Re: Streaming replication - unable to stop the standby

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> Hmm. When I committed that patch to fix smart shutdown on the
> standby, we discussed the fact that the startup process can't simply
> release its locks and die at shutdown time because the locks it holds
> prevent other backends from seeing the database in an inconsistent
> state. Therefore, if we were to terminate recovery as soon as the
> smart shutdown request is received, we might never complete, because a
> backend might be waiting on a lock that will never get released. If
> that's really a danger scenario, then it follows that we might also
> fail to shut down if we can't connect to the primary, because we might
> not be able to replay enough WAL to release the locks the remaining
> backends are waiting for. That sort of looks like what is happening
> to you, except based on your test scenario I can't figure out where
> this came from:

> FATAL: replication terminated by primary server

I suspect you have it right, because my experiments where the standby
did shut down correctly were all done with an idle master.

Seems like we could go ahead and forcibly kill the startup process *once
all the standby backends are gone*. There is then no need to worry
about not releasing locks, and re-establishing a consistent state when
we later restart is logic that we have to have anyway.

regards, tom lane