Depcrecated deletion support for ANN backends

README.md

@@ -37,6 +37,7 @@ Install the package with:
 pip install vicinity
 ```
 
+
 The following code snippet demonstrates how to use Vicinity for nearest neighbor search:
 ```python
 import numpy as np
@@ -68,7 +69,6 @@ vicinity = Vicinity.load('my_vector_store')
 Vicinity provides the following features:
 - Lightweight: Minimal dependencies and fast performance.
 - Flexible Backend Support: Use different backends for vector storage and search.
-- Dynamic Updates: Insert and delete items in the vector store.
 - Serialization: Save and load vector stores for persistence.
 - Easy to Use: Simple and intuitive API.
 
@@ -81,6 +81,8 @@ The following backends are supported:
 - [PYNNDescent](https://github.com/lmcinnes/pynndescent): ANN search using PyNNDescent.
 - [USEARCH](https://github.com/unum-cloud/usearch): ANN search using Usearch. This uses a highly optimized version of the HNSW algorithm.
 
+NOTE: the ANN backends do not support dynamic deletion. To delete items, you need to recreate the index. Insertion is supported in the following backends: `FAISS`, `HNSW`, and `Usearch`. The `BASIC` backend supports both insertion and deletion.
+
 ### Backend Parameters
 
 

tests/test_vicinity.py

@@ -156,6 +156,9 @@ def test_vicinity_delete_nonexistent(vicinity_instance: Vicinity) -> None:
     :param vicinity_instance: A Vicinity instance.
     :raises ValueError: If deleting items that do not exist.
     """
+    if vicinity_instance.backend.backend_type != Backend.BASIC:
+        # Skip delete for non-basic backends
+        return
     with pytest.raises(ValueError):
         vicinity_instance.delete(["item10002"])
 

vicinity/backends/annoy.py

@@ -113,11 +113,11 @@ def query(self, vectors: npt.NDArray, k: int) -> QueryResult:
 
     def insert(self, vectors: npt.NDArray) -> None:
         """Insert vectors into the backend."""
-        raise NotImplementedError("Annoy does not support insertion.")
+        raise NotImplementedError("Insertion is not supported in ANNOY backend.")
 
     def delete(self, indices: list[int]) -> None:
         """Delete vectors from the backend."""
-        raise NotImplementedError("Annoy does not support deletion.")
+        raise NotImplementedError("Deletion is not supported in ANNOY backend.")
 
     def threshold(self, vectors: npt.NDArray, threshold: float) -> list[npt.NDArray]:
         """Threshold the backend."""

vicinity/backends/faiss.py

@@ -124,10 +124,6 @@ def from_vectors(  # noqa: C901
 
         index.add(vectors)
 
-        # Enable DirectMap for IVF indexes so they can be used with delete
-        if isinstance(index, faiss.IndexIVF):
-            index.set_direct_map_type(faiss.DirectMap.Hashtable)
-
         arguments = FaissArgs(
             dim=dim,
             index_type=index_type,
@@ -169,17 +165,8 @@ def insert(self, vectors: npt.NDArray) -> None:
         self.index.add(vectors)
 
     def delete(self, indices: list[int]) -> None:
-        """Delete vectors from the backend, if supported."""
-        if hasattr(self.index, "remove_ids"):
-            if isinstance(self.index, faiss.IndexIVF):
-                # Use IDSelectorArray for IVF indexes
-                id_selector = faiss.IDSelectorArray(np.array(indices, dtype=np.int64))
-            else:
-                # Use IDSelectorBatch for other indexes
-                id_selector = faiss.IDSelectorBatch(np.array(indices, dtype=np.int64))
-            self.index.remove_ids(id_selector)
-        else:
-            raise NotImplementedError("This FAISS index type does not support deletion.")
+        """Delete vectors from the backend."""
+        raise NotImplementedError("Deletion is not supported in FAISS backends.")
 
     def threshold(self, vectors: npt.NDArray, threshold: float) -> list[npt.NDArray]:
         """Query vectors within a distance threshold, using range_search if supported."""

vicinity/backends/hnsw.py

@@ -87,8 +87,7 @@ def insert(self, vectors: npt.NDArray) -> None:
 
     def delete(self, indices: list[int]) -> None:
         """Delete vectors from the backend."""
-        for index in indices:
-            self.index.mark_deleted(index)
+        raise NotImplementedError("Deletion is not supported in HNSW backend.")
 
     def threshold(self, vectors: npt.NDArray, threshold: float) -> list[npt.NDArray]:
         """Threshold the backend."""

vicinity/backends/pynndescent.py

@@ -69,11 +69,11 @@ def query(self, vectors: npt.NDArray, k: int) -> QueryResult:
 
     def insert(self, vectors: npt.NDArray) -> None:
         """Insert vectors into the index (not supported by pynndescent)."""
-        raise NotImplementedError("Dynamic insertion is not supported by pynndescent.")
+        raise NotImplementedError("Insertion is not supported by pynndescent.")
 
     def delete(self, indices: list[int]) -> None:
         """Delete vectors from the index (not supported by pynndescent)."""
-        raise NotImplementedError("Dynamic deletion is not supported by pynndescent.")
+        raise NotImplementedError("Deletion is not supported in pynndescent backend.")
 
     def threshold(self, vectors: npt.NDArray, threshold: float) -> list[npt.NDArray]:
         """Find neighbors within a distance threshold."""