select @@global.lock_order_debug_loop; @@global.lock_order_debug_loop 0 select @@session.lock_order_debug_loop; ERROR HY000: Variable 'lock_order_debug_loop' is a GLOBAL variable show global variables like 'lock_order_debug_loop'; Variable_name Value lock_order_debug_loop OFF show session variables like 'lock_order_debug_loop'; Variable_name Value lock_order_debug_loop OFF select * from performance_schema.global_variables where variable_name='lock_order_debug_loop'; VARIABLE_NAME VARIABLE_VALUE lock_order_debug_loop OFF select * from performance_schema.session_variables where variable_name='lock_order_debug_loop'; VARIABLE_NAME VARIABLE_VALUE lock_order_debug_loop OFF set global lock_order_debug_loop=1; ERROR HY000: Variable 'lock_order_debug_loop' is a read only variable set session lock_order_debug_loop=1; ERROR HY000: Variable 'lock_order_debug_loop' is a read only variable