787 Server System Variables This variable is the user interface to the Debug Sync facility. 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 system variable is not available. The global variable value is read only and indicates whether the facility is enabled. By default, Debug Sync is disabled and the value of  debug_sync  is  OFF . If the server is started with  --debug-sync- timeout= N , where  N  is a timeout value greater than 0, Debug Sync is enabled and the value of debug_sync  is  ON - current signal  followed by the signal name. Also,  N  becomes the default timeout for individual synchronization points. The session value can be read by any user and has the same value as the global variable. The session value can be set to control synchronization points. For a description of the Debug Sync facility and how to use synchronization points, see MySQL Internals: Test Synchronization. Setting the session value of this system variable is a restricted operation. The session user must have privileges sufficient to set restricted session variables. See Section 5.1.9.1, “System Variable Privileges” . • default_authentication_plugin • mysql_native_password : Use MySQL native passwords; see Section 6.4.1.1, “Native Pluggable Authentication” . • sha256_password : Use SHA-256 passwords; see Section 6.4.1.3, “SHA-256 Pluggable Authentication” . The default authentication plugin. These values are permitted: Command-Line Format --default-authentication- plugin=plugin_name System Variable default_authentication_plugin Scope Global Dynamic No SET_VAR  Hint Applies No Type Enumeration Default Value caching_sha2_password Valid Values mysql_native_password sha256_password caching_sha2_password System Variable debug_sync Scope Session Dynamic Yes SET_VAR  Hint Applies No Type String