MDEV-7390 alter online table xxxx (no options) should be possible

Merge branch 'openquery:mdev-7390-alter-online-table-xx-possible-10.0' into 10.0

mysql-test/r/alter_table.result

@@ -1693,8 +1693,10 @@ INSERT INTO tm1 VALUES (1,1,1), (2,2,2);
 INSERT INTO tm2 VALUES (1,1,1), (2,2,2);
 ALTER TABLE ti1;
 affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
 ALTER TABLE tm1;
 affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
 ALTER TABLE ti1 ADD COLUMN d VARCHAR(200);
 affected rows: 0
 info: Records: 0  Duplicates: 0  Warnings: 0

mysql-test/r/alter_table_online.result

@@ -11,6 +11,10 @@ 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;
+alter table t1 lock=NONE;
 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/r/innodb_mysql_sync.result

@@ -528,6 +528,7 @@ SET DEBUG_SYNC= 'RESET';
 # This should not do anything
 ALTER TABLE t1;
 affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
 SET DEBUG_SYNC = 'row_log_table_apply1_before SIGNAL rebuild';
 # Check that we rebuild the table
 ALTER TABLE t1 engine=innodb;

mysql-test/t/alter_table_online.test

@@ -7,7 +7,7 @@
 drop table if exists t1,t2,t3;
 --enable_warnings
 #
-# Test of things that can be done online
+# Test of things that can not be done online
 #
 
 create table t1 (a int not null primary key, b int, c varchar(80), e enum('a','b'));
@@ -24,6 +24,13 @@ alter online table t1 comment "new comment";
 --error ER_ALTER_OPERATION_NOT_SUPPORTED
 alter online table t1 rename to t2;
 
+# No OPs
+
+alter online table t1 algorithm=INPLACE, lock=NONE;
+alter online table t1;
+alter table t1 algorithm=INPLACE;
+alter table t1 lock=NONE;
+
 drop table t1;
 
 #

sql/sql_table.cc

@@ -8429,6 +8429,23 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
     mysql_audit_alter_table(thd, table_list);
 
   THD_STAGE_INFO(thd, stage_setup);
+
+  handle_if_exists_options(thd, table, alter_info);
+
+  /*
+    Look if we have to do anything at all.
+    ALTER can become NOOP after handling
+    the IF (NOT) EXISTS options.
+  */
+  if (alter_info->flags == 0)
+  {
+    my_snprintf(alter_ctx.tmp_name, sizeof(alter_ctx.tmp_name),
+                ER(ER_INSERT_INFO), 0L, 0L,
+                thd->get_stmt_da()->current_statement_warn_count());
+    my_ok(thd, 0L, 0L, alter_ctx.tmp_name);
+    DBUG_RETURN(false);
+  }
+
   if (!(alter_info->flags & ~(Alter_info::ALTER_RENAME |
                               Alter_info::ALTER_KEYS_ONOFF)) &&
       alter_info->requested_algorithm !=
@@ -8449,22 +8466,6 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
     DBUG_RETURN(res);
   }
 
-  handle_if_exists_options(thd, table, alter_info);
-
-  /*
-    Look if we have to do anything at all.
-    Normally ALTER can become NOOP only after handling
-    the IF (NOT) EXISTS options.
-  */
-  if (alter_info->flags == 0)
-  {
-    my_snprintf(alter_ctx.tmp_name, sizeof(alter_ctx.tmp_name),
-                ER(ER_INSERT_INFO), 0L, 0L,
-                thd->get_stmt_da()->current_statement_warn_count());
-    my_ok(thd, 0L, 0L, alter_ctx.tmp_name);
-    DBUG_RETURN(false);
-  }
-
   /* We have to do full alter table. */
 
 #ifdef WITH_PARTITION_STORAGE_ENGINE