Rabbitmq

“Should we move the queue to Streams? They are the proper way now.” A colleague, this week, about our Redis list queue. Wrong question. Streams are not a newer version of the same thing. A list queue is a hand-off. LPUSH on one side, BRPOP on the other, and once a consumer takes the message, it is gone. Crash after the pop and the message died with you, unless you built the pending-list dance yourself. No history, no second reader. For “send this email eventually” it is honestly enough. ...

About once a month an order existed and nobody heard about it. The order service saved the order, then published order.created to RabbitMQ, and once a month the process died between the two. Rare enough to be mysterious. Frequent enough to ruin a weekend. Two operations, two systems, no common transaction. Whatever order you do them in, you lose. Commit first, then publish: the order exists, the event never leaves. Publish first, then commit: the commit fails, consumers are already busy with an order that does not exist. We had the first variant in production. ...