SET @start_global_value = @@global.innodb_old_blocks_pct; SELECT @start_global_value; @start_global_value 37 Valid values are between 5 and 95 select @@global.innodb_old_blocks_pct between 5 and 95; @@global.innodb_old_blocks_pct between 5 and 95 1 select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 37 select @@session.innodb_old_blocks_pct; ERROR HY000: Variable 'innodb_old_blocks_pct' is a GLOBAL variable show global variables like 'innodb_old_blocks_pct'; Variable_name Value innodb_old_blocks_pct 37 show session variables like 'innodb_old_blocks_pct'; Variable_name Value innodb_old_blocks_pct 37 select * from information_schema.global_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 37 select * from information_schema.session_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 37 set global innodb_old_blocks_pct=10; select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 10 select * from information_schema.global_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 10 select * from information_schema.session_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 10 set session innodb_old_blocks_pct=1; ERROR HY000: Variable 'innodb_old_blocks_pct' is a GLOBAL variable and should be set with SET GLOBAL set global innodb_old_blocks_pct=1.1; ERROR 42000: Incorrect argument type to variable 'innodb_old_blocks_pct' set global innodb_old_blocks_pct=1e1; ERROR 42000: Incorrect argument type to variable 'innodb_old_blocks_pct' set global innodb_old_blocks_pct="foo"; ERROR 42000: Incorrect argument type to variable 'innodb_old_blocks_pct' set global innodb_old_blocks_pct=4; Warnings: Warning 1292 Truncated incorrect innodb_old_blocks_pct value: '4' select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 5 select * from information_schema.global_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 5 set global innodb_old_blocks_pct=-7; Warnings: Warning 1292 Truncated incorrect innodb_old_blocks_pct value: '-7' select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 5 select * from information_schema.global_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 5 set global innodb_old_blocks_pct=96; Warnings: Warning 1292 Truncated incorrect innodb_old_blocks_pct value: '96' select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 95 select * from information_schema.global_variables where variable_name='innodb_old_blocks_pct'; VARIABLE_NAME VARIABLE_VALUE INNODB_OLD_BLOCKS_PCT 95 set global innodb_old_blocks_pct=5; select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 5 set global innodb_old_blocks_pct=95; select @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 95 SET @@global.innodb_old_blocks_pct = @start_global_value; SELECT @@global.innodb_old_blocks_pct; @@global.innodb_old_blocks_pct 37