A message queue is an abstract data type that manages the handoff from one or more producers to one or more consumers in a data stream.Kleppman claims that “message broker” is synonymous with “message queue” (p 687).
The particular implementation depends on:
- The cardinality of producers and consumers
- FAT LAD requirements
Since message queues abstract the management of storing and publishing messages, they enable arbitrary stream cardinalities.
Message queues can be thought of as a kind of database.