How to Get message count in a durable subscriber in IBM MQ?

Question

I am using a default IBM mq topic 'dev/' and have a durable subscriber attached to this topic. Using a JMS Producer client if I produce some message but do not consume them, they are held in the subscription for the durable client.

So I want to check the message count for that subscription using MQSC Command, I'm able to check it using MQ Explorer in the status of the subscription, but want to check it via command line, using MQSC. So far I've got

DISPLAY SUB('JMS:QM1:LOCALDB.vanshaj.pump_fs_ns_Pump:LOCALDB.vanshaj.pump_fs_ns_Pump') ALL

but this only displays the following property

AMQ8096I: IBM MQ subscription inquired.
   SUBID(414D5120514D31202020202020202020CDBBF261053D4321)
   SUB(JMS:QM1:LOCALDB.vanshaj.pump_fs_ns_Pump:LOCALDB.vanshaj.pump_fs_ns_Pump)
   TOPICSTR(dev/)                          TOPICOBJ( )
   DISTYPE(RESOLVED)                    
   DEST(SYSTEM.MANAGED.DURABLE.61F2BBCD21433D04)
   DESTQMGR(QM1)                           PUBAPPID( )
   SELECTOR( )                             SELTYPE(NONE)
   USERDATA( )                          
   PUBACCT(0000000000000000000000000000000000000000000000000000000000000000)
   DESTCORL(414D5120514D31202020202020202020CDBBF261053D4321)
   DESTCLAS(MANAGED)                       DURABLE(YES)
   EXPIRY(UNLIMITED)                       PSPROP(MSGPROP)
   PUBPRTY(ASPUB)                          REQONLY(NO)
   SUBSCOPE(ALL)                           SUBLEVEL(1)
   SUBTYPE(API)                            VARUSER(ANY)
   WSCHEMA(TOPIC)                          SUBUSER(app)
   CRDATE(2022-01-28)                      CRTIME(12:11:30)
   ALTDATE(2022-01-28)                     ALTTIME(12:14:14)

what I need is the message count which can be seen in the below image

Do you want to know how many messages have been sent to the durable subscriber (this is what I think Explorer is showing), or do you want to know how many unconsumed messages are waiting for the durable subscriber. These could be two different values. — JoshMc, Jan 31 '22 at 21:46
@JoshMc So, I Assumed that the count of messages seen in the image is the unconsumed messages — Vanshaj Behl, Feb 01 '22 at 05:22
No - the count of messages seen in the image is the number of messages delivered to that subscriber queue. Whether they have been consumed from the subscriber queue or not, is not reflected in that number. — Morag Hughson, Feb 02 '22 at 09:43

Morag Hughson · Answer 1 · 2022-02-01T08:09:53.173

There are two commands to look at subscriptions, similar to many other IBM MQ resources.

DISPLAY SUB

to look at the static configuration.

DISPLAY SBSTATUS

to look at the live run-time status numbers.

It is in this latter command that you will find the Subscription Status details that you have shown in your screenshot.

AMQ8099I: IBM MQ subscription status inquired.
   SUB(ABC.1)                           
   SUBID(414D51204D51473120202020202020207E20475E2237A83F)
   SUBUSER(mqgusr1)                        RESMDATE( )
   RESMTIME( )                             LMSGDATE( )
   LMSGTIME( )                          
   ACTCONN(000000000000000000000000000000000000000000000000)
   DURABLE(YES)                            MCASTREL( , )
   NUMMSGS(0)                              SUBTYPE(ADMIN)
   TOPICSTR(xx/yy/zz)

If you want to see how many messages have been delivered to the subscriber, but have not yet been consumed by the application, then you should issue the following command against the queue name listed in the DISPLAY SUB() DEST attribute.

DISPLAY QLOCAL(SYSTEM.MANAGED.DURABLE.61F2BBCD21433D04) CURDEPTH

I thought maybe because they mentioned "if I produce some message but do not consume them, they are held in the subscription for the durable client" that they really want the queue CURDEPTH. — JoshMc, Feb 01 '22 at 03:02
Hi @JoshMc I just answered the sentence "what I need is the message count which can be seen in the below image" - which shows an MQ Explorer subscription status window. — Morag Hughson, Feb 01 '22 at 03:17

JoshMc · Accepted Answer · 2022-02-01T12:49:28.133

IBM MQ subscriptions are each associated with a queue that is used to hold the messages. The queue is displayed in the DEST field of the subscription. In your example the queue name is SYSTEM.MANAGED.DURABLE.61F2BBCD21433D04.

If you want to view the count of unconsumed messages you will need to display the CURDEPTH of the queue associated with the subscription, for example:

DIS QLOCAL(SYSTEM.MANAGED.DURABLE.61F2BBCD21433D04) CURDEPTH

The output will look something like this:

AMQ8409I: Display Queue details.
   QUEUE(SYSTEM.MANAGED.DURABLE.61F2BBCD21433D04)
   TYPE(QLOCAL)                            CURDEPTH(128)

IBM MQ managed subscriptions (all JMS subscriptions are manged since you are unable to specify your own queue to use) will have name in the following format:

For nondurable subscriptions:

SYSTEM.MANAGED.NDURABLE.*

For durable subscriptions:

SYSTEM.MANAGED.DURABLE.*

If you are interested in all managed subscriptions with unconsumed messages you can use this command:

DIS QLOCAL(SYSTEM.MANAGED.*) WHERE(CURDEPTH GT 0)

How to Get message count in a durable subscriber in IBM MQ?

2 Answers2