| Type: | string |
| Default: | stderr |
| Context: | sighup |
| Restart: | false |
PostgreSQL supports several methods for logging server messages, including stderr, csvlog, jsonlog, and syslog. On Windows, eventlog is also supported. Set this parameter to a list of desired log destinations separated by commas. The default is to log to stderr only. This parameter can only be set in the postgresql.conf file or on the server command line.
If csvlog is included in log_destination, log entries are output in comma separated value (CSV) format, which is convenient for loading logs into programs. See runtime-config-logging-csvlog for details. logging_collector must be enabled to generate CSV-format log output.
If jsonlog is included in log_destination, log entries are output in JSON format, which is convenient for loading logs into programs. See runtime-config-logging-jsonlog for details. logging_collector must be enabled to generate JSON-format log output.
When either stderr, csvlog or jsonlog are included, the file current_logfiles is created to record the location of the log file(s) currently in use by the logging collector and the associated logging destination. This provides a convenient way to find the logs currently in use by the instance. Here is an example of this file's content:stderr log/postgresql.logcsvlog log/postgresql.csvjsonlog log/postgresql.jsoncurrent_logfiles is recreated when a new log file is created as an effect of rotation, and when log_destination is reloaded. It is removed when none of stderr, csvlog or jsonlog are included in log_destination, and when the logging collector is disabled.
On most Unix systems, you will need to alter the configuration of your system's syslog daemon in order to make use of the syslog option for log_destination. PostgreSQL can log to syslog facilities LOCAL0 through LOCAL7 (see syslog_facility), but the default syslog configuration on most platforms will discard all such messages. You will need to add something like:local0.* /var/log/postgresql to the syslog daemon's configuration file to make it work.
On Windows, when you use the eventlog option for log_destination, you should register an event source and its library with the operating system so that the Windows Event Viewer can display event log messages cleanly. See event-log-registration for details.