Sample17_BatchDelete.md

Deleting batches of messages

This sample demonstrates how to delete batches of messages from a Service Bus entity without needing to download them locally by receiving and completing them. This can be helpful for clearing out the dead-letter queue or removing messages of a certain age which are no longer of interest to applications.

Purge all messages from an entity

For scenarios when you'd like to delete all messages from an entity, you would use the PurgeMessagesAsync method of the ServiceBusReceiver. It is important to be aware that this method may invoke multiple service requests to delete all of the messages and, as a result, may exceed the configured TryTimeout. If you need control over the amount of time the operation takes, it is recommended that you pass a CancellationToken with the desired timeout set for cancellation.

Because multiple service requests may be made, it is possible to experience partial success when an exception is encountered. In this scenario, the method will stop attempting to delete additional messages and will throw the exception.

It is also important to be aware that if there is a receiver reading the entity when PurgeAllMessgesAsync is called, any locked messages will not be deleted.

stringfullyQualifiedNamespace="<fully_qualified_namespace>";stringqueueName="<queue_name>";awaitusingServiceBusClientclient=new(fullyQualifiedNamespace,newDefaultAzureCredential());awaitusingServiceBusReceiverreceiver=client.CreateReceiver(queueName);// Delete all messages in the queue.intnumberOfMessagesDeleted=awaitreceiver.PurgeMessagesAsync();

Purge all messages enqueued before a specific date

For scenarios where you would like to delete all messages enqueued before a given date, PurgeMessagesAsync accepts an optional parameter to specify the cut-off point.

stringfullyQualifiedNamespace="<fully_qualified_namespace>";stringqueueName="<queue_name>";;awaitusingServiceBusClientclient=new(fullyQualifiedNamespace,newDefaultAzureCredential());awaitusingServiceBusReceiverreceiver=client.CreateReceiver(queueName);// Delete all messages in the queue that were enqueued more than a year ago.DateTimeOffsetdeleteBefore=DateTimeOffset.UtcNow.AddYears(-1);intnumberOfMessagesDeleted=awaitreceiver.PurgeMessagesAsync(deleteBefore);

Delete a batch of old messages

When you wish to only delete some number of messages from the entity, rather than purging all messages, the DeleteMessagesAsync method should be used. This method will invoke a single service operation to request deletion of some number of messages. Service Bus will choose the oldest messages to delete by considering the enqueued time.

Note that the service may delete fewer messages than were requested, but will never delete more. It is also important to be aware that if there is a receiver reading the entity when DeleteMessages is called, any locked messages will not be deleted.

stringfullyQualifiedNamespace="<fully_qualified_namespace>";stringqueueName="<queue_name>";awaitusingServiceBusClientclient=new(fullyQualifiedNamespace,newDefaultAzureCredential());awaitusingServiceBusReceiverreceiver=client.CreateReceiver(queueName);// Delete the oldest 50 messages in the queue.intmaxBatchSize=50;intnumberOfMessagesDeleted=awaitreceiver.DeleteMessagesAsync(maxBatchSize);

Delete a batch of messages enqueued before a specific date

When you wish to delete the oldest messages in the entity but restrict it to only those enqueued before a given date, DeleteMessagesAsync accepts an optional parameter to specify the cut-off point.

stringfullyQualifiedNamespace="<fully_qualified_namespace>";stringqueueName="<queue_name>";awaitusingServiceBusClientclient=new(fullyQualifiedNamespace,newDefaultAzureCredential());awaitusingServiceBusReceiverreceiver=client.CreateReceiver(queueName);// Delete the oldest 50 messages in the queue which were enqueued// more than a month ago.intmaxBatchSize=50;DateTimeOffsetdeleteBefore=DateTimeOffset.UtcNow.AddMonths(-1);intnumberOfMessagesDeleted=awaitreceiver.DeleteMessagesAsync(maxBatchSize,deleteBefore);