Because the Pub/Sub API is a binary API, delivered events are formatted as raw Avro binary and sometimes contain fields that are not plaintext-readable. This manifests in Change Data Capture events, causing them to look different from how they are delivered when subscribing via Streaming API.

For example, a Change Data Capture event received via Pub/Sub API might look like this:

{'ChangeEventHeader': 
	{
		...
		'nulledFields': [],
		'diffFields': [],
		'changedFields': ['0x650004E0']
	},
 ...
}

In this example, changedFields is encoded as a bitmap string. This method is more space efficient than using a list of field names. A bit set to 1 in the changedFields bitmap value indicates that the field at the corresponding position in the Avro schema was changed. More information about bitmap fields can be found in Event Deserialization Considerations in the Pub/Sub API documentation.

We have provided this example to demonstrate how bitmap values can be decoded so that they are human-readable and you can process the event by using the values in the bitmap fields.