MDEV-28332: Alter on temporary table causes ER_TABLE_EXISTS_ERROR note

- Additionally update comments
Reviewed by: <monty@mariadb.org>

8 files changed, 40 insertions, 20 deletions

diff --git a/mysql-test/main/information_schema_temp_table.result b/mysql-test/main/information_schema_temp_table.result
index e85def6bfd2..ab2cd811ba2 100644
--- a/mysql-test/main/information_schema_temp_table.result
+++ b/mysql-test/main/information_schema_temp_table.result
@@ -96,3 +96,15 @@ drop table test.t_temp;
 drop table test.t_temp;
 drop database my_db;
 drop database some_db;
+#
+# MDEV-28332: Alter on temporary table causes ER_TABLE_EXISTS_ERROR note
+#
+create table t (a int);
+create temporary table t (b int);
+Warnings:
+Level	Note
+Code	1050
+Message	Table 't' already exists
+alter table t add c int;
+drop temporary table t;
+drop table t;
diff --git a/mysql-test/main/information_schema_temp_table.test b/mysql-test/main/information_schema_temp_table.test
index 7a34324f919..4257a5dd7d6 100644
--- a/mysql-test/main/information_schema_temp_table.test
+++ b/mysql-test/main/information_schema_temp_table.test
@@ -92,3 +92,14 @@ drop database some_db;
 
 # Wait till all disconnects are completed
 --source include/wait_until_count_sessions.inc
+
+--echo #
+--echo # MDEV-28332: Alter on temporary table causes ER_TABLE_EXISTS_ERROR note
+--echo #
+create table t (a int);
+create temporary table t (b int);
+alter table t add c int;
+
+# Cleanup
+drop temporary table t;
+drop table t;
diff --git a/mysql-test/main/lock_multi.result b/mysql-test/main/lock_multi.result
index 6d0a1807d6e..83e20bc5e33 100644
--- a/mysql-test/main/lock_multi.result
+++ b/mysql-test/main/lock_multi.result
@@ -611,8 +611,6 @@ CREATE TEMPORARY TABLE t1 (id INT);
 Warnings:
 Note	1050	Table 't1' already exists
 ALTER TABLE t1 ADD COLUMN j INT;
-Warnings:
-Note	1050	Table 't1' already exists
 connection default;
 disconnect con1;
 UNLOCK TABLES;
diff --git a/mysql-test/main/temp_table.result b/mysql-test/main/temp_table.result
index 97ef065dcc6..ff8156f9ace 100644
--- a/mysql-test/main/temp_table.result
+++ b/mysql-test/main/temp_table.result
@@ -60,8 +60,6 @@ a	b
 5	f
 6	g
 alter table t2 add primary key (a,b);
-Warnings:
-Note	1050	Table 't2' already exists
 drop table t1,t2;
 select * from t1;
 c	d
diff --git a/mysql-test/suite/maria/temporary.result b/mysql-test/suite/maria/temporary.result
index c414d2e49b1..4184731c774 100644
--- a/mysql-test/suite/maria/temporary.result
+++ b/mysql-test/suite/maria/temporary.result
@@ -20,7 +20,6 @@ test.t1	check	status	OK
 ALTER TABLE t1 CHANGE COLUMN IF EXISTS x x INT;
 Warnings:
 Note	1054	Unknown column 'x' in 't1'
-Note	1050	Table 't1' already exists
 ALTER TABLE t1;
 DROP TEMPORARY TABLE t1;
 DROP TABLE t1;
diff --git a/mysql-test/suite/plugins/r/audit_null.result b/mysql-test/suite/plugins/r/audit_null.result
index 1a88e8d7716..221ea5d9ebd 100644
--- a/mysql-test/suite/plugins/r/audit_null.result
+++ b/mysql-test/suite/plugins/r/audit_null.result
@@ -48,8 +48,6 @@ select * from t2;
 a
 2020-10-09
 alter table t2 add column b int;
-Warnings:
-Note	1050	Table 't2' already exists
 drop table t2;
 explain select distinct * from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -106,7 +104,6 @@ root[root] @ localhost []	>> SHOW WARNINGS
 root[root] @ localhost []	>> insert t2 values ('2020-10-09')
 root[root] @ localhost []	>> select * from t2
 root[root] @ localhost []	>> alter table t2 add column b int
-root[root] @ localhost []	>> SHOW WARNINGS
 root[root] @ localhost []	>> drop table t2
 root[root] @ localhost []	>> explain select distinct * from t2
 root[root] @ localhost []	test.t2 : read
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index fde04014760..1589c80e5bb 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -5875,14 +5875,14 @@ err:
 
 /**
  @brief           Fill IS.table with temporary tables
+ @param[in]       thd                  thread handle
  @param[in]       table                I_S table (TABLE)
- @param[in]       db_name              db name of temporary table
- @param[in]       table_name           table name of temporary table
+ @param[in]       tmp_tbl              temporary table
  @return          Operation status
    @retval        0   - success
    @retval        1   - failure
 */
-void process_i_s_table_temporary_tables(THD *thd, TABLE * table, TABLE *tmp_tbl)
+void process_i_s_table_temporary_tables(THD *thd, TABLE *table, TABLE *tmp_tbl)
 {
   TABLE_LIST table_list;
   bzero((char*) &table_list, sizeof(TABLE_LIST));
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index ae280f2b0ed..8de0515e795 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -4344,23 +4344,28 @@ int create_table_impl(THD *thd,
     ddl_log_state_create= 0;
     ddl_log_state_rm= 0;
 
-    if (ha_table_exists(thd, &orig_db, &orig_table_name, NULL, NULL, NULL))
+    if (create_table_mode != C_ALTER_TABLE_FRM_ONLY &&
+        create_table_mode != C_ALTER_TABLE)
     {
+      if (ha_table_exists(thd, &orig_db, &orig_table_name, NULL, NULL, NULL))
+      {
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
-      TABLE_LIST table_acl_check;
-      bzero((char*) &table_acl_check, sizeof(table_acl_check));
-      table_acl_check.db= orig_db;
-      table_acl_check.table_name= orig_table_name;
-      if (!check_table_access(thd, TABLE_ACLS, &table_acl_check, true, 1, true))
-        warning_given= 1;
+        TABLE_LIST table_acl_check;
+        bzero((char*) &table_acl_check, sizeof(table_acl_check));
+        table_acl_check.db= orig_db;
+        table_acl_check.table_name= orig_table_name;
+        if (!check_table_access(thd, TABLE_ACLS, &table_acl_check, true, 1, true))
+          warning_given= 1;
 #else
-      warning_given=1;
+        warning_given=1;
 #endif /* NO_EMBEDDED_ACCESS_CHECKS */
-      if (warning_given)
+
+        if (warning_given)
           push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
                               ER_TABLE_EXISTS_ERROR,
                               ER_THD(thd, ER_TABLE_EXISTS_ERROR),
                               orig_table_name.str);
+      }
     }
   }