diff --git a/arcaflow_plugin_opensearch/opensearch_plugin.py b/arcaflow_plugin_opensearch/opensearch_plugin.py
index cf1addf..587392a 100644
--- a/arcaflow_plugin_opensearch/opensearch_plugin.py
+++ b/arcaflow_plugin_opensearch/opensearch_plugin.py
@@ -46,7 +46,8 @@ def process_bulk_list_generator():
             yield operation
             doc = item[1]
             # Append the global metadata to the document
-            doc.update(params.metadata)
+            if params.metadata:
+                doc.update(params.metadata)
             yield doc
 
     if params.username: