Re: BUG #14109: pg_rewind fails to update target control file in one scenario

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> Date: Mon, 25 Apr 2016 23:03:23 +0900
> Subject: Re: [BUGS] BUG #14109: pg_rewind fails to update target control file in one scenario
> From: michael(dot)paquier(at)gmail(dot)com
> To: johnlumby(at)hotmail(dot)com
> CC: pgsql-bugs(at)postgresql(dot)org
>
> On Mon, Apr 25, 2016 at 10:48 PM, John Lumby <johnlumby(at)hotmail(dot)com> wrote:
>>
>> Note the difference in timeline
>
> Yes, and? System A is still on its previous timeline 11, and will jump
> to timeline 12 once it has connected back. That's possible since 9.3.

Answering your "and?" : In my testing, 
        "and no WAL replicated from B, new Primary , to A , new Standby".
That is why I concluded there is a bug.
Also on System A (new Standby) timeline did not jump up to 12,  it remained at 11.
Are you indicating that the admin (me) needs to do something to make that happen?
If so what?

>
>> and then, as I described, no WAL is replicated from B to A.
>> Did you try this scenario yourself?
>
> Yes.

And did you perform updates on System B (new Primary)
and then observe them replicated to System A?
I consistently see that *not* happening.

>
>> I hope you agree it is a bug?
>
> No. In this case pg_rewind is a no-op: system A was shut down *before*
> B was promoted, so it knows about the shutdown checkpoint record of
> system A. No rewind would be needed here. One potential issue with

Yes,  no rewind is needed,  I agree.   But,  as you stated earlier,
the timeline on System A needs to be incremented.
So the question is,  what is supposed to make that happen?

>
> Again there is no bug here.
> --
> Michael