don't crash if ALTER TABLE fails and a long transaction blocks MDL upgrade

mysql-test/main/alter_table_online.result

@@ -22,6 +22,36 @@ a	b
 123	NULL
 456	NULL
 789	NULL
+# Insert, error
+create or replace table t1 (a int);
+insert t1 values (5), (5);
+connection con2;
+set debug_sync= 'now WAIT_FOR ended';
+connection default;
+set session lock_wait_timeout=1;
+set debug_sync= 'alter_table_copy_end SIGNAL ended WAIT_FOR end';
+alter table t1 add unique (a), algorithm= copy, lock= none;
+connection con2;
+start transaction;
+insert into t1 values (123), (456), (789);
+set debug_sync= 'now SIGNAL end';
+connection default;
+ERROR 23000: Duplicate entry '5' for key 'a'
+connection con2;
+commit;
+connection default;
+select variable_value into @otd from information_schema.session_status where variable_name='Opened_table_definitions';
+select * from t1;
+a
+5
+5
+123
+456
+789
+select variable_value-@otd from information_schema.session_status where variable_name='Opened_table_definitions';
+variable_value-@otd
+1
+set session lock_wait_timeout=default;
 # long transaction and add column
 create or replace table t1 (a int);
 insert t1 values (5);

mysql-test/main/alter_table_online.test

@@ -34,6 +34,38 @@ set debug_sync= 'now SIGNAL end';
 --reap
 select * from t1;
 
+--echo # Insert, error
+create or replace table t1 (a int);
+insert t1 values (5), (5);
+
+--connection con2
+--send
+set debug_sync= 'now WAIT_FOR ended';
+
+--connection default
+set session lock_wait_timeout=1;
+set debug_sync= 'alter_table_copy_end SIGNAL ended WAIT_FOR end';
+
+--send
+alter table t1 add unique (a), algorithm= copy, lock= none;
+
+--connection con2
+--reap
+start transaction;
+insert into t1 values (123), (456), (789);
+set debug_sync= 'now SIGNAL end';
+
+--connection default
+--error ER_DUP_ENTRY
+--reap
+--connection con2
+commit;
+--connection default
+select variable_value into @otd from information_schema.session_status where variable_name='Opened_table_definitions';
+select * from t1;
+select variable_value-@otd from information_schema.session_status where variable_name='Opened_table_definitions';
+set session lock_wait_timeout=default;
+
 --echo # long transaction and add column
 create or replace table t1 (a int);
 insert t1 values (5);

mysql-test/suite/heap/heap.result

@@ -398,9 +398,10 @@ qq
 *a       *a*a       *
 *a        *a*a        *
 *a         *a*a         *
+flush tables;
 explain select * from t1 where v='a';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	v	v	13	const	10	Using where
+1	SIMPLE	t1	ref	v	v	13	const	9	Using where
 select v,count(*) from t1 group by v limit 10;
 v	count(*)
 a
	1

mysql-test/suite/heap/heap.test

@@ -277,6 +277,7 @@ explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a  '
 --error ER_DUP_ENTRY
 alter table t1 add unique(v);
 select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));
+flush tables;
 explain select * from t1 where v='a';
 
 # GROUP BY

sql/sql_table.cc

@@ -11592,17 +11592,7 @@ static int online_alter_read_from_binlog(THD *thd, rpl_group_info *rgi,
 
   return error;
 }
-#endif // HAVE_REPLICATION
-
-static void online_alter_cleanup_binlog(THD *thd, TABLE_SHARE *s)
-{
-#ifdef HAVE_REPLICATION
-  if (!s->online_alter_binlog)
-    return;
-  s->online_alter_binlog->cleanup();
-  s->online_alter_binlog= NULL;
 #endif
-}
 
 static int
 copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
@@ -11805,7 +11795,7 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
 #ifdef HAVE_REPLICATION
     if (online)
     {
-      from->s->online_alter_binlog= new (thd->mem_root) Cache_flip_event_log();
+      from->s->online_alter_binlog= new (&from->s->mem_root) Cache_flip_event_log();
       if (!from->s->online_alter_binlog)
         DBUG_RETURN(1);
       from->s->online_alter_binlog->init_pthread_objects();
@@ -11813,7 +11803,8 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
 
       if (error)
       {
-        online_alter_cleanup_binlog(thd, from->s);
+        from->s->online_alter_binlog->cleanup();
+        from->s->online_alter_binlog= NULL;
         goto err;
       }
 
@@ -12023,21 +12014,7 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
   }
   else if (online) // error was on copy stage
   {
-    /*
-       We need to issue a barrier to clean up gracefully.
-       Without this, following possible:
-       T1: ALTER TABLE starts
-       T2: INSERT starts
-       T1: ALTER TABLE fails with error (i.e. ER_DUP_KEY)
-       T1: from->s->online_alter_binlog sets to NULL
-       T2: INSERT committs
-       T2: thd->online_alter_cache_list is not empty
-       T2: binlog_commit: DBUG_ASSERT(binlog); is issued.
-    */
-    // Ignore the return result. We already have an error.
-    thd->mdl_context.upgrade_shared_lock(from->mdl_ticket, 
-                                         MDL_SHARED_NO_WRITE,
-                                         thd->variables.lock_wait_timeout);
+    from->s->tdc->flushed= 1; // to free the binlog
   }
 #endif
 
@@ -12058,9 +12035,6 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
   if (bulk_insert_started)
     (void) to->file->ha_end_bulk_insert();
 
-/* Free resources */
-  online_alter_cleanup_binlog(thd, from->s);
-
   if (init_read_record_done)
     end_read_record(&info);
   delete [] copy;

sql/table.cc

@@ -505,6 +505,14 @@ void TABLE_SHARE::destroy()
     }
   }
 
+#ifdef HAVE_REPLICATION
+  if (online_alter_binlog)
+  {
+    online_alter_binlog->cleanup();
+    online_alter_binlog= NULL;
+  }
+#endif
+
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   plugin_unlock(NULL, default_part_plugin);
 #endif /* WITH_PARTITION_STORAGE_ENGINE */