Java, Massive message processing with queue manager (trading)_问答_开发者

I would like to design a simple application (without j2ee and jms) that can process massive amount of messages (like in trading systems)

I have created a service that can receive messages and place them in a queue to so that the system won't stuck when overloaded.

Then I created a service (QueueService) that wraps the queue and has a pop method that pops out a message from the queue and if there is no messages returns null, this method is marked as "synchronized" for the next s开发者_开发百科tep.

I have created a class that knows how process the message (MessageHandler) and another class that can "listen" for messages in a new thread (MessageListener). The thread has a "while(true)" and all the time tries to pop a message.

If a message was returned, the thread calls the MessageHandler class and when it's done, he will ask for another message.

Now, I have configured the application to open 10 MessageListener to allow multi message processing.

I have now 10 threads that all time are in a loop.

Is that a good design??

Can anyone reference me to some books or sites how to handle such scenario??

Thanks, Ronny

Seems from your description that you are on the right path, with one little exception. You implemented a busy wait on the retrieval of messages from the Queue.

A better way is to block your threads in the synchronised popMessage() method, doing a wait() on the queue resource when no more messages can be pop-ed. When adding (a) message(s) to the queue, the waiting threads are woken up via a notifyAll(), one or more threads will get a message and the rest re-enter the wait() state.

This way the distribution of CPU resources will be smoother.

I understand that queuing providers like Websphere and Sonic cost money, but there's always JBoss Messaging, FUSE with ApacheMQ, and others. Don't try and make a better JMS than JMS. Most JMS providers have persistence capabilities that for provide fault tolerance if the Queue or App server dies. Don't reinvent the wheel.

Reading between the lines a little it sounds like your not using a JMS provider such as MQ. Your solution sounds in the most parts to be ok however I would question your reasons for not using JMS.

You mention something about trading, I can confirm a lot of trading systems use JMS with and without j2ee. If you really want high performance, reliability and piece of mind don't reinvent the wheel by writing your own queuing system take a look at some of the JMS providers and their client API's.

karl

Event loop

How about using a event loop/message pump instead? I actually learned this technique from watching the excellent node.js video presentation from Ryan which I think you should really watch if not already.

You push at most 10 messages from Thread a, to Thread b(blocking if full). Thread a has an unbounded [LinkedBlockingQueue][3](). Thread b has a bounded [ArrayBlocking][4] of size 10 (new ArrayBlockingQueue(10)). Both thread a and thread b have an endless "while loop". Thread b will process messages available from the ArrayBlockingQueue. This way you will only have 2 endless "while loops". As a side note it might even be better to use 2 arrayBlockingQueues when reading the specification because of the following sentence:

Linked queues typically have higher throughput than array-based queues but less predictable performance in most concurrent applications.

Off course the array backed queue has a disadvantage that it will use more memory because you will have to set the size prior(too small is bad, as it will block when full, too big could also be a problem if low on memory) use.

Accepted solution:

In my opinion you should prefer my solution above the accepted solution. The reason is that if it all posible you should only use the java.util.concurrent package. Writing proper threaded code is hard. When you make a mistake you will end up with deadlocks, starvations, etc.

Redis:

Like others already mentioned you should use a JMS for this. My suggestion is something along the line of this, but in my opinion simpler to use/install. First of all I assume your server is running Linux. I would advise you to install Redis. Redis is really awesome/fast and you should also use it as your datastore. It has blocking list operations which you can use. Redis will store your results to disc, but in a very efficient manner.

Good luck!

While it is now showing it's age, Practical .NET for Financial Markets demonstrates some of the universal concepts you should consider when developing a financial trading system. Athough it is geared toward .Net, you should be able to translate the general concepts to Java.

The separation of listening for the message and it's processing seems sensible to me. Having a scalable number of processing threads also is good, you can tune the number as you find out how much parallel processing works on your platform.

The bit I'm less happy about is the way that the threads poll for message arrival - here you're doing busy work, and if you add sleeps to reduce that then you don't react immediately to message arrival. The JMS APIs and MDBs take a more event driven approach. I would take a look at how that's implemented in an open source JMS so that you can see alternatives. [I also endorse the opinion that re-inventing JMS for yourself is probably a bad idea.] The thing to bear in mind is that as your systems get more complex, you add more queues and more processing busy work has greater impact.

The other concern taht I have is that you will hit limitiations of using a single machine, first you may allow greater scalability my allowing listeners to be on many machines. Second, you have a single point of failure. Clearly solving this sort of stuff is where the Messaging vendors make their money. This is another reason why Buy rather than Build tends to be a win for complex middleware.

You need very light, super fast, scalable queuing system. Try Hazelcast distributed queue!

It is a distributed implementation of java.util.concurrent.BlockingQueue. Check out the documentation for detail.

Hazelcast is actually a little more than a distributed queue; it is transactional, distributed implementation of queue, topic, map, multimap, lock, executor service for Java.

It is released under Apache license.