Retained messages

Inspecting the retained message store

To list the retained messages simply invoke vmq-admin retain show:

$ vmq-admin retain show
+------------------+----------------+
|     payload      |     topic      |
+------------------+----------------+
| a-third-message  | a/third/topic  |
|some-other-message|some/other/topic|
|    a-message     |   some/topic   |
|    a-message     | another/topic  |
+------------------+----------------+

Note, by default a maximum of 100 results are returned. This is a mechanism to protect the from overload as there can be millions of retained messages. Use --limit=<RowLimit> to override the default value.

Besides listing the retained messages it is also possible to filter them:

$ vmq-admin retain show --payload --topic=some/topic
+---------+
| payload |
+---------+
|a-message|
+---------+

In the above example we list only the payload for the topic some/topic.

Another example where all topics are list with retained messages with a specific payload:

$ vmq-admin retain show --payload a-message --topic
+-------------+
|    topic    |
+-------------+
| some/topic  |
|another/topic|
+-------------+

See the full set of options and documentation by invoking vmq-admin retain show --help:

$ sudo vmq-admin retain --help
Usage: vmq-admin retain show

  Show and filter MQTT retained messages.

Default options:
  --payload --topic

Options

  --limit=<NumberOfResults>
      Limit the number of results returned. Defaults is 100.
  --payload
  --topic
  --mountpoint