FIFO in Service Bus
The explantion below is taken out of the context of an internal email exchange, and while we already have product documentation about this topic, this also seemed worth sharing. The email context stated that the customer asked for string First-In-First-Out (FIFO) assurances, but without any specifics about their scenario. Scenarios for hard FIFO requirements are not very common, I might add:
"It’s usually helpful to ask the customer back on exactly why they want they want true in-order delivery, i.e. FIFO, and then look at the use-case.
Service Bus has a specific feature for helping with order assurances, namely Sessions.
Order preservation requires a grouping criterion for the sequence you need ordered, and it needs a mechanism that ensures that messages are delivered to a receiver in that order. That includes not only that the sequence sorting is observed, but that also that no messages go missing b