Cassandra Practice Test

Which of the following is NOT a feature of the Memtable?

1. It is stored in RAM

2. It is ordered by partition key

3. It is directly responsible for data queries

4. It plays a role in write operations

The correct answer is: It is directly responsible for data queries

The Memtable is an essential component of a Cassandra database, functioning as a write-back cache for incoming data before it gets flushed to disk. The choice indicating it is directly responsible for data queries is correct because while Memtables do play a significant role in write operations, they do not directly handle data queries. Instead, data queries are typically served from SSTables that reside on disk, which contain the flushed and immutable data. Memtables store data temporarily in RAM during write operations, making it faster to write and prepare data for eventual disk storage. In contrast, the other features associated with Memtables are as follows: they are stored in RAM for speed, they are ordered by partition key to facilitate efficient data retrieval once they are flushed to disk, and they indeed play a fundamental role in write operations as they temporarily hold writes before these are persisted. This organization helps maintain the performance characteristics that Cassandra is known for, particularly in write-heavy applications.