Resetting Message Retrieval Start Position

Scenario

Reset the message retrieval start position if you want to skip certain messages that are never retrieved, or retrieve certain messages again, or retrieve only the messages later than a certain point in time regardless of whether these messages have been retrieved.

You can start message retrieval:

• From the beginning of the chosen queue

  All messages in the queue are retrieved again, regardless of whether they have been retrieved.

• From the end of the chosen queue

  All messages in the queue are skipped. Only the messages right after the new retrieval start position will be retrieved.

• From a specified point in time

  Only the messages in the queue that are later than a specified point time are retrieved.

After the retrieval start position is reset, messages ahead of the new retrieval start position will be flagged as retrieved messages, regardless of whether they have been retrieved.

Prerequisites

A queue has been created. The queue has at least one consumer group and the consumer group has retrieved messages.

Procedure

1. Log in to the management console.
2. Click in the upper left corner of the management console and 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 the name of a queue for which you want to reset the message retrieval start position.
6. On the queue details page, click the Consumer Groups tab.
7. In the consumer group list, choose More > Reset Retrieval Start Position in the same row as the consumer group for which you want to reset the message retrieval start position.
8. Specify Start Message Retrieval and Force Reset parameters. Click OK.

   Table 1 Parameter description

   Parameter	Description
   Start Message Retrieval	From beginning of queue The consumer group starts retrieving messages from the beginning of the queue. From a specified point in time The consumer group starts retrieving messages from a specified point in time. From end of queue The consumer group starts retrieving messages from the end of the queue. This means that the consumer group retrieves the messages newly sent into the queue. Default value: From beginning of queue
   Start Point	The message retrieval start time must fall within the message retention period (up to 72 hours). This parameter is mandatory only if Start Message Retrieval is set to From a Specified Point in Time.
   Force Reset	Disable If messages are currently being retrieved, the reset will fail. Enable The retrieval start position will be reset even if messages are currently being retrieved. This may cause the message retrieval in progress to fail. By default, this parameter is disabled.