MQSeries

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“MQSeries job interview preparation guide. Number of MQSeries frequently asked questions(FAQs) asked in many MQSeries interviews”



42 MQSeries Questions And Answers

1⟩ What is a message in MQSeries?

A message is a string of bytes that has meaning to the

applications that use it

Message = Header(s) + Application Data

A message consists of a header and the attached application

data.

Headers like:

Unique Message Id, Routing information, Message format

The data part of a message:

A record from an indexed or flat file

A row from a DB2 table

Individual columns from DB2 tables

Multiple rows or records

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2⟩ What are different queues used?

1.Local queue -is a real queue

2.Cluster queue -is a local queue that is known throughout

a cluster of queue managers

3.Remote queue -structure describing a queue

4.Transmission queue(xmit quueue) -local queue with special

purpose

5.Initiation queue -local queue with special purpose

6.Dynamic queue -local queue created "on the fly"

7.Alias queue -if you dont like the name

8.Dead-letter queue -one for each queue manager

9.Reply-to-queue -specified in request message

10.Model queue -model for local queues

11.Repository queue -holds cluster information

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3⟩ What are the difference between internet explorer and Netscape Navigator on different versions?

When you are using Internet Explorer (IE) attached

documents created in Microsoft Office (Word, Excel,

PowerPoint) will open up in the content frame. Attached

Office documents in Netscape will ask you if you want to

"download the document to your hard drive" or "open it in

its current location." The former will not open the document

but save it to your computer. The latter will launch the

program in which the document was created.

With IE, pressing the Enter key will activate such buttons

as "Submit" and "Log-in". In Netscape you must actually

click on these buttons.

Note: Netscape does not always work properly. Sometimes

items an instructor adds will not appear where they should,

links may not function properly, etc. This is why it is

strongly encouraged that everyone use Internet Explorer 5.5

or above for all functions of Blackboard. In any case DO NOT

use the AOL browser. Certain functions such as assessments

do not work properly.

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6⟩ What is MQSeries Channel?

Channel means logical communication link. There are two

types of channels

1) message channel,

2) MQI channel

1) Mesage channel use for communication between QMgr to

QMgr.

2) MQI channel use for for communication between QMgr to

MQ client

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7⟩ How to create DLQ rules table?

DLQ - Dead Letter Queue

If an application tries to put a message to another

application and if it is not delivered then it goes to the

DLQ. So DLQ is nothing but all undelivered messages stored

in DLQ.

Alterenate Defination:

The dead-letter queue is a local queue where messages are

put if they cannot be routed to their intended destination

You need to create a DLQ at the time of creating a Queue

Manager.

crtmqm -q -d MY.DEFAULT.XMIT.QUEUE -u

SYSTEM.DEAD.LETTER.QUEUE SATURN.QUEUE.MANAGER

where -u is dead letter queue

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8⟩ What is MQSeries Cluster?

Cluster is said to be group of queue manager's logically

connected together to balance the load on the remote machine

(i.e if it is remote queue managers which processes your

message). And there are two types of grouping on the queue

managers.

1) Full repository

2) Partial repository.

The full repository queue manager knows all other queue

managers in the cluster and whenever a message comes to it,

and if that is unable to process the message, it will find

a queue in other queue manager in the cluster and ask it to

process the message.

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9⟩ What is a Queue in MQSeries?

Queue is a data structure which is store the messages.and

every queue has own queue manager.queue manager are

maintaining the all queues.different types of queues are

available in web sphere mq in different purpose.but

generally 4 types of queues r there

1)local queue

2)remote queue

3)alias queue

4)model queue

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14⟩ What is the difference between logfile & log space?

we have 2 types of Logfiles in MQ.

1. Error logs.

these logs can be found under

/var/mqm/qmgrs/<QMGRNAME>/errors and the log files starts

with AMQERR01.LOG/AMQERR02.LOG/AMQERR03.LOG. These logs are

used to capture error logs to that particular logs.

/var/mqm/errors. Unthis DIR again you see same files. This

will capture errror logs related to all QMGRS in the server.

2. Transacational(ACTIVE) logs.

These logs are used for media recovery and restat recovery.

Location:/var/mqm/log/QMGR/active. File names starts with S.

Space to these files are allocated based on your settings in

qm.ini file.

This we call as logspace.

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16⟩ What is IBM WebSphere MQSeries?

IBM MQ is a family of network software products that IBM launched in March 1992. It was originally called MQSeries, and was renamed WebSphere MQ in 2002 to join the suite of WebSphere products. In April 2014, it was renamed IBM MQ.

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17⟩ Define the two parts of Message queue (MQ)?

Message:

Messages are collections of binary or character (for instance ASCII or EBCDIC) data that have some meaning to a participating program. As in other communications protocols, storage, routing, and delivery information is added to the message before transmission and stripped from the message prior to delivery to the receiving application.

Queue:

Message queues are objects that store messages in an application.

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18⟩ What is dead letter queue in IBM MQ Series?

Dead letter Queue in WebSphere MQ is a queue which is used by QueueManager to archive messages for a non existent queue. For example of Queue Manager QMGR, receives a messages for queue ABC and if it didn't exist on that Queue Manager then message will be routed to dead letter queue.

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19⟩ Define channel in IBM webSphere MQ?

In WebSphere MQ or WMQ, Queue Manager use channel to transmit messages to other QueueManager. Channel carries one way traffic in MQ Series (i.e. channels are uni directional). You can have either sending channel or receiving channel in MQ.

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20⟩ What is CCDT file on WebSphere MQ or WMQ?

CCDT file or Client Channel Definition table is a binary file which contains connection details required by MQ clients e.g. Java application using JMS to connect to MQ Server. In order to connect to MQ Server, MQ clients needs MQ Server host name, MQ Server port name and server channel name. All these details are encapsulated in CCDT file named as AMQCLCHL.TAB. In order to create MQ Connection, MQ clients needs location of this file, which is provided as configuration. most of MQ errors comes either with incorrect CCDT files.

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