1SET @start_global_value = @@global.innodb_tmpdir; 2SELECT @start_global_value; 3@start_global_value 4NULL 5select @@session.innodb_tmpdir; 6@@session.innodb_tmpdir 7NULL 8show global variables like 'innodb_tmpdir'; 9Variable_name Value 10innodb_tmpdir 11show session variables like 'innodb_tmpdir'; 12Variable_name Value 13innodb_tmpdir 14select * from information_schema.global_variables where variable_name='innodb_tmpdir'; 15VARIABLE_NAME VARIABLE_VALUE 16INNODB_TMPDIR 17select * from information_schema.session_variables where variable_name='innodb_tmpdir'; 18VARIABLE_NAME VARIABLE_VALUE 19INNODB_TMPDIR 20set global innodb_tmpdir=@@global.tmpdir; 21set session innodb_tmpdir=@@global.tmpdir; 22set global innodb_tmpdir=1.1; 23ERROR 42000: Incorrect argument type to variable 'innodb_tmpdir' 24set global innodb_tmpdir=1e1; 25ERROR 42000: Incorrect argument type to variable 'innodb_tmpdir' 26set global innodb_tmpdir=repeat('a',1000); 27ERROR 42000: Variable 'innodb_tmpdir' can't be set to the value of 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...' 28show warnings; 29Level Code Message 30Warning 1210 Path length should not exceed 512 bytes 31Error 1231 Variable 'innodb_tmpdir' can't be set to the value of 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...' 32SET @@global.innodb_tmpdir = @start_global_value; 33SELECT @@global.innodb_tmpdir; 34@@global.innodb_tmpdir 35NULL 36