Discussion:
Queue entry number question
(too old to reply)
Chris Townley
2021-04-24 10:18:59 UTC
Permalink
I am confused! Every time I reboot my VSI V8.4-2L1 running on FreeAXP
emulator the entry numbers restart at 1

Not that it really matters, but I have never seen this before.

Any idea how I reinstate the normal behaviour of continuing where it
was, and then rolling over at whatever it limit it has set?


Thanks


Chris
Volker Halle
2021-04-24 10:38:07 UTC
Permalink
Chris,

could there be a START/QUEUE/MANAGER/NEW command in SYSTARTUP_VMS.COM ? If so, just comment it out. The QUEUE_MANAGER starts automatically...

Volker.
Chris Townley
2021-04-24 10:51:02 UTC
Permalink
Post by Volker Halle
Chris,
could there be a START/QUEUE/MANAGER/NEW command in SYSTARTUP_VMS.COM ? If so, just comment it out. The QUEUE_MANAGER starts automatically...
Volker.
No - checked that. I even removed the re-initialisation of the queues
from startup, in case that was doing it.
I also checked the whole of sys$startup for this.

BTW this is a standalone instance - no cluster

Chris
Volker Halle
2021-04-24 11:11:33 UTC
Permalink
Chris,

if there is any pending job in any queue, when you shut down the system, the entry numbers do NOT start again at 1 after the reboot...

Don't know, if it would have been like this before V8.4-2L2...

Volker.
Chris Townley
2021-04-24 11:16:10 UTC
Permalink
Post by Volker Halle
Chris,
if there is any pending job in any queue, when you shut down the system, the entry numbers do NOT start again at 1 after the reboot...
Don't know, if it would have been like this before V8.4-2L2...
Volker.
Good thought - I know is when entry numbers extended, not rolled over. I
will try that

Chris
Chris Townley
2021-04-24 11:33:04 UTC
Permalink
Post by Chris Townley
Post by Volker Halle
Chris,
if there is any pending job in any queue, when you shut down the
system, the entry numbers do NOT start again at 1 after the reboot...
Don't know, if it would have been like this before V8.4-2L2...
Volker.
Good thought - I know is when entry numbers extended, not rolled over. I
will try that
Chris
Well, that worked.

It would seem that the numbers get reset unless there are existing jobs.
That is why I have not seen it before - I would normally have loads of
timed jobs. The emulator is used for play rather than anything serious

Thanks

Chris
Jan-Erik Söderholm
2021-04-24 13:12:50 UTC
Permalink
Post by Chris Townley
Post by Chris Townley
Post by Volker Halle
Chris,
if there is any pending job in any queue, when you shut down the system,
the entry numbers do NOT start again at 1 after the reboot...
Don't know, if it would have been like this before V8.4-2L2...
Volker.
Good thought - I know is when entry numbers extended, not rolled over. I
will try that
Chris
Well, that worked.
It would seem that the numbers get reset unless there are existing jobs.
That is why I have not seen it before - I would normally have loads of
timed jobs. The emulator is used for play rather than anything serious
Thanks
Chris
Good that you found out how it works. So now, what does it matter
if the entry numbers starts over at 1 at reboot?
David Jones
2021-04-24 13:29:04 UTC
Permalink
Post by Jan-Erik Söderholm
Good that you found out how it works. So now, what does it matter
if the entry numbers starts over at 1 at reboot?
It means few digits to type when referencing jobs by number. I assume that also means
max job number also resets to 999 if you had a runaway incident that forced usage of
of 4 or 5 digit job numbers.
Chris Townley
2021-04-24 14:41:14 UTC
Permalink
Post by Jan-Erik Söderholm
Good that you found out how it works. So now, what does it matter
if the entry numbers starts over at 1 at reboot?
As I said in the OP it is no great thing - it just confused me as I had
never seen it before.

On my physical Alpha, there are always pending batch jobs (and often too
many job logs on printer queues)

Likewise on all the VMS systems I had used in my working life.

Also always good to learn - even if as Hoff suggests, partially!


Chris

Phillip Helbig (undress to reply)
2021-04-24 11:37:00 UTC
Permalink
could there be a START/QUEUE/MANAGER/NEW command in SYSTARTUP_VMS.COM?
If so, just comment it out. The QUEUE_MANAGER starts automatically...
Also, if on a cluster, do /ON=(<node_list>) so that it can run on more
than one node. (Just do it once, not at startup.) It will then fail
over automatically if the node it is running on goes down. (One can
also set up batch queues to behave the same way. Alternatively, one
could have generic queues and execution queues. Perhaps also print and
SMTP queues, though I have no experience with failover for the last
two.)
Stephen Hoffman
2021-04-24 13:43:51 UTC
Permalink
Post by Chris Townley
I am confused! Every time I reboot my VSI V8.4-2L1 running on FreeAXP
emulator the entry numbers restart at 1
Not that it really matters, but I have never seen this before.
Any idea how I reinstate the normal behaviour of continuing where it
was, and then rolling over at whatever it limit it has set?
The queue entry number is opaque 32-bit value.

The assigned queue entry number is unique over the lifetime of a job.

Queue entry numbers are not unique over the life of a running system,
nor over reboots.

The existing queue entry number algorithm design is quite effective at
causing developers to acquire misleading or incorrect inferences about
the entry allocation order.

The queue entry number allocation order is undocumented, and has
surprises as queue managers are added and as numbers of concurrent
entries increase.

It'd probably have been better if the initial queue entry numbers were
at least somewhat randomized, as that'd reduce the assumptions and the
ensuing mistakes.

One of my favorite developer mistakes has been a word-length entry
number storage field in an app, because the developer made some
mistaken inferences, and/or had never seen larger values.

That mistake has become less common as memory has gotten cheaper and
developer preferences for VAX-ish data packing have waned.
--
Pure Personal Opinion | HoffmanLabs LLC
Phillip Helbig (undress to reply)
2021-04-24 13:57:02 UTC
Permalink
Post by Stephen Hoffman
The queue entry number is opaque 32-bit value.
I knew you were going to say that! Have you already ordered the
tombstone with the corresponding epitaph? :-)
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