enforce index attempt deduping on secondary indexing. (#2054)

* enforce index attempt deduping on secondary indexing.

* black fix

* typo fixes

---------

Co-authored-by: Richard Kuo <rkuo@rkuo.com>

backend/danswer/background/celery/celery_app.py

@@ -103,7 +103,7 @@ def cleanup_connector_credential_pair_task(
 @build_celery_task_wrapper(name_cc_prune_task)
 @celery_app.task(soft_time_limit=JOB_TIMEOUT)
 def prune_documents_task(connector_id: int, credential_id: int) -> None:
-    """connector pruning task. For a cc pair, this task pulls all docuement IDs from the source
+    """connector pruning task. For a cc pair, this task pulls all document IDs from the source
     and compares those IDs to locally stored documents and deletes all locally stored IDs missing
     from the most recently pulled document ID list"""
     with Session(get_sqlalchemy_engine()) as db_session:

backend/danswer/background/update.py

@@ -72,10 +72,18 @@ def _should_create_new_indexing(
     # When switching over models, always index at least once
     if model.status == IndexModelStatus.FUTURE:
         if last_index:
-            # secondary indexes should not index again after success
-            # or else the model will never be able to swap
+            # No new index if the last index attempt succeeded
+            # Once is enough. The model will never be able to swap otherwise.
             if last_index.status == IndexingStatus.SUCCESS:
                 return False
+
+            # No new index if the last index attempt is waiting to start
+            if last_index.status == IndexingStatus.NOT_STARTED:
+                return False
+
+            # No new index if the last index attempt is running
+            if last_index.status == IndexingStatus.IN_PROGRESS:
+                return False
         else:
             if connector.id == 0:  # Ingestion API
                 return False

backend/danswer/db/document_set.py

@@ -277,7 +277,7 @@ def mark_cc_pair__document_set_relationships_to_be_deleted__no_commit(
     `cc_pair_id` as not current and returns the list of all document set IDs
     affected.
 
-    NOTE: rases a `ValueError` if any of the document sets are currently syncing
+    NOTE: raises a `ValueError` if any of the document sets are currently syncing
     to avoid getting into a bad state."""
     document_set__cc_pair_relationships = db_session.scalars(
         select(DocumentSet__ConnectorCredentialPair).where(