RabbitMQ based

• rabbitmq_delayed_message_exchange plugin

  • Flowchart

  • Cons

• Dead letter queue

  • Flowchart

  • Cons

rabbitmq_delayed_message_exchange plugin

Flowchart

1. The message will be put into delayed exchange. Within delayed exchange, the message will be stored inside Mnesia (A file-based database).

2. Once the delayed period is passed, messages will be delivered to the message queue.

Cons

• Before messages are delivered to target queue, they are stored in servers' local file-based DB Mnesia. If the node becomes unavailable or the data has not been flushed to disk, they will be lost.

• It does not support high concurrent volume and big data size.

Dead letter queue

Flowchart

1. Delay queue has no consumers and an expiration time.

2. When messages get expired, they will be delivered to dead letter queue.

Cons

• TTL threshold is set on the queue level. Each queue will have a different expiration time. If customized delay time is needed, then lots of queue need to be created.