Wednesday, February 9, 2011

what is Apache qpid

  • Supports transactions
  • Persistence using a pluggable layer — I believe the default is Apache Derby
  • This like the other Java based product is HIGHLY configurable
  • Management using JMX and an Eclipse Management Console application -
  • The management console is very feature rich
  • Supports message Priorities
  • Automatic client failover using configurable connection properties -
  • Cluster is nothing but a set of machines have all the queues replicated
  • All queue data and metadata is replicated across all nodes that make up a cluster
  • All clients need to know in advance which nodes make up the cluster
  • Retry logic lies in the client code
  • Durable Queues/Subscriptions
  • Has bindings in many languages
  • For the curious:
  • In our tests -
    • Speed: Non-persistent mode: 5000 messages/sec (receive rate), Persistent mode: 1100 messages/sec (receive rate) (send rate will be typically a bit more, but when you start off with an empty queue, they are almost the same for most queue implementations). However, the interesting bit is that even in transacted mode, I saw a lot of message loss if I crashed the broker (by crash I mean Ctrl+C, not even the more -9 signal type of thing that I usually do). Why I stress this is that apps. can usually hook on to Ctrl+C and save data before quitting, but qpid didn’t think it prudent to do so. Out of 1265 messages sent (and committed), only 1218 were received by the consumer (before the inflicted crash). Even on restarting the broker and consumer, that didn’t change. We observed similar behaviour with RabbitMQ in our tests. However, RabbitMQ docs. mention that you need to run in TRANSACTED mode (not just durable/persistent) for guaranteed delivery. We haven’t run that test yet.