diff --git a/src/opserver/opserver.py b/src/opserver/opserver.py
index 8bccd19931c..9b34c8e3465 100644
--- a/src/opserver/opserver.py
+++ b/src/opserver/opserver.py
@@ -133,7 +133,7 @@ def redis_query_start(host, port, redis_password, qid, inp, columns):
     if columns is not None:
         for col in columns:
             m = TableSchema(name = col.name, datatype = col.datatype, index = col.index, suffixes = col.suffixes)
-            col_list.append(m.__dict__)
+            col_list.append(m._asdict())
     query_metadata = {}
     query_metadata['enqueue_time'] = OpServerUtils.utc_timestamp_usec()
     redish.hset("QUERY:" + qid, 'query_metadata', json.dumps(query_metadata))