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author | Erik Selin <erik.selin@jadedpixel.com> | 2014-06-03 13:31:16 -0700 |
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committer | Matei Zaharia <matei@databricks.com> | 2014-06-03 13:31:16 -0700 |
commit | 8edc9d0330c94b50e01956ae88693cff4e0977b2 (patch) | |
tree | 6adf5d8d5e416f5ce80647006f434bbd2802fa18 | |
parent | b1f285359a12345d94ae59f979d9a75482e732ce (diff) | |
download | spark-8edc9d0330c94b50e01956ae88693cff4e0977b2.tar.gz spark-8edc9d0330c94b50e01956ae88693cff4e0977b2.tar.bz2 spark-8edc9d0330c94b50e01956ae88693cff4e0977b2.zip |
[SPARK-1468] Modify the partition function used by partitionBy.
Make partitionBy use a tweaked version of hash as its default partition function
since the python hash function does not consistently assign the same value
to None across python processes.
Associated JIRA at https://issues.apache.org/jira/browse/SPARK-1468
Author: Erik Selin <erik.selin@jadedpixel.com>
Closes #371 from tyro89/consistent_hashing and squashes the following commits:
201c301 [Erik Selin] Make partitionBy use a tweaked version of hash as its default partition function since the python hash function does not consistently assign the same value to None across python processes.
-rw-r--r-- | python/pyspark/rdd.py | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/python/pyspark/rdd.py b/python/pyspark/rdd.py index f3b1f1a665..1b3c460dd6 100644 --- a/python/pyspark/rdd.py +++ b/python/pyspark/rdd.py @@ -1062,7 +1062,7 @@ class RDD(object): return python_right_outer_join(self, other, numPartitions) # TODO: add option to control map-side combining - def partitionBy(self, numPartitions, partitionFunc=hash): + def partitionBy(self, numPartitions, partitionFunc=None): """ Return a copy of the RDD partitioned using the specified partitioner. @@ -1073,6 +1073,9 @@ class RDD(object): """ if numPartitions is None: numPartitions = self.ctx.defaultParallelism + + if partitionFunc is None: + partitionFunc = lambda x: 0 if x is None else hash(x) # Transferring O(n) objects to Java is too expensive. Instead, we'll # form the hash buckets in Python, transferring O(numPartitions) objects # to Java. Each object is a (splitNumber, [objects]) pair. |