Feature request: separate logging - Mailing list pgsql-general

A glaring weakness in Postgresql for production systems is that the administrator has no way of controlling what types of logs go where. There are at least two types of logs: errors and statement logs. (I could also add: connection, syntax error, query duration, audit). It has becomes increasingly important in the Linux world, with its over reliance on systemd, that we admins be able to distinguish between these log outputs. Systemd wants to control all the daemons and services run on a Linux host. To do this effectively, it needs to capture the stdout and stderr or possibly parse the external logfile of the daemon it spawns. The benefits of systemd's journald subsystem include being able to automatically identify daemons that are failing to start properly. (The merits of systemd are beyond the scope of this discussion; it is now the all-but-ubiquitous standard of linux distributions, and has become nearly intractable). 

The Postgresql startup process could greatly benefit from systemd. As it is now, PGDG distributes postgresql with init scripts which really do very little to check if postgresql bombed shortly after startup. I have improved upon that script to do some smart detection of a failed startup, but the result is having two different files to monitor. On the one hand, I want to use postgresql's built-in file or CSV logging. On the other, I need to check the output of the startup process. These logs have different formats, especially for the smart DBA who wants to customize the log prefix with a more usable timestamp and other fields. Logging to external files is nice because postgresql rotates the logs for us automatically. (External log rotation is problematic and risky because it requires a configuration reload which may lead to undesirable side-effects. Right?)