PreEmptive Analytics Data Hub User Guide

Deleting Messages

The Dispatch Service maintains a set of queues in RabbitMQ for each configured destination, named pahub.<destination id>_offline and pahub.<destination id>_errored. If a message fails to be dispatched to the destination, it will be queued and retried at a later time.

In some scenarios, it may be necessary to manually remove messages from these queues. These procedures cause data loss.

Removing Some Messages

To remove a fixed number of messages from the front of a queue, e.g. to help resolve a disk-full scenario:

  1. Open the RabbitMQ management console's queue page as a user with administrative privileges.
  2. Click on the queue name in question to open that queue's detail page.
  3. Locate the Get messages section. Expand if necessary.
  4. Choose No for the Requeue field.
  5. Enter the number of messages to remove in the Messages field.
    • Large numbers of messages (e.g., over 1000) may cause the management console to freeze up. Using smaller increments, multiple times, is more effective.
  6. Click Get Message(s).
  7. Locate the Overview section. Expand if necessary.
  8. Wait at least five seconds. Ensure that the Total number of messages has decreased appropriately. Repeat from step 3 otherwise.
  9. Close the browser window.

Purging Entire Queues

When removing a destination, the contents of the destination's queues will not be purged automatically, to prevent accidental data loss. If you are sure that you wish to remove the data, you must purge the queues manually before restarting the Dispatch Service.

To manually purge a queue:

  1. Open the RabbitMQ management console's queue page as a user with administrative privileges.
  2. Click on the queue name in question to open that queue's detail page.
  3. Locate the Delete / purge section. Expand if necessary.
  4. Click Purge.
  5. Click Close on the dialog that appears.
  6. Locate the Overview section. Expand if necessary.
  7. Wait at least five seconds. Ensure that the Total number of messages is 0. Repeat from step 3 otherwise.
  8. Close the browser window.


Data Hub Version 1.5.0. Copyright © 2015 PreEmptive Solutions, LLC