From c6509db19dcd6f7530630d22aebf2c87f28475a4 Mon Sep 17 00:00:00 2001
From: Corey Huinker <chuinker@amazon.com>
Date: Thu, 26 Dec 2024 05:02:06 -0500
Subject: [PATCH v6 3/5] Expose attribute statistics functions for use in
 extended_stats.

Many of the operations of attribute stats have analogous operations in
extended stats.

* get_attr_stat_type()
* init_empty_stats_tuple()
* text_to_stavalues()
* get_elem_stat_type()
---
 src/include/statistics/statistics.h      | 17 +++++++++++++++++
 src/backend/statistics/attribute_stats.c | 24 +++++-------------------
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h
index 7dd0f975545..a0ab4b7633c 100644
--- a/src/include/statistics/statistics.h
+++ b/src/include/statistics/statistics.h
@@ -127,4 +127,21 @@ extern StatisticExtInfo *choose_best_statistics(List *stats, char requiredkind,
 												int nclauses);
 extern HeapTuple statext_expressions_load(Oid stxoid, bool inh, int idx);
 
+extern void get_attr_stat_type(Oid reloid, AttrNumber attnum,
+							   Oid *atttypid, int32 *atttypmod,
+							   char *atttyptype, Oid *atttypcoll,
+							   Oid *eq_opr, Oid *lt_opr);
+extern void init_empty_stats_tuple(Oid reloid, int16 attnum, bool inherited,
+								   Datum *values, bool *nulls, bool *replaces);
+
+extern void set_stats_slot(Datum *values, bool *nulls, bool *replaces,
+						   int16 stakind, Oid staop, Oid stacoll,
+						   Datum stanumbers, bool stanumbers_isnull,
+						   Datum stavalues, bool stavalues_isnull);
+
+extern Datum text_to_stavalues(const char *staname, FmgrInfo *array_in, Datum d,
+							   Oid typid, int32 typmod, bool *ok);
+extern bool get_elem_stat_type(Oid atttypid, char atttyptype,
+							   Oid *elemtypid, Oid *elem_eq_opr);
+
 #endif							/* STATISTICS_H */
diff --git a/src/backend/statistics/attribute_stats.c b/src/backend/statistics/attribute_stats.c
index 1db6a7f784c..cc5a2557f07 100644
--- a/src/backend/statistics/attribute_stats.c
+++ b/src/backend/statistics/attribute_stats.c
@@ -100,23 +100,9 @@ static struct StatsArgInfo cleararginfo[] =
 
 static bool attribute_statistics_update(FunctionCallInfo fcinfo);
 static Node *get_attr_expr(Relation rel, int attnum);
-static void get_attr_stat_type(Oid reloid, AttrNumber attnum,
-							   Oid *atttypid, int32 *atttypmod,
-							   char *atttyptype, Oid *atttypcoll,
-							   Oid *eq_opr, Oid *lt_opr);
-static bool get_elem_stat_type(Oid atttypid, char atttyptype,
-							   Oid *elemtypid, Oid *elem_eq_opr);
-static Datum text_to_stavalues(const char *staname, FmgrInfo *array_in, Datum d,
-							   Oid typid, int32 typmod, bool *ok);
-static void set_stats_slot(Datum *values, bool *nulls, bool *replaces,
-						   int16 stakind, Oid staop, Oid stacoll,
-						   Datum stanumbers, bool stanumbers_isnull,
-						   Datum stavalues, bool stavalues_isnull);
 static void upsert_pg_statistic(Relation starel, HeapTuple oldtup,
 								Datum *values, bool *nulls, bool *replaces);
 static bool delete_pg_statistic(Oid reloid, AttrNumber attnum, bool stainherit);
-static void init_empty_stats_tuple(Oid reloid, int16 attnum, bool inherited,
-								   Datum *values, bool *nulls, bool *replaces);
 
 /*
  * Insert or Update Attribute Statistics
@@ -571,7 +557,7 @@ get_attr_expr(Relation rel, int attnum)
 /*
  * Derive type information from the attribute.
  */
-static void
+void
 get_attr_stat_type(Oid reloid, AttrNumber attnum,
 				   Oid *atttypid, int32 *atttypmod,
 				   char *atttyptype, Oid *atttypcoll,
@@ -653,7 +639,7 @@ get_attr_stat_type(Oid reloid, AttrNumber attnum,
 /*
  * Derive element type information from the attribute type.
  */
-static bool
+bool
 get_elem_stat_type(Oid atttypid, char atttyptype,
 				   Oid *elemtypid, Oid *elem_eq_opr)
 {
@@ -693,7 +679,7 @@ get_elem_stat_type(Oid atttypid, char atttyptype,
  * to false. If the resulting array contains NULLs, raise a WARNING and set ok
  * to false. Otherwise, set ok to true.
  */
-static Datum
+Datum
 text_to_stavalues(const char *staname, FmgrInfo *array_in, Datum d, Oid typid,
 				  int32 typmod, bool *ok)
 {
@@ -746,7 +732,7 @@ text_to_stavalues(const char *staname, FmgrInfo *array_in, Datum d, Oid typid,
  * Find and update the slot with the given stakind, or use the first empty
  * slot.
  */
-static void
+void
 set_stats_slot(Datum *values, bool *nulls, bool *replaces,
 			   int16 stakind, Oid staop, Oid stacoll,
 			   Datum stanumbers, bool stanumbers_isnull,
@@ -870,7 +856,7 @@ delete_pg_statistic(Oid reloid, AttrNumber attnum, bool stainherit)
 /*
  * Initialize values and nulls for a new stats tuple.
  */
-static void
+void
 init_empty_stats_tuple(Oid reloid, int16 attnum, bool inherited,
 					   Datum *values, bool *nulls, bool *replaces)
 {
-- 
2.51.0