SET @start_global_value = @@global.innodb_spin_wait_delay; SELECT @start_global_value; @start_global_value 6 Valid values are zero or above select @@global.innodb_spin_wait_delay >=0; @@global.innodb_spin_wait_delay >=0 1 select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay 6 select @@session.innodb_spin_wait_delay; ERROR HY000: Variable 'innodb_spin_wait_delay' is a GLOBAL variable show global variables like 'innodb_spin_wait_delay'; Variable_name Value innodb_spin_wait_delay 6 show session variables like 'innodb_spin_wait_delay'; Variable_name Value innodb_spin_wait_delay 6 select * from information_schema.global_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE INNODB_SPIN_WAIT_DELAY 6 select * from information_schema.session_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE INNODB_SPIN_WAIT_DELAY 6 set global innodb_spin_wait_delay=10; select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay 10 select * from information_schema.global_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE INNODB_SPIN_WAIT_DELAY 10 select * from information_schema.session_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE INNODB_SPIN_WAIT_DELAY 10 set session innodb_spin_wait_delay=1; ERROR HY000: Variable 'innodb_spin_wait_delay' is a GLOBAL variable and should be set with SET GLOBAL set global innodb_spin_wait_delay=1.1; ERROR 42000: Incorrect argument type to variable 'innodb_spin_wait_delay' set global innodb_spin_wait_delay=1e1; ERROR 42000: Incorrect argument type to variable 'innodb_spin_wait_delay' set global innodb_spin_wait_delay="foo"; ERROR 42000: Incorrect argument type to variable 'innodb_spin_wait_delay' set global innodb_spin_wait_delay=-7; Warnings: Warning 1292 Truncated incorrect innodb_spin_wait_delay value: '-7' select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay 0 select * from information_schema.global_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE INNODB_SPIN_WAIT_DELAY 0 SET @@global.innodb_spin_wait_delay = @start_global_value; SELECT @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay 6