SET @start_global_value = @@global.innodb_io_capacity; SELECT @start_global_value; @start_global_value 200 Valid value 100 or more select @@global.innodb_io_capacity > 99; @@global.innodb_io_capacity > 99 1 select @@global.innodb_io_capacity; @@global.innodb_io_capacity 200 select @@session.innodb_io_capacity; ERROR HY000: Variable 'innodb_io_capacity' is a GLOBAL variable show global variables like 'innodb_io_capacity'; Variable_name Value innodb_io_capacity 200 show session variables like 'innodb_io_capacity'; Variable_name Value innodb_io_capacity 200 select * from information_schema.global_variables where variable_name='innodb_io_capacity'; VARIABLE_NAME VARIABLE_VALUE INNODB_IO_CAPACITY 200 select * from information_schema.session_variables where variable_name='innodb_io_capacity'; VARIABLE_NAME VARIABLE_VALUE INNODB_IO_CAPACITY 200 set global innodb_io_capacity=123; select @@global.innodb_io_capacity; @@global.innodb_io_capacity 123 select * from information_schema.global_variables where variable_name='innodb_io_capacity'; VARIABLE_NAME VARIABLE_VALUE INNODB_IO_CAPACITY 123 select * from information_schema.session_variables where variable_name='innodb_io_capacity'; VARIABLE_NAME VARIABLE_VALUE INNODB_IO_CAPACITY 123 set session innodb_io_capacity=444; ERROR HY000: Variable 'innodb_io_capacity' is a GLOBAL variable and should be set with SET GLOBAL set global innodb_io_capacity=1.1; ERROR 42000: Incorrect argument type to variable 'innodb_io_capacity' set global innodb_io_capacity=1e1; ERROR 42000: Incorrect argument type to variable 'innodb_io_capacity' set global innodb_io_capacity="foo"; ERROR 42000: Incorrect argument type to variable 'innodb_io_capacity' set global innodb_io_capacity=7; Warnings: Warning 1292 Truncated incorrect innodb_io_capacity value: '7' select @@global.innodb_io_capacity; @@global.innodb_io_capacity 100 select * from information_schema.global_variables where variable_name='innodb_io_capacity'; VARIABLE_NAME VARIABLE_VALUE INNODB_IO_CAPACITY 100 set global innodb_io_capacity=-7; Warnings: Warning 1292 Truncated incorrect innodb_io_capacity value: '-7' select @@global.innodb_io_capacity; @@global.innodb_io_capacity 100 select * from information_schema.global_variables where variable_name='innodb_io_capacity'; VARIABLE_NAME VARIABLE_VALUE INNODB_IO_CAPACITY 100 set global innodb_io_capacity=100; select @@global.innodb_io_capacity; @@global.innodb_io_capacity 100 SET @@global.innodb_io_capacity = @start_global_value; SELECT @@global.innodb_io_capacity; @@global.innodb_io_capacity 200