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? > > If yes, how about a generic message for both of the functions - > "signalling postmaster process is not allowed" or "cannot signal > postmaster process" or some other better suggestion? > > [1] 2471176 ---> is postmaster PID. > postgres=# select pg_terminate_backend(2471176); > WARNING: PID 2471176 is not a PostgreSQL server process > pg_terminate_backend > ---------------------- > f > (1 row) > postgres=# select pg_cancel_backend(2471176); > WARNING: PID 2471176 is not a PostgreSQL server process > pg_cancel_backend > ------------------- > f > (1 row)
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. With Regards, Bharath Rupireddy. EnterpriseDB: http://www.enterprisedb.com
v1-0001-Improve-PID-XXXX-is-not-a-PostgreSQL-server-proce.patch
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