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https://issues.apache.org/jira/browse/SPARK-12717?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16092756#comment-16092756
]
Maciej Bryński commented on SPARK-12717:
----------------------------------------
Any progress with this error ?
I have patched from this thread merged and it's working fine.
Maybe we can merge this to master? (and other branches)
> pyspark broadcast fails when using multiple threads
> ---------------------------------------------------
>
> Key: SPARK-12717
> URL: https://issues.apache.org/jira/browse/SPARK-12717
> Project: Spark
> Issue Type: Bug
> Components: PySpark
> Affects Versions: 1.6.0
> Environment: Linux, python 2.6 or python 2.7.
> Reporter: Edward Walker
> Priority: Critical
> Attachments: run.log
>
>
> The following multi-threaded program that uses broadcast variables
> consistently throws exceptions like: *Exception("Broadcast variable '18' not
> loaded!",)* --- even when run with "--master local[10]".
> {code:title=bug_spark.py|borderStyle=solid}
> try:
>
> import pyspark
>
> except:
>
> pass
>
> from optparse import OptionParser
>
>
>
> def my_option_parser():
>
> op = OptionParser()
>
> op.add_option("--parallelism", dest="parallelism", type="int",
> default=20)
> return op
>
>
>
> def do_process(x, w):
>
> return x * w.value
>
>
>
> def func(name, rdd, conf):
>
> new_rdd = rdd.map(lambda x : do_process(x, conf))
>
> total = new_rdd.reduce(lambda x, y : x + y)
>
> count = rdd.count()
>
> print name, 1.0 * total / count
>
>
>
> if __name__ == "__main__":
>
> import threading
>
> op = my_option_parser()
>
> options, args = op.parse_args()
>
> sc = pyspark.SparkContext(appName="Buggy")
>
> data_rdd = sc.parallelize(range(0,1000), 1)
>
> confs = [ sc.broadcast(i) for i in xrange(options.parallelism) ]
>
> threads = [ threading.Thread(target=func, args=["thread_" + str(i),
> data_rdd, confs[i]]) for i in xrange(options.parallelism) ]
>
> for t in threads:
>
> t.start()
>
> for t in threads:
>
> t.join()
> {code}
> Abridged run output:
> {code:title=abridge_run.txt|borderStyle=solid}
> % spark-submit --master local[10] bug_spark.py --parallelism 20
> [snip]
> 16/01/08 17:10:20 ERROR Executor: Exception in task 0.0 in stage 9.0 (TID 9)
> org.apache.spark.api.python.PythonException: Traceback (most recent call
> last):
> File
> "/Network/Servers/mother.adverplex.com/Volumes/homeland/Users/walker/.spark/spark-1.6.0-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/worker.py",
> line 98, in main
> command = pickleSer._read_with_length(infile)
> File
> "/Network/Servers/mother.adverplex.com/Volumes/homeland/Users/walker/.spark/spark-1.6.0-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/serializers.py",
> line 164, in _read_with_length
> return self.loads(obj)
> File
> "/Network/Servers/mother.adverplex.com/Volumes/homeland/Users/walker/.spark/spark-1.6.0-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/serializers.py",
> line 422, in loads
> return pickle.loads(obj)
> File
> "/Network/Servers/mother.adverplex.com/Volumes/homeland/Users/walker/.spark/spark-1.6.0-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/broadcast.py",
> line 39, in _from_id
> raise Exception("Broadcast variable '%s' not loaded!" % bid)
> Exception: (Exception("Broadcast variable '6' not loaded!",), <function
> _from_id at 0xce7a28>, (6L,))
> at
> org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRDD.scala:166)
> at
> org.apache.spark.api.python.PythonRunner$$anon$1.<init>(PythonRDD.scala:207)
> at org.apache.spark.api.python.PythonRunner.compute(PythonRDD.scala:125)
> at org.apache.spark.api.python.PythonRDD.compute(PythonRDD.scala:70)
> at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
> at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
> at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66)
> at org.apache.spark.scheduler.Task.run(Task.scala:89)
> at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:213)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:745)
> [snip]
> {code}
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