diff --git a/python/biopro/server/database.py b/python/biopro/server/database.py
index 5e8fd99..cbe091a 100644
--- a/python/biopro/server/database.py
+++ b/python/biopro/server/database.py
@@ -364,15 +364,13 @@ class DataBaseProcess(Process):
         with self._psql_conn as conn:
             with self._psql_conn.cursor() as sql_cursor:
                 for _channel in _channel_list:
-                    compressed_value = _data_dict[_channel] + '"***"'
                     sql_str = 'UPDATE "public"."' + str(_channel) + '_recording_data_raws" SET data = concat(data, %s) where id = %s'
-                    sql_set = [compressed_value, _id_dict[_channel]]
-
+                    sql_set = [_data_dict[_channel] + '"***"', _id_dict[_channel]]
                     sql_cursor.execute(sql_str, sql_set)
-
-                    del _data_dict[_channel]
-                    del compressed_value
-                    gc.collect()
+        
+        for _channel in _channel_list:
+            del _data_dict[_channel]
+        gc.collect()
 
         return None