Thanks for the advice Nicholas.

As mentioned in the original email, I have tried JDBC + SSH Tunnel using
pymysql and sshtunnel and it worked fine. The problem happens only with
Spark.

*Thanks,*
*Venkat*



On Wed, Dec 6, 2023 at 10:21 PM Nicholas Chammas <nicholas.cham...@gmail.com>
wrote:

> This is not a question for the dev list. Moving dev to bcc.
>
> One thing I would try is to connect to this database using JDBC + SSH
> tunnel, but without Spark. That way you can focus on getting the JDBC
> connection to work without Spark complicating the picture for you.
>
>
> On Dec 5, 2023, at 8:12 PM, Venkatesan Muniappan <
> venkatesa...@noonacademy.com> wrote:
>
> Hi Team,
>
> I am facing an issue with SSH Tunneling in Apache Spark. The behavior is
> same as the one in this Stackoverflow question
> <https://stackoverflow.com/questions/68278369/how-to-use-pyspark-to-read-a-mysql-database-using-a-ssh-tunnel>
> but there are no answers there.
>
> This is what I am trying:
>
>
> with SSHTunnelForwarder(
> (ssh_host, ssh_port),
> ssh_username=ssh_user,
> ssh_pkey=ssh_key_file,
> remote_bind_address=(sql_hostname, sql_port),
> local_bind_address=(local_host_ip_address, sql_port)) as tunnel:
> tunnel.local_bind_port
> b1_semester_df = spark.read \
> .format("jdbc") \
> .option("url", b2b_mysql_url.replace("<<local_bind_port>>", 
> str(tunnel.local_bind_port)))
> \
> .option("query", b1_semester_sql) \
> .option("database", 'b2b') \
> .option("password", b2b_mysql_password) \
> .option("driver", "com.mysql.cj.jdbc.Driver") \
> .load()
> b1_semester_df.count()
>
> Here, the b1_semester_df is loaded but when I try count on the same Df it
> fails saying this
>
> 23/12/05 11:49:17 ERROR TaskSetManager: Task 0 in stage 2.0 failed 4
> times; aborting job
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/usr/lib/spark/python/pyspark/sql/dataframe.py", line 382, in show
>     print(self._jdf.showString(n, 20, vertical))
>   File
> "/usr/lib/spark/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line
> 1257, in __call__
>   File "/usr/lib/spark/python/pyspark/sql/utils.py", line 63, in deco
>     return f(*a, **kw)
>   File "/usr/lib/spark/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py",
> line 328, in get_return_value
> py4j.protocol.Py4JJavaError: An error occurred while calling
> o284.showString.
> : org.apache.spark.SparkException: Job aborted due to stage failure: Task
> 0 in stage 2.0 failed 4 times, most recent failure: Lost task 0.3 in stage
> 2.0 (TID 11, ip-172-32-108-1.eu-central-1.compute.internal, executor 3):
> com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link
> failure
>
> However, the same is working fine with pandas df. I have tried this below
> and it worked.
>
>
> with SSHTunnelForwarder(
> (ssh_host, ssh_port),
> ssh_username=ssh_user,
> ssh_pkey=ssh_key_file,
> remote_bind_address=(sql_hostname, sql_port)) as tunnel:
> conn = pymysql.connect(host=local_host_ip_address, user=sql_username,
> passwd=sql_password, db=sql_main_database,
> port=tunnel.local_bind_port)
> df = pd.read_sql_query(b1_semester_sql, conn)
> spark.createDataFrame(df).createOrReplaceTempView("b1_semester")
>
> So wanted to check what I am missing with my Spark usage. Please help.
>
> *Thanks,*
> *Venkat*
>
>
>

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