diff --git a/job_controller/jobs/source_file_sorter/job.py b/job_controller/jobs/source_file_sorter/job.py
index 0bba22aa06e6b46f8b2af831efa4e86c6ab87ad4..a532c7d98c1230fa6ff65d4da1ee9aa13555ce78 100644
--- a/job_controller/jobs/source_file_sorter/job.py
+++ b/job_controller/jobs/source_file_sorter/job.py
@@ -292,6 +292,8 @@ def execute(database, own_job_id, input_data: CJsonObject):
         try:
             database.execute_write_transaction_and_commit(
                 _sort_file, own_job_id, db_path, on_transaction_failure,
+                isolation_level=TransactionIsolationLevel.REPEATABLE_READ
+                # Repeatable read as serializable often causes serialization conflicts
             )
         except Exception:
             if on_transaction_failure.func is not None: