Statistics and Metrics

EMQX provides metrics monitoring functions, based on which the operation and maintenance personnel can monitor the current service status and troubleshoot possible system malfunctions.

EMQX divides monitoring status into Statistics and Metrics.

• Statistics are integer-type gauges used to return a single value at the point of time the metric was requested.
• Metrics are integer-type counters used to measure simple incrementing and decrementing numbers, such as the number of bytes and messages sent or received.

EMQX provides users with multiple ways to view statistics and metrics. Most directly, you can view these data on the EMQX Dashboard. When it is not convenient to access the Dashboard, you can also get the data through REST API and system topic messages. Additionally, you can easily integrate the monitoring functions with your own monitoring system, see Integrate with Prometheus.

View Statistics on Dashboard

On EMQX Dashboard, click Monitoring -> Cluster Overview from the left navigation menu. On the Cluster Overview page, click the Nodes tab. Click the name of the node to see the statistics details on the right.

Statistics include two values: current values and historical maximums, for example, the current number of subscriptions and the historical maximum number of subscriptions. Here is the EMQX statistics list:

View Metrics on Dashboard

On EMQX Dashboard, click Monitoring -> Cluster Overview from the left navigation menu. On the Cluster Overview page, you can see metrics by clicking the Metrics tab. EMQX Metrics currently covers four dimensions: bytes, packets, messages, and events.

Connection and Session Metrics

You can see the event-related metrics for the cluster or node, such as client connection, connection sessions, and client access.

Connections

Sessions

Access

Messaging

Scroll down the Metrics page, and you can see message-related metrics, including bytes, packets, messages, and delivery.

Bytes

Packets

Message (PUBLISH packet)

Delivery

Request Monitoring Status via REST API

You can also get the metrics and statistics through the API. Click Metrics on the left navigation menu on the UI to execute this API request. For how to work with EMQX API, see REST API.

Get Monitoring Status via System Topics

EMQX periodically publishes messages about the running status, message statistics, and client online and offline events through system topics. Clients can subscribe to system topics by adding the prefix $SYS/ before the topic name. For more information on different types of system topics, see System Topic.

You can configure system topic settings on Dashboard. Click Management -> MQTT Settings from the left navigation menu. Select System Topic tab.

• Messages publish interval: Set the time interval for sending $sys topic.
• Heartbeat interval: Set the time interval for sending heartbeat messages.
• Client connected notification: Enabled by default and event messages about client being connected will be published.
• Client disconnected notification: Enabled by default and event messages about client being disconnected will be published.
• Client subscribed notification: Disabled by default; When enabled, event messages about a client subscribing to a topic will be published.
• Client unsubscribed notification: Disabled by default; When enabled, event messages about a client unsubscribing to a topic will be published.