# ANNIndexConfig

> **Class** in `langgraph.store.postgres`

📖 [View in docs](https://reference.langchain.com/python/langgraph.store.postgres/base/ANNIndexConfig)

Configuration for vector index in PostgreSQL store.

## Signature

```python
ANNIndexConfig()
```

## Extends

- `TypedDict`

## Constructors

```python
__init__(
    kind: Literal['hnsw', 'ivfflat', 'flat'],
    vector_type: Literal['vector', 'halfvec'],
)
```

| Name | Type |
|------|------|
| `kind` | `Literal['hnsw', 'ivfflat', 'flat']` |
| `vector_type` | `Literal['vector', 'halfvec']` |


## Properties

- `kind`
- `vector_type`

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[View source on GitHub](https://github.com/langchain-ai/langgraph/blob/aa322c13cd5f16a3f6254a931a4104e412cd687c/libs/checkpoint-postgres/langgraph/store/postgres/base.py#L177)