QueueExplorer Limitations when working with Azure Service Bus

Although QueueExplorer makes queues and messages look similar to folders and files, under the hood they are still first-in first-out queues. For some operations QueueExplorer will perform Receive and/or Send operations. Send operation will create new message and they'll be put at the end of the queue.

General limitations

• In order to delete, schedule, defer, etc. message from a middle of a queue, QueueExplorer has to receive messages which come before wanted one, and to "Abandon" them afterwards. That increases Delivery Count of these messages, and if it reaches 10 (default, can be changed from queue properties), these messages will be deadlettered.
• Requeue for deadletter messages in subscription will return messages to its parent topic - therefore these messages will not go just to that subscription, but to other subscriptions within that topic as well, depending on how rules and filters are set up.
• When you load, copy, drag&drop or edit message it will go to the end of queue.
• Since these messages are actually new messages in Azure Service Bus, some properties will be changed like time sent, time arrived, etc.
• QueueExplorer doesn't update display in real time. If some other application or another QueueExplorer window modifies some queue, you have to use "Refresh" to see these changes.
• Some operations could fail or produce undesirable results if messages are removed in the mean time by some other program. It's advisable to stop other processes that use queue while operations like copy, move, etc. are performed.

Throttling

Azure Service Bus can activate throttling if there are too many operations going on. Unfortunately, one of effects of throttling is that QueueExplorer can get partial list of queues and topics, without any error messages. In this case, it's impossible to know whether these queues were deleted or just temporarily not listed because of throttling.

As a workaround since version 4.5.29, QueueExplorer will use cached queues/topics if they are missing within 30 seconds. It will also always keep currently displayed node (queue, topic, subscription, etc) even if it's no longer listed by Service Bus. These workarounds are applied only for automatic refresh. If refresh is manually invoked, or as a result of operation like delete/add queue, QueueExplorer will show whatever Service Bus returns.

Subscription deadletters

Deadlettered messages in a subscription can't be requeued to that subscription alone. That's because Azure Service Bus has no way to send a message to single specific subscription - messages can only be sent to parent topic, and then distributed to all its subscriptions based on rules. Therefore, if you want to requeue a message from subscription's deadletter, it will be sent to other applicable subscriptions as well.