Message-ID: <52A5B499.3060008@2ndquadrant.com>
Date: Mon, 09 Dec 2013 20:16:25 +0800
From: Craig Ringer <craig@2ndquadrant.com>
Organization: 2nd Quadrant
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To: Robert Haas <robertmhaas@gmail.com>, =?ISO-8859-1?Q?Fabr=EDzio_Mell?=
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CC: Christian Kruse <christian@2ndquadrant.com>,
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Subject: Re: Time-Delayed Standbys
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On 12/04/2013 02:46 AM, Robert Haas wrote:
>> Thanks for your review Christian...
> 
> So, I proposed this patch previously and I still think it's a good
> idea, but it got voted down on the grounds that it didn't deal with
> clock drift.  I view that as insufficient reason to reject the
> feature, but others disagreed.  Unless some of those people have
> changed their minds, I don't think this patch has much future here.

Surely that's the operating system / VM host / sysadmin / whatever's
problem?

The only way to "deal with" clock drift that isn't fragile in the face
of variable latency, etc, is to basically re-implement (S)NTP in order
to find out what the clock difference with the remote is.

If we're going to do that, why not just let the OS deal with it?

It might well be worth complaining about obvious aberrations like
timestamps in the local future - preferably by complaining and not
actually dying. It does need to be able to cope with a *skewing* clock,
but I'd be surprised if it had any issues there in the first place.

-- 
 Craig Ringer                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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