Using System Variables Type Integer Default Value 28800 Minimum Value 1 Maximum Value (Windows) 2147483 Maximum Value (Other) 31536000 The number of seconds the server waits for activity on a noninteractive connection before closing it. On thread startup, the session  wait_timeout  value is initialized from the global  wait_timeout value or from the global  interactive_timeout  value, depending on the type of client (as defined by the  CLIENT_INTERACTIVE  connect option to  mysql_real_connect() ). See also interactive_timeout . The number of errors, warnings, and notes that resulted from the last statement that generated messages. This variable is read only. See Section 13.7.7.42, “SHOW WARNINGS Statement” . • warning_count • windowing_use_high_precision Command-Line Format --windowing-use-high-precision[={OFF| ON}] System Variable windowing_use_high_precision Scope Global, Session Dynamic Yes SET_VAR  Hint Applies Yes Type Boolean Default Value ON Whether to compute window operations without loss of precision. See Section 8.2.1.21, “Window Function Optimization” . 5.1.9 Using System Variables The MySQL server maintains many system variables that configure its operation. Section 5.1.8, “Server System Variables” , describes the meaning of these variables. Each system variable has a default value. System variables can be set at server startup using options on the command line or in an option file. Most of them can be changed dynamically while the server is running by means of the  SET  statement, which enables you to modify operation of the server without having to stop and restart it. You can also use system variable values in expressions. Many system variables are built in. System variables may also be installed by server plugins or components: •System variables implemented by a server plugin are exposed when the plugin is installed and have names that begin with the plugin name. For example, the  audit_log  plugin implements a system variable named  audit_log_policy . •System variables implemented by a component are exposed when the component is installed and have names that begin with a component-specific prefix. For example, the  log_filter_dragnet  error log filter component implements a system variable named  log_error_filter_rules , the full name of which is  dragnet.log_error_filter_rules . To refer to this variable, use the full name. 916