From: Steve Wampler <swampler@noao.edu>
To: John Hasler <jhasler@newsguy.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: What does PostgreSQL do when time goes backward?
Date: Wed, 04 Aug 2010 10:50:51 -0700
Message-ID: <4C59A87B.1050005@noao.edu> (raw)
In-Reply-To: <87wrs671vz.fsf@thumper.dhh.gt.org>
References: <87eiegblzq.fsf@thumper.dhh.gt.org>
<BLU0-SMTP860B73D3D0E9B478E3DF80ACAF0@phx.gbl>
<20100804125524.GV12093@aart.is.rice.edu>
<87wrs671vz.fsf@thumper.dhh.gt.org>
John Hasler wrote:
> Frank writes:
>> My ntp client changes clock (by small amount) at any time:
>> Jul 25 05:29:38 bax ntpd[10269]: adjusting local clock by 0.098724s
>> Jul 25 05:31:43 bax ntpd[10269]: adjusting local clock by 0.038991s
>> Jul 25 06:13:38 bax ntpd[10269]: adjusting local clock by -0.037131s
>> Jul 25 15:01:52 bax ntpd[10269]: adjusting local clock by -0.112429s
>
> Ken writes:
>> These do seem to be larger values than you might expect from a clock
>> conditioned with ntpd. Is it a VM or is there something going on that
>> would stop or suspend your system?
>
John writes:
> There is certainly something wrong there.
I saw very bad clock performance on one Linux box I had (dual-single core
AMD cpus, no VMs), even with NTP, until I changed the clocksource kernel
parameter to hpet. Unfortunately (or fortunately) I no longer have that box.
--
Steve Wampler -- swampler@noao.edu
The gods that smiled on your birth are now laughing out loud.
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To: pgsql-sql@postgresql.org
Cc: swampler@noao.edu, jhasler@newsguy.com
Subject: Re: What does PostgreSQL do when time goes backward?
In-Reply-To: <4C59A87B.1050005@noao.edu>
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