IBM Websphere MQ interview Questions Part 1 - Middleware News

IBM Websphere MQ interview Questions Part 1 - Middleware News
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What is MQ and what does it do?

Ans. MQ stands for MESSAGE QUEUEING. WebSphere MQ allows application programs to use message queuing to participate in message-driven processing. Application programs can communicate across different platforms by using the appropriate message queuing software products.

What is Message driven process?

Ans . When messages arrive on a queue, they can automatically start an application using triggering. If necessary, the applications can be stopped when the message (or messages) have been processed.

What are advantages of the MQ?

Ans. 1. Integration.

2. Asynchrony

3. Assured Delivery

4. Scalability.

How does it support the Integration?

Ans. Because the MQ is independent of the Operating System you use i.e. it may be Windows, Solaris,AIX.It is independent of the protocol (i.e. TCP/IP, LU6.2, SNA, NetBIOS, UDP).It is not required that both the sender and receiver should be running on the same platform

What is Asynchrony?

Ans. With message queuing, the exchange of messages between the sending and receiving programs is independent of time. This means that the sending and receiving application programs are decoupled; the sender can continue processing without having to wait for the receiver to acknowledge receipt of the message. The target application does not even have to be running when the message is sent. It can retrieve the message after it is has been started.

What are the hardware and Software requirements for MQ Installation in AIX?

Ans. WebSphere MQ for AIX, V5.3 runs on any machine that supports the AIX V4.3.3 PowerPC® 32.bit, or AIX® V5.1 Power 32 bit only operating system.

Disk Storage: Typical storage requirements are as follows:

1 Server installation: 50 MB

2. Client installation: 15 MB

3 Data storage (server): 50 MB

4. Data storage (client): 5 MB.

Software Requirements:

Operating system: The operating systems supported by WebSphere MQ for AIX, V5.3 are:

1. AIX V4.3.3, with PTF U472177, running in a 32 bit environment, on 32 or 64 bit hardware.

2. AIX V5.1, with PTFs U476879, U477366, U477367 and U477368, and APAR fix IY29345 running 32 bit kernel running on 32 or 64 bit hardware.

3. AIX V5.1, with PTF U476879, U477366, U477367 and U477368, and APAR fix IY29345 running 64 bit kernel running on 64 bit hardware.

Connectivity The network protocols supported by WebSphere MQ for AIX, V5.3 are:

1. TCP/IP

2. SNA LU 6.2.

Databases: DB2 7.1, 7.2

Oracle 8i and 9i

Sybase v12 or v 12.5

Java: If you want to use the Java Messaging Support, you need the Java Runtime Environment Version 1.3 or later

What are the software and hardware requirements for installing MQ on Windows?

Ans: MQ v 5.3 supports Windows 2000, Windows 2000XP,Windows 2000NT,

Windows 2003 SE, Windows 2003EE.

Disk Storage: Typical storage requirements are as follows:

1 Server installation: 50 MB

2. Client installation: 15 MB

3 Data storage (server): 50 MB

4. Data storage (client): 5 MB.

Connectivity The network protocols supported by WebSphere MQ for AIX, V5.3 are:

1. TCP/IP

2. SNA LU 6.2.

3. LU 6.2

4. NetBIOS

Databases: DB2 7.1, 7.2

Oracle 8i and 9i

Sybase v12 or v 12.5

Java: If you want to use the Java Messaging Support, you need the Java Runtime Environment Version 1.3 or later

what is a Message and what does it contain?

Ans: A message is a string of bytes that is meaningful to the applications that use it. Messages are used to transfer information from one application program to another (or between different parts of the same application). The applications can be running on the same platform, or on different platforms.

WebSphere MQ messages have two parts:

1. The application data. The content and structure of the application data is defined by the application programs that use it.

2. A message descriptor. The message descriptor identifies the message and contains additional control information, such as the type of message and the priority assigned to the message by the sending application. WebSphere MQ defines the format of the message descriptor. For a complete description of the message descriptor,

What is the Max Length of the message does MQ support/

Ans: The default maximum message length is 4 MB, although you can increase this to a maximum length of 100 MB (where 1 MB equals 1 048 576 bytes).

What is the difference between Persistent and Non Persistent Messages?

Ans: In Web Sphere MQ, messages can be either persistent or non persistent. Persistent messages are logged and can be recovered in the event of a WebSphere MQ failure. Thus, persistent messages are guaranteed to be delivered once and only once. Nonpersistent messages are not logged. Web Sphere still guarantees to deliver them not more than once, but it does not promise to deliver them once.

What is the effect of using Persistant messages?

Ans: Persistent messages are usually logged. Logging messages reduces the performance of your application, so use persistent messages for essential data only. If the data in a message can be discarded if the queue manager stops or fails, use a nonpersistent message.

WebSphere MQ messages:

Messages are made up of Two parts: Message descriptor, Application data

Types of messages?

Datagram: A Message sent with no response expected.

Request: A Message sent for which a response is expected.

Reply: A Response Message for a requested message.

Report: A Message that describes the occurrence or event

Ex COA/COD
Sizes ?

Qmanagerà10000 Msgs Maxmsglengthà4 Mb

Queueà5000 Msgs Maxmsglengthà4 Mb

What is the attribute used to see the Message length?

Ans: MaxMsgLength

What is MQ Client?

Ans: A Web Sphere MQ client is a component that allows an application running on a system to issue MQI calls to a queue manager running on another system. The output from the call is sent back to the client, which passes it back to the application.

What is MQ Server?

Ans: A Web Sphere MQ server is a queue manager that provides queuing services to one or more clients. All the Web Sphere MQ objects, for example queues, exist only on the queue manager machine (the Web Sphere MQ server machine), and not on the client. A Web Sphere MQ server can also support local Web Sphere MQ

Applications

What are the Objects used in Web sphere MQ?

Ans: 1. Queue Manager 2. Queues

3. Channels 4. Processes 5. Name lists.

Mention the No of Characters required for creating names of the MQ objects?

Ans: For MQ Channels it is 20 Characters

For Remaining objects it is 48 characters.

What about is the Default port number for MQ Queue Manager?

Ans: 1414
Difference between MQSC commands and Control commands?

MQSC Commands – These commands are used to handle the admin related functions for the components that are present in the MQ Series. In general MQSC commands are used for creating and maintaining Message channels, Queue Managers, Clusters etc…

Control Commands – These commands are used to manage the processes and services that are helpful in the functioning of the MQ Series. In general these commands are used for Channel listener, Channel Initiator, Trigger monitor etc…

Is the MQSC attributes are Case sensitive?

Ans: MQSC commands, including their attributes, can be written in uppercase or lowercase. Object names in MQSC commands are folded to uppercase (that is, QUEUE and queue are not differentiated), unless the names are enclosed within single quotation marks. If quotation marks are not used, the object is processed with a name in uppercase.

SCRIPT COMMANDS:-

After entering in to queue manager we can find script commands.

Script commands are same for every queue manager.

(These Commands should be used in CAPITAL LETTERS)

· DEFINE :-To define/create MQ manager objects like queue,

Channels, process, and listener.

· ALTER :-to update or modify the existing objects

· DISPLAY :-to view all the properties of a particular object or to

Display all objects

· DELETE :-to delete created objects

· CLEAR :-to clear the message from the queue

· END :-to come out of the queue manager

· PING :-to check whether other side channel / queue manager is ready to accept our request.

· START :- to start the particular channel or listener

· STOP :-to stop particular channel or listener

· REFRESH :-used to refresh the security every time after giving or executing, set mgr or command for queue manager or object

· RESET :-used to reset channel,cluster,queue manager

· RESOLVE :-to resolve the channel which is in indoubt state

· SUSPEND :-to suspend a queue manager from a cluster environment

· RESUME :-to remove a queue manager from a cluster environment

How can we write the MQSC commands that have too many parameters/

Ans: For commands that have too many parameters to fit on one line, use continuation characters to indicate that a command is continued on the following line:

1. A minus sign ( ) indicates that the command is to be continued from the start of _ the following line.

2. A plus sign (+) indicates that the command is to be continued from the first nonblank character on the following line.
What is programmable command format (PCF) commands?

These commands are issued from a programme for local or remote administration done by programmers.

What are commands used for creating the Queue manager from the Command prompt?

Ans: crtmqm -q -d MY.DEFAULT.XMIT.QUEUE -u DEAD.LETTER.QUEUE QM1

Here -q used to define the Queue manager QM1 as a Default Queue manager

-d is used to define the default transmission Queue -u is used to define the default dead letter queue.

How can U make the existing Queue Manager as an default Queue Manager?

Ans: On Windows systems, use the Web Sphere MQ Services snap-in to display the properties of the queue manager, and check the Make queue manager the default box. You need to stop and restart the queue manager for the change to take effect.

Where are the backup files are present after creating the Queue Manager?

Ans: Windows systems: If you use Web Sphere MQ for Windows NT and Windows 2000, configuration information is stored in the Windows Registry.

UNIX Systems: 1. When you install the product, the Web Sphere MQ configuration file (mqs.ini) is created. It contains a list of queue managers that is updated each time you create or delete a queue manager. There is one mqs.ini file per node.

2. When you create a new queue manager, a new queue manager configuration file (qm.ini) is automatically created. This contains configuration parameters for the queue manager.

What is the command used for starting the Queue Manager?

Ans: strmqm QMName

What is the command used for stopping the Queue manager?

Ans: endmqm -w QMName

The command waits until all applications have stopped and the queue manager has ended.

endmqm –i QMName

This type of shutdown does not wait for applications to disconnect from the queue manager.

What’s the message code for Stopping a Queue Manager?

AMQ4044 Queue manager stopping

What is the command used to delete the QueueManager?

Ans: dltmqm QMName

Display the attributes of the Queue Manager QM1?

Ans: runmqsc QM1 Display qmgr