Date: Tue, 28 Aug 2018 08:21:50 -0400
From: Stephen Frost <sfrost@snowman.net>
To: Michael Paquier <michael@paquier.xyz>
Cc: Alexander Kukushkin <cyberdemn@gmail.com>,
	Alvaro Herrera <alvherre@2ndquadrant.com>,
	Dmitry Dolgov <9erthalion6@gmail.com>,
	pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #15346: Replica fails to start after the crash
Message-ID: <20180828122150.GC3326@tamriel.snowman.net>
References: 
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 <20180822175034.lnvwk5js32k6mjyz@alvherre.pgsql>
 <20180823041420.GA1158@paquier.xyz>
 <CAFh8B==4gpwor6ODercru0iifqwd0nQrdRvXzmorWkMRQa4q=g@mail.gmail.com>
 <CAFh8B=nHdsX83hTZMqGqbht39ud+DRQOv4_Te+xu3DuPssQbZA@mail.gmail.com>
 <CAFh8B=mYGP1J8ueHKU40Dr4bNBUPJj1rTbZ6Wpg4gR30uCRunA@mail.gmail.com>
 <20180828024409.GB29157@paquier.xyz>
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Greetings,

* Michael Paquier (michael@paquier.xyz) wrote:
> On Sat, Aug 25, 2018 at 09:54:39AM +0200, Alexander Kukushkin wrote:
> > Why the number of tuples in the xlog is greater than the number of
> > tuples on the index page?
> > Because this page was already overwritten and its LSN is HIGHER than
> > the current LSN!
>=20
> That's annoying.  Because that means that the control file of your
> server maps to a consistent point which is older than some of the
> relation pages.  How was the base backup of this node created?  Please
> remember that when taking a base backup from a standby, you should
> backup the control file last, as there is no control of end backup with
> records available.  So it seems to me that the origin of your problem
> comes from an incorrect base backup expectation?=20

Yeah, we really need to know how this system was built.  If it was built
using the low-level pg_start/stop_backup, then which API was used- the
old one that creates a backup_label file, or the new API which requires
the user to create the backup_label file?  I haven't followed this
thread very closely, but I wonder if maybe the new API was used, but no
backup_label file was created, making PG think it was doing crash
recovery instead of restoring from a file-level backup...

Thanks!

Stephen

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