CASSANDRA MCQ 3

Question 1

In a Cassandra primary key defined as PRIMARY KEY ((account_id), event_time), what is the role of event_time?

Accepted Answer

Clustering column

Answer

event_time is a clustering column that determines the sort order of rows within the partition identified by account_id.

Question 2

Which CQL statement creates a table-level snapshot for backup purposes?

Accepted Answer

nodetool snapshot -t snap_name keyspace

Answer

`nodetool snapshot` creates hard-link snapshots of SSTables, providing a point-in-time backup without interrupting writes.

Question 3

What happens when you execute a CQL BATCH statement in Cassandra?

Accepted Answer

Statements targeting the same partition key are applied atomically; cross-partition atomicity is not guaranteed

Answer

An unlogged batch achieves atomicity only at the partition level; a logged batch provides server-side atomicity but only for mutations to the same partition.

Question 4

Which CQL collection type preserves insertion order and allows duplicate values?

Accepted Answer

list

Answer

A list is an ordered collection of values that permits duplicates, unlike a set which is unordered and deduplicates, or a map which stores key-value pairs.

Question 5

What is the purpose of the ALLOW FILTERING clause in a CQL SELECT statement?

Accepted Answer

Enables server-side post-processing of results not supported by the primary key or index

Answer

ALLOW FILTERING instructs Cassandra to perform an in-memory filter on data that cannot be satisfied by the partition key or a secondary index, which can be expensive.

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA MCQ 3