The other day I bumped into an old friend (Tim) that specializes in Java and database development. He asked what me about my interests and I told him that I have been working with web services. He said, "Oh, aren't those slow?"
Sure, I had 101 smart-ass answers loaded in my arsenal, but this individual was asking a serious question that deserved a real answer.
I answer him, "Well, I guess it depends. Generally speaking, anytime you use distributed computing techniques you will incur extra overhead - and that overhead could lead to poorer performance or response times." This answer clearly annoyed him. He responded, "Yea, I know that you use 'distibuted computing' to distribute computing and the effects that this has... my concern is that web services leverage a bunch of abstract protocols that just weren't designed with performance in mind."
"Ah... I get your point. The protocols suck?"
"Yes - the protocols suck - if you have any concern for performance."
Ok - now we were getting somewhere.
"Tim, the reason they suck is because the big-boys (IBM/MS) chose to roll out 'Least Common Denominator' (LCD) solutions to distributed computing first. When you need to create an ad-hoc computing platform and you don't know the capabilities of all of the participants you must choose only those capabilities that are guaranteed to be available across all nodes. You have to create an LCD baseline (which I call the suckline). The suckline is the decision to use the lowest common denominator capabilities across participating nodes in order to guaranteed communications."
Tim nodded in agreement and commented, "But what you implying is that there is something else out there that doesn't suck - - like a Greatest Common Factor (GCF) solution?"
"EXACTLY - - but there isn't! And that my friend, is the beauty of it...(laugh)..." He looked at me like I was insane - which is a look that I thrive on. "Web services are about protocol negotiation. Currently, we only have one solution for just about any facet of web service computing - encoding, encryption, reliability, transactions, discovery - you name it - we have a version of it that more or less sucks! And you know what - that's ok! IBM and Microsoft have had the patience to work on an LCD platform for as long as they have - and in the face of 'performance critics' - I tip my hat to them. If the protocol negotiation is done correctly you should be able to use a metadata described invocation and interface description mechanism that is linked to a protocol policy for runtime resolution."
Tim asked, "So you believe that it really is just an issue of 'premature optimization'"?
"Absolutely - two communicating java applications will be more efficient at sending serialized java objects then they will be at sending and receiving XML documents. If the applications are on the executing on the same vm, it would be more efficient if they used some kind of shared memory. The GCF capabilities of the participants MUST be determined dynamically (or cached). Should the two applications be prepared to go down to the suckline? Sure - the suckline represents the ubiquity baseline of modern computing."
"Jeff, you just crossed from distributed document oriented to distributed object-oriented computing. I thought that web services was all about document oriented, XML based, loosely coupled, asynchronous..."
"No! - and yes..." - I injected. "This is where I disagree with most of the world. If you ask most people that live and breathe web services... they would agree with your comments. However, I'm not one of them. To me, web services describe a programming model that is evolve-able. The SINGLE most important feature for me is the ability to use protocol negotiation to determine the instance of the programming features and functions that you deem necessary to create a dynamic virtual computing platform. The document oriented problem is really a fatty-chatty problem - and there are solutions to this as well."
Tim commented, "That's cool. But we still have the problem that today web services are slow and we are stuck with the suckline."
"Yep - you are correct. Microsoft has already moved Indigo towards a GCF programming model. IBM is doing the same. What is unclear is if a generic J2EE type solution will become available (in time) to compete against the MS solution. Otherwise, you will see a splintering in the next-gen Java SOA marketplace with only 1 or 2 vendors agreeing to agree on the GCF solution. And yes, it is very possible that the GCF solutions will have patents hung all over them."
"Tim, I can't predict the future, however - I bet on smart people and funded projects. Right now MS, IBM and others are putting their best people on web services and throwing lots of cash at it. Trust me - we will move way beyond the suckline - there is too much money on the table."