Rewrite AppendColumnNames for Pg14

Postgres changed stats expression types as of PG14. Hence we needed to
write the AppendColumnNames method. Also they removed the error on PG
side so we remove it as well.

Relevant commits on pg14:
a4d75c86bf15220df22de0a92c819ecef9db3849
388e75ad33489b77cfb9a8590a91e9287d8fb960

src/backend/distributed/deparser/deparse_statistics_stmts.c

@@ -12,6 +12,8 @@
  */
 #include "postgres.h"
 
+#include "distributed/pg_version_constants.h"
+
 #include "distributed/citus_ruleutils.h"
 #include "distributed/deparser.h"
 #include "distributed/listutils.h"
@@ -231,7 +233,25 @@ AppendStatTypes(StringInfo buf, CreateStatsStmt *stmt)
 	appendStringInfoString(buf, ")");
 }
 
+#if PG_VERSION_NUM >= PG_VERSION_14
+static void
+AppendColumnNames(StringInfo buf, CreateStatsStmt *stmt)
+{
+	StatsElem *column = NULL;
 
+	foreach_ptr(column, stmt->exprs)
+	{
+		char *columnName = NameListToQuotedString(list_make1(makeString(column->name)));
+
+		appendStringInfoString(buf, columnName);
+
+		if (column != llast(stmt->exprs))
+		{
+			appendStringInfoString(buf, ", ");
+		}
+	}
+}
+#else
 static void
 AppendColumnNames(StringInfo buf, CreateStatsStmt *stmt)
 {
@@ -257,7 +277,7 @@ AppendColumnNames(StringInfo buf, CreateStatsStmt *stmt)
 		}
 	}
 }
-
+#endif
 
 static void
 AppendTableName(StringInfo buf, CreateStatsStmt *stmt)

src/test/regress/expected/propagate_statistics.out

@@ -100,11 +100,12 @@ SELECT create_distributed_table('test','x');
 (1 row)
 
 CREATE STATISTICS stats_xy ON (x, y) FROM test;
-ERROR:  only simple column references are allowed in CREATE STATISTICS
+ERROR:  syntax error at or near ","
 CREATE STATISTICS stats_xy ON x+y FROM test;
-ERROR:  only simple column references are allowed in CREATE STATISTICS
+ERROR:  syntax error at or near "+"
 CREATE STATISTICS stats_xy ON x,y FROM test;
 CREATE STATISTICS IF NOT EXISTS stats_xy ON x+y FROM test;
+ERROR:  syntax error at or near "+"
 \c - - - :worker_1_port
 SELECT stxname
 FROM pg_statistic_ext

src/test/regress/expected/propagate_statistics_0.out

@@ -0,0 +1,246 @@
+CREATE SCHEMA "statistics'Test";
+SET search_path TO "statistics'Test";
+SET citus.next_shard_id TO 980000;
+SET client_min_messages TO WARNING;
+SET citus.shard_count TO 32;
+SET citus.shard_replication_factor TO 1;
+-- test create statistics propagation
+CREATE TABLE test_stats (
+    a   int,
+    b   int
+);
+SELECT create_distributed_table('test_stats', 'a');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE STATISTICS s1 (dependencies) ON a, b FROM test_stats;
+-- test for distributing an already existing statistics
+CREATE TABLE "test'stats2" (
+    a   int,
+    b   int
+);
+CREATE STATISTICS s2 (dependencies) ON a, b FROM "test'stats2";
+SELECT create_distributed_table('test''stats2', 'a');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+-- test when stats is on a different schema
+CREATE SCHEMA sc1;
+CREATE TABLE tbl (a int, "B" text);
+SELECT create_distributed_table ('tbl', 'a');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE STATISTICS sc1.st1 ON a, "B" FROM tbl;
+-- test distributing table with already created stats on a new schema
+CREATE TABLE test_stats3 (
+    a int,
+    b int
+);
+CREATE SCHEMA sc2;
+CREATE STATISTICS sc2."neW'Stat" ON a,b FROM test_stats3;
+SELECT create_distributed_table ('test_stats3','a');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+-- test dropping statistics
+CREATE TABLE test_stats4 (
+    a int,
+    b int
+);
+SELECT create_reference_table ('test_stats4');
+ create_reference_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE STATISTICS s3 ON a,b FROM test_stats3;
+CREATE STATISTICS sc2.s4 ON a,b FROM test_stats3;
+CREATE STATISTICS s5 ON a,b FROM test_stats4;
+-- s6 doesn't exist
+DROP STATISTICS IF EXISTS s3, sc2.s4, s6;
+DROP STATISTICS s5,s6;
+ERROR:  statistics object "statistics'Test.s6" does not exist
+DROP STATISTICS IF EXISTS s5,s5,s6,s6;
+-- test renaming statistics
+CREATE STATISTICS s6 ON a,b FROM test_stats4;
+DROP STATISTICS s7;
+ERROR:  statistics object "statistics'Test.s7" does not exist
+ALTER STATISTICS s6 RENAME TO s7;
+ALTER STATISTICS sc1.st1 RENAME TO st1_new;
+-- test altering stats schema
+CREATE SCHEMA test_alter_schema;
+ALTER STATISTICS s7 SET SCHEMA test_alter_schema;
+-- test alter owner
+ALTER STATISTICS sc2."neW'Stat" OWNER TO pg_monitor;
+-- test alter owner before distribution
+CREATE TABLE ownertest(a int, b int);
+CREATE STATISTICS sc1.s9 ON a,b FROM ownertest;
+ALTER STATISTICS sc1.s9 OWNER TO pg_signal_backend;
+SELECT create_distributed_table('ownertest','a');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+-- test invalid column expressions
+CREATE TABLE test (x int, y int);
+SELECT create_distributed_table('test','x');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE STATISTICS stats_xy ON (x, y) FROM test;
+ERROR:  only simple column references are allowed in CREATE STATISTICS
+CREATE STATISTICS stats_xy ON x+y FROM test;
+ERROR:  only simple column references are allowed in CREATE STATISTICS
+CREATE STATISTICS stats_xy ON x,y FROM test;
+CREATE STATISTICS IF NOT EXISTS stats_xy ON x+y FROM test;
+\c - - - :worker_1_port
+SELECT stxname
+FROM pg_statistic_ext
+WHERE stxnamespace IN (
+	SELECT oid
+	FROM pg_namespace
+	WHERE nspname IN ('public', 'statistics''Test', 'sc1', 'sc2')
+)
+ORDER BY stxname ASC;
+     stxname
+---------------------------------------------------------------------
+ neW'Stat_980096
+ neW'Stat_980098
+ neW'Stat_980100
+ neW'Stat_980102
+ neW'Stat_980104
+ neW'Stat_980106
+ neW'Stat_980108
+ neW'Stat_980110
+ neW'Stat_980112
+ neW'Stat_980114
+ neW'Stat_980116
+ neW'Stat_980118
+ neW'Stat_980120
+ neW'Stat_980122
+ neW'Stat_980124
+ neW'Stat_980126
+ s1_980000
+ s1_980002
+ s1_980004
+ s1_980006
+ s1_980008
+ s1_980010
+ s1_980012
+ s1_980014
+ s1_980016
+ s1_980018
+ s1_980020
+ s1_980022
+ s1_980024
+ s1_980026
+ s1_980028
+ s1_980030
+ s2_980032
+ s2_980034
+ s2_980036
+ s2_980038
+ s2_980040
+ s2_980042
+ s2_980044
+ s2_980046
+ s2_980048
+ s2_980050
+ s2_980052
+ s2_980054
+ s2_980056
+ s2_980058
+ s2_980060
+ s2_980062
+ s9_980129
+ s9_980131
+ s9_980133
+ s9_980135
+ s9_980137
+ s9_980139
+ s9_980141
+ s9_980143
+ s9_980145
+ s9_980147
+ s9_980149
+ s9_980151
+ s9_980153
+ s9_980155
+ s9_980157
+ s9_980159
+ st1_new_980064
+ st1_new_980066
+ st1_new_980068
+ st1_new_980070
+ st1_new_980072
+ st1_new_980074
+ st1_new_980076
+ st1_new_980078
+ st1_new_980080
+ st1_new_980082
+ st1_new_980084
+ st1_new_980086
+ st1_new_980088
+ st1_new_980090
+ st1_new_980092
+ st1_new_980094
+ stats_xy_980161
+ stats_xy_980163
+ stats_xy_980165
+ stats_xy_980167
+ stats_xy_980169
+ stats_xy_980171
+ stats_xy_980173
+ stats_xy_980175
+ stats_xy_980177
+ stats_xy_980179
+ stats_xy_980181
+ stats_xy_980183
+ stats_xy_980185
+ stats_xy_980187
+ stats_xy_980189
+ stats_xy_980191
+(96 rows)
+
+SELECT count(DISTINCT stxnamespace)
+FROM pg_statistic_ext
+WHERE stxnamespace IN (
+	SELECT oid
+	FROM pg_namespace
+	WHERE nspname IN ('public', 'statistics''Test', 'sc1', 'sc2')
+);
+ count
+---------------------------------------------------------------------
+     3
+(1 row)
+
+SELECT COUNT(DISTINCT stxowner)
+FROM pg_statistic_ext
+WHERE stxnamespace IN (
+	SELECT oid
+	FROM pg_namespace
+	WHERE nspname IN ('public', 'statistics''Test', 'sc1', 'sc2')
+);
+ count
+---------------------------------------------------------------------
+     3
+(1 row)
+
+\c - - - :master_port
+SET client_min_messages TO WARNING;
+DROP SCHEMA "statistics'Test" CASCADE;
+DROP SCHEMA test_alter_schema CASCADE;
+DROP SCHEMA sc1 CASCADE;
+DROP SCHEMA sc2 CASCADE;