All terms
Glossary
Message queue
A buffer between sender and receiver: messages wait until someone processes them.
The queue decouples speed. A rush in the morning does not have to be processed immediately, it is worked off as capacity allows.
It also decouples availability: if the consumer is briefly gone, messages are not lost, they pile up.
How you notice it
- Load spikes overwhelm downstream systems.
- A transaction must not be lost when a service is briefly gone.
- Processing takes longer than a request can wait.
Frequently asked
What happens to messages that cannot be processed?
Without a place of their own they either loop forever or vanish. A dead letter queue plus an alert is mandatory. Otherwise the backlog is discovered when a customer asks about their order.