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

Michael Paquier wrote:
> On Wed, Apr 27, 2016 at 9:47 AM, Michael Paquier
> <michael(dot)paquier(at)gmail(dot)com> wrote:

> > Replication slots are perfectly able to retain WAL segments from a
> > prior timeline, so I am not sure that this would be much a gain.
>
> Or to put in in other words, a slot that activates automatically
> itself at promotion to retain WAL from the previous timeline would be
> interesting for pg_rewind, but the use case we have here is only
> pg_rewind. so it seems a bit narrow to bother modifying the core core
> to add this support in the replication slot code. And this can be
> solved lightly with an archive. Thoughts from others are welcome.

Sounds to me like it should be enough to document (in pg_rewind's page)
that activating a slot prior to the promotion. Maybe we could have
"pg_ctl promote" have an option to create a slot, to make this simpler?

--
Álvaro Herrera http://www.2ndQuadrant.com/
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