SET @start_global_value = @@global.thread_pool_min_threads; select @@global.thread_pool_min_threads; @@global.thread_pool_min_threads 1 select @@session.thread_pool_min_threads; ERROR HY000: Variable 'thread_pool_min_threads' is a GLOBAL variable show global variables like 'thread_pool_min_threads'; Variable_name Value thread_pool_min_threads 1 show session variables like 'thread_pool_min_threads'; Variable_name Value thread_pool_min_threads 1 select * from information_schema.global_variables where variable_name='thread_pool_min_threads'; VARIABLE_NAME VARIABLE_VALUE THREAD_POOL_MIN_THREADS 1 select * from information_schema.session_variables where variable_name='thread_pool_min_threads'; VARIABLE_NAME VARIABLE_VALUE THREAD_POOL_MIN_THREADS 1 set global thread_pool_min_threads=1; select @@global.thread_pool_min_threads; @@global.thread_pool_min_threads 1 set global thread_pool_min_threads=65536; Warnings: Warning 1292 Truncated incorrect thread_pool_min_threads value: '65536' select @@global.thread_pool_min_threads; @@global.thread_pool_min_threads 256 set session thread_pool_min_threads=1; ERROR HY000: Variable 'thread_pool_min_threads' is a GLOBAL variable and should be set with SET GLOBAL set global thread_pool_min_threads=1.1; ERROR 42000: Incorrect argument type to variable 'thread_pool_min_threads' set global thread_pool_min_threads=1e1; ERROR 42000: Incorrect argument type to variable 'thread_pool_min_threads' set global thread_pool_min_threads="foo"; ERROR 42000: Incorrect argument type to variable 'thread_pool_min_threads' set global thread_pool_min_threads=0; Warnings: Warning 1292 Truncated incorrect thread_pool_min_threads value: '0' select @@global.thread_pool_min_threads; @@global.thread_pool_min_threads 1 set global thread_pool_min_threads=10000000000; Warnings: Warning 1292 Truncated incorrect thread_pool_min_threads value: '10000000000' select @@global.thread_pool_min_threads; @@global.thread_pool_min_threads 256 SET @@global.thread_pool_min_threads = @start_global_value;