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Stats & Metrics Panel

The Stats panel displays real-time metrics about topic activity, message frequencies, and system health.

Overview

Property Value
Data Source Zenoh subscription metadata
Display Metrics table and charts
Use Case Monitoring, debugging

Features

  • Topic frequency — Messages per second (Hz) for each topic
  • Message counts — Total messages received
  • Active subscriptions — Currently subscribed topics
  • Connection status — Zenoh connection health
  • Latency metrics — End-to-end timing (when available)

Panel Interface

Topic List

Displays all active topics:

Column Description
Topic Topic name/key expression
Hz Message frequency
Count Total messages
Last Time since last message

Metrics Summary

Overview statistics:

Metric Description
Total Topics Number of active topics
Total Messages Sum of all message counts
Avg Frequency Average Hz across topics
Connection WebSocket status

Understanding Metrics

Frequency (Hz)

Message frequency indicates how often data is published:

Hz Typical Source
25-30 Camera main stream
10-15 Camera sub stream
0.03 Current weather (every 30s)
0.0006 Hourly forecast (every 30min)

Message Count

Running total of messages received since:

  • Dashboard load
  • Last refresh
  • Panel creation

Last Message

Time since the last message was received:

  • < 1s: Active, real-time
  • 1-5s: Normal for low-frequency topics
  • > 10s: May indicate issues

Topic Patterns

Camera Topics

0/camera%front_door%compressed/**
├── Hz: 25.0
├── Count: 15,234
└── Last: 0.04s

Weather Topics

0/weather%current/**
├── Hz: 0.03
├── Count: 42
└── Last: 15s

0/weather%hourly/**
├── Hz: 0.0006
├── Count: 3
└── Last: 180s

Adding a Stats Panel

  1. Click Add Panel
  2. Select "Stats" panel type
  3. Panel displays all topic metrics

Or use the TUI /topics command for a terminal-based view.

Diagnostic Use Cases

Verifying Data Flow

Check that expected topics are active:

  1. Start a component (cameras, weather)
  2. Observe new topic appears in stats
  3. Verify Hz matches expected rate

Detecting Issues

Identify problems through metrics:

Symptom Possible Cause
Hz = 0 Publisher not running
Low Hz Network issues, overload
Gaps in data Connection drops
Missing topics Service not started

Performance Monitoring

Track system performance:

  • Camera FPS vs. expected
  • Weather update intervals
  • Message delivery latency

Connection Metrics

WebSocket Status

Status Description
Connected Active WebSocket connection
Reconnecting Attempting to reconnect
Disconnected No connection

Zenoh Router

Information about the Zenoh router:

  • Router address
  • Protocol version
  • Session ID

Comparing with TUI

The Stats panel provides similar information to the TUI /topics command:

Feature Dashboard Stats TUI /topics
Topic list Yes Yes
Frequency Yes Yes
Count Yes Yes
Visual chart Yes No
History Yes No
Export No No

Performance

Update Rate

  • Stats update every second
  • Frequency calculated over rolling window
  • Counts increment in real-time

Resource Usage

  • Minimal CPU overhead
  • Small memory footprint
  • No impact on data flow

Troubleshooting

No topics displayed

  1. Check that services are running
  2. Verify Zenoh bridge connection
  3. Refresh the dashboard

Incorrect frequency

  1. Frequency is averaged over time
  2. Wait for sufficient samples
  3. Check for intermittent connectivity

Missing expected topics

  1. Verify service is publishing
  2. Check topic name/pattern
  3. Use TUI /topics to compare

Next Steps