diff --git a/tsdb/ooo_head.go b/tsdb/ooo_head.go
index d90163a18b..b2556d62e9 100644
--- a/tsdb/ooo_head.go
+++ b/tsdb/ooo_head.go
@@ -15,9 +15,10 @@ package tsdb
 
 import (
 	"fmt"
-	"github.com/prometheus/prometheus/tsdb/chunkenc"
 	"sort"
 
+	"github.com/prometheus/prometheus/tsdb/chunkenc"
+
 	"github.com/oklog/ulid"
 
 	"github.com/prometheus/prometheus/tsdb/chunks"