1select @@global.host_cache_size; 2@@global.host_cache_size 3123 4select @@session.host_cache_size; 5ERROR HY000: Variable 'host_cache_size' is a GLOBAL variable 6show global variables like 'host_cache_size'; 7Variable_name Value 8host_cache_size 123 9show session variables like 'host_cache_size'; 10Variable_name Value 11host_cache_size 123 12select * from information_schema.global_variables 13where variable_name='host_cache_size'; 14VARIABLE_NAME VARIABLE_VALUE 15HOST_CACHE_SIZE 123 16select * from information_schema.session_variables 17where variable_name='host_cache_size'; 18VARIABLE_NAME VARIABLE_VALUE 19HOST_CACHE_SIZE 123 20set global host_cache_size=1; 21select @@global.host_cache_size; 22@@global.host_cache_size 231 24set global host_cache_size=12; 25select @@global.host_cache_size; 26@@global.host_cache_size 2712 28set global host_cache_size=0; 29select @@global.host_cache_size; 30@@global.host_cache_size 310 32set session host_cache_size=1; 33ERROR HY000: Variable 'host_cache_size' is a GLOBAL variable and should be set with SET GLOBAL 34set global host_cache_size=123; 35select @@global.host_cache_size; 36@@global.host_cache_size 37123 38