Py4JError: An error occurred while calling o90.fit - apache-spark

Question

I want to apply random forest algorithm over a dataframe consisting of three columns namely JournalID, IndexedJournalID(Obtained using StringIndexer of Spark) and feature vector. I used below code to read the dataframe from parquet file and apply String Indexer over JournalID column to convert it to categorical type.
from pyspark.ml import Pipeline
from pyspark.ml.classification import RandomForestClassifier
from pyspark.ml.feature import IndexToString, StringIndexer, VectorIndexer
from pyspark.ml.evaluation import MulticlassClassificationEvaluator
from pyspark.sql.functions import udf
from pyspark.ml.linalg import Vectors
from pyspark.ml.linalg import VectorUDT
df=spark.read.parquet('JouID-UBTFIDFVectors-server22.parquet')
labelIndexer = StringIndexer(inputCol="journalid", outputCol="IndexedJournalID")
labelsDF=labelIndexer.fit(df)
df1=labelsDF.transform(df)
# This function converts sparse vectors to dense vectors....I applied this on raw features column to convert them to VectorUDT type.....
parse_ = udf(lambda l: Vectors.dense(l), VectorUDT())
df2 = df1.withColumn("featuresNew", parse_(df1["features"])).drop('features')
New Dataframe Schema(df2) is as follows:
root
|-- journalid: string (nullable = true)
|-- indexedLabel: double (nullable = false)
|-- featuresNew: vector (nullable = true)
Then I split df2 into training and test set and create object of random forest classifier as below:
(trainingData, testData) = df2.randomSplit([0.8, 0.2])
rf = RandomForestClassifier(labelCol="indexedLabel", featuresCol="featuresNew", numTrees=2 )
Finally apply fit() method over trainingData obtained above.
rfModel=rf.fit(trainingData)
With this I am able to train model on 100 instances of input dataframe. However,over whole training data, this line gives following error.
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 53652)
Traceback (most recent call last):
File "/data/sntps/code/conda3/lib/python3.6/socketserver.py", line 317, in _handle_request_noblock
self.process_request(request, client_address)
File "/data/sntps/code/conda3/lib/python3.6/socketserver.py", line 348, in process_request
self.finish_request(request, client_address)
File "/data/sntps/code/conda3/lib/python3.6/socketserver.py", line 361, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/data/sntps/code/conda3/lib/python3.6/socketserver.py", line 696, in __init__
self.handle()
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/pyspark/accumulators.py", line 235, in handle
num_updates = read_int(self.rfile)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/pyspark/serializers.py", line 685, in read_int
raise EOFError
EOFError
----------------------------------------
ERROR:root:Exception while sending command.
Traceback (most recent call last):
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 1159, in send_command
raise Py4JNetworkError("Answer from Java side is empty")
py4j.protocol.Py4JNetworkError: Answer from Java side is empty
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 985, in send_command
response = connection.send_command(command)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 1164, in send_command
"Error while receiving", e, proto.ERROR_ON_RECEIVE)
py4j.protocol.Py4JNetworkError: Error while receiving
ERROR:py4j.java_gateway:An error occurred while trying to connect to the Java server (127.0.0.1:41060)
Traceback (most recent call last):
File "/data/sntps/code/conda3/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2910, in run_code
exec(code_obj, self.user_global_ns, self.user_ns)
File "<ipython-input-10-46d7488961c7>", line 1, in <module>
rfModel=rf.fit(trainingData)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/pyspark/ml/base.py", line 132, in fit
return self._fit(dataset)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/pyspark/ml/wrapper.py", line 288, in _fit
java_model = self._fit_java(dataset)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/pyspark/ml/wrapper.py", line 285, in _fit_java
return self._java_obj.fit(dataset._jdf)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 1257, in __call__
answer, self.gateway_client, self.target_id, self.name)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/pyspark/sql/utils.py", line 63, in deco
return f(*a, **kw)
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py", line 336, in get_return_value
format(target_id, ".", name))
py4j.protocol.Py4JError: An error occurred while calling o90.fit
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/data/sntps/code/conda3/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 1828, in showtraceback
stb = value._render_traceback_()
AttributeError: 'Py4JError' object has no attribute '_render_traceback_'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/data/sp/spark-2.3.1-bin-hadoop2.7/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 929, in _get_connection
connection = self.deque.pop()
IndexError: pop from an empty deque
During handling of the above exception, another exception occurred:
.(traceback...not writing due to space issue)
.
.
Py4JError: An error occurred while calling o90.fit
This error is not very descriptive and hence it has become difficult for me to identify the where I am going wrong. Any help would help a lot.
Input Description:
Input Dataframe Contains 2696512 rows and each row's feature vector is of 262144 length.

Answer 1

After going through lot of related questions on stackoverflow , I thought this may be happening because of running this in jupyter-notebook. So later I ran it on commandline using spark-submit script and I am not getting this error anymore. I don't know though why this error is popping up if I run this in jupyter-notebook.