On Fri, Oct 14, 2016 at 11:51 AM, Andres Freund <andres@anarazel.de> wrote:
On 2016-10-14 13:11:51 +0200, Christoph Berg wrote: > Re: Michael Paquier 2016-02-10 <CAB7nPqS=wBbZzBcty1KyN-5Y9bPXZ+deJbfcCtebf06eF2Uyvg@mail.gmail.com> > > On Mon, Feb 8, 2016 at 11:32 PM, Andres Freund <andres@anarazel.de> wrote: > > > Frequently when reading postgres logs to do some post mortem analysis > > > I'm left wondering what process emitted an error/log message. After the > > > fact it's often hard to know wether an error message was emitted by a > > > user backend or by something internal, say the checkpointer or > > > autovacuum. Logging all process starts is often impractical given the > > > log volume that causes. > > > > > > So I'm proposing adding an escape displaying the process title (say 'k' > > > for kind?). So %k would emit something like "autovacuum worker process", > > > "wal sender process" etc. > > > > It would be nice to get something consistent between the ps output and > > this new prefix, say with for example a miscadmin.h parameter like > > MyProcName. > > > > > I'm thinking it might make sense to give normal connections "" as the > > > name, they're usually already discernible. > > > > Yeah, that sounds fine for me. What about background workers? I would > > think that they should use BackgroundWorker->bgw_name. > > (Rediscovering an old horse) > > Couldn't these processes just set %a = application_name?
It'd not get me what I'd want, no. E.g for walsenders that'd not be parsable in a meaningful way. I really would like an escape that'd always output one of: Postmaster, Startup, BgWriter, Checkpointer, WalWriter, WalReceiver, AutovacLauncher, AutovacWorker, PgArch, PgStat, SysLogger, Backend, BackgroundWorker.
I'm not sure what you are proposing. Which of those 13 strings you listed would a walsender advertise itself as? Why would stuffing one of those words into %k be different than stuffing that same word into %a, where %a would otherwise be the empty string? The only problem I can see is if someone has an application which calls itself "WalReceiver", for example, so you can't distinguish a real WalReceiver from a self-declared WalReceiver.
I'd be happy to replace the %a in my log_line_prefix with %a%k, but I don't really see the point of of %a and %k being different things.
