amqp

I have one direct exchange. There is also one queue, bound to this exchange. I have two consumers for that queue. The consumers are manually ack'ing the messages once they've done the corresponding processing. The messages are logically ordered/sorted, and should be processed in that order. Is it possible to enforce that all messages are received and processed sequentially accross consumer A and consumer B? In other words, prevent A and B from processing messages at the same time. Note: the consumers are not sharing the same connection and/or channel. This means I cannot use <channel>.basicQoS

I was poking around the rabbitmq documentation, and it seems that rabbitmq does not handle message redelivery count. If I were to manually ACK/NACK messages, I would need to either keep the retry count in memory (say, by using correlationId as the unique key in a map), or by setting my own header in the message, and redelivering it (thus putting it at the end of the queue) However, this is a case that spring handles. Specifically, I am referring to RetryInterceptorBuilder.stateful().maxAttempts(x). Is this count specific to a JVM though, or is it manipulating the message somehow? For example,

I have been given access to a RabbitMQ server to do a load test on it. I'm completely new to servers and AMQ protocol. I've been researching online to see what are some different methods. So far I'm investigating two methods. JMeter; I have found this project: https://github.com/jlavallee/JMeter-Rabbit-AMQP#build-dependencies . It gives me a jar file which I can create JMeter AMQP consumer and publisher, but I have no idea what to put in the fields. (virtual host vs host - dunno my ports -..) Python; using Pika. I have a simple sender script which connects from my client to my server and sends

什么是消息队列？ 消息队列是在消息的传输过程中保存消息的容器，用于接收消息并以文件的方式存储，一个队列的消息可以同时被多个消息消费者消费。分布式消息服务DMS则是分布式的队列系统，消息队列中的消息分布存储，且每条消息存储多个副本，以实现高可用性，如下图所示。 一般来说，消息队列具有如下属性： 消息顺序 普通队列支持“分区有序”和“全局队列”两种模式，ActiveMQ队列和Kafka队列均为分区有序。 分区有序的队列通过分布式处理，支持更高的并发，但由于队列的分布式特性，DMS无法保证能够以接收消息的精确顺序进行消费。如果用户要求保持顺序，建议在每条消息中放置排序信息，以便在收到消息时对消息重新排序。 全局有序的队列对消息消费遵循先入先出规则（FIFO），适用于对消费顺序要求较高的场景。 至少一次传递 在极少数情况下，当用户接收或删除消息时，存储消息副本的服务器之一可能不可用。如果出现这种情况，则该不可用服务器上的消息副本将不会被删除，并且在接收消息时可能会再次获得该消息副本。 这被称为“至少一次传递”，因此，用户的应用程序应该设计为幂等的应用程序（即，如果应用程序多次处理同一条消息，则不得受到不利影响）。 消息较少时单次消费不能获取指定数量的消息 从消息队列中消费消息时，DMS每次从部分消息存储分区中读取消息返回消息给消费者，如果队列中的消息数比较少，则单次消费可能会少于指定条数

From what I have seen, the task state depends entirely on the value set for CELERY_TASK_RESULT_EXPIRES - if I check the task state within this interval after the task has finished executing, the state returned by: AsyncResult(task_id).state is correct. If not, the state will not be updated and will remain forever PENDING. Can anyone explain me why does this happen? Is this a feature or a bug? Why is the task state depending on the result expiry time, even if I am ignoring results? (Celery version: 3.0.23, result backend: AMQP) State and result is the same. The result backend was initially used

I'm fairly new to Celery/AMQP and am trying to come up with a task/queue/worker design to meet the following requirements. I have multiple types of "per-user" tasks: e.g., TaskA, TaskB, TaskC. Each of these "per-user" tasks read/write data for one particular user in the system. So at any given time, I might need to create tasks User1_TaskA, User1_TaskB, User1_TaskC, User2_TaskA, User2_TaskB, etc. I need to ensure that, for each user , no two tasks of any task type execute concurrently. I want a system in which no worker can execute User1_TaskA at the same time as any other worker is executing