The Error Log To set  log_error_services  to take effect at server startup, use the instructions at Section 5.4.2.1, “Error Log Configuration” . Those instructions apply to other error-logging system variables as well. It is permitted to name  log_sink_json  multiple times in the  log_error_services  value. For example, to write unfiltered events with one instance and filtered events with another instance, you could set log_error_services  like this: The JSON sink determines its output destination based on the default error log destination, which is given by the  log_error  system variable. If  log_error  names a file, the JSON sink bases output file naming on that file name, plus a numbered  . NN .json  suffix, with  NN  starting at 00. For example, if  log_error  is file_name , successive instances of  log_sink_json  named in the  log_error_services  value write to  file_name .00.json ,  file_name .01.json , and so forth. If  log_error  is  stderr , the JSON sink writes to the console. If  log_sink_json  is named multiple times in the  log_error_services  value, they all write to the console, which is likely not useful. It is possible to have  mysqld  write the error log to the system log (the Event Log on Windows, and syslog  on Unix and Unix-like systems). This section describes how to configure error logging using the built-in filter,  log_filter_internal , and the system log sink,  log_sink_syseventlog , to take effect immediately and for subsequent server startups. For general information about configuring error logging, see Section 5.4.2.1, “Error Log Configuration” . To enable the system log sink, first load the sink component, then modify the  log_error_services value: To set  log_error_services  to take effect at server startup, use the instructions at Section 5.4.2.1, “Error Log Configuration” . Those instructions apply to other error-logging system variables as well. For MySQL 8.0 configuration, you must enable error logging to the system log explicitly. This differs from MySQL 5.7 and earlier, for which error logging to the system log is enabled by default on Windows, and on all platforms requires no component loading. Error logging to the system log may require additional system configuration. Consult the system log documentation for your platform. On Windows, error messages written to the Event Log within the Application log have these characteristics: On Unix and Unix-like systems, logging to the system log uses  syslog . The following system variables affect  syslog  messages: 5.4.2.8 Error Logging to the System Log Note SET PERSIST log_error_services = ’log_sink_json; log_filter_internal; log_sink_json’; INSTALL COMPONENT ’file://component_log_sink_syseventlog’; SET PERSIST log_error_services = ’log_filter_internal; log_sink_syseventlog’; •Entries marked as  Error ,  Warning , and  Note  are written to the Event Log, but not messages such as information statements from individual storage engines. •Event Log entries have a source of  MySQL  (or  MySQL- tag  if  syseventlog.tag  is defined as  tag ). • syseventlog.facility : The default facility for  syslog  messages is  daemon . Set this variable to specify a different facility. 1041