOidIndex(Relation relation);
 extern Oid	RelationGetPrimaryKeyIndex(Relation relation);
 extern Oid	RelationGetReplicaIndex(Relation relation);
diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h
index b35faf81b9e..36805ebefba 100644
--- a/src/include/utils/syscache.h
+++ b/src/include/utils/syscache.h
@@ -86,6 +86,8 @@ enum SysCacheIdentifier
 	PUBLICATIONRELMAP,
 	RULERELNAME,
 	SEQRELID,
+	STATEXTNAMENSP,
+	STATEXTOID,
 	STATRELATTINH,
 	SUBSCRIPTIONOID,
 	SUBSCRIPTIONNAME,