- Innodb is not always available, which means t is not always
possible to use innodb system variables, or innodb information schema
tables.

Thus creation of objects that use Innodb information_schema is enclosed
into BEGIN NOT ATOMIC blocks with dummy SQLEXCEPTION handler.

- sys_config table uses Aria, just like other system tables.

- several tables that exist in MySQL, do not exist in MariaDB
   performance_schema.replication_applier_status, mysql.slave_master_info,
   mysql.slave_relay_log_info