To: Ray Stell <stellr@cns.vt.edu>
cc: alvherre <alvherre@commandprompt.com>,
	pgsql-admin <pgsql-admin@postgresql.org>, pgsql-hackers@postgresql.org
Subject: Re: command tag logging 
In-reply-to: <20100527172547.GA9472@cns.vt.edu> 
References: <20100526210833.GA14469@cns.vt.edu>
	<1274908611-sup-6661@alvh.no-ip.org>
	<3713.1274978989@sss.pgh.pa.us> <20100527172547.GA9472@cns.vt.edu>
Comments: In-reply-to Ray Stell <stellr@cns.vt.edu>
	message dated "Thu, 27 May 2010 13:25:47 -0400"
Date: Thu, 27 May 2010 14:23:06 -0400
Message-ID: <4976.1274984586@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Ray Stell <stellr@cns.vt.edu> writes:
> On Thu, May 27, 2010 at 12:49:49PM -0400, Tom Lane wrote:
>> That is in the right place, isn't it.  That would suggest that
>> get_ps_display() is returning a wrong length on Ray's machine.
>> It works okay here, but since that's platform-specific code that
>> hardly proves much.  Ray, what platform is this exactly?

> [postgres ~]$ cat /etc/issue
> Red Hat Enterprise Linux Server release 5.5 (Tikanga)

OK, I can reproduce it when I try on my Fedora box.  The problem is that
log_connections emits a log message before init_ps_display() has been
called, and the ps_status.c logic isn't careful to ensure that it
returns something sane in that case.  It accidentally failed to fail
too badly before I changed the elog.c logic, because there'd be an
embedded null after the program name in most cases.  I suppose people
might even have thought that printing "postmaster" or "postgres" for
%i was intended behavior there.

I think the most useful fix is to create a static variable to hold the
notional strlen(ps_buffer), which will initialize to zero, and then
we can use that instead of groveling over the string in get_ps_display.
Should improve performance a tad as well as fixing this problem.
Will work on that.

			regards, tom lane