Value Changed

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Description

The Value Changed processor detects changes in field values and outputs events only when changes occur. It supports:

• Any data type comparison
• Dimension-based state tracking
• Change timestamp tracking
• State size management
• Multi-dimensional monitoring

This processor is essential for:

• Detecting value changes
• Tracking state transitions
• Monitoring field updates
• Building change logs
• Implementing change triggers

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Required input

The processor requires a data stream containing at least one field to monitor for changes.

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Configuration

Keep Fields

Select the field to monitor for changes. The processor will output an event only when the selected field's value changes.

Output

The processor creates a new event containing:

• All original fields from the input event
• A new field named "change_detected" containing the timestamp when the change occurred
• Only when the monitored field changes value

Example

Input Event Stream

{
  "deviceId": "sensor01",
  "location": "l1",
  "value": 12,
  "timestamp": 1586380104915
}

{
  "deviceId": "sensor01",
  "location": "l1",
  "value": 15,
  "timestamp": 1586380105015
}

Configuration

• Keep Fields: value

Output Event

{
  "deviceId": "sensor01",
  "location": "l1",
  "value": 15,
  "timestamp": 1586380105015,
  "change_detected": 1586380105015
}

Use Cases

1. Change Detection

   • Monitor value changes
   • Track state transitions
   • Detect field updates
   • Build change logs

2. State Monitoring

   • Track state changes
   • Monitor transitions
   • Detect updates
   • Log changes

Notes

• Supports any data type
• Processing is stateful
• State size limited to 5000 entries
• Events only emitted on value changes
• Original fields are preserved
• Change timestamps are added
• Dimension-based state tracking
• Multi-dimensional monitoring supported