v2-0001-refactor-CreateStatsStmt.patch

From 04975c4b93e60e2554b3d247d9bc38b5385530a3 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Fri, 29 Aug 2025 12:03:49 +0800
Subject: [PATCH v2 1/1] refactor CreateStatsStmt

discussion: https://postgr.es/m/
---
 src/backend/commands/statscmds.c        | 14 ++++++++++++--
 src/backend/commands/tablecmds.c        |  2 +-
 src/backend/tcop/utility.c              | 25 +------------------------
 src/include/commands/defrem.h           |  2 +-
 src/test/regress/expected/stats_ext.out | 20 ++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 12 ++++++++++++
 6 files changed, 47 insertions(+), 28 deletions(-)

diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index e24d540cd45..094d1a4fc1b 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -29,6 +29,7 @@
 #include "miscadmin.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
+#include "parser/parse_utilcmd.h"
 #include "statistics/statistics.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
@@ -57,9 +58,11 @@ compare_int16(const void *a, const void *b)
 
 /*
  *		CREATE STATISTICS
+ * ensure queryString is not NULL when we need do parse analysis for stmt!
+ * stmt changed on the go, espepcially transformStatsStmt.
  */
 ObjectAddress
-CreateStatistics(CreateStatsStmt *stmt)
+CreateStatistics(CreateStatsStmt *stmt, const char *queryString)
 {
 	int16		attnums[STATS_MAX_DIMENSIONS];
 	int			nattnums = 0;
@@ -112,7 +115,8 @@ CreateStatistics(CreateStatsStmt *stmt)
 		if (!IsA(rln, RangeVar))
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("only a single relation is allowed in CREATE STATISTICS")));
+					 errmsg("cannot create statistics on specified relation"),
+					 errdetail("CREATE STATISTICS only supports tables, materialized views, foreign tables, and partitioned tables")));
 
 		/*
 		 * CREATE STATISTICS will influence future execution plans but does
@@ -150,6 +154,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 	Assert(rel);
 	relid = RelationGetRelid(rel);
 
+	if (queryString != NULL && !stmt->transformed)
+	{
+		/* Run parse analysis ... */
+		(void) transformStatsStmt(relid, stmt, queryString);
+	}
+
 	/*
 	 * If the node has a name, split it up and determine creation namespace.
 	 * If not, put the object in the same namespace as the relation, and cons
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 082a3575d62..b8dd9306b93 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -9654,7 +9654,7 @@ ATExecAddStatistics(AlteredTableInfo *tab, Relation rel,
 	/* The CreateStatsStmt has already been through transformStatsStmt */
 	Assert(stmt->transformed);
 
-	address = CreateStatistics(stmt);
+	address = CreateStatistics(stmt, NULL);
 
 	return address;
 }
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 4f4191b0ea6..8d35ae971d5 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -1867,32 +1867,9 @@ ProcessUtilitySlow(ParseState *pstate,
 
 			case T_CreateStatsStmt:
 				{
-					Oid			relid;
 					CreateStatsStmt *stmt = (CreateStatsStmt *) parsetree;
-					RangeVar   *rel = (RangeVar *) linitial(stmt->relations);
 
-					if (!IsA(rel, RangeVar))
-						ereport(ERROR,
-								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-								 errmsg("only a single relation is allowed in CREATE STATISTICS")));
-
-					/*
-					 * CREATE STATISTICS will influence future execution plans
-					 * but does not interfere with currently executing plans.
-					 * So it should be enough to take ShareUpdateExclusiveLock
-					 * on relation, conflicting with ANALYZE and other DDL
-					 * that sets statistical information, but not with normal
-					 * queries.
-					 *
-					 * XXX RangeVarCallbackOwnsRelation not needed here, to
-					 * keep the same behavior as before.
-					 */
-					relid = RangeVarGetRelid(rel, ShareUpdateExclusiveLock, false);
-
-					/* Run parse analysis ... */
-					stmt = transformStatsStmt(relid, stmt, queryString);
-
-					address = CreateStatistics(stmt);
+					address = CreateStatistics(stmt, queryString);
 				}
 				break;
 
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index dd22b5efdfd..684f62109fd 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -85,7 +85,7 @@ extern void RemoveOperatorById(Oid operOid);
 extern ObjectAddress AlterOperator(AlterOperatorStmt *stmt);
 
 /* commands/statscmds.c */
-extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt);
+extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt, const char *queryString);
 extern ObjectAddress AlterStatistics(AlterStatsStmt *stmt);
 extern void RemoveStatisticsById(Oid statsOid);
 extern void RemoveStatisticsDataById(Oid statsOid, bool inh);
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index c66e09f8b16..fb920312b4d 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -88,6 +88,26 @@ ERROR:  statistics creation on system columns is not supported
 -- statistics without a less-than operator not supported
 CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
 ERROR:  column "w" cannot be used in statistics because its type xid has no default btree operator class
+CREATE STATISTICS tst ON (x is not null) FROM ext_stats_test s, lateral(values(s.x));
+ERROR:  only a single relation is allowed in CREATE STATISTICS
+CREATE STATISTICS tst ON (x is not null) FROM (SELECT * FROM ext_stats_test);
+ERROR:  cannot create statistics on specified relation
+DETAIL:  CREATE STATISTICS only supports tables, materialized views, foreign tables, and partitioned tables
+CREATE STATISTICS tst ON (x is not null) FROM ext_stats_test s TABLESAMPLE system (x) REPEATABLE (200);
+ERROR:  cannot create statistics on specified relation
+DETAIL:  CREATE STATISTICS only supports tables, materialized views, foreign tables, and partitioned tables
+CREATE STATISTICS tst ON (x is not null) FROM JSON_TABLE(jsonb '123', '$' COLUMNS (item int PATH '$'));
+ERROR:  cannot create statistics on specified relation
+DETAIL:  CREATE STATISTICS only supports tables, materialized views, foreign tables, and partitioned tables
+CREATE FUNCTION tftest(int) returns table(a int, b int) as $$
+BEGIN
+  RETURN QUERY SELECT $1, $1+i FROM generate_series(1,5) g(i);
+END;
+$$ LANGUAGE plpgsql IMMUTABLE STRICT;
+CREATE STATISTICS alt_stat2 ON a, b FROM tftest(1);
+ERROR:  cannot create statistics on specified relation
+DETAIL:  CREATE STATISTICS only supports tables, materialized views, foreign tables, and partitioned tables
+DROP FUNCTION tftest;
 DROP TABLE ext_stats_test1;
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 9ce4c670ecb..f63048f4c96 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -58,6 +58,18 @@ CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
 CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
 -- statistics without a less-than operator not supported
 CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+
+CREATE STATISTICS tst ON (x is not null) FROM ext_stats_test s, lateral(values(s.x));
+CREATE STATISTICS tst ON (x is not null) FROM (SELECT * FROM ext_stats_test);
+CREATE STATISTICS tst ON (x is not null) FROM ext_stats_test s TABLESAMPLE system (x) REPEATABLE (200);
+CREATE STATISTICS tst ON (x is not null) FROM JSON_TABLE(jsonb '123', '$' COLUMNS (item int PATH '$'));
+CREATE FUNCTION tftest(int) returns table(a int, b int) as $$
+BEGIN
+  RETURN QUERY SELECT $1, $1+i FROM generate_series(1,5) g(i);
+END;
+$$ LANGUAGE plpgsql IMMUTABLE STRICT;
+CREATE STATISTICS alt_stat2 ON a, b FROM tftest(1);
+DROP FUNCTION tftest;
 DROP TABLE ext_stats_test1;
 
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
-- 
2.34.1