DSE Big Data Technologies 4

Question 1

Which consistency model does Apache Cassandra use by default to optimize for availability?

Accepted Answer

Eventual consistency

Answer

Cassandra defaults to eventual consistency, trading strict consistency for high availability and partition tolerance in line with the CAP theorem.

Question 2

What does the term 'hot partition' mean in a distributed NoSQL system?

Accepted Answer

A partition receiving disproportionately high read or write traffic, creating a bottleneck

Answer

A hot partition occurs when one partition key attracts far more traffic than others, overloading the node responsible for that partition.

Question 3

In Apache Spark, what is a 'shuffle' operation?

Accepted Answer

Redistributing data across partitions, typically during wide transformations like groupBy or join

Answer

A shuffle redistributes data across the network to group records with the same key onto the same partition, and is one of the most expensive Spark operations.

Question 4

What is Apache NiFi primarily designed for?

Accepted Answer

Automating and managing data flow between systems with a visual interface

Answer

Apache NiFi provides a web-based graphical interface for designing, managing, and monitoring data flows between systems with built-in provenance tracking.

Question 5

Which of the following best describes a Delta Lake?

Accepted Answer

An open-source storage layer that adds ACID transactions and versioning to data lakes

Answer

Delta Lake is an open-source storage layer that brings ACID transactions, schema enforcement, and time-travel versioning to data lakes built on cloud object storage.

DSE - Data Science Practice Test

DSE - Data Science Practice Test

DSE Big Data Technologies 4