MDEV-9103 Altering table comment does a full copy

following InnoDB's logic, altering a comment or a default
field's value needs "NO_LOCK", not EXCLUSIVE

mysql-test/r/alter_table_online.result

@@ -2,15 +2,9 @@ drop table if exists t1,t2,t3;
 create table t1 (a int not null primary key, b int, c varchar(80), e enum('a','b'));
 insert into t1 (a) values (1),(2),(3);
 alter online table t1 modify b int default 5;
-ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
 alter online table t1 change b new_name int;
-ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
 alter online table t1 modify e enum('a','b','c');
-ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
 alter online table t1 comment "new comment";
-ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
-alter online table t1 rename to t2;
-ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
 alter online table t1 algorithm=INPLACE, lock=NONE;
 alter online table t1;
 alter table t1 algorithm=INPLACE;
@@ -40,10 +34,13 @@ alter online table t1 add f int;
 ERROR 0A000: LOCK=NONE is not supported for this operation. Try LOCK=SHARED.
 alter online table t1 engine=memory;
 ERROR 0A000: LOCK=NONE is not supported. Reason: COPY algorithm requires a lock. Try LOCK=SHARED.
+alter online table t1 rename to t2;
+ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
 alter table t1 engine=innodb;
 alter table t1 add index (b);
 alter online table t1 add index c (c);
 alter online table t1 drop index b;
+alter online table t1 comment "new comment";
 drop table t1;
 create temporary table t1 (a int not null primary key, b int, c varchar(80), e enum('a','b'));
 insert into t1 (a) values (1),(2),(3);

mysql-test/t/alter_table_online.test

@@ -7,22 +7,16 @@
 drop table if exists t1,t2,t3;
 --enable_warnings
 #
-# Test of things that can not be done online
+# Test of things that can be done online
 #
 
 create table t1 (a int not null primary key, b int, c varchar(80), e enum('a','b'));
 insert into t1 (a) values (1),(2),(3);
 
---error ER_ALTER_OPERATION_NOT_SUPPORTED
 alter online table t1 modify b int default 5;
---error ER_ALTER_OPERATION_NOT_SUPPORTED
 alter online table t1 change b new_name int;
---error ER_ALTER_OPERATION_NOT_SUPPORTED
 alter online table t1 modify e enum('a','b','c');
---error ER_ALTER_OPERATION_NOT_SUPPORTED
 alter online table t1 comment "new comment";
---error ER_ALTER_OPERATION_NOT_SUPPORTED
-alter online table t1 rename to t2;
 
 # No OPs
 
@@ -68,11 +62,14 @@ alter online table t1 modify c varchar(100);
 alter online table t1 add f int;
 --error ER_ALTER_OPERATION_NOT_SUPPORTED_REASON
 alter online table t1 engine=memory;
+--error ER_ALTER_OPERATION_NOT_SUPPORTED
+alter online table t1 rename to t2;
 
 alter table t1 engine=innodb;
 alter table t1 add index (b);
 alter online table t1 add index c (c);
 alter online table t1 drop index b;
+alter online table t1 comment "new comment";
 drop table t1;
 
 create temporary table t1 (a int not null primary key, b int, c varchar(80), e enum('a','b'));

sql/handler.cc

@@ -4236,7 +4236,7 @@ handler::check_if_supported_inplace_alter(TABLE *altered_table,
     IS_EQUAL_PACK_LENGTH : IS_EQUAL_YES;
   if (table->file->check_if_incompatible_data(create_info, table_changes)
       == COMPATIBLE_DATA_YES)
-    DBUG_RETURN(HA_ALTER_INPLACE_EXCLUSIVE_LOCK);
+    DBUG_RETURN(HA_ALTER_INPLACE_NO_LOCK);
 
   DBUG_RETURN(HA_ALTER_INPLACE_NOT_SUPPORTED);
 }