postmaster-is-alive-bsd-workaround.patch

*** a/src/backend/storage/ipc/pmsignal.c
--- b/src/backend/storage/ipc/pmsignal.c
***************
*** 260,281 **** PostmasterIsAlive(bool amDirectChild)
  #ifndef WIN32
  	if (amDirectChild)
  	{
  		/*
! 		 * If the postmaster is alive, we'll still be its child.  If it's
! 		 * died, we'll be reassigned as a child of the init process.
! 		 */
! 		return (getppid() == PostmasterPid);
! 	}
! 	else
! 	{
! 		/*
! 		 * Use kill() to see if the postmaster is still alive.	This can
! 		 * sometimes give a false positive result, since the postmaster's PID
! 		 * may get recycled, but it is good enough for existing uses by
! 		 * indirect children.
  		 */
- 		return (kill(PostmasterPid, 0) == 0);
  	}
  #else							/* WIN32 */
  	return (WaitForSingleObject(PostmasterHandle, 0) == WAIT_TIMEOUT);
  #endif   /* WIN32 */
--- 260,289 ----
  #ifndef WIN32
  	if (amDirectChild)
  	{
+ 		pid_t	ppid = getppid();
+ 
+ 		/* If the postmaster is still our parent, it must be alive. */
+ 		if (ppid == PostmasterPid)
+ 			return true;
+ 
+ 		/* If the init process is our parent, postmaster must be dead. */
+ 		if (ppid == 1)
+ 			return false;
+ 
  		/*
! 		 * If we get here, our parent process is neither the postmaster nor
! 		 * init.  This can occur on BSD and MacOS systems if a debugger has
! 		 * been attached.  We fall through to the less-reliable kill() method.
  		 */
  	}
+ 
+ 	/*
+ 	 * Use kill() to see if the postmaster is still alive.	This can
+ 	 * sometimes give a false positive result, since the postmaster's PID
+ 	 * may get recycled, but it is good enough for existing uses by
+ 	 * indirect children and in debugging environments.
+ 	 */
+ 	return (kill(PostmasterPid, 0) == 0);
  #else							/* WIN32 */
  	return (WaitForSingleObject(PostmasterHandle, 0) == WAIT_TIMEOUT);
  #endif   /* WIN32 */