Comments on: Queues are still queues

By: David Holt

David Holt — Mon, 26 Nov 2012 20:43:00 +0000

A better analogy would be an airline check-in counter, where First Class customers get their own queue, which is much shorter than the Coach passenger queue.

By: RhysC

RhysC — Fri, 26 Nov 2010 14:36:04 +0000

I would also like to point out many of these issues are dealt with on Udi Dahan’s course, which is fantastic. The amount of faux pars that we have avoid because of that course has paid for its self many time over. Rhys C

By: Scooletz

Scooletz — Sat, 20 Nov 2010 19:01:18 +0000

@Mikalai,
from the solutions you mentioned: working by selector seems to be not as easy concept as separated queues? How would you filter messages in a cloud environment having remote queues with only Get,Confirm/Delete,Put operations?
Virtual queues will finally go to other queues, right? Splitting up the messages across well defined list of queues seems to be the only real solution, doesn’t it?

By: Mikalai Alimenkou

Mikalai Alimenkou — Sat, 20 Nov 2010 10:13:04 +0000

Queues are used in middleware because of architectural reasons. SLA on particular type of message processing may be archived in different ways: separate queue, priorities for messages, exclusive subscriber working by selector, virtual queues for message distribution, etc. Separate queue is not always the best solution because you can quickly come to unmanageable long list of queues and complex code on both producer and consumer side to separate processing.

By: John Teague

John Teague — Fri, 19 Nov 2010 16:55:37 +0000

It’s not as much about organizing by SLA, but by the components that make up your business service. Udi suggest creating a queue per component. The advantage is just what you realized, SLA can now be broken down to smaller components. Now that they are separate queues, you don’t have to add more resources for all of your components just to make sure one meets it’s SLA.

By: Udi Dahan

Udi Dahan — Fri, 19 Nov 2010 06:35:04 +0000

The issue with priority queues is that they often result in starvation and therefore SLA violation.

By: Sean C. Stapleton

Sean C. Stapleton — Thu, 18 Nov 2010 17:57:18 +0000

… Unless it is a priority queue; which is what you really wanted. I know nothing about nservice bus, but there is no conceptual reason you shouldn’t be able to implement the queue as a priority queue. There may, of course, be many practical reasons. E.g., the same concerns you might have about a DB table with a clustered index on (Priority tinyint, ID int) instead of (ID Identity(1,1)).