deal db session in celery worker (#17549)

api/tasks/create_segment_to_index_task.py

@@ -5,7 +5,6 @@ from typing import Optional
 
 import click
 from celery import shared_task  # type: ignore
-from werkzeug.exceptions import NotFound
 
 from core.rag.index_processor.index_processor_factory import IndexProcessorFactory
 from core.rag.models.document import Document
@@ -27,7 +26,9 @@ def create_segment_to_index_task(segment_id: str, keywords: Optional[list[str]]
 
     segment = db.session.query(DocumentSegment).filter(DocumentSegment.id == segment_id).first()
     if not segment:
-        raise NotFound("Segment not found")
+        logging.info(click.style("Segment not found: {}".format(segment_id), fg="red"))
+        db.session.close()
+        return
 
     if segment.status != "waiting":
         return
@@ -93,3 +94,4 @@ def create_segment_to_index_task(segment_id: str, keywords: Optional[list[str]]
         db.session.commit()
     finally:
         redis_client.delete(indexing_cache_key)
+        db.session.close()