diff -r af8d8513d7de -r 44f5acfb9ad2 mercurial/revlog.py
--- a/mercurial/revlog.py	Mon Jul 09 09:50:23 2018 -0400
+++ b/mercurial/revlog.py	Fri Jun 22 01:42:38 2018 +0200
@@ -615,7 +615,7 @@
         # How much data to read and cache into the raw revlog data cache.
         self._chunkcachesize = 65536
         self._maxchainlen = None
-        self._aggressivemergedeltas = False
+        self._aggressivemergedeltas = True
         self.index = []
         # Mapping of partial identifiers to full nodes.
         self._pcache = {}