diff --git a/datasette/app.py b/datasette/app.py
index 460464ab..ceb987e4 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -130,6 +130,10 @@ class ConnectedDatabase:
             self.hash = inspect_hash(p)
             self.size = p.stat().st_size
 
+    @property
+    def mtime_ns(self):
+        return Path(self.path).stat().st_mtime_ns
+
     @property
     def name(self):
         if self.is_memory: