diff --git a/library/Director/Data/Db/DbObject.php b/library/Director/Data/Db/DbObject.php
index 733166f9..c4f0b8b8 100644
--- a/library/Director/Data/Db/DbObject.php
+++ b/library/Director/Data/Db/DbObject.php
@@ -966,4 +966,10 @@ abstract class DbObject
         $obj->setConnection($connection)->setKey($id);
         return $obj->existsInDb();
     }
+
+    public function __destruct()
+    {
+        unset($this->db);
+        unset($this->connection);
+    }
 }
diff --git a/library/Director/Objects/IcingaObject.php b/library/Director/Objects/IcingaObject.php
index 31f69449..4162b6dc 100644
--- a/library/Director/Objects/IcingaObject.php
+++ b/library/Director/Objects/IcingaObject.php
@@ -1125,4 +1125,17 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
             }
         }
     }
+
+    public function __destruct()
+    {
+        unset($this->resolveCache);
+        unset($this->vars);
+        unset($this->groups);
+        unset($this->imports);
+        unset($this->ranges);
+        unset($this->arguments);
+
+
+        parent::__destruct();
+    }
 }