diff --git a/storage/hybrid/PML.txt b/storage/hybrid/PML.txt
index 2b6bc7c..7fd64c5 100644
--- a/storage/hybrid/PML.txt
+++ b/storage/hybrid/PML.txt
@@ -12,7 +12,8 @@ This is PML format:
 0: -
 1: -
 2: new session ID
-3: (key)|(val) - create and update DATA (key) only for delete key
+3: (key)|(val) - create and update DATA or (key) only for delete key
+key && val in format: [length (int64)][gob data bytes with this length]
 
 
 PML log file: