Re: backend hangs at immediate shutdown (Re: Back-branch update releases coming in a couple weeks)

From: "Alvaro Herrera" <alvherre(at)2ndquadrant(dot)com>
> Actually, I think it would be cleaner to have a new state in pmState,
> namely PM_IMMED_SHUTDOWN which is entered when we send SIGQUIT. When
> we're in this state, postmaster is only waiting for the timeout to
> expire; and when it does, it sends SIGKILL and exits. Pretty much the
> same you have, except that instead of checking AbortStartTime we check
> the pmState variable.

Are you suggesting simplifying the following part in ServerLoop()? I
welcome the idea if this condition becomes simpler. However, I cannot
imagine how.

if (AbortStartTime > 0 && /* SIGKILL only once */
(Shutdown == ImmediateShutdown || (FatalError && !SendStop)) &&
now - AbortStartTime >= 10)
{
SignalAllChildren(SIGKILL);
AbortStartTime = 0;
}

I thought of adding some new state of pmState for some reason (that might be
the same as your idea).
But I refrained from doing that, because pmState has already many states. I
was afraid adding a new pmState value for this bug fix would complicate the
state management (e.g. state transition in PostmasterStateMachine()). In
addition, I felt PM_WAIT_BACKENDS was appropriate because postmaster is
actually waiting for backends to terminate after sending SIGQUIT. The state
name is natural.

I don't have strong objection to your idea if it makes the code cleaner and
more understandable. Thank you very much.

Regards
MauMau