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

From: "Alvaro Herrera" <alvherre@2ndquadrant.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