Cassandra Practice Test

What are the main steps in the Write Path in Cassandra?

1. Store data in a ring, Append writes to commit log, Flush data to SSTable

2. Append writes to commit log, Store data in a memtable, Acknowledge only

3. Write data, Store in cache, Acknowledge the result

4. Append writes to commit log, Store data in a memtable, Acknowledge the write, Flush to disk

The correct answer is: Append writes to commit log, Store data in a memtable, Acknowledge the write, Flush to disk

The main steps in the Write Path in Cassandra primarily involve how data is processed and persisted to ensure durability and performance. The correct option accurately outlines these steps. First, when a write is initiated, Cassandra appends the write operation to the commit log. This commit log is crucial for durability because it allows the system to recover data in case of a failure. Once the write is logged, it is then stored in a memtable, which is an in-memory structure designed to provide fast access to recent write operations before they are flushed to disk. After the data is safely held in the memtable, the system acknowledges the write to the client, indicating that the write operation was received and processed successfully. This acknowledgment can happen before the data is flushed to disk, which helps maintain high throughput and low latency. Finally, at some point, the memtable is flushed to disk into an SSTable (Sorted String Table) when it reaches a certain size or based on specific conditions. This step is essential for persistent storage, ensuring that data is not only held in memory but also saved to disk for long-term retention. This answer encapsulates the entire write process from logging the write to acknowledging it and eventually persisting it on disk, capturing the core workflow that optim