On 2021-03-16 20:51, Bharath Rupireddy wrote:
On Mon, Mar 15, 2021 at 11:23 AM torikoshia
<torikos...@oss.nttdata.com> wrote:
On 2021-03-07 19:16, Bharath Rupireddy wrote:
> On Fri, Feb 5, 2021 at 5:15 PM Bharath Rupireddy
> <bharath.rupireddyforpostg...@gmail.com> wrote:
>>
>> pg_terminate_backend and pg_cancel_backend with postmaster PID produce
>> "PID XXXX is not a PostgresSQL server process" warning [1], which
>> basically implies that the postmaster is not a PostgreSQL process at
>> all. This is a bit misleading because the postmaster is the parent of
>> all PostgreSQL processes. Should we improve the warning message if the
>> given PID is postmasters' PID?
+1. I felt it was a bit confusing when reviewing a thread[1].
Hmmm.
> I'm attaching a small patch that emits a warning "signalling
> postmaster with PID %d is not allowed" for postmaster and "signalling
> PostgreSQL server process with PID %d is not allowed" for auxiliary
> processes such as checkpointer, background writer, walwriter.
>
> However, for stats collector and sys logger processes, we still get
> "PID XXXXX is not a PostgreSQL server process" warning because they
> don't have PGPROC entries(??). So BackendPidGetProc and
> AuxiliaryPidGetProc will not help and even pg_stat_activity is not
> having these processes' pid.
I also ran into the same problem while creating a patch in [2].
I have not gone through that thread though. Is there any way we can
detect those child processes(stats collector, sys logger) that are
forked by the postmaster from a backend process? Thoughts?
I couldn't find good ways to do that, and thus I'm now wondering
just changing the message.
I'm now wondering if changing the message to something like
"PID XXXX is not a PostgreSQL backend process".
"backend process' is now defined as "Process of an instance
which acts on behalf of a client session and handles its
requests." in Appendix.
Yeah, that looks good to me. IIUC, we can just change the message from
"PID XXXX is not a PostgreSQL server process" to "PID XXXX is not a
PostgreSQL backend process" and we don't need look for AuxiliaryProcs
or PostmasterPid.
Changing log messages can affect operations, especially when people
monitor the log message strings, but improving "PID XXXX is not a
PostgreSQL server process" does not seem to cause such problems.
Regards,
--
Atsushi Torikoshi
NTT DATA CORPORATION
