Date: Tue, 20 Jun 2017 10:36:43 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Sergey Burladyan <eshkinkot@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>,
	Amit Kapila <amit.kapila16@gmail.com>,
	Dmitriy Sarafannikov <dsarafannikov@yandex.ru>,
	Vladimir Borodin <root@simply.name>
Subject: Re: Broken hint bits (freeze)
Message-ID: <20170620143643.GA24975@momjian.us>
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On Tue, Jun 20, 2017 at 01:10:26PM +0300, Sergey Burladyan wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > > Uh, as I understand it the rsync is going to copy the missing WAL file
> > > from the new master to the standby, right, and I think pg_controldata
> > > too, so it should be fine.  Have you tested to see if it fails?
> 
> It need old WAL files from old version for correct restore heap
> files. New WAL files from new version does not have this information.
> 
> > The point is that we are checking the "Latest checkpoint location" to
> > make sure all the WAL was replayed.   We are never going to start the
> > old standby server.  Rsync is going to copy the missing/changed files.
> 
> Only if missing/changed files changed in size, because rsync run with
> --size-only it does not copy changed files with same size.

I am sorry but I am not understanding.  Step 10.b says:

	10.b Make sure the new standby data directories do not exist
	
	Make sure the new standby data directories do not exist or are empty. If
	initdb was run, delete the standby server data directories.

so the _entire_ new data directory is empty before rsync is run, meaning
that it is an exact copy of the new master.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +


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