How we optimized Cassandra cqlsh COPY FROM

This article discusses performance improvements made to Apache Cassandra's COPY FROM command using profiling tools like cProfile and line_profiler. The changes introduced by CASSANDRA-11053 optimized the process, increasing performance from around 35,000 rows per second to as much as 117,000 rows per second. The optimization involved introducing a feeder process for reading data and moving csv decoding to worker processes. Additionally, replacing the queue with a pool of pipes improved communication across processes. Python performance recommendations were also applied, such as using built-in Integers instead of Python types and storing function references in local variables before entering loops. The final performance results varied depending on factors like CPU scheduling and data type complexity.