--- a/mercurial/changelog.py	Wed May 17 23:01:56 2017 +0900
+++ b/mercurial/changelog.py	Wed May 17 20:14:27 2017 -0700
@@ -273,7 +273,9 @@
         else:
             indexfile = '00changelog.i'
 
-        revlog.revlog.__init__(self, opener, indexfile, checkambig=True)
+        datafile = '00changelog.d'
+        revlog.revlog.__init__(self, opener, indexfile, datafile=datafile,
+                               checkambig=True)
 
         if self._initempty:
             # changelogs don't benefit from generaldelta