Cassandra Practice Test

Which of the following are stored by clustering columns in Cassandra?

1. MemTable

2. SStable

3. Commit log

4. Heap table

The correct answer is: SStable

In Cassandra, data is organized and stored in a way that is optimized for efficient retrieval and writing through the use of tables. Clustering columns play a crucial role in the organization of data within those tables. Specifically, clustering columns determine the order in which data is stored within a partition. When you define a table in Cassandra, you can have both partition keys and clustering columns. While the partition key determines the distribution of data across the nodes in the cluster, clustering columns are used to sort the data within each partition. This ordering is stored in the SSTable, which is the immutable data structure that Cassandra uses to store data on disk. SSTables are created during the write process when data from the MemTable is flushed to disk. They serve as the ultimate storage format for Cassandra, keeping the records in an organized manner and allowing for efficiency in read operations, particularly through efficient use of disk and caching mechanisms. Therefore, the choice that correctly identifies where data organized by clustering columns is stored is the SSTable.