diff --git a/src/caosadvancedtools/cache.py b/src/caosadvancedtools/cache.py
index fcba542f0378574c483778fe8980e87b39999f76..9a3fe0fd975eeb393d78f5f0ece086607ef71afb 100644
--- a/src/caosadvancedtools/cache.py
+++ b/src/caosadvancedtools/cache.py
@@ -330,7 +330,7 @@ class UpdateCache(AbstractCache):
     """
 
     def get_cache_schema_version(self):
-        return 2
+        return 3
 
     def get_default_file_name(self):
         return "/tmp/crawler_update_cache.db"
@@ -382,8 +382,8 @@ class UpdateCache(AbstractCache):
     def create_cache(self):
         """ initialize the cache """
         self.run_sql_commands([
-            ('''CREATE TABLE updates (olddigest TEXT PRIMARY KEY, newdigest TEXT, oldrep TEXT,
-             newrep  TEXT, run_id TEXT)''',),
+            ('''CREATE TABLE updates (olddigest TEXT, newdigest TEXT, oldrep TEXT,
+             newrep  TEXT, run_id TEXT, primary key (olddigest, newdigest, run_id))''',),
             ('''CREATE TABLE version (schema INTEGER)''',),
             ("INSERT INTO version VALUES (?)", (self.get_cache_schema_version(),))])