diff --git a/api/controllers/console/datasets/datasets_document.py b/api/controllers/console/datasets/datasets_document.py
index 242ce9e3ee..f36573ebd1 100644
--- a/api/controllers/console/datasets/datasets_document.py
+++ b/api/controllers/console/datasets/datasets_document.py
@@ -1462,9 +1462,6 @@ class DocumentSummaryStatusApi(DocumentResource):
         dataset_id = str(dataset_id)
         document_id = str(document_id)
 
-        # Get document
-        document = self.get_document(dataset_id, document_id)
-
         # Get dataset
         dataset = DatasetService.get_dataset(dataset_id)
         if not dataset:
diff --git a/api/controllers/console/datasets/datasets_segments.py b/api/controllers/console/datasets/datasets_segments.py
index 77d0c94be1..c88cf1f71d 100644
--- a/api/controllers/console/datasets/datasets_segments.py
+++ b/api/controllers/console/datasets/datasets_segments.py
@@ -43,7 +43,7 @@ from tasks.batch_create_segment_to_index_task import batch_create_segment_to_ind
 
 def _get_segment_with_summary(segment, dataset_id):
     """Helper function to marshal segment and add summary information."""
-    segment_dict = marshal(segment, segment_fields)
+    segment_dict = dict(marshal(segment, segment_fields))
     # Query summary for this segment (only enabled summaries)
     summary = (
         db.session.query(DocumentSegmentSummary)
@@ -219,7 +219,7 @@ class DatasetDocumentSegmentListApi(Resource):
         # Add summary to each segment
         segments_with_summary = []
         for segment in segments.items:
-            segment_dict = marshal(segment, segment_fields)
+            segment_dict = dict(marshal(segment, segment_fields))
             segment_dict["summary"] = summaries.get(segment.id)
             segments_with_summary.append(segment_dict)
 
diff --git a/api/core/workflow/nodes/knowledge_index/knowledge_index_node.py b/api/core/workflow/nodes/knowledge_index/knowledge_index_node.py
index abc2575600..b88c2d510f 100644
--- a/api/core/workflow/nodes/knowledge_index/knowledge_index_node.py
+++ b/api/core/workflow/nodes/knowledge_index/knowledge_index_node.py
@@ -229,9 +229,6 @@ class KnowledgeIndexNode(Node[KnowledgeIndexNodeData]):
         invoke_from = variable_pool.get(["sys", SystemVariableKey.INVOKE_FROM])
         is_preview = invoke_from and invoke_from.value == InvokeFrom.DEBUGGER
 
-        # Determine if only parent chunks should be processed
-        only_parent_chunks = dataset.chunk_structure == "parent_child_index"
-
         if is_preview:
             try:
                 # Query segments that need summary generation
diff --git a/api/services/summary_index_service.py b/api/services/summary_index_service.py
index e59ba4c378..2ac6f10d29 100644
--- a/api/services/summary_index_service.py
+++ b/api/services/summary_index_service.py
@@ -216,7 +216,7 @@ class SummaryIndexService:
                 db.session.add(summary_record)
                 db.session.flush()
                 # Success, exit function
-                return
+                return 
 
             except (ConnectionError, Exception) as e:
                 error_str = str(e).lower()
@@ -333,7 +333,9 @@ class SummaryIndexService:
             error: Error message
         """
         summary_record = (
-            db.session.query(DocumentSegmentSummary).filter_by(chunk_id=segment.id, dataset_id=dataset.id).first()
+            db.session.query(DocumentSegmentSummary)
+            .filter_by(chunk_id=segment.id, dataset_id=dataset.id)
+            .first()
         )
 
         if summary_record:
@@ -342,7 +344,9 @@ class SummaryIndexService:
             db.session.add(summary_record)
             db.session.flush()
         else:
-            logger.warning("Summary record not found for segment %s when updating error", segment.id)
+            logger.warning(
+                "Summary record not found for segment %s when updating error", segment.id
+            )
 
     @staticmethod
     def generate_and_vectorize_summary(
@@ -367,12 +371,16 @@ class SummaryIndexService:
         """
         # Get existing summary record (should have been created by batch_create_summary_records)
         summary_record = (
-            db.session.query(DocumentSegmentSummary).filter_by(chunk_id=segment.id, dataset_id=dataset.id).first()
+            db.session.query(DocumentSegmentSummary)
+            .filter_by(chunk_id=segment.id, dataset_id=dataset.id)
+            .first()
         )
 
         if not summary_record:
             # If not found (shouldn't happen), create one
-            logger.warning("Summary record not found for segment %s, creating one", segment.id)
+            logger.warning(
+                "Summary record not found for segment %s, creating one", segment.id
+            )
             summary_record = SummaryIndexService.create_summary_record(
                 segment, dataset, summary_content="", status="generating"
             )
@@ -804,7 +812,7 @@ class SummaryIndexService:
                 logger.info("Successfully created and vectorized summary for segment %s", segment.id)
                 return summary_record
 
-        except Exception:
+        except Exception as e:
             logger.exception("Failed to update summary for segment %s", segment.id)
             # Update summary record with error status if it exists
             summary_record = (
diff --git a/api/tasks/generate_summary_index_task.py b/api/tasks/generate_summary_index_task.py
index 99f957abaa..b0efd1d976 100644
--- a/api/tasks/generate_summary_index_task.py
+++ b/api/tasks/generate_summary_index_task.py
@@ -94,7 +94,7 @@ def generate_summary_index_task(dataset_id: str, document_id: str, segment_ids:
             )
         )
 
-    except Exception:
+    except Exception as e:
         logger.exception("Failed to generate summary index for document %s", document_id)
         # Update document segments with error status if needed
         if segment_ids:
diff --git a/api/tasks/regenerate_summary_index_task.py b/api/tasks/regenerate_summary_index_task.py
index 2c688652d2..f746036404 100644
--- a/api/tasks/regenerate_summary_index_task.py
+++ b/api/tasks/regenerate_summary_index_task.py
@@ -245,6 +245,7 @@ def regenerate_summary_index_task(
                     )
 
                     for segment in segments:
+                        summary_record = None
                         try:
                             # Get existing summary record
                             summary_record = (