1select @@global.performance_schema_events_waits_history_long_size;
2@@global.performance_schema_events_waits_history_long_size
315000
4select @@session.performance_schema_events_waits_history_long_size;
5ERROR HY000: Variable 'performance_schema_events_waits_history_long_size' is a GLOBAL variable
6show global variables like 'performance_schema_events_waits_history_long_size';
7Variable_name	Value
8performance_schema_events_waits_history_long_size	15000
9show session variables like 'performance_schema_events_waits_history_long_size';
10Variable_name	Value
11performance_schema_events_waits_history_long_size	15000
12select * from information_schema.global_variables
13where variable_name='performance_schema_events_waits_history_long_size';
14VARIABLE_NAME	VARIABLE_VALUE
15PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_LONG_SIZE	15000
16select * from information_schema.session_variables
17where variable_name='performance_schema_events_waits_history_long_size';
18VARIABLE_NAME	VARIABLE_VALUE
19PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_LONG_SIZE	15000
20set global performance_schema_events_waits_history_long_size=1;
21ERROR HY000: Variable 'performance_schema_events_waits_history_long_size' is a read only variable
22set session performance_schema_events_waits_history_long_size=1;
23ERROR HY000: Variable 'performance_schema_events_waits_history_long_size' is a read only variable
24