diff --git a/src/command_line.cc b/src/command_line.cc
index 5caff871..6d2b66ad 100644
--- a/src/command_line.cc
+++ b/src/command_line.cc
@@ -917,6 +917,7 @@ bool IndexMain_DoCreateIndexUpdate(
   IdMap* previous_id_map = nullptr;
   IndexFile* previous_index = nullptr;
   if (response->previous) {
+    LOG_S(INFO) << "Creating delta update for " << response->previous->file->path;
     previous_id_map = response->previous->ids.get();
     previous_index = response->previous->file.get();
   }