In addition to immediate channel jobs created automatically when messages are first submitted into PMDF, or to manually created delivery jobs as described above in Section 34.2.7 , PMDF also has periodic jobs that perform clean up tasks, and retry delivery of previously undelivered messages.
The command
$ SHOW QUEUE/ALL MAIL$BATCHlists all jobs pending and executing in the default PMDF processing queue, MAIL$BATCH. Under idle conditions the command should result in output similar to that seen in Figure 34-2 or Figure 34-3 .
Figure 34-2 Output of SHOW QUEUE/ALL MAIL$BATCH on a basic PMDF system
$ SHOW QUEUE/ALL MAIL$BATCH
 
Generic server queue MAIL$BATCH 
 
  Entry  Jobname         Username  Blocks  Status 
  -----  -------         --------  ------  ------ 
    153  PMDF delivery   SYSTEM        11  Holding until 18-NOV-1997 15:13 (1)
     56  PMDF message bouncer 
                         SYSTEM        12  Holding until 19-NOV-1997 00:30 (2)
Figure 34-3 Output of SHOW QUEUE/ALL MAIL$BATCH on a system with optional jobs
$ show queu/all mail$batch 
Generic server queue MAIL$BATCH 
 
  Entry  Jobname         Username     Blocks  Status 
  -----  -------         --------     ------  ------ 
     95  PMDF delivery   SYSTEM           14  Holding until 18-NOV-1997 15:52:00 (1)
    810  PMDF message bouncer 
                         SYSTEM           14  Holding until 19-NOV-1997 00:30:00 (2)
    399  PMDF PC Post    SYSTEM            8  Holding until 18-NOV-1997 13:05:03 (3)
    811  PMDF popstore message bouncer 
                         SYSTEM            5  Holding until 19-NOV-1997 00:30:00 (4)
The two holding jobs indicated in the figures as
(1)
and
(2)
should always be present during normal operation of PMDF. They run 
periodically and resubmit themselves automatically. If you are using 
the PMDF popstore, you should also see a popstore return job,
(4)
, either holding or running (perhaps in an execution queue, if 
MAIL$BATCH is a generic queue). If you are using PMDF-LAN channels, 
then depending on just how you have configured it you may also see an 
additional job, the PMDF PC post job,
(3)
; if you are using DECUS UUCP and have defined the PMDF_DO_RETURN_VN 
logical so that pmdf_submit_jobs.com also submits the 
DECUS UUCP message bouncer job, then you should see that job as well.
periodic channel keyword, which defers immediate delivery, 
will not function reliably.
notices channel 
keyword. If the PMDF message bouncer job is not running, messages that 
cannot be delivered will sit in the message queue indefinitely and no 
notification will be sent to either the sender or the local Postmaster.
If one or both of the PMDF delivery job and the PMDF message bouncer 
job is not present in the queue, (or if one of the other periodic jobs 
that your site uses is missing), it should be resubmitted using the 
pmdf_submit_jobs.com procedure
$ @SYS$STARTUP:pmdf_submit_jobs.comThe procedure is safe to run at any time, as it will not submit a job that is already present. As indicated in the OpenVMS Edition of the PMDF Installation Guide , Innosoft recommends that
pmdf_submit_jobs.com be executed as part of your normal 
system startup procedure to ensure that the basic PMDF periodic jobs 
are properly submitted and holding.