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I was trying to use an UDF in spark. After applying the udf to a column, df.show() was not working neither I was able to apply any further operation on that dataframe. So, I ran the code which is given in the documentation here and got the same error

The code was:

from pyspark.sql.types import IntegerType
slen = udf(lambda s: len(s), IntegerType())
@udf
def to_upper(s):
    if s is not None:
        return s.upper()

@udf(returnType=IntegerType())
def add_one(x):
    if x is not None:
        return x + 1

df = spark.createDataFrame([(1, "John Doe", 21)], ("id", "name", "age"))
df.select(slen("name").alias("slen(name)"), to_upper("name"), add_one("age")).show()

Here is the error:

Py4JJavaError                             Traceback (most recent call last)
Cell In[13], line 14
     11         return x + 1
     13 df = spark.createDataFrame([(1, "John Doe", 21)], ("id", "name", "age"))
---> 14 df.select(slen("name").alias("slen(name)"), to_upper("name"), add_one("age")).show()

File C:\Program Files\Python310\lib\site-packages\pyspark\sql\dataframe.py:606, in DataFrame.show(self, n, truncate, vertical)
    603     raise TypeError("Parameter 'vertical' must be a bool")
    605 if isinstance(truncate, bool) and truncate:
--> 606     print(self._jdf.showString(n, 20, vertical))
    607 else:
    608     try:

File C:\Program Files\Python310\lib\site-packages\py4j\java_gateway.py:1321, in JavaMember.__call__(self, *args)
   1315 command = proto.CALL_COMMAND_NAME +\
   1316     self.command_header +\
   1317     args_command +\
   1318     proto.END_COMMAND_PART
   1320 answer = self.gateway_client.send_command(command)
-> 1321 return_value = get_return_value(
   1322     answer, self.gateway_client, self.target_id, self.name)
   1324 for temp_arg in temp_args:
   1325     temp_arg._detach()

File C:\Program Files\Python310\lib\site-packages\pyspark\sql\utils.py:190, in capture_sql_exception.<locals>.deco(*a, **kw)
    188 def deco(*a: Any, **kw: Any) -> Any:
    189     try:
--> 190         return f(*a, **kw)
    191     except Py4JJavaError as e:
    192         converted = convert_exception(e.java_exception)

File C:\Program Files\Python310\lib\site-packages\py4j\protocol.py:326, 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)
    329 else:
    330     raise Py4JError(
    331         "An error occurred while calling {0}{1}{2}. Trace:\n{3}\n".
    332         format(target_id, ".", name, value))

Py4JJavaError: An error occurred while calling o134.showString.
: org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 3.0 failed 1 times, most recent failure: Lost task 0.0 in stage 3.0 (TID 2) (LAPTOP-SI50IG8L executor driver): org.apache.spark.SparkException: Python worker failed to connect back.
    at org.apache.spark.api.python.PythonWorkerFactory.createSimpleWorker(PythonWorkerFactory.scala:189)
    at org.apache.spark.api.python.PythonWorkerFactory.create(PythonWorkerFactory.scala:109)
    at org.apache.spark.SparkEnv.createPythonWorker(SparkEnv.scala:124)
    at org.apache.spark.api.python.BasePythonRunner.compute(PythonRunner.scala:157)
    at org.apache.spark.api.python.PythonRDD.compute(PythonRDD.scala:65)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:90)
    at org.apache.spark.scheduler.Task.run(Task.scala:136)
    at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$3(Executor.scala:548)
    at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1504)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:551)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.net.SocketTimeoutException: Accept timed out
    at java.net.DualStackPlainSocketImpl.waitForNewConnection(Native Method)
    at java.net.DualStackPlainSocketImpl.socketAccept(Unknown Source)
    at java.net.AbstractPlainSocketImpl.accept(Unknown Source)
    at java.net.PlainSocketImpl.accept(Unknown Source)
    at java.net.ServerSocket.implAccept(Unknown Source)
    at java.net.ServerSocket.accept(Unknown Source)
    at org.apache.spark.api.python.PythonWorkerFactory.createSimpleWorker(PythonWorkerFactory.scala:176)
    ... 38 more

Driver stacktrace:
    at org.apache.spark.scheduler.DAGScheduler.failJobAndIndependentStages(DAGScheduler.scala:2672)
    at org.apache.spark.scheduler.DAGScheduler.$anonfun$abortStage$2(DAGScheduler.scala:2608)
    at org.apache.spark.scheduler.DAGScheduler.$anonfun$abortStage$2$adapted(DAGScheduler.scala:2607)
    at scala.collection.mutable.ResizableArray.foreach(ResizableArray.scala:62)
    at scala.collection.mutable.ResizableArray.foreach$(ResizableArray.scala:55)
    at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:49)
    at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:2607)
    at org.apache.spark.scheduler.DAGScheduler.$anonfun$handleTaskSetFailed$1(DAGScheduler.scala:1182)
    at org.apache.spark.scheduler.DAGScheduler.$anonfun$handleTaskSetFailed$1$adapted(DAGScheduler.scala:1182)
    at scala.Option.foreach(Option.scala:407)
    at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:1182)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.doOnReceive(DAGScheduler.scala:2860)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:2802)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:2791)
    at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:49)
    at org.apache.spark.scheduler.DAGScheduler.runJob(DAGScheduler.scala:952)
    at org.apache.spark.SparkContext.runJob(SparkContext.scala:2238)
    at org.apache.spark.SparkContext.runJob(SparkContext.scala:2259)
    at org.apache.spark.SparkContext.runJob(SparkContext.scala:2278)
    at org.apache.spark.sql.execution.SparkPlan.executeTake(SparkPlan.scala:506)
    at org.apache.spark.sql.execution.SparkPlan.executeTake(SparkPlan.scala:459)
    at org.apache.spark.sql.execution.CollectLimitExec.executeCollect(limit.scala:48)
    at org.apache.spark.sql.Dataset.collectFromPlan(Dataset.scala:3868)
    at org.apache.spark.sql.Dataset.$anonfun$head$1(Dataset.scala:2863)
    at org.apache.spark.sql.Dataset.$anonfun$withAction$2(Dataset.scala:3858)
    at org.apache.spark.sql.execution.QueryExecution$.withInternalError(QueryExecution.scala:510)
    at org.apache.spark.sql.Dataset.$anonfun$withAction$1(Dataset.scala:3856)
    at org.apache.spark.sql.execution.SQLExecution$.$anonfun$withNewExecutionId$6(SQLExecution.scala:109)
    at org.apache.spark.sql.execution.SQLExecution$.withSQLConfPropagated(SQLExecution.scala:169)
    at org.apache.spark.sql.execution.SQLExecution$.$anonfun$withNewExecutionId$1(SQLExecution.scala:95)
    at org.apache.spark.sql.SparkSession.withActive(SparkSession.scala:779)
    at org.apache.spark.sql.execution.SQLExecution$.withNewExecutionId(SQLExecution.scala:64)
    at org.apache.spark.sql.Dataset.withAction(Dataset.scala:3856)
    at org.apache.spark.sql.Dataset.head(Dataset.scala:2863)
    at org.apache.spark.sql.Dataset.take(Dataset.scala:3084)
    at org.apache.spark.sql.Dataset.getRows(Dataset.scala:288)
    at org.apache.spark.sql.Dataset.showString(Dataset.scala:327)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
    at py4j.Gateway.invoke(Gateway.java:282)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.ClientServerConnection.waitForCommands(ClientServerConnection.java:182)
    at py4j.ClientServerConnection.run(ClientServerConnection.java:106)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.spark.SparkException: Python worker failed to connect back.
    at org.apache.spark.api.python.PythonWorkerFactory.createSimpleWorker(PythonWorkerFactory.scala:189)
    at org.apache.spark.api.python.PythonWorkerFactory.create(PythonWorkerFactory.scala:109)
    at org.apache.spark.SparkEnv.createPythonWorker(SparkEnv.scala:124)
    at org.apache.spark.api.python.BasePythonRunner.compute(PythonRunner.scala:157)
    at org.apache.spark.api.python.PythonRDD.compute(PythonRDD.scala:65)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:52)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:365)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:329)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:90)
    at org.apache.spark.scheduler.Task.run(Task.scala:136)
    at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$3(Executor.scala:548)
    at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1504)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:551)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    ... 1 more
Caused by: java.net.SocketTimeoutException: Accept timed out
    at java.net.DualStackPlainSocketImpl.waitForNewConnection(Native Method)
    at java.net.DualStackPlainSocketImpl.socketAccept(Unknown Source)
    at java.net.AbstractPlainSocketImpl.accept(Unknown Source)
    at java.net.PlainSocketImpl.accept(Unknown Source)
    at java.net.ServerSocket.implAccept(Unknown Source)
    at java.net.ServerSocket.accept(Unknown Source)
    at org.apache.spark.api.python.PythonWorkerFactory.createSimpleWorker(PythonWorkerFactory.scala:176)
    ... 38 more

I don't know what is the problem. Versions Python: 3.10.10 Pyspark: 3.3.2

I read one answer on stack overflow saying that UDF's are slow but I think it should work with the code given in the documentation.

1 Answers1

1

It's caused by the connection between PySpark and Python. You can either set the environment variable PYSPARK_DRIVER_PYTHON and PYSPARK_PYTHON to your python or spark.pyspark.driver and spark.pyspark.python when you use spark-submit commit.

Jonathan Lam
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