message-queue | 易学教程

Low-latency, large-scale message queuing

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问题 I'm going through a bit of a re-think of large-scale multiplayer games in the age of Facebook applications and cloud computing. Suppose I were to build something on top of existing open protocols, and I want to serve 1,000,000 simultaneous players, just to scope the problem. Suppose each player has an incoming message queue (for chat and whatnot), and on average one more incoming message queue (guilds, zones, instances, auction, ...) so we have 2,000,000 queues. A player will listen to 1-10

Rabbitmq- Designing a message replay service

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I am trying to design a replay mechanism that will enable users to replay messages from the queues. The best design I have come up for an exchange that contains multiple queues and multiple consumers is: Create a recorder service that will: Create a queue and bind all routing keys to it. Consume all messages from the exchange. Save all messages to the DB. Subscriber request for replay. Each subscriber creates a new exchange, queue and binds to it with same bindings as its regular queue. Subscriber sends a rest requests to a web server to start replay with a filter ( startdate, etc). Request

ActiveMQ vs Apollo vs Kafka

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问题 I don't have any previous experience with *MQs and I'm looking to build knowledge on JMS and message queues in general. That way, I wonder whether I should start with ActiveMQ or just "ignore" it altogether and start by teaching myself Apollo. Is Apollo as feature-complete as ActiveMQ? Does it implement JMS 2.0 (I see that ActiveMQ got stuck with 1.1)? Will I be missing something really important? Also, how does Kafka compare to these two solutions? 回答1: Apache ActiveMQ is a great workhorse

Why use Celery instead of RabbitMQ?

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问题 From my understanding, Celery is a distributed task queue, which means the only thing that it should do is dispatching tasks/jobs to others servers and get the result back. RabbitMQ is a message queue, and nothing more. However, a worker could just listen to the MQ and execute the task when a message is received. This achieves exactly what Celery offers, so why need Celery at all? 回答1: You are right, you don't need Celery at all. When you are designing a distributed system there are a lot of

How to retract a message in RabbitMQ?

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I've got something like a job queue over RabbitMQ and, upon a request to cancel a job, I'd like to retract the tasks that have not yet started processing (their messages have not been ack'd), which corresponds to retracting these messages from the queues that they've been routed to. I haven't found this functionality in AMQP or in the RabbitMQ API; perhaps I haven't searched well enough? Or will I have to use a workaround (it's not hard, but still)? I would solve this scenario by having the worker check some sort of authoritative data source to determine if the the job should proceed or not.

In which domains are message oriented middleware like AMQP useful?

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问题 What problem do MOM (Message Oriented Middleware) solve? Scalability? Integration? In which domain are they typically used and in which domains are they typically not used? For example, say, is Google using such solution for it's main search engine or to power GMail? What about big websites like Walmart, eBay, FedEx (pretty much a Java shop) and buy.com (pretty much an MS shop)? Does MOM solve a need there? Does it make any sense when you're writing a Webapp where you control the server-side

Are message queues obsolete in linux?

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问题 I've been playing with message queues (System V, but POSIX should be ok too) in Linux recently and they seem perfect for my application, but after reading The Art of Unix Programming I'm not sure if they are really a good choice. http://www.faqs.org/docs/artu/ch07s02.html#id2922148 The upper, message-passing layer of System V IPC has largely fallen out of use. The lower layer, which consists of shared memory and semaphores, still has significant applications under circumstances in which one

Mock or simulate Message Queue (JMS)

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There is a message(text), which format and content i definitely know. For now,class in Java,that parses and reads this message from file,is implemented. In real world, this message will come from Message Queue. For now I should simulate, mock or generate Message Queue on my local PC for testing purposes. Java spec( java jms ): JMS provider: A messaging system that implements the JMS specification. JMS clients: Java applications that send and receive messages. Messages: Objects that are used to communicate information between JMS clients. Concerning this specification, i need JMS provider . JMS

Understanding zeromq java binding

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I'm investigating zeromq as a message passing solution in a java project, but I find the instructions on java binding somewhat difficult to follow. http://www.zeromq.org/bindings:java I am unfamiliar with java bindings, so these may be stupid questions, but can someone help me understand: Why do I need to install anything? Will jars I build on one machine work on another system? I need this application to be portable. If so, why do I need to build my own jars to begin with? I feel like the instructions provided on zeromq require base familiarity with building C projects that I lack, so perhaps

Can you/should you use SQL Server Service Broker with .NET applications?

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I have many operations in the database that need to trigger application code. Currently I am using database polling, but I hear that SQL Server Service Broker can give me MSMQ-like functionality. Can I listen to SQL Server Service Broker queues from .NET applications running on a different machine? If so, should I do it? If not, what would you recommend? RickNZ To answer your questions: Can I listen to SQL Server Service Broker queues from .NET applications running on a different machine? Yes. If so, should I do it? If not, what would you recommend? You might consider using SqlDependency . It