Premium

DataStax Cassandra Developer Certification Certification Questions and Answer (Dumps and Practice Questions)



Question : Which of the following are advantages of Cassandra Database?

A. Its not a Single Point of failure DB
B. It can be scaled linearly
C. Its a reliable DB
D. Data can be stored close to client

: Which of the following are advantages of Cassandra Database?
1. A,B,C
2. B,C,D
3. A,C,D
4. A,B,C,D

Correct Answer : 4
Explanation: About Apache Cassandra

FAULT TOLERANT: Data is automatically replicated to multiple nodes for fault-tolerance. Replication across multiple data
centers is supported. Failed nodes can be replaced with no downtime.

PERFORMANT: Cassandra consistently outperforms popular NoSQL alternatives in benchmarks and real applications, primarily
because of fundamental architectural choices.

DECENTRALIZED: There are no single points of failure. There are no network bottlenecks. Every node in the cluster is
identical.

SCALABLE: Some of the largest production deployments include Apple's, with over 75,000 nodes storing over 10 PB of data,
Netflix (2,500 nodes, 420 TB, over 1 trillion requests per day), Chinese search engine Easou (270 nodes, 300 TB, over 800
million requests per day), and eBay (over 100 nodes, 250 TB).

DURABLE: Cassandra is suitable for applications that can't afford to lose data, even when an entire data center goes down.

YOU'RE IN CONTROL: Choose between synchronous or asynchronous replication for each update. Highly available asynchronous
operations are optimized with features like Hinted Handoff and Read Repair.

ELASTIC: Read and write throughput both increase linearly as new machines are added, with no downtime or interruption to
applications.





Question : Primary purpose of Cassandra keyspace, is to define replication factor?


: Primary purpose of Cassandra keyspace, is to define replication factor?
1. True
2. False

Correct Answer : 1
Explanation: Yes, replication factor is defined on Keyspace level. Keyspace is similar to database schema.




Question : Cassandra uses sequence to generate unique id number across all the nodes in cluster
: Cassandra uses sequence to generate unique id number across all the nodes in cluster
1. True
2. False

Correct Answer : 2
Explanation: It is almost impossible to generate unique number in a distributed system. Cassandra uses UUID and
timeuuid to generate unique number across the cluster.


Related Questions

Question : You have below sample data from a csv file.

1be43390-9fe4-41e3-8d05-425861b86ab6, 1be43390-9fe4-11e3-8d05-425861b86ab6, Amit Jain, I am learning Cassandra from
HadoopExam, 111

Which of the following is correct definition of Cassandra table for this data.
 : You have below sample data from a csv file.
1.
2.
3. Access Mostly Uused Products by 50000+ Subscribers


4.



Question : You have been given below table definitions
CREATE TABLE HADOOPEXAM (

id uuid,
t_id timeuuid,
name text,
description text,
price int
primary key (t_id));

Now you run the below query

Select * from HADOOPEXAM where name='Amit Jain'

What is the expected result?
 : You have been given below table definitions
1. It will successfully return all the rows, where name matches.

2. It will run successfully, but result set would be empty, saying this is not supported.

 3. Access Mostly Uused Products by 50000+ Subscribers

4. It will return first 5 matching rows only.



Question : You have been given below table definition, which of the following is a partition key?

CREATE TABLE HADOOPEXAM (

id uuid,
t_id timeuuid,
name text,
description text,
price int
primary key (t_id));
 : You have been given below table definition, which of the following is a partition key?
1. ID

2. NAME

 3. Access Mostly Uused Products by 50000+ Subscribers

4. cannot be determined and will decided by Cassandra



Question : As you know, Cassandra storage has a altogether different way of storing the data in underline storage to make is
more efficient for read data for a particular scenario. Which of the following is the smallest atomic unit of storage in
Cassandra?
 : As you know, Cassandra storage has a altogether different way of storing the data in underline storage to make is
1. keyspace

2. key-value

 3. Access Mostly Uused Products by 50000+ Subscribers

4. partition



Question : What is a Cell in a Cassandra?
 : What is a Cell in a Cassandra?
1. table block

2. key-value pair

 3. Access Mostly Uused Products by 50000+ Subscribers

4. partition value



Question : As you know, in Cassandra cluster data spread across the nodes in Cluster as well as data splitted in partitions,
what exactly is a partition?
 : As you know, in Cassandra cluster data spread across the nodes in Cluster as well as data splitted in partitions,
1. key-value pair

2. database slice

 3. Access Mostly Uused Products by 50000+ Subscribers

4. group of nodes