diff --git a/storage/tsdb/tsdb.go b/storage/tsdb/tsdb.go
index e580d0a65..7cc8294dd 100644
--- a/storage/tsdb/tsdb.go
+++ b/storage/tsdb/tsdb.go
@@ -167,6 +167,7 @@ func (a adapter) StartTime() (int64, error) {
 			return startTime, err
 		}
 	}
+	defer indexr.Close()
 
 	joblabel := "job"
 	tpls, err := indexr.LabelValues(joblabel)