select @@global.innodb_doublewrite_batch_size between 1 and 127;
@@global.innodb_doublewrite_batch_size between 1 and 127
1
select @@global.innodb_doublewrite_batch_size;
@@global.innodb_doublewrite_batch_size
120
select @@session.innodb_doublewrite_batch_size;
ERROR HY000: Variable 'innodb_doublewrite_batch_size' is a GLOBAL variable
show global variables like 'innodb_doublewrite_batch_size';
Variable_name	Value
innodb_doublewrite_batch_size	120
show session variables like 'innodb_doublewrite_batch_size';
Variable_name	Value
innodb_doublewrite_batch_size	120
select * from information_schema.global_variables where variable_name='innodb_doublewrite_batch_size';
VARIABLE_NAME	VARIABLE_VALUE
INNODB_DOUBLEWRITE_BATCH_SIZE	120
select * from information_schema.session_variables where variable_name='innodb_doublewrite_batch_size';
VARIABLE_NAME	VARIABLE_VALUE
INNODB_DOUBLEWRITE_BATCH_SIZE	120
set global innodb_doublewrite_batch_size=1;
ERROR HY000: Variable 'innodb_doublewrite_batch_size' is a read only variable
set @@session.innodb_doublewrite_batch_size='some';
ERROR HY000: Variable 'innodb_doublewrite_batch_size' is a read only variable
