Creating a Queue

Scenario

The first task in using DMS is to create one or more queues.

Procedure

1. Log in to the management console.
2. Click in the upper left corner to select a region.
   

   Select the same region as your application service.

3. Click Service List, and choose Application > Distributed Message Service to open the DMS console.
4. In the navigation pane, choose Queue Manager.
5. Click Create Queue.

   The remaining number of queues that can be created is displayed above the Delete button. By default, a maximum of 30 queues can be created under a project. To create more than the default number of queues, contact customer service to increase your quota.

6. Specify parameters listed in Table 1.

   Table 1 Parameter description

   Parameter	Description
   Name	Unique name of a queue. When you create a queue, a default queue name is generated, which you can change if required. A queue name is 1 to 64 characters long. Only letters, digits, underscores (_), and hyphens (-) are allowed. The queue name cannot be modified after creation of the queue.
   Type	Standard queue or Advanced queue
   Mode	When the queue type is standard, the queue mode can be: Partition-level FIFO: Messages may be retrieved out of sequence, but the concurrency is higher. Global FIFO: Messages are retrieved in the order they were sent. When the queue type is Advanced queue, the queue mode can be: High throughput: All message replicas are flushed to disk asynchronously. Select this mode when high message delivery performance is required. High reliability: All message replicas are flushed to disk synchronously. Select this mode when high message delivery reliability is required.
   Dead Letter Queue	This parameter is displayed only if the Queue Type is set to Standard queue. An indicator of whether to enable dead letter queue, which accommodates messages that cannot be correctly retrieved. If a message fails to be retrieved for a preset number of times, it will be sent to the dead letter queue and retained for 72 hours. You can then retrieve the message from the dead letter queue. Messages in the dead letter queue are specific to individual consumer groups, and consumer groups cannot retrieve each other's dead letter messages. Dead letter messages from global FIFO queues are sent to the dead letter queue in the FIFO order. By default, Dead Letter Queue is disabled.
   Message Retention Period (h)	This parameter is available only for advanced queues. The number of hours for which messages will be preserved in an advanced queue. Messages older than that period will be deleted. Deleted messages are not retrievable to consumer groups. Value range: integers from 1 to 72 Default value: 72
   Maximum Retrievals	This parameter is displayed only if Dead Letter Queue is enabled. The maximum number of times a message can be retrieved before it is sent to the dead letter queue. Value range: 1 to 100 Default value: 3
   Description (optional)	The description is 0 to 160 characters long and cannot contain angle brackets (< and >).

7. Click OK.

   After the queue is created, you can click the name of a queue to view queue details.