diff --git a/daemon/table/measurements.hpp b/daemon/table/measurements.hpp
index 1ace0b9..7478c58 100644
--- a/daemon/table/measurements.hpp
+++ b/daemon/table/measurements.hpp
@@ -86,7 +86,7 @@
    *  The entry will be kept until at least now()+lifetime.
    */
   void
-  extendLifetime(measurements::Entry& entry, const time::nanoseconds& lifetime);
+  extendLifetime(shared_ptr<measurements::Entry> entry, const time::nanoseconds& lifetime);
 
   size_t
   size() const;