Merge branch 'master' into selitvin/remove_legacy

docs/release-notes.rst

@@ -4,12 +4,17 @@
 Release notes
 =============
 
-Release 0.11.4 (unreleased)
+Release 0.11.5 (unreleased)
+===========================
+
+
+Release 0.11.4
 ===========================
 - `PR 730 <https://github.com/uber/petastorm/pull/730>`_ (resolves `PR 724 <https://github.com/uber/petastorm/issues/724>`_): Hadoop 3 support: allow more than 2 nodenames in hadoop configuration file.
 - `PR 731 <https://github.com/uber/petastorm/pull/731>`_ (resolves `PR 728 <https://github.com/uber/petastorm/issues/728>`_): Support passing multiple parquet dataset urls to make_reader.
 - `PR 732 <https://github.com/uber/petastorm/pull/732>`_ (resolves `PR 585 <https://github.com/uber/petastorm/issues/585>`_): Restructure process_pool implementation code in a way that resolves ``RuntimeWarning: 'petastorm.workers_pool.exec_in_new_process' found in sys.modules after
   import of package 'petastorm.workers_pool', but prior to execution of 'petastorm.workers_pool.exec_in_new_process'; this may result in unpredictable behaviou when using process pool`` warning.
+- `PR 737 <https://github.com/uber/petastorm/pull/737>`_: Use highest available pickle protocol for internal serialization.
 
 
 Release 0.11.3

petastorm/__init__.py

@@ -16,4 +16,4 @@
 from petastorm.reader import make_reader, make_batch_reader  # noqa: F401
 from petastorm.transform import TransformSpec  # noqa: F401
 
-__version__ = '0.11.3rc0'
+__version__ = '0.11.4'

petastorm/reader_impl/pickle_serializer.py

@@ -17,7 +17,7 @@
 class PickleSerializer(object):
 
     def serialize(self, rows):
-        return pickle.dumps(rows)
+        return pickle.dumps(rows, protocol=pickle.HIGHEST_PROTOCOL)
 
     def deserialize(self, serialized_rows):
         return pickle.loads(serialized_rows)