diff --git a/td/telegram/files/FileLocation.h b/td/telegram/files/FileLocation.h
index 9c98664d6..67bd63199 100644
--- a/td/telegram/files/FileLocation.h
+++ b/td/telegram/files/FileLocation.h
@@ -989,6 +989,12 @@ inline bool operator!=(const PartialLocalFileLocation &lhs, const PartialLocalFi
   return !(lhs == rhs);
 }
 
+inline StringBuilder &operator<<(StringBuilder &sb, const PartialLocalFileLocation &location) {
+  return sb << "[partial local location of " << location.file_type_ << " with part size " << location.part_size_
+            << " and ready parts " << Bitmask(Bitmask::Decode{}, location.ready_bitmask_) << "] at \"" << location.path_
+            << '"';
+}
+
 struct FullLocalFileLocation {
   FileType file_type_;
   string path_;
diff --git a/td/telegram/files/FileManager.cpp b/td/telegram/files/FileManager.cpp
index d75a5356e..386285b34 100644
--- a/td/telegram/files/FileManager.cpp
+++ b/td/telegram/files/FileManager.cpp
@@ -2313,7 +2313,8 @@ void FileManager::on_partial_download(QueryId query_id, const PartialLocalFileLo
 
   auto file_id = query->file_id_;
   auto file_node = get_file_node(file_id);
-  LOG(DEBUG) << "Receive on_partial_download for file " << file_id;
+  LOG(DEBUG) << "Receive on_partial_download for file " << file_id << " with " << partial_local
+             << ", ready_size = " << ready_size << " and size = " << size;
   if (!file_node) {
     return;
   }