An attribute error comes up when I try to parallelize a function in python in Databricks. The original code is quite large, but I simpled it down to a following setting:
I have a notebook with class car, which has a function get_colour():
class car:
def __init__(self,colour):
self.colour=colour
def get_colour(self):
return self.colour
I import this class into databricks by using %run directory/car, and then run the following script in my main script:
colours= ['grey','black']
cars= [car(col) for col in colours]
def func(car):
return car.get_colour()
workers= sc.parallelize(cars)
work = workers.map(func)
result = work.collect()
The function func() works properly, e.g. func(cars[0]) returns ''grey'' but I get an error on the last line:
org.apache.spark.SparkException: Job aborted due to stage failure: Task 7 in stage 3174.0 failed 4 times, most recent failure: Lost task 7.3 in stage 3174.0 (TID 42178) (10.75.129.14 executor 0): org.apache.spark.api.python.PythonException:
'pyspark.serializers.SerializationError: Caused by Traceback (most recent call last):
Py4JJavaError Traceback (most recent call last)
<command-4237662788496550> in <module>
9 workers= sc.parallelize(cars)
10 work = workers.map(func)
---> 11 result = work.collect()
/databricks/spark/python/pyspark/rdd.py in collect(self)
965 # Default path used in OSS Spark / for non-credential passthrough clusters:
966 with SCCallSiteSync(self.context) as css:
--> 967 sock_info = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
968 return list(_load_from_socket(sock_info, self._jrdd_deserializer))
969
/databricks/spark/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py in __call__(self, *args)
1302
1303 answer = self.gateway_client.send_command(command)
-> 1304 return_value = get_return_value(
1305 answer, self.gateway_client, self.target_id, self.name)
1306
/databricks/spark/python/pyspark/sql/utils.py in deco(*a, **kw)
115 def deco(*a, **kw):
116 try:
--> 117 return f(*a, **kw)
118 except py4j.protocol.Py4JJavaError as e:
119 converted = convert_exception(e.java_exception)
/databricks/spark/python/lib/py4j-0.10.9-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name)
324 value = OUTPUT_CONVERTER[type](answer[2:], gateway_client)
325 if answer[1] == REFERENCE_TYPE:
--> 326 raise Py4JJavaError(
327 "An error occurred while calling {0}{1}{2}.\n".
328 format(target_id, ".", name), value)
Py4JJavaError: An error occurred while calling z:org.apache.spark.api.python.PythonRDD.collectAndServe.
: org.apache.spark.SparkException: Job aborted due to stage failure: Task 7 in stage 3174.0 failed 4 times, most recent failure: Lost task 7.3 in stage 3174.0 (TID 42178) (10.75.129.14 executor 0): org.apache.spark.api.python.PythonException: 'pyspark.serializers.SerializationError: Caused by Traceback (most recent call last):
File "/databricks/spark/python/pyspark/serializers.py", line 165, in _read_with_length
return self.loads(obj)
File "/databricks/spark/python/pyspark/serializers.py", line 469, in loads
return pickle.loads(obj, encoding=encoding)
AttributeError: Can't get attribute 'car' on <module 'pyspark.daemon' from '/databricks/spark/python/pyspark/daemon.py'>'. Full traceback below:
Traceback (most recent call last):
File "/databricks/spark/python/pyspark/serializers.py", line 165, in _read_with_length
return self.loads(obj)
File "/databricks/spark/python/pyspark/serializers.py", line 469, in loads
return pickle.loads(obj, encoding=encoding)
AttributeError: Can't get attribute 'car' on <module 'pyspark.daemon' from '/databricks/spark/python/pyspark/daemon.py'>
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/databricks/spark/python/pyspark/worker.py", line 754, in main
process()
File "/databricks/spark/python/pyspark/worker.py", line 746, in process
serializer.dump_stream(out_iter, outfile)
File "/databricks/spark/python/pyspark/serializers.py", line 267, in dump_stream
vs = list(itertools.islice(iterator, batch))
File "/databricks/spark/python/pyspark/serializers.py", line 142, in load_stream
yield self._read_with_length(stream)
File "/databricks/spark/python/pyspark/serializers.py", line 168, in _read_with_length
raise SerializationError("Caused by " + traceback.format_exc())
pyspark.serializers.SerializationError: Caused by Traceback (most recent call last):
File "/databricks/spark/python/pyspark/serializers.py", line 165, in _read_with_length
return self.loads(obj)
File "/databricks/spark/python/pyspark/serializers.py", line 469, in loads
return pickle.loads(obj, encoding=encoding)
AttributeError: Can't get attribute 'car' on <module 'pyspark.daemon' from '/databricks/spark/python/pyspark/daemon.py'>
at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.handlePythonException(PythonRunner.scala:642)
at org.apache.spark.api.python.PythonRunner$$anon$3.read(PythonRunner.scala:830)
at org.apache.spark.api.python.PythonRunner$$anon$3.read(PythonRunner.scala:812)
at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.hasNext(PythonRunner.scala:595)
at org.apache.spark.InterruptibleIterator.hasNext(InterruptibleIterator.scala:37)
at scala.collection.Iterator.foreach(Iterator.scala:941)
at scala.collection.Iterator.foreach$(Iterator.scala:941)
at org.apache.spark.InterruptibleIterator.foreach(InterruptibleIterator.scala:28)
at scala.collection.generic.Growable.$plus$plus$eq(Growable.scala:62)
at scala.collection.generic.Growable.$plus$plus$eq$(Growable.scala:53)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:105)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:49)
at scala.collection.TraversableOnce.to(TraversableOnce.scala:315)
at scala.collection.TraversableOnce.to$(TraversableOnce.scala:313)
at org.apache.spark.InterruptibleIterator.to(InterruptibleIterator.scala:28)
at scala.collection.TraversableOnce.toBuffer(TraversableOnce.scala:307)
at scala.collection.TraversableOnce.toBuffer$(TraversableOnce.scala:307)
at org.apache.spark.InterruptibleIterator.toBuffer(InterruptibleIterator.scala:28)
at scala.collection.TraversableOnce.toArray(TraversableOnce.scala:294)
at scala.collection.TraversableOnce.toArray$(TraversableOnce.scala:288)
at org.apache.spark.InterruptibleIterator.toArray(InterruptibleIterator.scala:28)
at org.apache.spark.rdd.RDD.$anonfun$collect$2(RDD.scala:1038)
at org.apache.spark.scheduler.ResultTask.$anonfun$runTask$3(ResultTask.scala:75)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.scheduler.ResultTask.$anonfun$runTask$1(ResultTask.scala:75)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:55)
at org.apache.spark.scheduler.Task.doRunTask(Task.scala:150)
at org.apache.spark.scheduler.Task.$anonfun$run$1(Task.scala:119)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.scheduler.Task.run(Task.scala:91)
at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$13(Executor.scala:813)
at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1657)
at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$4(Executor.scala:816)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:672)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Driver stacktrace:
at org.apache.spark.scheduler.DAGScheduler.failJobAndIndependentStages(DAGScheduler.scala:2828)
at org.apache.spark.scheduler.DAGScheduler.$anonfun$abortStage$2(DAGScheduler.scala:2775)
at org.apache.spark.scheduler.DAGScheduler.$anonfun$abortStage$2$adapted(DAGScheduler.scala:2769)
at scala.collection.mutable.ResizableArray.foreach(ResizableArray.scala:62)
at scala.collection.mutable.ResizableArray.foreach$(ResizableArray.scala:55)
at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:49)
at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:2769)
at org.apache.spark.scheduler.DAGScheduler.$anonfun$handleTaskSetFailed$1(DAGScheduler.scala:1305)
at org.apache.spark.scheduler.DAGScheduler.$anonfun$handleTaskSetFailed$1$adapted(DAGScheduler.scala:1305)
at scala.Option.foreach(Option.scala:407)
at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:1305)
at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.doOnReceive(DAGScheduler.scala:3036)
at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:2977)
at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:2965)
at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:49)
at org.apache.spark.scheduler.DAGScheduler.runJob(DAGScheduler.scala:1067)
at org.apache.spark.SparkContext.runJobInternal(SparkContext.scala:2477)
at org.apache.spark.rdd.RDD.$anonfun$collect$1(RDD.scala:1036)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:165)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:125)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
at org.apache.spark.rdd.RDD.withScope(RDD.scala:419)
at org.apache.spark.rdd.RDD.collect(RDD.scala:1034)
at org.apache.spark.api.python.PythonRDD$.collectAndServe(PythonRDD.scala:260)
at org.apache.spark.api.python.PythonRDD.collectAndServe(PythonRDD.scala)
at sun.reflect.GeneratedMethodAccessor668.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:380)
at py4j.Gateway.invoke(Gateway.java:295)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.GatewayConnection.run(GatewayConnection.java:251)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.spark.api.python.PythonException: 'pyspark.serializers.SerializationError: Caused by Traceback (most recent call last):
File "/databricks/spark/python/pyspark/serializers.py", line 165, in _read_with_length
return self.loads(obj)
File "/databricks/spark/python/pyspark/serializers.py", line 469, in loads
return pickle.loads(obj, encoding=encoding)
AttributeError: Can't get attribute 'car' on <module 'pyspark.daemon' from '/databricks/spark/python/pyspark/daemon.py'>'. Full traceback below:
Traceback (most recent call last):
File "/databricks/spark/python/pyspark/serializers.py", line 165, in _read_with_length
return self.loads(obj)
File "/databricks/spark/python/pyspark/serializers.py", line 469, in loads
return pickle.loads(obj, encoding=encoding)
AttributeError: Can't get attribute 'car' on <module 'pyspark.daemon' from '/databricks/spark/python/pyspark/daemon.py'>
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/databricks/spark/python/pyspark/worker.py", line 754, in main
process()
File "/databricks/spark/python/pyspark/worker.py", line 746, in process
serializer.dump_stream(out_iter, outfile)
File "/databricks/spark/python/pyspark/serializers.py", line 267, in dump_stream
vs = list(itertools.islice(iterator, batch))
File "/databricks/spark/python/pyspark/serializers.py", line 142, in load_stream
yield self._read_with_length(stream)
File "/databricks/spark/python/pyspark/serializers.py", line 168, in _read_with_length
raise SerializationError("Caused by " + traceback.format_exc())
pyspark.serializers.SerializationError: Caused by Traceback (most recent call last):
File "/databricks/spark/python/pyspark/serializers.py", line 165, in _read_with_length
return self.loads(obj)
File "/databricks/spark/python/pyspark/serializers.py", line 469, in loads
return pickle.loads(obj, encoding=encoding)
AttributeError: Can't get attribute 'car' on <module 'pyspark.daemon' from '/databricks/spark/python/pyspark/daemon.py'>
at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.handlePythonException(PythonRunner.scala:642)
at org.apache.spark.api.python.PythonRunner$$anon$3.read(PythonRunner.scala:830)
at org.apache.spark.api.python.PythonRunner$$anon$3.read(PythonRunner.scala:812)
at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.hasNext(PythonRunner.scala:595)
at org.apache.spark.InterruptibleIterator.hasNext(InterruptibleIterator.scala:37)
at scala.collection.Iterator.foreach(Iterator.scala:941)
at scala.collection.Iterator.foreach$(Iterator.scala:941)
at org.apache.spark.InterruptibleIterator.foreach(InterruptibleIterator.scala:28)
at scala.collection.generic.Growable.$plus$plus$eq(Growable.scala:62)
at scala.collection.generic.Growable.$plus$plus$eq$(Growable.scala:53)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:105)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:49)
at scala.collection.TraversableOnce.to(TraversableOnce.scala:315)
at scala.collection.TraversableOnce.to$(TraversableOnce.scala:313)
at org.apache.spark.InterruptibleIterator.to(InterruptibleIterator.scala:28)
at scala.collection.TraversableOnce.toBuffer(TraversableOnce.scala:307)
at scala.collection.TraversableOnce.toBuffer$(TraversableOnce.scala:307)
at org.apache.spark.InterruptibleIterator.toBuffer(InterruptibleIterator.scala:28)
at scala.collection.TraversableOnce.toArray(TraversableOnce.scala:294)
at scala.collection.TraversableOnce.toArray$(TraversableOnce.scala:288)
at org.apache.spark.InterruptibleIterator.toArray(InterruptibleIterator.scala:28)
at org.apache.spark.rdd.RDD.$anonfun$collect$2(RDD.scala:1038)
at org.apache.spark.scheduler.ResultTask.$anonfun$runTask$3(ResultTask.scala:75)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.scheduler.ResultTask.$anonfun$runTask$1(ResultTask.scala:75)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:55)
at org.apache.spark.scheduler.Task.doRunTask(Task.scala:150)
at org.apache.spark.scheduler.Task.$anonfun$run$1(Task.scala:119)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.scheduler.Task.run(Task.scala:91)
at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$13(Executor.scala:813)
at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1657)
at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$4(Executor.scala:816)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
at com.databricks.spark.util.ExecutorFrameProfiler$.record(ExecutorFrameProfiler.scala:110)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:672)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
... 1 more
It seems that pyspark does not see the car class. I have already tried updating Pyspark, which did not work. Thanks in advance!