feat(qdrant): allow payload indexing

integrations/qdrant/src/haystack_integrations/document_stores/qdrant/document_store.py

@@ -84,6 +84,7 @@ def __init__(
         metadata: Optional[dict] = None,
         write_batch_size: int = 100,
         scroll_size: int = 10_000,
+        payload_field_to_index: Optional[List[dict]] = None,
     ):
         super().__init__()
 
@@ -130,9 +131,10 @@ def __init__(
         self.init_from = init_from
         self.wait_result_from_api = wait_result_from_api
         self.recreate_index = recreate_index
+        self.payload_field_to_index = payload_field_to_index
 
         # Make sure the collection is properly set up
-        self._set_up_collection(index, embedding_dim, recreate_index, similarity)
+        self._set_up_collection(index, embedding_dim, recreate_index, similarity, payload_field_to_index)
 
         self.embedding_dim = embedding_dim
         self.content_field = content_field
@@ -334,19 +336,35 @@ def _get_distance(self, similarity: str) -> rest.Distance:
             )
             raise QdrantStoreError(msg) from ke
 
+    def _create_payload_index(self, collection_name: str, payload_field_to_index: Optional[List[dict]] = None):
+        """
+        Create payload index for the collection if payload_field_to_index is provided
+        See: https://qdrant.tech/documentation/concepts/indexing/#payload-index
+        """
+        if payload_field_to_index is not None:
+            for payload_index in payload_field_to_index:
+                self.client.create_payload_index(
+                    collection_name=collection_name,
+                    field_name=payload_index["field_name"],
+                    field_schema=payload_index["field_schema"],
+                )
+
     def _set_up_collection(
         self,
         collection_name: str,
         embedding_dim: int,
         recreate_collection: bool,  # noqa: FBT001
         similarity: str,
+        payload_field_to_index: Optional[List[dict]] = None,
     ):
         distance = self._get_distance(similarity)
 
         if recreate_collection:
             # There is no need to verify the current configuration of that
             # collection. It might be just recreated again.
             self._recreate_collection(collection_name, distance, embedding_dim)
+            # Create Payload index if payload_field_to_index is provided
+            self._create_payload_index(collection_name, payload_field_to_index)
             return
 
         try:
@@ -361,6 +379,8 @@ def _set_up_collection(
             # with the remote server UnexpectedResponse / RpcError is raised.
             # Until that's unified, we need to catch both.
             self._recreate_collection(collection_name, distance, embedding_dim)
+            # Create Payload index if payload_field_to_index is provided
+            self._create_payload_index(collection_name, payload_field_to_index)
             return
 
         current_distance = collection_info.config.params.vectors.distance