SET @start_global_value = @@global.slave_checkpoint_period;
SELECT @start_global_value;
@start_global_value
300
select @@global.slave_checkpoint_period;
@@global.slave_checkpoint_period
300
select @@session.slave_checkpoint_period;
ERROR HY000: Variable 'slave_checkpoint_period' is a GLOBAL variable
show global variables like 'slave_checkpoint_period';
Variable_name	Value
slave_checkpoint_period	period
show session variables like 'slave_checkpoint_period';
Variable_name	Value
slave_checkpoint_period	period
select * from information_schema.global_variables where variable_name='slave_checkpoint_period';
VARIABLE_NAME	VARIABLE_VALUE
SLAVE_CHECKPOINT_PERIOD	period
select * from information_schema.session_variables where variable_name='slave_checkpoint_period';
VARIABLE_NAME	VARIABLE_VALUE
SLAVE_CHECKPOINT_PERIOD	period
set global slave_checkpoint_period=1;
select @@global.slave_checkpoint_period;
@@global.slave_checkpoint_period
1
set session slave_checkpoint_period=1;
ERROR HY000: Variable 'slave_checkpoint_period' is a GLOBAL variable and should be set with SET GLOBAL
set global slave_checkpoint_period=1.1;
ERROR 42000: Incorrect argument type to variable 'slave_checkpoint_period'
set global slave_checkpoint_period=1e1;
ERROR 42000: Incorrect argument type to variable 'slave_checkpoint_period'
set global slave_checkpoint_period="foo";
ERROR 42000: Incorrect argument type to variable 'slave_checkpoint_period'
set global slave_checkpoint_period=1;
select @@global.slave_checkpoint_period;
@@global.slave_checkpoint_period
1
set global slave_checkpoint_period=cast(-1 as unsigned int);
Warnings:
Warning	1292	Truncated incorrect slave_checkpoint_period value: '18446744073709551615'
select @@global.slave_checkpoint_period as "truncated to the maximum";
truncated to the maximum
4294967295
SET @@global.slave_checkpoint_period = @start_global_value;
SELECT @@global.slave_checkpoint_period;
@@global.slave_checkpoint_period
300
