Re: [xml-dev] XML Feeds vs SQL Queries

[Jonathan Robie <jonathan.robie@redhat.com>]

Elliotte Harold wrote:
> I've been neck deep in messaging systems for the last two months, and 
> "reliable" is the last word I'd use to describe them. The first word 
> I'd use? It's hard to pick, but "annoying", "hideous", "buggy" and 
> "error-prone" all come to mind. We're getting ready to rip out the 
> messaging system completely because it just can't handle, well, anything.

Like Mike Kay, I use "messaging systems" as a synonym for "reliable 
messaging systems". I think you're neck-deep in the wrong systems. Time 
for a better open source solution?

> Possibly if you've got the budget for MQSeries and multiple expensive 
> professionals dedicated to babysitting it full-time, you can make 
> messaging reliable. I've certainly heard bedtime stories about 
> companies that run like that; but on anything approximating a startup 
> or small business budget, messaging is a sure-fire way to kill a system.

Yes, reliable messaging systems have traditionally been expensive and 
difficult to administer. You had to either spend a lot of money, or use 
a system that wasn't up to the task - which is precisely why AMQP is 
being developed as an open messaging standard. To steal a paragraph from 
something I wrote:

> Messaging is a crucial component for enterprise and high-performance 
> computing, SOA deployments, and platform services. Until recently, 
> enterprise-level messaging systems were proprietary, mutually 
> incompatible, and quite expensive. Open messaging systems existed, but 
> until now, they did not offer the reliability or performance needed 
> for demanding applications. Red Hat Messaging offers the 
> predictability, high speed, reliability, security and scalability 
> needed for enterprise-level messaging in an open-source product with 
> multi-vendor interoperability.

This is still pre-release, and there's not much in the way of 
documentation or examples, but AMQP is already being used in production 
systems, where it is serving very high message volumes. For example, one 
bank has a worldwide deployment that delivers over 100 million messages 
per day in a 7 hour trading window in its Tokyo hub. Apache Qpid and Red 
Hat Messaging, which builds on Apache Qpid to optimize it for Linux and 
add functionality beyond that of Qpid, are open source implementations 
that are being used in production now. Clients are available in C++, 
Java, Python, and Ruby.

One way to use AMQP is to write to the JMS API, which Qpid supports. 
That gets you better speed and reliability using a familiar API.

Jonathan