MySQL 8.0 Release Notes
MySQL 8.0 Source Code Documentation
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 7.4.2.1, “Error Log Configuration”.
To enable the system log sink, first load the sink component,
then modify the
log_error_services value:
INSTALL COMPONENT 'file://component_log_sink_syseventlog';
SET PERSIST log_error_services = 'log_filter_internal; log_sink_syseventlog';
To set log_error_services to
take effect at server startup, use the instructions at
Section 7.4.2.1, “Error Log Configuration”. Those instructions
apply to other error-logging system variables as well.
Note
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:
Entries marked as
Error,Warning, andNoteare written to the Event Log, but not messages such as information statements from individual storage engines.Event Log entries have a source of
MySQL(orMySQL-iftagsyseventlog.tagis defined astag).
On Unix and Unix-like systems, logging to the system log uses
syslog. The following system variables affect
syslog messages:
syseventlog.facility: The default facility forsyslogmessages isdaemon. Set this variable to specify a different facility.syseventlog.include_pid: Whether to include the server process ID in each line ofsyslogoutput.syseventlog.tag: This variable defines a tag to add to the server identifier (mysqld) insyslogmessages. If defined, the tag is appended to the identifier with a leading hyphen.
Note
Prior to MySQL 8.0.13, use the
log_syslog_facility,
log_syslog_include_pid, and
log_syslog_tag system
variables rather than the
syseventlog.
variables.
xxx
MySQL uses the custom label “System” for important
system messages about non-error situations, such as startup,
shutdown, and some significant changes to settings. In logs that
do not support custom labels, including the Event Log on
Windows, and syslog on Unix and Unix-like
systems, system messages are assigned the label used for the
information priority level. However, these messages are printed
to the log even if the MySQL
log_error_verbosity setting
normally excludes messages at the information level.
When a log sink must fall back to a label of
“Information” instead of “System” in
this way, and the log event is further processed outside of the
MySQL server (for example, filtered or forwarded by a
syslog configuration), these events may by
default be processed by the secondary application as being of
“Information” priority rather than
“System” priority.