You're right — the new **archival and move feature in Auto Loader** depends on the `_commit_timestamp` column. If that value is coming as `null`, the feature won't work, as mentioned in the documentation.

To fix this, you need to make sure you're explicitly enabling the `commitTime` metadata column using the following option in your Auto Loader configuration:

```python
.option("cloudFiles.addColumns", "commitTime")
```

This ensures that the `_commit_timestamp` field gets populated during ingestion.

Here’s the corrected version of your code:

```python
df = (
spark.readStream.format("cloudfiles")
.option("cloudFiles.format", "json")
.option("cloudFiles.schemaLocation", checkpoint_path)
.option("multiLine", "true")
.option("cloudFiles.backfillInterval", "10 minutes")
.option("cloudFiles.inferColumnTypes", "true")
.option("cloudFiles.addColumns", "commitTime") # Required to get _commit_timestamp
.load(ingestDirectory)
)
```

Once this is set, `_commit_timestamp` should be populated properly, and the archival/move feature should start working as expected.