Simon Riggs <simon@2ndQuadrant.com> writes:
> Having some trouble trying to get a clean state change from recovery to
> normal mode.
> Startup needs to be able to write WAL at the end of recovery so it can
> write a ShutdownCheckpoint, yet must not be allowed to write WAL before
> that. Other services are still not fully up yet. So every other process
> apart from Startup musn't write WAL until Startup has fully completed
> its actions, which is sometime later.
> ...
> We *might* solve this by making the final checkpoint that Startup writes
> into an online checkpoint.
Do we really need a checkpoint there at all? I can't recall right now
if there was a good reason why Vadim made it do that. I have a feeling
that it might have had to do with an assumption that the recovery
environment was completely distinct from live environment; which is a
statement that's certainly not going to be true in a query-answering
slave.
regards, tom lane