1select @@global.innodb_read_io_threads; 2@@global.innodb_read_io_threads 32 4select @@session.innodb_read_io_threads; 5ERROR HY000: Variable 'innodb_read_io_threads' is a GLOBAL variable 6show global variables like 'innodb_read_io_threads'; 7Variable_name Value 8innodb_read_io_threads 2 9show session variables like 'innodb_read_io_threads'; 10Variable_name Value 11innodb_read_io_threads 2 12select * from information_schema.global_variables where variable_name='innodb_read_io_threads'; 13VARIABLE_NAME VARIABLE_VALUE 14INNODB_READ_IO_THREADS 2 15select * from information_schema.session_variables where variable_name='innodb_read_io_threads'; 16VARIABLE_NAME VARIABLE_VALUE 17INNODB_READ_IO_THREADS 2 18set global innodb_read_io_threads=1; 19ERROR HY000: Variable 'innodb_read_io_threads' is a read only variable 20set session innodb_read_io_threads=1; 21ERROR HY000: Variable 'innodb_read_io_threads' is a read only variable 22