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MySQL 8.0 Reference Manual  /  ...  /  Error Log Message Format Error Log Message Format

Each error log sink (writer) component has a characteristic output format it uses to write messages to its destination, but other factors may influence the content of the messages:

For all log writers, the ID included in error log messages is that of the thread within mysqld responsible for writing the message. This indicates which part of the server produced the message, and is consistent with general query log and slow query log messages, which include the connection thread ID.

Output Format for log_sink_internal

This log writer produces the traditional error log output. It writes messages using this format:

timestamp thread_id [severity] [err_code] [subsystem] message

The [ and ] square bracket characters are literal characters in the message format. They do not indicate that fields are optional.

The [err_code] and [subsystem] fields were added in MySQL 8.0.4 and 8.0.5, respectively. They will be missing from logs generated by older servers. Log parsers can treat these fields as parts of the message text that will be present only for logs written by servers recent enough to include them. Parsers must treat the err_code part of [err_code] indicators as a string value.


2018-03-22T12:35:47.538083Z 0 [Note] [MY-012487] [InnoDB] InnoDB: DDL log recovery : begin
2018-03-22T12:35:47.550565Z 0 [Warning] [MY-010068] [Server] CA certificate /var/mysql/sslinfo/cacert.pem is self signed.
2018-03-22T12:35:47.669397Z 4 [Note] [MY-010051] [Server] Event Scheduler: scheduler thread started with id 4
2018-03-22T12:35:47.550939Z 0 [Note] [MY-010253] [Server] IPv6 is available.
Output Format for log_sink_json

The JSON-format log writer produces messages as JSON objects that contain key/value pairs. For example:

{ "prio": 3, "err_code": 10051, "subsystem": "Server",
  "source_file": "", "function": "run",
  "msg": "Event Scheduler: scheduler thread started with id 4",
  "time": "2018-03-22T12:35:47.669397Z", "thread": 4,
  "err_symbol": "ER_SCHEDULER_STARTED", "SQL_state": "HY000",
  "label": "Note" }
Output Format for log_sink_syseventlog

The system log writer produces output that conforms to the system log format used on the local platform.

System Variables That Affect Error Log Format

The log_timestamps system variable controls the time zone of timestamps in messages written to the error log (as well as to general query log and slow query log files). Permitted values are UTC (the default) and SYSTEM (local system time zone).

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