当我尝试使用 Pyspark 从 Amazon Keyspaces 获取数据时，出现不支持的分区程序：com.amazonaws.cassandra.DefaultPartitioner 错误

Question

I'm not experienced in Java or Hadoop ecosystem. I configured my Spark cluster to connect to Amazon Keyspaces by using spark-cassandra-connector from Datastax. I'm using Pyspark to fetch data from Cassandra. I can successfully connect to Keyspaces/Cassandra cluster. But, when I try to fetch data from it.

df = spark.sql("SELECT * FROM cass.tutorialkeyspace.tutorialtable")
print ("Table Row Count: ")
print (df.count())

I get this error:

Unsupported partitioner: com.amazonaws.cassandra.DefaultPartitioner

Yes, keyspace & table exists and has data. How can I fix/workaround this? Thanks!

Answer 1

As an FYI, Keyspaces now supports using the RandomPartitioner, which enables reading and writing data in Apache Spark by using the open-source Spark Cassandra Connector.

Docs: https://docs.aws.amazon.com/keyspaces/latest/devguide/spark-integrating.html

Launch announcement: https://aws.amazon.com/about-aws/whats-new/2022/04/amazon-keyspaces-read-write-data-apache-spark/

Answer 2

Spark Cassandra Connector is relying on specific partitioner implementation to define data splits, etc. There is no workaround for this problem right now, until somebody adds the implementation of corresponding TokenFactory into this code . It shouldn't be very complex, just should be done by someone who is interested in it.

Answer 3

Thank you for the feedback. At this time, You can write to Keyspaces using the Cassandra Spark Connector. Reading requires support for token rage. Please see the following doc page to see list of supported APIs https://docs.aws.amazon.com/keyspaces/latest/devguide/cassandra-apis.html .

Although we don't have timelines to share at the moment, we prioritize our roadmap based on customer feedback. We are releasing new features all the time. To learn more about our roadmap and upcoming features please contact your AWS Account manager.