diff --git a/src/policy_cache.hpp b/src/policy_cache.hpp
index 6208ea86..1141a4cf 100644
--- a/src/policy_cache.hpp
+++ b/src/policy_cache.hpp
@@ -79,6 +79,7 @@ public:
   }
 
 private:
-  unsigned _max_size;
-  Map      _cache;
+  unsigned  _max_size;
+  Map       _cache;
+  strpool_t _strpool;
 };