Converting Pyspark Dataframe to Dictionary is not working

I have a requirment to load the data in Salesforce using Databricks. I am using simple_salesforce library to load the data. As Salesforce accepts data in dictionary format I need to convert the pyspark dataframe to dictionary and it is failing as below.

from pyspark.sql.types import StructType,StructField, StringType, IntegerType
data2 = [("Test_Conv1","testmailconv1@yopmail.com","Olivia","A",'3000000000'),
("Test_Conv2","testmailconv2@yopmail.com","Jack","B",4000000000),
("Test_Conv3","testmailconv3@yopmail.com","Williams","C",5000000000),
("Test_Conv4","testmailconv4@yopmail.com","Jones","D",6000000000),
("Test_Conv5","testmailconv5@yopmail.com","Brown",None,9000000000)]
schema = StructType([ \
StructField("LastName",StringType(),True), \
StructField("Email",StringType(),True), \
StructField("FirstName",StringType(),True), \
StructField("MiddleName", StringType(), True), \
StructField("Phone", StringType(), True)])
df = spark.createDataFrame(data=data2,schema=schema)

It is failing in the below line

df_contact = df.rdd.map(lambda row: row.asDict()).collect()

Error message

py4j.security.Py4JSecurityException: Method public org.apache.spark.rdd.RDD org.apache.spark.api.java.JavaRDD.rdd() is not whitelisted on class class org.apache.spark.api.java.JavaRDD

Loading to Target

sf.bulk.Contact.insert(df_contact,batch_size=20000,use_serial=True)

The error you encountered seems to be related to the interaction between PySpark and the simple_salesforce library. It appears that the df.rdd.map(lambda row: row.asDict()).collect() operation is causing the error.

Instead of converting the PySpark DataFrame to an RDD and then mapping it to a dictionary, you can directly convert the DataFrame to a Pandas DataFrame and then to a dictionary. Here's an updated version of your code that should work:

from pyspark.sql.types import StructType, StructField, StringType
import pandas as pd

data2 = [
    ("Test_Conv1", "testmailconv1@yopmail.com", "Olivia", "A", '3000000000'),
    ("Test_Conv2", "testmailconv2@yopmail.com", "Jack", "B", '4000000000'),
    ("Test_Conv3", "testmailconv3@yopmail.com", "Williams", "C", '5000000000'),
    ("Test_Conv4", "testmailconv4@yopmail.com", "Jones", "D", '6000000000'),
    ("Test_Conv5", "testmailconv5@yopmail.com", "Brown", None, '9000000000')
]

schema = StructType([
    StructField("LastName", StringType(), True),
    StructField("Email", StringType(), True),
    StructField("FirstName", StringType(), True),
    StructField("MiddleName", StringType(), True),
    StructField("Phone", StringType(), True)
])

df = spark.createDataFrame(data=data2, schema=schema)

# Convert PySpark DataFrame to Pandas DataFrame
pandas_df = df.toPandas()

# Convert Pandas DataFrame to dictionary
df_contact = pandas_df.to_dict(orient='records')

# Load data into Salesforce
sf.bulk.Contact.insert(df_contact, batch_size=20000, use_serial=True)

By converting the DataFrame to a Pandas DataFrame, you can easily use the to_dict() method to convert it to a list of dictionaries that can be accepted by the simple_salesforce library for insertion into Salesforce.

Yes, using the approach of converting a PySpark DataFrame to a Pandas DataFrame and then to a dictionary may introduce performance bottlenecks when dealing with large volumes of data. Converting the entire PySpark DataFrame to a Pandas DataFrame requires bringing all the data into the memory of a single machine, which can become a limitation when the dataset size exceeds the available memory.

In such cases, it's generally recommended to utilize distributed computing capabilities of PySpark to process large datasets efficiently. Instead of converting the DataFrame to a Pandas DataFrame, you can explore options within PySpark itself to transform the data and load it into Salesforce.

For example, you can use the foreachPartition() function in PySpark to iterate over partitions of the DataFrame and send each partition to Salesforce for insertion. This allows for parallel processing and efficient memory utilization, as the data is processed in smaller chunks.

Here's an example that demonstrates this approach:

from simple_salesforce import Salesforce

# Create a connection to Salesforce
sf = Salesforce(username='your_username', password='your_password', security_token='your_security_token')

# Define a function to insert data into Salesforce
def insert_to_salesforce(records):
    # Initialize the Salesforce bulk API
    bulk = sf.bulk.Contact

    # Convert each record to a dictionary and insert it into Salesforce
    for record in records:
        bulk.insert(record)

# Iterate over partitions and insert data into Salesforce
df.foreachPartition(insert_to_salesforce)

By using foreachPartition(), you can process the data in parallel across multiple partitions, which can help improve performance when dealing with large volumes of data.

Keep in mind that depending on your specific requirements and the capabilities of your Spark cluster, you may need to further optimize the code or consider other strategies like batch processing or distributed data loading tools provided by Salesforce to handle extremely large datasets efficiently.

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