--- a/mercurial/changelog.py Sat Sep 24 12:25:37 2016 -0700
+++ b/mercurial/changelog.py Thu Oct 13 12:50:27 2016 +0200
@@ -263,6 +263,12 @@
# changelogs don't benefit from generaldelta
self.version &= ~revlog.REVLOGGENERALDELTA
self._generaldelta = False
+
+ # Delta chains for changelogs tend to be very small because entries
+ # tend to be small and don't delta well with each. So disable delta
+ # chains.
+ self._storedeltachains = False
+
self._realopener = opener
self._delayed = False
self._delaybuf = None