CODEWITHSUNDEEP
rabbitmq
tangjiujun
tangjiujun

Reputation: 5

How RabbitMQ handle if queue message bytes length large than x-max-length-bytes?

I had declare a queue like below:

Map<String, Object> args = new HashMap<String, Object>();
args.put("x-max-length-bytes", 2 * 1024 * 1024);  // Max length is 2G
channel.queueDeclare("queueName", true, false, false, args);

When the queue messages count bytes is large than 2G, It will auto remove the message on the head of the queue.
But what I expected is That it reject produce the last message and return exception to the producer.
How can I get it?

Upvotes: 0

Views: 3399

Answers (2)

Gabriele Santomaggio
Gabriele Santomaggio

Reputation: 22682

A possible workaround is check the queue size before send your message using the HTTP API.

For example if you have a queue called: myqueuetest with max size = 20.

Before send the message you can call the HTTP API in this way: http://localhost:15672/api/queues/

the result is a JSON like this:

  "message_bytes":10,
  "message_bytes_ready":10,
  "message_bytes_unacknowledged":0,
  "message_bytes_ram":10,
  "message_bytes_persistent":0,
..
  "name":"myqueuetest",
  "vhost":"test",
  "durable":true,
  "auto_delete":false,
  "arguments":{
     "x-max-length-bytes":20
  },

then you cloud read the message_bytes field before send your message and then decide if send or not.

Hope it helps

EDIT

  1. This workaround could kill your application performance
  2. This workaround is not safe if you have multi-threading/more publisher
  3. This workaround is not a very "best practise"

Just try to see if it is ok for your application.

Upvotes: 1

old_sound
old_sound

Reputation: 2313

As explained on the official docs:

Messages will be dropped or dead-lettered from the front of the queue to make room for new messages once the limit is reached.

https://www.rabbitmq.com/maxlength.html

If you think RabbitMQ should drop messages form the end of the queue, feel free to open an issue here so we can discuss about it https://github.com/rabbitmq/rabbitmq-server/issues

Upvotes: 0

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