Deep Dive into the ScyllaDB Spark Migrator

The ScyllaDB Spark Migrator was developed with several design goals, including high resource efficiency and ease of use, to facilitate the migration of data from Cassandra to ScyllaDB using Apache Spark. The Migrator minimizes data shuffles to maintain performance and allows for minimal tuning by default, with parallel data transfer configurations and timestamp preservation capabilities. The process involves reading the schema from Cassandra, customizing queries to include TTL and WRITETIME timestamps for non-key columns, and using a combination of DataFrames and RDDs to manage schema modifications and data transformations. Additionally, the Migrator tracks the progress of data transfer by monitoring token ranges and using accumulators to save progress, enabling resumable migrations. The tool relies on a modified version of the Cassandra connector to achieve these functionalities, providing a robust solution for scalable and efficient NoSQL data migration.