VerneMQ
  • Welcome
  • Getting Started
  • MQTT Introduction
  • Installing VerneMQ
    • Running VerneMQ using Docker
  • Configuring VerneMQ
    • Introduction
    • The VerneMQ conf file
    • Auth using files
    • Auth using a database
    • Enhanced Auth
    • MQTT Options
    • MQTT Listeners
    • HTTP Listeners
    • Non-standard MQTT options
    • Websockets
    • Logging
    • Consumer session balancing
    • Plugins
    • Shared subscriptions
    • Advanced Options
    • Storage
    • No Op Engine
    • Generic offline store
    • Redis based message passing
    • Redis based subscription store
    • MQTT Bridge
  • VerneMQ Clustering
    • Introduction
    • Inter-node Communication
    • Dealing with Netsplits
  • Live Administration
    • Introduction
    • Inspecting and managing sessions
    • Retained messages
    • Live reconfiguration
    • Managing Listeners
    • HTTP API
    • Tracing
  • Monitoring
    • Introduction
    • $SYSTree
    • Graphite
    • Netdata
    • Prometheus
    • Health Checker
    • Status Page
  • Plugin Development
    • Introduction
    • Session lifecycle
    • Subscribe Flow
    • Publish Flow
    • Enhanced Auth Flow
    • Erlang Boilerplate
    • Lua Scripting Support
    • Webhooks
    • Events sidecar Plugin
  • Misc
    • Loadtesting VerneMQ
    • Not a tuning guide
    • Change Open File Limits
  • Guides
    • A typical VerneMQ deployment
    • VerneMQ on Kubernetes
    • Loadtesting VerneMQ
    • Clustering during development
    • Not a tuning guide
    • Change Open File Limits
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  1. Live Administration

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
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Last updated 2 years ago