Thread: [Fwd: Re: misc/72498: Libc timestamp code on jailed SMP machine generates incorrect results]
[Fwd: Re: misc/72498: Libc timestamp code on jailed SMP machine generates incorrect results]
From
Justin Clift
Date:
Hi all, Does anyone have further input on this? Regards and best wishes, Justin Clift Justin Clift wrote: > ------------------------------------------------------------------------ > > Subject: > [Fwd: Re: misc/72498: Libc timestamp code on jailed SMP machine > generates incorrect results] > From: > Justin Clift <jc@telstra.net> > Date: > Tue, 12 Oct 2004 10:47:30 +1000 > To: > pgsql-bugs@postgresql.org > > > Hi guys, > > Following up on the bug I posted the other day about incorrect > timestamps, the FreeBSD team are wondering if it might be caused by > conflicting PostgreSQL instances in different FreeBSD jails on the same > host machine. > > However, we've noticed no other problems with this configuration over > the last several and I was under the impression this is a fairly common > scenario. > > Is anyone able to verify or deny that PostgreSQL instances in different > jails (each with their own IP address) will not corrupt each other? I'm > aware they allocate shared memory from a "global pool" of it as made > available on the host system, but have been under the impression > PostgreSQL is coded to not corrupt in this kind of situation. > > Regards and best wishes, > > Justin Clift > > > -------- Original Message -------- > Subject: Re: misc/72498: Libc timestamp code on jailed SMP machine > generates incorrect results > Date: Mon, 11 Oct 2004 09:33:38 +0200 > From: Uwe Doering <gemini@geminix.org> > Organization: Private UNIX Site > To: Justin Clift <jc@telstra.net> > CC: freebsd-gnats-submit@FreeBSD.org > References: <200410110202.i9B228Ye060291@www.freebsd.org> > > 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@verdelho.telstra.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