--- a/mercurial/revlogutils/deltas.py	Fri Dec 21 15:31:16 2018 +0300
+++ b/mercurial/revlogutils/deltas.py	Wed Dec 19 10:54:25 2018 +0100
@@ -604,7 +604,7 @@
 # If a revision's full text is that much bigger than a base candidate full
 # text's, it is very unlikely that it will produce a valid delta. We no longer
 # consider these candidates.
-LIMIT_BASE2TEXT = 50
+LIMIT_BASE2TEXT = 500
 
 def _candidategroups(revlog, textlen, p1, p2, cachedelta):
     """Provides group of revision to be tested as delta base