* Store the size of a store path in the database (to be precise, the

size of the NAR serialisation of the path, i.e., `nix-store --dump
  PATH').  This is useful for Hydra.

src/libstore/remote-store.hh

@@ -29,6 +29,8 @@ public:
 
     PathSet queryValidPaths();
     
+    ValidPathInfo queryPathInfo(const Path & path);
+
     Hash queryPathHash(const Path & path);
 
     void queryReferences(const Path & path, PathSet & references);