diff --git a/ckan/lib/search/index.py b/ckan/lib/search/index.py
index bbf35f8d4a8..58344f20d01 100644
--- a/ckan/lib/search/index.py
+++ b/ckan/lib/search/index.py
@@ -13,6 +13,7 @@
 import pysolr
 from ckan.common import config
 from ckan.common import asbool
+import six
 from six import text_type
 from six.moves import map