deepset-ai#1047 Remove count_documents from delete_documents

Removed the expensive check to see if the collection is non-empty by performing a full count.

This is to fix issue deepset-ai#1047

integrations/astra/src/haystack_integrations/document_stores/astra/astra_client.py

@@ -231,6 +231,24 @@ def find_documents(self, find_query):
         else:
             logger.warning(f"No documents found: {response_dict}")
 
+    def find_one_document(self, find_query):
+        """
+        Find one document in the Astra index.
+
+        :param find_query: a dictionary with the query options
+        :returns: the document found in the index
+        """
+        response_dict = self._astra_db_collection.find_one(
+            filter=find_query.get("filter"),
+            options=find_query.get("options"),
+            projection={"*": 1},
+        )
+
+        if "data" in response_dict and "document" in response_dict["data"]:
+            return response_dict["data"]["document"]
+        else:
+            logger.warning(f"No document found: {response_dict}")
+
     def get_documents(self, ids: List[str], batch_size: int = 20) -> QueryResponse:
         """
         Get documents from the Astra index by their ids.

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

@@ -411,8 +411,8 @@ def delete_documents(self, document_ids: Optional[List[str]] = None, delete_all:
         :param delete_all: if `True`, delete all documents.
         :raises MissingDocumentError: if no document was deleted but document IDs were provided.
         """
-        deletion_counter = 0
-        if self.index.count_documents() > 0:
+        if self.index.find_one_document({"filter": {}}) is not None:
+            deletion_counter = 0
             if document_ids is not None:
                 for batch in _batches(document_ids, MAX_BATCH_SIZE):
                     deletion_counter += self.index.delete(ids=batch)