docusaurus/platform_versioned_docs/version-1.7/understanding-airbyte/airbyte-metadata-fields.md
In addition to the fields declared in a stream's schema, Airbyte destinations append additional columns to your data. These fields can aid in understanding your data and debugging errors.
| Airbyte field | Description | Column type |
|---|---|---|
_airbyte_raw_id | A random UUID assigned to each incoming record | String |
_airbyte_generation_id | Incremented each time you execute a refresh | String |
_airbyte_extracted_at | A timestamp for when Airbyte pulled the event from the data source | Timestamp with timezone |
_airbyte_loaded_at | Timestamp to indicate when Airbyte loaded the record into the destination | Timestamp with timezone |
_airbyte_meta | Additional information about the record; see below | Object |
Note that not all destinations populate the _airbyte_loaded_at field. It's typically only useful for destinations that execute typing and deduping.
_airbyte_meta fieldThis field contains additional information about the record. Airbyte writes it as a JSON object. It has two fields.
A sync_id field on this object. This ID has no inherent meaning, but increases monotonically across syncs.
A changes field, which records any modifications that Airbyte performed on the record. For example, if a record contained a value which didn't match the stream's schema, the destination connector could write null to the destination and add an entry to the changes list.
Each entry in the changes list is itself an object. The
Airbyte protocol defines the schema for these objects, as the AirbyteRecordMessageMetaChange struct.
For example, if you saw this value in _airbyte_meta:
{
"sync_id": 1234,
"changes": [
{
"field": "foo",
"change": "NULLED",
"reason": "DESTINATION_SERIALIZATION_ERROR"
}
]
}
You would know:
foo column because it wasn't a valid value for the destinationDestinations that predate Destinations V2 have a different set of metadata fields. Some fields aren't supported pre-DV2, and other fields are present under a different name.
| Airbyte field | Destinations V2 equivalent |
|---|---|
_airbyte_ab_id | _airbyte_raw_id |
_airbyte_emitted_at | _airbyte_extracted_at |
_airbyte_loaded_at | _airbyte_loaded_at |