Treat exit code 128 (ERROR_WAIT_NO_CHILDREN) as non-fatal on Win32,

since it can happen when a process fails to start when the system
is under high load.

Per several bug reports and many peoples investigation.

Back-patch to 8.4, which is as far back as the "deadman-switch"
for shared memory access exists.

src/backend/postmaster/postmaster.c

@@ -2588,6 +2588,19 @@ CleanupBackend(int pid,
 	 * assume everything is all right and proceed to remove the backend from
 	 * the active backend list.
 	 */
+#ifdef WIN32
+	/*
+	 * On win32, also treat ERROR_WAIT_NO_CHILDREN (128) as nonfatal
+	 * case, since that sometimes happens under load when the process fails
+	 * to start properly (long before it starts using shared memory).
+	 */
+	if (exitstatus == ERROR_WAIT_NO_CHILDREN)
+	{
+		LogChildExit(LOG, _("server process"), pid, exitstatus);
+		exitstatus = 0;
+	}
+#endif
+
 	if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
 	{
 		HandleChildCrash(pid, exitstatus, _("server process"));