misc/72498: Libc timestamp code on jailed SMP machine generates incorrect results

[gemini at geminix.org (Uwe Doering)]

The following reply was made to PR misc/72498; it has been noted by GNATS.

From: Uwe Doering <gemini_(_at_)_geminix_(_dot_)_org>
To: Justin Clift <jc_(_at_)_telstra_(_dot_)_net>
Cc: freebsd-gnats-submit_(_at_)_FreeBSD_(_dot_)_org
Subject: Re: misc/72498: Libc timestamp code on jailed SMP machine generates
   incorrect results
Date: Mon, 11 Oct 2004 09:33:38 +0200

 Justin Clift wrote:
 > 
 >>Environment:
 > 
 > FreeBSD was-dev.telstra.net 4.10-RELEASE FreeBSD 4.10-RELEASE #0: Fri Jun 25 14:23:42 EST 2004     root_(_at_)_verdelho_(_dot_)_telstra_(_dot_)_net:/usr/src/sys/compile/1GB_SHARED_V3  i386
 > 
 >>Description:
 > 
 > We're using PostgreSQL 7.4.5 in an SMP jailed environment on FreeBSD 4.10.
 > 
 > Inside this jail PostgreSQL is configured to output timestamp information in it's log file entries.  There appears to be a bug in the timestamp generation code, as for hours above 9 oclock (10am and onwards) the timestamp's being generated are occasionally incorrect:
 > [...]
 
 Do you happen to run more than one instance of PostgreSQL on that 
 machine, each in its own jail?  If so, are you aware that jails don't 
 have separate SysV shared resources (memory regions etc.), at least not 
 in FreeBSD's original 4.x implementation?  In this scenario your problem 
 might be caused by clashing PostgreSQL instances, and you're likely to 
 be in for more serious problems than just time stamp corruption.
 
 Just an educated guess, of course.
 
     Uwe
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