1select @@global.innodb_doublewrite_batch_size between 1 and 127; 2@@global.innodb_doublewrite_batch_size between 1 and 127 31 4select @@global.innodb_doublewrite_batch_size; 5@@global.innodb_doublewrite_batch_size 6120 7select @@session.innodb_doublewrite_batch_size; 8ERROR HY000: Variable 'innodb_doublewrite_batch_size' is a GLOBAL variable 9show global variables like 'innodb_doublewrite_batch_size'; 10Variable_name Value 11innodb_doublewrite_batch_size 120 12show session variables like 'innodb_doublewrite_batch_size'; 13Variable_name Value 14innodb_doublewrite_batch_size 120 15select * from information_schema.global_variables where variable_name='innodb_doublewrite_batch_size'; 16VARIABLE_NAME VARIABLE_VALUE 17INNODB_DOUBLEWRITE_BATCH_SIZE 120 18select * from information_schema.session_variables where variable_name='innodb_doublewrite_batch_size'; 19VARIABLE_NAME VARIABLE_VALUE 20INNODB_DOUBLEWRITE_BATCH_SIZE 120 21set global innodb_doublewrite_batch_size=1; 22ERROR HY000: Variable 'innodb_doublewrite_batch_size' is a read only variable 23set @@session.innodb_doublewrite_batch_size='some'; 24ERROR HY000: Variable 'innodb_doublewrite_batch_size' is a read only variable 25