What’s a Message Queue?

A Message Queue is a technology used to transfer information from one computer to another, one message at a time.  A message is defined as any type of data (text or binary) that can be sent in one chunk.  The purpose of a message queue is to allow one (or more) programs or computers on a network to send messages to a central place.  Messages are guaranteed to be sent, even if the network is occasionally down.  This is accomplished with the client side drivers that receive the messages from the local applications and queues them up locally, if the network is down, until the network or the message queue server becomes available, then starts sending the messages across.

The message queue server hosts a message queue and can receive messages from any program or computer on the network.  Generally, another application will monitor the message queue for new messages and pull them off, then act on them appropriately.

Depending on which vendor’s MQ product you choose, you’ll have different priorities set on how messages are sent.  Some set priorities on guaranteeing that message always arrive in the right order, others set a higher priority on guaranteeing that a message is never duplicated.

Security:

Message Queues can be secured by denying write or read access to all but selected accounts.

There are many competing technologies available to support message queues.  Microsoft provides a message queuing technology built into Windows clients and servers called “Microsoft Message Queues”.  IBM has WebSphere MQ (formerly MQ Series).  Oracle has “Oracle Advanced Queuing”.  Java has “Java Message Services”.  There are many others available, both paid and free.

To Create a Message Queue in Windows:

  1. Right-Click “My Computer” and choose “manage”.
  2. Expand “Message Queuing”, then “Public Queues” (to see a list of message queues already set up on your server.  It’s not likely that there are already any there unless you or someone at your organization has manually set one up).image
  3. Right-Click “Public Queues” and choose “New” then “Public Queue” and give it a name.image
  4. Click “OK”.

You’ve now created a message queue.  Now programmers can write code to send messages to the queue and pop messages off the queue.  It’s probably a good idea to secure the queue too:

  1. Right-Click the queue, choose “Properties”.
  2. Click on “Security” tab and secure the queue.

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