• Distributed Message Service

dms
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  2. Distributed Message Service
  3. User Guide
  4. Getting Started
  5. Creating a Queue

Creating a Queue

Scenario

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

Prerequisites

None.

Procedure

  1. Log in to the management console.
  2. Click  in the upper left corner of the management console and select a region and a project.
  3. Click Service List, and choose Application > Distributed Message Service to launch 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, 5 queues can be created under a project. To create more than 5 queues, contact customer service to increase your quota.

  6. Specify queue parameters.

    Table 1 Parameter description

    Parameter

    Description

    Region

    Region in which the new queue will be created.

    Queue Name

    Unique name of a queue.

    When creating 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 parameter cannot be modified after creation of the queue.

    Queue Type

    • Standard

      Messages may be retrieved out of sequence. The concurrent performance of a standard queue is higher than that of a FIFO queue.

    • Kafka

      Messages in Kafka queues can be created, retrieved, and acknowledged using open-source Kafka clients. In addition, messages in Kafka queues can be created and retrieved using the DMS console or HTTP APIs. Kafka queues support two modes: high throughput and high reliability.

    The default queue type is Standard.

    Queue Mode

    When the queue type is standard, the queue mode can be:
    • Normal: Messages may be retrieved out of sequence, but the concurrent performance is higher.
    • FIFO: Messages are retrieved in the order they were sent.
    When the queue type is Kafka, the queue mode can be:
    • High throughput

      All message replicas are flushed to disk asynchronously. Select the high throughput mode when message delivery performance is important.

    • High reliability

      All message replicas are flushed to disk synchronously. Select the high reliability mode when message reliability is important.

    Dead Letter Queue

    This parameter is displayed only if the Queue Type is set to Standard.

    An indicator of whether the dead letter queue is enabled. By default, the dead letter queue is disabled.

    Dead letter messages are messages that cannot be correctly retrieved.

    If a message fails to be retrieved for a preset number of times, the message will be sent to the dead letter queue and retained in the dead letter queue for at least 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 FIFO queues are sent to the dead letter queue in the FIFO order.

    Messages in Kafka queues cannot be sent to the dead letter queue.

    Message Retention Period (h)

    This parameter is displayed only if the Queue Type is set to Kafka.

    The number of hours for which messages will be preserved in a Kafka queue. Messages older than that period will be deleted and deleted messages are not retrievable to consumer groups.

    Value range: 1 to 72

    Default value: 72

    Maximum Retrievals

    This parameter is displayed only if the 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

    Tags

    Tag of a queue, which is used to identify the queue. You can classify queues by tag and search for a specific queue based on its tag.

    • Each queue must have a unique tag key.
    • You can customize tags or use tags predefined by TMS.
    • You can add a maximum of 10 tag keys to a queue.

    Description (optional)

    Queue description.

    The description is 0 to 160 characters long and cannot contain angle brackets (< and >).

  7. Click OK to create the queue.

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