CASSANDRA Architecture and Data Model 3

Question 1

In Cassandra, what is the 'coordinator node'?

Accepted Answer

The node that receives a client request and routes it to the correct replicas

Answer

The coordinator is whichever node a client connects to; it routes the request to the appropriate replica nodes based on the partition key.

Question 2

What is 'read repair' in Apache Cassandra?

Accepted Answer

Synchronizing divergent replicas by comparing and updating them during a read

Answer

Read repair detects inconsistencies between replicas during a read operation and writes the most recent data back to out-of-date replicas.

Question 3

What does the 'NetworkTopologyStrategy' replication strategy allow you to configure?

Accepted Answer

Different replication factors per data center

Answer

NetworkTopologyStrategy lets you specify a separate replication factor for each data center, enabling flexible multi-DC deployments.

Question 4

Which file in a Cassandra SSTable set stores the partition index for fast lookups?

Accepted Answer

Index.db

Answer

Index.db stores the byte offset of each partition key in Data.db, allowing Cassandra to seek directly to a partition without scanning the whole file.

Question 5

What is the purpose of 'gc_grace_seconds' in Cassandra?

Accepted Answer

The period tombstones must persist before being eligible for deletion during compaction

Answer

gc_grace_seconds ensures tombstones are not removed before all replicas have had a chance to propagate the deletion, preventing deleted data from re-appearing.

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA Architecture and Data Model 3