What goes on in that ‘black box’ known as the queue manager? This session will give you insight into each of the major components of a WebSphere MQ for z/OS queue manager and the resources it uses. Get information on what the buffer manager is really doing with the messages, what the message manager is really counting, how the log manager works, and more.

1. A9: WebSphere MQ for z/OS
The Inside Story
Damon Cross, Advisory Software Engineer
damon_cross@uk.ibm.com

2. © 2014 © 2014 IBM Corpora ItBioMn Corporation
Please Note
IBM’s statements regarding its plans, directions, and intent are subject to change or withdrawal
without notice at IBM’s sole discretion. Information regarding potential future products is
intended to outline our general product direction and it should not be relied on in making a
purchasing decision.
The information mentioned regarding potential future products is not a commitment, promise,
or legal obligation to deliver any material, code or functionality. Information about potential
future products may not be incorporated into any contract. The development, release, and
timing of any future features or functionality described for our products remains at our sole
discretion
Performance is based on measurements and projections using standard IBM benchmarks in a
controlled environment. The actual throughput or performance that any user will experience
will vary depending upon many factors, including considerations such as the amount of
multiprogramming in the user’s job stream, the I/O configuration, the storage configuration, and
the workload processed. Therefore, no assurance can be given that an individual user will
achieve results similar to those stated here.

3. Agenda
• Transactions
• Queue managers
• Resource managers
• Scenario walk-through
• Summary
© 2014 IBM Corporation

4. Transactions
 An attempt to change the state
- Either fully completes or is fully restored to the original state
- Like a contract
- Atomicity, Consistency, Isolation, Durability
 Business is all about transactions
- e.g. Banking, Order processing, Inventory management
 Transactional messaging
- Once and only once delivery of messages
 Coordination is essential for Extended Transactions
- Transactions that update multiple resources
© 2014 IBM Corporation

5. Agenda
• Transactions
• Queue managers
• Resource managers
• Scenario walk-through
• Summary
© 2014 IBM Corporation

6. The queue manager – delivering
messages
© 2014 IBM Corporation
APPLICATION
EXEC SQL QUERY
EXEC SQL INSERT
DATABASE
Read
Write
APPLICATION
MQGET
MQPUT
Read / Write
Write
MQ
DB/2 CICS IMS
z/OS
CLIENT
CLIENT
CLIENT
QUEUE
MQI

7. Core technology – logging and
buffering
B4 C3 A1 ...
Conveyor Belt Log
© 2014 IBM Corporation
A1
C3
B4
Pigeon Hole Page set
1
12
2
3
4
5
6
7
10
8
9
11
B4 C3 A1
?

8. Accessing the MQI - stubs and
adapters
BATCH / TSO
CHANNEL INITIATOR
PROGRAM CALLS
(QRPL)
© 2014 IBM Corporation
CICS REGION
APPLICATION
MQI STUB
RMI TRUE
APPLICATION
MQI STUB
ADAPTER
PROCESS
MQI STUB
ADAPTER
IMS REGION
(BMP/FP/MPP)
APPLICATION
MQI STUB
CONTROL
ESAF
EXITS
QUEUE MANAGER

9. Agenda
• Transactions
• Queue managers
• Resource managers
• Scenario walk-through
• Summary
© 2014 IBM Corporation

10. Building blocks – resource managers
COMMIT / BACKOUT UR
© 2014 IBM Corporation
CONNECTION
MANAGER
RECOVERY
MANAGER
LOG
MANAGER
MESSAGE
MANAGER
DATA
MANAGER
BUFFER
MANAGER
LOCK
MANAGER
CF
MANAGER
MQI
CKPT
CKPT
REDO / UNDO
RELEASE UR
MQOPEN

11. Handling applications – Connection
Manager
ADDRESS SPACE BOUNDARY
© 2014 IBM Corporation
APPLICATION
MQCONN
MQOPEN
MQPUT
…
TRANSACTION
COORDINATOR
THREAD
EOT
CONTROL
BLOCKS
PHASE 1 EOM
PHASE 2
CONNECTION
MANAGER
OTHER RESOURCE
MANAGERS
DATA
LOGS
CONTROL
BLOCKS
CONTROL
BLOCKS

12. Supporting the MQI & MQSC –
Message Manager
COMMAND, RUNTIME & GROUP APPLICATION
MQGET
MESSAGE MANAGER
© 2014 IBM Corporation
SERVERS
MQSC
CONSOLE
QSG
MQOPEN
MQCLOSE
MQPUT
MQSET
MQINQ
MQSUB
OBJECTS
SYSTEM.CLUSTER.*
MQOPEN
BASE
VALIDATION, CONSISTENCY CHECKING, NAME RESOLUTION, TRIGGERING, GET-WAIT
PROCESSING, PUT-TO-WAITING-GETTER

13. Managing messages and objects –
Data Manager
© 2014 IBM Corporation
12 1
2
3
4
7 6 5
10
9
8
11
SCAVENGER
LOG
REDO
UNDO
OBJECTS
MESSAGES
QUEUE
ATTRIBUTES
SUB-QUEUE
MESSAGE
POINTERS
SPACE
GROUP
SPACE
GROUP
SPACE
GROUP
PAGE SET 0
PAGE SETS
1--99

14. Improving performance – Buffer
Manager
NO FORCE
© 2014 IBM Corporation
PAGE SET
BUFFER
PAGES
READ
PAGE SET
DEFINE BUFFPOOL(bpid) BUFFERS(nnnn)
DEFINE PSID(psid) BUFFPOOL(bpid)
STEAL
LRU
DIRTY
DIRTY
DIRTY
CHECKPOINT,
STEAL,
WRITE AHEAD
WRITE OLDEST
PAGESET
CHECKPOINT FORCE DIRTY PAGES > 2 CHECKPOINTS

15. Local message queue storage
© 2014 IBM Corporation
HEAD
START
SCAN
TAIL
SUB-QUEUE
(x 20)
PAGE SET 0
MSG 1
(DELETED)
MSG 2
(≤ 4 KB) MQMD + DATA
MSG 3
(≤ 4 MB)
MQMD + DATA NEXT DATA
MSG 4
(≤ 100 MB)
PAGE SET n
MQMD + DATA NEXT DATA NEXT DATA NEXT DATA

16. Local message queue storage
• Pages are generally deallocated as messages removed from
queues.
© 2014 IBM Corporation
••
Asynchronous deallocation is performed by the scavenger task
– Acquires exclusive locks on pages for all messages to be
deleted.
••
Pure text pages don't suffer contention and can always be
deleted during MQGET processing.
••
Page allocation for small (<4KB) messages changed in V6.
••
Objects are stored much like messages on pageset 0.

17. Handling transactions – Recovery
Manager
TRANSACTION STATES
10
9
© 2014 IBM Corporation
12 1
2
3
4
7 6 5
10
9
8
11 12 1
2
3
4
7 6 5
10
9
8
11 12 1
2
3
4
7 6 5
8
11 12 1
2
3
4
7 6 5
10
8
9
11 12 1
2
3
4
7 6 5
10
9
8
11
1-PHASE
COMMIT
1-PHASE
BACKOUT
2-PHASE
COMMIT
BEGIN
BEGIN
BEGIN
IN FLIGHT
IN FLIGHT
IN FLIGHT
IN COMMIT
IN BACKOUT
IN DOUBT
COMMITTED
BACKED OUT
IN COMMIT COMMITTED
LOG
LOGLOAD
(zPARM)  CHECKPOINT
LOG
PAGE
SET
RESTART
/
RECOVERY

18. Providing logging interfaces – Log
Manager
• Log read and write functions
• Log shunting
• Multiple active log data sets and archive
• Archive inventory management
• Duplexed for reliability
• “Bootstrap” file
© 2014 IBM Corporation
– End of log location
– Archive inventory
– CSQJU004
• Various Utilities – CSQ1LOGP, CSQ4LOGS

19. Examining transactions – a log print
00000000D569 00000000D569 URID(00000000D569)
RM(RECOVERY)
TYPE( START UR )
**** 00640024 00200001 03000000 0000D569 00000000 D545
0000 00240000 0000D000 00000000 00000700 00000000 00000000 00000000 0000D6C4
0020 D6E6C4C1 4040B5B4 8FA08793 02864040 40404040 4040C2C1 E3C3C840 4040D6C4
0040 D6E6C4C1 40400000 00000000 0000
RM(DATA)
00000000D5CD URID(00000000D569) RM(DATA) LRID(00000000.00000E01)
LRID(00000001.00000201)
TYPE( END COMMIT2 )
© 2014 IBM Corporation
SUBTYPE( DECREMENT BY )
SUBTYPE( DECREMENT BY )
**** 002A0064 0600000F C9000000 0000D569 00000000 D569
0000 00000000 00000E01 00040326 00000001 00000001
00000000D5F7 URID(00000000D569) RM(DATA) LRID(00000001.00000201) TYPE( UNDO REDO )
SUBTYPE( DELETE )
SUBTYPE( DELETE )
**** 0026002A 06000008 C9000000 0000D569 00000000 D5CD
0000 00000001 00000201 00000000 00000E01
00000000D61D URID(00000000D569) RM(RECOVERY) TYPE( START COMMIT1 )
**** 007C0026 00200002 03000000 0000D569 00000000 D5F7
0000 00240000 0000D000 00000000 00000700 00000000 00000000 00000000 00004040
0020 40404040 40400000 00000000 00000000 00000000 00000000 00000000 00000000
0040 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
0060 00000000 0000
00000000D699 URID(00000000D569) RM(RECOVERY) TYPE( PHASE 1 TO 2 )
**** 0024007C 0020000C 03000000 0000D569 00000000 D61D
0000 00240000 0000D000 00000000 0000
00000000D6BD URID(00000000D569) RM(RECOVERY) TYPE( END COMMIT2 )
**** 00240024 00200010 03000000 0000D569 00000000 D699
0000 00240000 0000D000 00000000 0000
TYPE( UNDO REDO )
00000000D699 URID(00000000D569) RM(RECOVERY) TYPE( PHASE 1 TO 2 )
**** 0024007C 0020000C 03000000 0000D569 00000000 D61D
0000 00240000 0000D000 00000000 0000

20. Concurrency and isolation – Lock
Manager
10
9
© 2014 IBM Corporation
MQOO_INPUT_SHARED
MQOO_INPUT_EXCLUSIVE
A
B
C
A B C
PAGE
(shared)
MESSAGE
(exclusive)
MESSAGE
(exclusive)
12 1
2
3
4
7 6 5
10
9
8
11 12 1
2
3
4
7 6 5
10
9
8
11 12 1
2
3
4
7 6 5
8
11 12 1
2
3
4
7 6 5
10
9
8
11
REQUEST
COMMIT
ALLOCATION
MQOPEN
vs
DELETE QLOCAL
API Request
Transaction
Lifetime

21. Managing shared messages – CF
Manager
QM1
CF MANAGER
LIST STRUCTURE
© 2014 IBM Corporation
QM2
CF MANAGER
QM3
CF MANAGER
IXL*
DEFINE QLOCAL(...)
QSGDISP(SHARED)
CFSTRUCT(...)

22. Shared message queue storage
© 2014 IBM Corporation
SQ1 LH
SQ2 LH
SQM1 LH
LIST STRUCTURE
COMMITTED PUTS
UNCOMMITTED GETS
UNCOMMITTED PUTS QUEUE DETAILS
EXPIRED MESSAGES
MQCMIT
MQCMIT
MQGET
(MQGET)
MQPUT
MQGET
KEYS
DATA
READ
WRITE
MOVE
DELETE
MONITOR
State Priority Time Queue Manager
MsgId / CorrelationId

23. Agenda
• Transactions
• Queue managers
• Resource managers
• Scenario walk-through
• Summary
© 2014 IBM Corporation

24. Scenario: MQPUT to a triggered queue
APPLICATION MESSAGE MGR DATA MGR BUFFER MGR RECOVERY MGR LOG MGR LOCK MGR
MQOPEN
© 2014 IBM Corporation
ACQUIRE LOCK
LOCATE QUEUE
(HASH TABLE)
SECURITY CHECK
RESOLVE NAME
GET HANDLE
MQPUT
USE HANDLE
LOCATE NEW PAGE
(FOR MESSAGE)
BUFFER PAGE
START UR LOG RECORDS
LOG RECORDS
CHECK TRIGGER
RULES
MQCMIT
FORCE LOG
RELEASE LOCKS

25. Scenario: MQGET from a queue
APPLICATION MESSAGE MGR DATA MGR BUFFER MGR RECOVERY MGR LOG MGR LOCK MGR
MQOPEN
© 2014 IBM Corporation
ACQUIRE LOCK
LOCATE QUEUE
(HASH TABLE)
SECURITY CHECK
RESOLVE NAME
GET HANDLE
MQGET
USE HANDLE
FIND MESSAGE
(INDEX / NEXT)
BUFFER PAGE
START UR LOG RECORDS
LOG RECORDS
MQCMIT
FORCE LOG
RELEASE LOCKS

26. Summary
• Delivers transactional messaging
– Enables robust business applications
• Complex, but well organised
– Adapters
– Address spaces
– Resource managers
• Designed for throughput, availability and scalability
– Logging
– Buffering
– Locking
– Communications
© 2014 IBM Corporation

27. A9: WebSphere MQ for z/OS
The Inside Story
Questions?

28. For Additional Information
© 2014 IBM Corporation
 IBM Training
 http://www.ibm.com/training
 IBM WebSphere
 http://www.ibm.com/software/websphere/
 http://www.ibm.com/software/products/ibm-mq
 IBM developerWorks
 http://www.ibm.com/developerworks/websphere
 https://www.ibm.com/developerworks/community/blogs/messaging
 WebSphere forums and community
 http://www.ibm.com/developerworks/websphere/community/

29. IBM MQ Sessions this week
10:30 - 12:00 13:15 - 14:15 14:30 - 15:30 16:00 - 17:00 17:15 - 18:15
© 2014 IBM Corporation
Tue
sday
Opening General Session- IBM Digital
Experience and WebSphere Technical
University
Session A31: IBM
MQ CHLAUTH rules
– with MQ V8
updates
Speaker: Morag
Hughson
Room 02
Session A4: WebSphere
MQ for z/OS:
Performance and
Accounting
Speaker: Alexander Ross
Room 8
Session I26:
DataPower-MQ
Connectivity Deep Dive
(Theory)
Speaker: Robin Wiley
Room 27
Session Z1: WebSphere
MQ for z/OS V8: Latest
Features Deep Dive
Speaker: Damon Cross
Room 6
9:00 - 10:00 10:30 - 11:30 11:45 - 12:45 14:00 - 15:00 15:15 - 16:15 16:45 - 17:45
Wed
nes
day
Session Z5:
WebSphere MQ for
z/OS: Security
Speaker: Damon
Cross
Room 02
Session A21: What's
New in IBM
Messaging
Speaker: Morag
Hughson
Room 8
Session C7:
Messaging in the
Cloud with IBM MQ
Light and IBM
Bluemix
Speaker: Rob
Nicholson
Room 27
Session A17: Managing
work-loads, scaling and
availability with IBM MQ
clusters
Speaker: David Ware
Room 6
Lab IL5: DataPower-MQ Connectivity Deep Dive
(Hands-On)
Speaker: Robin Wiley
Room 7b
Session A9: WebSphere
MQ for z/OS: The Inside
Story
Speaker: Damon Cross
Room 6
Thur
sday
Session A35: How to
Develop Responsive
Applications with IBM
MQ Light
Speaker: Rob
Nicholson
Room 27
Session A22: New
IBM MQ V8 Security
Features
Speaker: Morag
Hughson
Room 01
Session A3: WebSphere
MQ for z/OS: Shared
Queues
Speaker: Alex Ross
Room 6
Session A18: Using
Publish /Subscribe with
IBM MQ
Speaker: David Ware
Room 27
Frid
Lab AL6: Developing a First Application
with IBM WebSphere MQ Light
Speakers: Robert Nicholson, Alex Ross
Room 7b

30. A9: WebSphere MQ for z/OS
The Inside Story
Thank you!