Re: Send duration output to separate log files

On Thu, Jul 11, 2024 at 6:47 AM Alastair Turner <minion@decodable.me> wrote:

 The other category of logging which would benefit from a separate file is audit. It also can create massive volumes of log content. Splitting audit information off into a separate file for use by a separate team or function is also a request I have heard from some financial institutions adopting Postgres. With audit being provided by an extension, this would become quite an intrusive change.

Thanks for the feedback. I agree pgaudit is another thing that can create massive log files, and should be solved at some point.  However, I wanted to keep this patch self-contained to in-core stuff. And pgaudit is already an odd duck, in that it puts CSV into your stderr stream (and into your json!). Ideally it would put a single CSV stream into a separate csv file. Perhaps even something that did not necessarily live in log_directory.

Would an extension be able to safely modify the message_type field you have added using emit_log_hook? If so, the field becomes more of a log destination label than a type marker. If an extension could hook into the log file creation/rotation process, that would be a nice basis for enabling extensions (I'm particularly thinking of pgAudit) to manage separate logging destinations.

Yes, I had more than duration in mind when I created errmessagetype. A hook to set it would be the obvious next step, and then some sort of way of mapping that to arbitrary log files. But I see that as mostly orthagonal to this patch (and certainly a much larger endeavor).