diff --git a/runtime/vam/op/hashjoin.go b/runtime/vam/op/hashjoin.go
index ce30a22bc..2c56385a6 100644
--- a/runtime/vam/op/hashjoin.go
+++ b/runtime/vam/op/hashjoin.go
@@ -280,7 +280,7 @@ func (j *hashJoin) wrap(l, r *super.Value) super.Value {
 	if j.style == "right" {
 		l, r = r, l
 	}
-	j.builder.Reset()
+	j.builder.Truncate()
 	var fields []super.Field
 	if l != nil {
 		left := l.Deunion()