MDEV-4851: BUG#11763447: 'YOU CANNOT 'ALTER' A LOG TABLE IF LOGGING I…

…S ENABLED'

               EVEN IF I LOG TO FILE.

Analysis:
----------

MYSQL_UPGRADE of the master breaks the replication when
the query logging is enabled with FILE/NONE 'log-output'
option on the slave.

mysql_upgrade modifies the 'general_log' and 'slow_log'
tables after the logging is disabled as below:

SET @old_log_state = @@global.general_log;
SET GLOBAL general_log = 'OFF';
ALTER TABLE general_log
MODIFY event_time TIMESTAMP NOT NULL,
( .... );
SET GLOBAL general_log = @old_log_state;

and

SET @old_log_state = @@global.slow_query_log;
SET GLOBAL slow_query_log = 'OFF';
ALTER TABLE slow_log
MODIFY start_time TIMESTAMP NOT NULL,
( .... );
SET GLOBAL slow_query_log = @old_log_state;

In the binary log, only the ALTER statements are logged
but not the SET statements which turns ON/OFF the logging.
So when the slave replays the binary log,the ALTER of LOG
tables throws an error since the logging is enabled. Also
the 'log-output' option is not checked to determine
whether to allow/disallow the ALTER operation.

Fix:
----
The 'log-output' option is included in the check while
determining whether the query logging happens using the
log tables.

Picked from mysql respository at 0daaf8aecd8f84ff1fb400029139222ea1f0d812

sql/log.cc

@@ -1,4 +1,4 @@
-/* Copyright (c) 2000, 2018, Oracle and/or its affiliates.
+/* Copyright (c) 2000, 2012, 2018, Oracle and/or its affiliates.
    Copyright (c) 2009, 2019, MariaDB Corporation
 
    This program is free software; you can redistribute it and/or modify
@@ -534,9 +534,11 @@ bool LOGGER::is_log_table_enabled(uint log_table_type)
 {
   switch (log_table_type) {
   case QUERY_LOG_SLOW:
-    return (table_log_handler != NULL) && global_system_variables.sql_log_slow;
+    return (table_log_handler != NULL) && global_system_variables.sql_log_slow
+            && (log_output_options & LOG_TABLE);
   case QUERY_LOG_GENERAL:
-    return (table_log_handler != NULL) && opt_log ;
+    return (table_log_handler != NULL) && opt_log
+            && (log_output_options & LOG_TABLE);
   default:
     DBUG_ASSERT(0);
     return FALSE;                             /* make compiler happy */