1SELECT @@global.optimizer_trace_max_mem_size; 2@@global.optimizer_trace_max_mem_size 316384 4SET @@global.optimizer_trace_max_mem_size=5; 5show global variables like 'optimizer_trace_max_mem_size'; 6Variable_name Value 7optimizer_trace_max_mem_size 5 8select * from information_schema.global_variables where variable_name='optimizer_trace_max_mem_size'; 9VARIABLE_NAME VARIABLE_VALUE 10OPTIMIZER_TRACE_MAX_MEM_SIZE 5 11select @@session.optimizer_trace_max_mem_size; 12@@session.optimizer_trace_max_mem_size 1316384 14show session variables like 'optimizer_trace_max_mem_size'; 15Variable_name Value 16optimizer_trace_max_mem_size 16384 17select * from information_schema.session_variables where variable_name='optimizer_trace_max_mem_size'; 18VARIABLE_NAME VARIABLE_VALUE 19OPTIMIZER_TRACE_MAX_MEM_SIZE 16384 20set session optimizer_trace_max_mem_size=10; 21select @@session.optimizer_trace_max_mem_size; 22@@session.optimizer_trace_max_mem_size 2310 24show session variables like 'optimizer_trace_max_mem_size'; 25Variable_name Value 26optimizer_trace_max_mem_size 10 27set session optimizer_trace_max_mem_size=0; 28select @@session.optimizer_trace_max_mem_size; 29@@session.optimizer_trace_max_mem_size 300 31show session variables like 'optimizer_trace_max_mem_size'; 32Variable_name Value 33optimizer_trace_max_mem_size 0 34set session optimizer_trace_max_mem_size=-100; 35Warnings: 36Warning 1292 Truncated incorrect optimizer_trace_max_mem_size value: '-100' 37select @@session.optimizer_trace_max_mem_size; 38@@session.optimizer_trace_max_mem_size 390 40show session variables like 'optimizer_trace_max_mem_size'; 41Variable_name Value 42optimizer_trace_max_mem_size 0 43set session optimizer_trace_max_mem_size=2000000000; 44select @@session.optimizer_trace_max_mem_size; 45@@session.optimizer_trace_max_mem_size 462000000000 47show session variables like 'optimizer_trace_max_mem_size'; 48Variable_name Value 49optimizer_trace_max_mem_size 2000000000 50set session optimizer_trace_max_mem_size=default; 51select @@session.optimizer_trace_max_mem_size; 52@@session.optimizer_trace_max_mem_size 535 54show session variables like 'optimizer_trace_max_mem_size'; 55Variable_name Value 56optimizer_trace_max_mem_size 5 57set global optimizer_trace_max_mem_size=default; 58select @@global.optimizer_trace_max_mem_size; 59@@global.optimizer_trace_max_mem_size 6016384 61show global variables like 'optimizer_trace_max_mem_size'; 62Variable_name Value 63optimizer_trace_max_mem_size 16384 64set optimizer_trace_max_mem_size=1.1; 65ERROR 42000: Incorrect argument type to variable 'optimizer_trace_max_mem_size' 66set optimizer_trace_max_mem_size="foobar"; 67ERROR 42000: Incorrect argument type to variable 'optimizer_trace_max_mem_size' 68