1select @@global.max_long_data_size=20;
2@@global.max_long_data_size=20
30
4select @@session.max_long_data_size;
5ERROR HY000: Variable 'max_long_data_size' is a GLOBAL variable
6SELECT @@global.max_long_data_size = VARIABLE_VALUE
7FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
8WHERE VARIABLE_NAME='max_long_data_size';
9@@global.max_long_data_size = VARIABLE_VALUE
101
11set global max_long_data_size=1;
12ERROR HY000: Variable 'max_long_data_size' is a read only variable
13set session max_long_data_size=1;
14ERROR HY000: Variable 'max_long_data_size' is a read only variable
15