CASSANDRA MCQ 2

Question 1

Which internal Cassandra component stores recently written data in memory before flushing to disk?

Accepted Answer

Memtable

Answer

The memtable is an in-memory structure that accumulates writes until it reaches a threshold and is flushed to an SSTable on disk.

Question 2

What is the purpose of the Bloom filter in Apache Cassandra?

Accepted Answer

Quickly check if a partition key exists in an SSTable

Answer

Bloom filters are probabilistic data structures that allow Cassandra to skip reading SSTables that definitely do not contain a requested partition key.

Question 3

Which Cassandra compaction strategy is best suited for time-series data with predictable expiration via TTL?

Accepted Answer

TimeWindowCompactionStrategy (TWCS)

Answer

TWCS groups SSTables into time windows so that entire windows can be dropped when their TTL expires, making it ideal for time-series workloads.

Question 4

What does the Cassandra gossip protocol accomplish?

Accepted Answer

Exchange state information about nodes across the cluster

Answer

Gossip is a peer-to-peer communication protocol where nodes periodically exchange metadata (status, load, schema version) with a few peers to propagate cluster state.

Question 5

In Cassandra's write path, which file provides durability by recording every mutation before it is acknowledged?

Accepted Answer

Commit log

Answer

The commit log is a sequential append-only file written before the memtable, ensuring data is not lost if the node crashes before the memtable is flushed.

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA MCQ 2