--- a/bench.py	Sat May 23 17:10:09 2015 +0800
+++ b/bench.py	Sat May 23 17:34:12 2015 +0800
@@ -170,7 +170,7 @@
     conn.execute(
         'CREATE INDEX IF NOT EXISTS idx_results_node ON results (node)')
     conn.execute(
-        'CREATE INDEX IF NOT EXISTS idx_results_mark_cache ON results (mark, cache)')
+        'CREATE INDEX IF NOT EXISTS idx_results_limits ON results (mark, cache, time ASC)')
     conn.commit()
     conn.close()