Cassandra Practice Test 2025 – Comprehensive All-in-One Guide to Exam Success!

The purpose of compaction in Cassandra is to merge SSTables (Sorted String Tables) and free up space. Compaction occurs as a crucial background process that consolidates multiple SSTables into fewer ones. This merging process not only improves read performance by reducing the number of SSTables that need to be accessed for query operations but also reclaims disk space by removing tombstones and obsolete data that has been marked for deletion.

As data is written to Cassandra, it is stored in memory and then periodically flushed to SSTables on disk. Over time, these SSTables can accumulate, leading to inefficiencies in both storage and read paths. Compaction ensures that these SSTables are managed effectively, optimizing performance and ensuring that only the necessary data is maintained on disk. This process contributes to the overall health and performance of a Cassandra database by maintaining an efficient data structure and reducing the overhead associated with multiple SSTables.