Problem with stopping postmaster with pg_ctl

John Pagakis john@pagakis.com
Wed Sep 17 15:28:00 GMT 2003


Here is what I have found and surmised .....

The way Postgres controls things is, when it starts up, it stores the PID it
started under in a file called postgresql.pid in the data directory.  When
you use "pg_ctl stop", it reads the pid file and the issues a kill -15 on
that pid.  It then sits and waits for postgresql.pid to disappear.  After
one minute, if the file is still there, the script gives up and announces
that the postmaster will not stop.

If you try this, you'll notice that when you get to the kill in the script,
you'll get the Usage info on screen.  There is nothing wrong with how pg_ctl
is formatting the kill.  If you echo out that command and execute it from
the command line, it works just fine.

I believe the problem is Cygwin's implementation of kill.  From the command
line if you say kill -sig pid, it works.  If you say /etc/kill -sig pid it
gives you Usage.  There is something about when you give the fully qualified
path that it finds offensive.  The script does not give the fully qualified
path, but based on the behavior, I'm guessing the interpreter resolves to
the fully qualified path before executing.

Anyway, to work around this problem do this:

1) ps
This gives you a list of active processes.

2) Find the pid for Postgres who's ppid is 1.

3) kill -15 that pid.

4) Wait for the message that the database is shut down.

You are now shut down.

__________________________________________________________________
John Pagakis
Email: john@pagakis.com

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-----Original Message-----
From: Igor Pechtchanski [mailto:pechtcha@cs.nyu.edu]
Sent: Tuesday, September 16, 2003 1:47 PM
To: John Pagakis
Cc: pgsql-cygwin@postgresql.org; cygwin@cygwin.com
Subject: Re: Problem with stopping postmaster with pg_ctl


On Tue, 16 Sep 2003, John Pagakis wrote:

> I'm trying to get Postgres working under Cygwin.  The good news is, it
> mostly is.  The bad news is, I can't shut it down with pg_ctl.
>
> I loaded the full Cygwin installation on my Win2K Pro machine, and later
on
> my XP Pro box.  Both behave the same way.
>
> When I run pg_ctl stop, it motors for the duration of the wait period and
> then says the postmaster does not shut down.
>
> Upon further review ......
>
> It looks like pg_ctl looks through the process list for the Postgres
process
> and then tries to kill it.  You can specify the shutdown as smart (which
> translates to kill -TERM), fast (kill -INT) or immediate (kill -QUIT).
>
> When the script hits the kill, I get Usage info on the screen!!  So, the
> interpreter is not seeing this as a valid command line string for kill.  I
> have echoed the command being generated out and it looks fine.  I can take
> that same command and execute it: it shuts Postgres down.
>
> Why would the interpreter rejecting the command line for kill when it
> appears to be well formed?
>
> Any help would be greatly appreciated.

You probably have another "kill" in the path before "/bin/kill".  Try
"bash -c 'exec -l sh'", and from there "which kill".

Had you attached the output of "cygcheck -svr", as requested in the
problem reporting guidelines at <http://cygwin.com/problems.html>, it
would have provided some information for a more intelligent guess.
	Igor
--
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     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"I have since come to realize that being between your mentor and his route
to the bathroom is a major career booster."  -- Patrick Naughton


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