CASSANDRA Skills 2

Question 1

Which CQL command exports a table's data to a CSV file on the local filesystem?

Accepted Answer

COPY TO

Answer

COPY TO writes rows from a Cassandra table into a delimited file, most commonly CSV.

Question 2

What is the purpose of the `nodetool repair` command in Cassandra?

Accepted Answer

Synchronizes replicas to fix inconsistencies

Answer

`nodetool repair` runs anti-entropy repair, comparing and reconciling data across replicas to ensure consistency.

Question 3

When designing a Cassandra data model, what drives the primary choice of partition key?

Accepted Answer

Supporting the application's most common query patterns

Answer

The partition key determines data distribution and must be chosen based on how the application will query the data.

Question 4

Which Cassandra feature allows you to set an automatic expiration time on individual rows or columns?

Accepted Answer

TTL (Time To Live)

Answer

TTL sets a time-to-live in seconds on data, after which Cassandra marks it with a tombstone and eventually removes it.

Question 5

What does the `ALLOW FILTERING` clause do in a CQL SELECT statement?

Accepted Answer

Enables server-side filtering that may require a full partition scan

Answer

ALLOW FILTERING permits Cassandra to filter data server-side, potentially scanning many partitions, which can be very slow at scale.

CASSANDRA - Apache Cassandra Database Practice Test