Re: BUG #7643: Issuing a shutdown request while server startup leads to server hang

Hari Babu <haribabu(dot)kommi(at)huawei(dot)com> writes:
>> We're going to need more details about how to reproduce this.

> The problem occurs only when active server is restarting by just adding a
> recovery.conf file to the data directory.

Well, you can't just put an empty file there, but I eventually managed
to reproduce this with the suggested hack in xlog.c.

I think the key problem is that postmaster.c's sigusr1_handler() is
willing to start new children even after shutdown has been initiated.
I don't see any good reason for it to do that, so I think the
appropriate patch is as attached.

Changing that still leaves us with the postmaster thinking that the
eventual exit(1) of the startup process is a "crash". This is mostly
cosmetic since it still shuts down okay, but we can fix it by reversing
the order of the first two checks in reaper() --- that is, if Shutdown
is set, we should prefer that code path even if we're in PM_STARTUP
state.

I concluded that it probably wasn't a good idea to have the additional
state transition in SIGINT handling. Generally PM_STARTUP means "we're
running the startup process and nothing else", and that's useful state
info that we shouldn't throw away lightly.

regards, tom lane