diff --git a/lib/galaxy/tools/data/__init__.py b/lib/galaxy/tools/data/__init__.py
index 6c05b60ccb1..e4a13d0e207 100644
--- a/lib/galaxy/tools/data/__init__.py
+++ b/lib/galaxy/tools/data/__init__.py
@@ -624,13 +624,13 @@ class TabularToolDataTable(ToolDataTable, Dictifiable):
                 except IOError as e:
                     log.warning('Error opening data table file (%s) with r+b, assuming file does not exist and will open as wb: %s', filename, e)
                     data_table_fh = open(filename, 'wb')
-                if os.stat(filename)[6] != 0:
+                if os.stat(filename).st_size != 0:
                     # ensure last existing line ends with new line
                     data_table_fh.seek(-1, 2)  # last char in file
                     last_char = data_table_fh.read(1)
                     if last_char not in [b'\n', b'\r']:
                         data_table_fh.write(b'\n')
-                    fields = "%s\n" % self.separator.join(fields)
+                fields = "%s\n" % self.separator.join(fields)
                 data_table_fh.write(fields.encode('utf-8'))
         return not is_error