Github user srowen commented on a diff in the pull request:
https://github.com/apache/spark/pull/12233#discussion_r58833142
--- Diff: python/pyspark/context.py ---
@@ -428,15 +428,19 @@ def f(split, iterator):
# because it sends O(n) Py4J commands. As an alternative,
serialized
# objects are written to a file and loaded through textFile().
tempFile = NamedTemporaryFile(delete=False, dir=self._temp_dir)
- # Make sure we distribute data evenly if it's smaller than
self.batchSize
- if "__len__" not in dir(c):
- c = list(c) # Make it a list so we can compute its length
- batchSize = max(1, min(len(c) // numSlices, self._batchSize or
1024))
- serializer = BatchedSerializer(self._unbatched_serializer,
batchSize)
- serializer.dump_stream(c, tempFile)
- tempFile.close()
- readRDDFromFile = self._jvm.PythonRDD.readRDDFromFile
- jrdd = readRDDFromFile(self._jsc, tempFile.name, numSlices)
+ try:
+ # Make sure we distribute data evenly if it's smaller than
self.batchSize
+ if "__len__" not in dir(c):
+ c = list(c) # Make it a list so we can compute its
length
+ batchSize = max(1, min(len(c) // numSlices, self._batchSize or
1024))
+ serializer = BatchedSerializer(self._unbatched_serializer,
batchSize)
+ serializer.dump_stream(c, tempFile)
+ tempFile.close()
+ readRDDFromFile = self._jvm.PythonRDD.readRDDFromFile
+ jrdd = readRDDFromFile(self._jsc, tempFile.name, numSlices)
--- End diff --
So this reads the data into memory and parallelize-s it straight away --
seems right to delete the file then, yes. LGTM
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