Re: Replication origins and timelines

On 2017-05-31 21:27:56 -0400, Stephen Frost wrote:
> Craig,
>
> * Craig Ringer (craig(at)2ndquadrant(dot)com) wrote:
> > TL;DR: replication origins track LSN without timeline. This is
> > ambiguous when physical failover is present since XXXXXXXX/XXXXXXXX
> > can now represent more than one state due to timeline forks with
> > promotions. Replication origins should track timelines so we can tell
> > the difference, I propose to patch them accordingly for pg11.
>
> Uh, TL;DR, wow? Why isn't this something which needs to be addressed
> before PG10 can be released?

Huh? Slots are't present on replicas, ergo there's no way for the whole
issue to occur in v10.

> The further comments in your email seem to state that logical
> replication will just fail if a replica is promoted. While not ideal,
> that might barely reach the point of it being releasable, but turns it
> into a feature that I'd have a really hard time recommending to
> anyone,

Meh^10

> and are we absolutely sure that there aren't any cases where there might
> be an issue of undetected promotion, leading to the complications which
> you describe?

Yes, unless you manipulate things by hand, copying files around or such.

Greetings,

Andres Freund