Re: .ready and .done files considered harmful

Hi,

On 2021-05-05 16:13:08 -0400, Stephen Frost wrote:
> Just as a reminder for those following along at home, as I'm sure you're
> already aware, the way we figure out what timeline to switch to when a
> replica is getting promoted is that we go run the restore command asking
> for history files until we get back "nope, there is no file named
> 0000123.history", and then we switch to that timeline and then try to
> push such a history file into the repo and hope that it works.

Which is why the whole concept of timelines as we have them right now is
pretty much useless. It is fundamentally impossible to guarantee unique
timeline ids in all cases if they are assigned sequentially at timeline
creation - consider needing to promote a node on both ends of a split
network. I'm quite doubtful that pretending to tackle this problem via
archiving order is a good idea, given the fundamentally racy nature.

Greetings,

Andres Freund