Server System Variables The stack size for each thread. The default is large enough for normal operation. If the thread stack size is too small, it limits the complexity of the SQL statements that the server can handle, the recursion depth of stored procedures, and other memory-consuming actions. • time_zone The current time zone. This variable is used to initialize the time zone for each client that connects. By default, the initial value of this is  ’SYSTEM’  (which means, “use the value of  system_time_zone ” ). The value can be specified explicitly at server startup with the  --default-time-zone  option. See Section 5.1.15, “MySQL Server Time Zone Support” . If set to  SYSTEM , every MySQL function call that requires a time zone calculation makes a system library call to determine the current system time zone. This call may be protected by a global mutex, resulting in contention. • timestamp Scope Global Dynamic No SET_VAR  Hint Applies No Type Integer Default Value (64-bit platforms) 286720 Default Value (32-bit platforms) 221184 Minimum Value 131072 Maximum Value (64-bit platforms) 18446744073709547520 Maximum Value (32-bit platforms) 4294967295 Block Size 1024 System Variable time_zone Scope Global, Session Dynamic Yes SET_VAR  Hint Applies ( ≥  8.0.17) Yes SET_VAR  Hint Applies ( ≤  8.0.16) No Type String Default Value SYSTEM Minimum Value ( ≥  8.0.19) -13:59 Minimum Value ( ≤  8.0.18) -12:59 Maximum Value ( ≥  8.0.19) +14:00 Maximum Value ( ≤  8.0.18) +13:00 System Variable timestamp Scope Session Dynamic Yes SET_VAR  Hint Applies Yes 906 Note