select @@global.thread_concurrency;
@@global.thread_concurrency
10
select @@session.thread_concurrency;
ERROR HY000: Variable 'thread_concurrency' is a GLOBAL variable
show global variables like 'thread_concurrency';
Variable_name	Value
thread_concurrency	10
show session variables like 'thread_concurrency';
Variable_name	Value
thread_concurrency	10
select * from information_schema.global_variables where variable_name='thread_concurrency';
VARIABLE_NAME	VARIABLE_VALUE
THREAD_CONCURRENCY	10
select * from information_schema.session_variables where variable_name='thread_concurrency';
VARIABLE_NAME	VARIABLE_VALUE
THREAD_CONCURRENCY	10
set global thread_concurrency=1;
ERROR HY000: Variable 'thread_concurrency' is a read only variable
set session thread_concurrency=1;
ERROR HY000: Variable 'thread_concurrency' is a read only variable
