1select @@global.thread_concurrency; 2@@global.thread_concurrency 310 4select @@session.thread_concurrency; 5ERROR HY000: Variable 'thread_concurrency' is a GLOBAL variable 6show global variables like 'thread_concurrency'; 7Variable_name Value 8thread_concurrency 10 9show session variables like 'thread_concurrency'; 10Variable_name Value 11thread_concurrency 10 12select * from information_schema.global_variables where variable_name='thread_concurrency'; 13VARIABLE_NAME VARIABLE_VALUE 14THREAD_CONCURRENCY 10 15select * from information_schema.session_variables where variable_name='thread_concurrency'; 16VARIABLE_NAME VARIABLE_VALUE 17THREAD_CONCURRENCY 10 18set global thread_concurrency=1; 19ERROR HY000: Variable 'thread_concurrency' is a read only variable 20set session thread_concurrency=1; 21ERROR HY000: Variable 'thread_concurrency' is a read only variable 22