Server Command Options If MySQL is configured with the  -DWITH_DEBUG=1 CMake  option, you can use this option to get a trace file of what  mysqld  is doing. A typical  debug_options  string is  d:t:o, file_name . The default is d:t:i:o,/tmp/mysqld.trace  on Unix and  d:t:i:O,\mysqld.trace  on Windows. Using  -DWITH_DEBUG=1  to configure MySQL with debugging support enables you to use the  -- debug="d,parser_debug"  option when you start the server. This causes the Bison parser that is used to process SQL statements to dump a parser trace to the server’s standard error output. Typically, this output is written to the error log. This option may be given multiple times. Values that begin with  +  or  -  are added to or subtracted from the previous value. For example,  --debug=T --debug=+P  sets the value to  P:T . For more information, see Section 5.9.4, “The DBUG Package” . Controls whether the Debug Sync facility for testing and debugging is enabled. Use of Debug Sync requires that MySQL be configured with the  -DENABLE_DEBUG_SYNC=1 CMake  option (see Section 2.9.7, “MySQL Source-Configuration Options” ). If Debug Sync is not compiled in, this option is not available. The option value is a timeout in seconds. The default value is 0, which disables Debug Sync. To enable it, specify a value greater than 0; this value also becomes the default timeout for individual synchronization points. If the option is given without a value, the timeout is set to 300 seconds. For a description of the Debug Sync facility and how to use synchronization points, see MySQL Internals: Test Synchronization. Set the default server time zone. This option sets the global  time_zone  system variable. If this option is not given, the default time zone is the same as the system time zone (given by the value of the system_time_zone  system variable. Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, an error occurs. If  file_name  is not an absolute path name, it is interpreted relative to the current directory. This must be the first option on the command line if it is used. For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling” . 737 • --defaults-extra-file= file_name • --default-time-zone= timezone • --debug-sync-timeout[= N ] Command-Line Format --default-time-zone=name Type String Command-Line Format --debug-sync-timeout[=#] Type Integer Default Value (Unix) d:t:i:o,/tmp/mysqld.trace Default Value (Windows) d:t:i:O,\mysqld.trace