I am confused with whether or not message ordering delivery is supported by default for Queue and Topic.
It said below FIFO message delivery is supported for Queue. I assume this is the same as message ordering delivery.
Queues offer First In, First Out (FIFO) message delivery to one or more competing consumers. https://docs.microsoft.com/en-us/azure/service-bus-messaging/service-bus-queues-topics-subscriptions
However, why is Enabling Sessions required as the screenshot below shown.
To realize a FIFO guarantee in Service Bus, use Sessions.
https://docs.microsoft.com/en-us/azure/service-bus-messaging/message-sessions
Topics and Subscriptions
What about FIFO for Topics and Subscriptions?
Update
My question is:
Is message ordering delivery (FIFO) supported by default for Queues and Topics/Subscriptions, without using Sessons? Other brokers like RabbitMQ supports this by default if I remember correctly.
Am I correct that if I want FIFO for all messages in the Queue even thought I don't need sessions of ordered message, I need to enable Sessions?
For example:
All messages in the queue with ordering: I need all message ordering preserved without enabling session:
1, 2, 3, 4, ... n
Sessions of ordered messages: I don't want to enable sessions
session 1: 1, 2, 3, n
session 2: 1, 2, 3, n
session n: 1, 2, 3, n
Is this requirement of enabling session only to preserve message ordering cubersome, even when I don't want sessions of messages?
