diff --git a/CHANGELOG b/CHANGELOG
index 3d87e130..c840cdb4 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+ALTER TABLE `sample_var` ADD INDEX ( `var_id` );
+
 queXS 1.15.10 - Changes since 1.15.9
 
 Fixes some bugs including optimising the questionnaire outcome page queries. Translations have also been updated (Thank you!)
diff --git a/database/quexs.sql b/database/quexs.sql
index 96d52047..965045a8 100644
--- a/database/quexs.sql
+++ b/database/quexs.sql
@@ -1499,7 +1499,8 @@ CREATE TABLE `sample_var` (
   `var_id` bigint(20) unsigned NOT NULL,
   `val` varchar(256) COLLATE utf8_unicode_ci NOT NULL,
   PRIMARY KEY (`sample_id`,`var_id`),
-  KEY `sample_id` (`sample_id`)
+  KEY `sample_id` (`sample_id`),
+  KEY `var_id` (`var_id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
 
 -- --------------------------------------------------------