diff --git a/libs/libzkutil/include/zkutil/ZooKeeper.h b/libs/libzkutil/include/zkutil/ZooKeeper.h
index 7344b813719..fd9d9879004 100644
--- a/libs/libzkutil/include/zkutil/ZooKeeper.h
+++ b/libs/libzkutil/include/zkutil/ZooKeeper.h
@@ -12,6 +12,7 @@ namespace zkutil
 {
 
 const UInt32 DEFAULT_SESSION_TIMEOUT = 30000;
+const UInt32 MEDIUM_SESSION_TIMEOUT = 120000;
 const UInt32 BIG_SESSION_TIMEOUT = 600000;
 const UInt32 DEFAULT_RETRY_NUM = 3;