SET @start_global_value = @@global.innodb_adaptive_hash_index; SELECT @start_global_value; @start_global_value 1 Valid values are 'ON' and 'OFF' select @@global.innodb_adaptive_hash_index in (0, 1); @@global.innodb_adaptive_hash_index in (0, 1) 1 select @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 1 select @@session.innodb_adaptive_hash_index; ERROR HY000: Variable 'innodb_adaptive_hash_index' is a GLOBAL variable show global variables like 'innodb_adaptive_hash_index'; Variable_name Value innodb_adaptive_hash_index ON show session variables like 'innodb_adaptive_hash_index'; Variable_name Value innodb_adaptive_hash_index ON select * from information_schema.global_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON select * from information_schema.session_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON set global innodb_adaptive_hash_index='OFF'; select @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 0 select * from information_schema.global_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX OFF select * from information_schema.session_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX OFF set @@global.innodb_adaptive_hash_index=1; select @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 1 select * from information_schema.global_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON select * from information_schema.session_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON set global innodb_adaptive_hash_index=0; select @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 0 select * from information_schema.global_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX OFF select * from information_schema.session_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX OFF set @@global.innodb_adaptive_hash_index='ON'; select @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 1 select * from information_schema.global_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON select * from information_schema.session_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON set session innodb_adaptive_hash_index='OFF'; ERROR HY000: Variable 'innodb_adaptive_hash_index' is a GLOBAL variable and should be set with SET GLOBAL set @@session.innodb_adaptive_hash_index='ON'; ERROR HY000: Variable 'innodb_adaptive_hash_index' is a GLOBAL variable and should be set with SET GLOBAL set global innodb_adaptive_hash_index=1.1; ERROR 42000: Incorrect argument type to variable 'innodb_adaptive_hash_index' set global innodb_adaptive_hash_index=1e1; ERROR 42000: Incorrect argument type to variable 'innodb_adaptive_hash_index' set global innodb_adaptive_hash_index=2; ERROR 42000: Variable 'innodb_adaptive_hash_index' can't be set to the value of '2' NOTE: The following should fail with ER_WRONG_VALUE_FOR_VAR (BUG#50643) set global innodb_adaptive_hash_index=-3; select @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 1 select * from information_schema.global_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON select * from information_schema.session_variables where variable_name='innodb_adaptive_hash_index'; VARIABLE_NAME VARIABLE_VALUE INNODB_ADAPTIVE_HASH_INDEX ON set global innodb_adaptive_hash_index='AUTO'; ERROR 42000: Variable 'innodb_adaptive_hash_index' can't be set to the value of 'AUTO' SET @@global.innodb_adaptive_hash_index = @start_global_value; SELECT @@global.innodb_adaptive_hash_index; @@global.innodb_adaptive_hash_index 1