diff -r 9552f8af321e Lib/re.py
--- a/Lib/re.py	Wed Sep 28 07:53:32 2016 +0300
+++ b/Lib/re.py	Wed Sep 28 09:11:57 2016 +0300
@@ -128,6 +128,13 @@ try:
 except ImportError:
     _locale = None
 
+# try _collections first to reduce startup cost
+try:
+    from _collections import OrderedDict
+except ImportError:
+    from collections import OrderedDict
+
+
 # public symbols
 __all__ = [
     "match", "fullmatch", "search", "sub", "subn", "split",
@@ -278,7 +285,7 @@ def escape(pattern):
 # --------------------------------------------------------------------
 # internals
 
-_cache = {}
+_cache = OrderedDict()
 
 _pattern_type = type(sre_compile.compile("", 0))
 
@@ -301,7 +308,9 @@ def _compile(pattern, flags):
     p = sre_compile.compile(pattern, flags)
     if not (flags & DEBUG):
         if len(_cache) >= _MAXCACHE:
-            _cache.clear()
+            for k in _cache:
+                del _cache[k]
+                break
         if p.flags & LOCALE:
             if not _locale:
                 return p