4a377aff2d
This patch will bring support for broadcasting objects larger than 2G. pickle, zlib, FrameSerializer and Array[Byte] all can not support objects larger than 2G, so this patch introduce LargeObjectSerializer to serialize broadcast objects, the object will be serialized and compressed into small chunks, it also change the type of Broadcast[Array[Byte]]] into Broadcast[Array[Array[Byte]]]]. Testing for support broadcast objects larger than 2G is slow and memory hungry, so this is tested manually, could be added into SparkPerf. Author: Davies Liu <davies@databricks.com> Author: Davies Liu <davies.liu@gmail.com> Closes #2659 from davies/huge and squashes the following commits: 7b57a14 [Davies Liu] add more tests for broadcast 28acff9 [Davies Liu] Merge branch 'master' of github.com:apache/spark into huge a2f6a02 [Davies Liu] bug fix 4820613 [Davies Liu] Merge branch 'master' of github.com:apache/spark into huge 5875c73 [Davies Liu] address comments 10a349b [Davies Liu] address comments 0c33016 [Davies Liu] Merge branch 'master' of github.com:apache/spark into huge 6182c8f [Davies Liu] Merge branch 'master' into huge d94b68f [Davies Liu] Merge branch 'master' of github.com:apache/spark into huge 2514848 [Davies Liu] address comments fda395b [Davies Liu] Merge branch 'master' of github.com:apache/spark into huge 1c2d928 [Davies Liu] fix scala style 091b107 [Davies Liu] broadcast objects larger than 2G
95 lines
2.8 KiB
Python
95 lines
2.8 KiB
Python
#
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# Licensed to the Apache Software Foundation (ASF) under one or more
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# contributor license agreements. See the NOTICE file distributed with
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# this work for additional information regarding copyright ownership.
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# The ASF licenses this file to You under the Apache License, Version 2.0
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# (the "License"); you may not use this file except in compliance with
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# the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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"""
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>>> from pyspark.context import SparkContext
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>>> sc = SparkContext('local', 'test')
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>>> b = sc.broadcast([1, 2, 3, 4, 5])
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>>> b.value
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[1, 2, 3, 4, 5]
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>>> sc.parallelize([0, 0]).flatMap(lambda x: b.value).collect()
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[1, 2, 3, 4, 5, 1, 2, 3, 4, 5]
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>>> b.unpersist()
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>>> large_broadcast = sc.broadcast(list(range(10000)))
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"""
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import os
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from pyspark.serializers import LargeObjectSerializer
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__all__ = ['Broadcast']
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# Holds broadcasted data received from Java, keyed by its id.
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_broadcastRegistry = {}
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def _from_id(bid):
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from pyspark.broadcast import _broadcastRegistry
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if bid not in _broadcastRegistry:
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raise Exception("Broadcast variable '%s' not loaded!" % bid)
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return _broadcastRegistry[bid]
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class Broadcast(object):
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"""
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A broadcast variable created with
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L{SparkContext.broadcast()<pyspark.context.SparkContext.broadcast>}.
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Access its value through C{.value}.
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"""
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def __init__(self, bid, value, java_broadcast=None,
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pickle_registry=None, path=None):
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"""
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Should not be called directly by users -- use
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L{SparkContext.broadcast()<pyspark.context.SparkContext.broadcast>}
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instead.
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"""
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self.bid = bid
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if path is None:
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self._value = value
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self._jbroadcast = java_broadcast
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self._pickle_registry = pickle_registry
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self.path = path
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@property
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def value(self):
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""" Return the broadcasted value
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"""
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if not hasattr(self, "_value") and self.path is not None:
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ser = LargeObjectSerializer()
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self._value = ser.load_stream(open(self.path)).next()
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return self._value
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def unpersist(self, blocking=False):
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"""
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Delete cached copies of this broadcast on the executors.
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"""
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self._jbroadcast.unpersist(blocking)
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os.unlink(self.path)
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def __reduce__(self):
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self._pickle_registry.add(self)
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return (_from_id, (self.bid, ))
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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