Re: pg_ctl start may return 0 even if the postmaster has been already started on Windows

At Wed, 20 Sep 2023 14:18:41 +0900 (JST), Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com> wrote in
> I was able to see the trouble in the CI environment, but not
> locally. I'll delve deeper into this. Thanks you for bringing it to my
> attention.

I found two instances with multiple child processes.

# child-pid / parent-pid / given-pid : exec name
process parent PID child PID target PID exec file
shell 1228 6472 1228 cmd.exe
child 5184 1228 1228 cmd.exe
child 6956 1228 1228 postgres.exe
> launcher shell executed multiple processes

process parent PID child PID target PID exec file
shell 4296 5880 4296 cmd.exe
child 5156 4296 4296 agent.exe
child 5640 4296 4296 postgres.exe
> launcher shell executed multiple processes

It looks like the environment has autorun setups for cmd.exe. There's
another known issue related to auto-launching chcp at
startup. Ideally, we would avoid such behavior in the
postmaster-launcher shell. I think we should add "/D" flag to cmd.exe
command line, perhaps in a separate patch.

Even after making that change, I still see something being launched from the launcher cmd.exe...

process parent PID child PID target PID exec file
shell 2784 6668 2784 cmd.exe
child 6140 2784 2784 MicrosoftEdgeUpdate.exe
child 6260 2784 2784 postgres.exe
> launcher shell executed multiple processes

I'm not sure what triggers this; perhaps some other kind of hooks? If
we cannot avoid this behavior, we'll have to verify the executable
file name. It should be fine, given that the file name is constant,
but I'm not fully convinced that this is the ideal solution.

Another issue is.. that I haven't been able to cause the false
positive of pg_ctl start.. Do you have a concise reproducer of the
issue?

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center