[Fwd: Re: misc/72498: Libc timestamp code on jailed SMP machine generates incorrect results]

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(at)telstra(dot)net>
> Date:
> Tue, 12 Oct 2004 10:47:30 +1000
> To:
> pgsql-bugs(at)postgresql(dot)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(at)geminix(dot)org>
> Organization: Private UNIX Site
> To: Justin Clift <jc(at)telstra(dot)net>
> CC: freebsd-gnats-submit(at)FreeBSD(dot)org
> References: <200410110202(dot)i9B228Ye060291(at)www(dot)freebsd(dot)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(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