# read_delta_updates_since_snapshot

> **Function** in `langgraph`

📖 [View in docs](https://reference.langchain.com/python/langgraph/pregel/_checkpoint/read_delta_updates_since_snapshot)

Read the per-channel update counter from checkpoint metadata.

Returns an empty dict for missing/None metadata; the dict is
`total=False` on `CheckpointMetadata`, so absence means "no prior
delta-channel activity tracked."

## Signature

```python
read_delta_updates_since_snapshot(
    metadata: CheckpointMetadata | None,
) -> dict[str, int]
```

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[View source on GitHub](https://github.com/langchain-ai/langgraph/blob/398d6cc59d4cf81ab23c09f037e9f521c3fedcd6/libs/langgraph/langgraph/pregel/_checkpoint.py#L236)