Implemented list batching in cPickle.

pep-0307.txt

@@ -718,6 +718,20 @@ Protocol identification
     immediately.
 
 
+Pickling of large lists and dicts
+
+    Protocol 1 pickles large lists and dicts "in one piece", which
+    minimizes pickle size, but requires that unpickling create a temp
+    object as large as the object being unpickled.  Part of the
+    protocol 2 changes break large lists and dicts into pieces of no
+    more than 1000 elements each, so that unpickling needn't create
+    a temp object larger than needed to hold 1000 elements.  This
+    isn't part of protocol 2, however:  the opcodes produced are still
+    part of protocol 1.  __reduce__ implementations that return the
+    optional new listitems or dictitems iterators also benefit from
+    this unpickling temp-space optimization.
+
+
 Copyright
 
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