Premium

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



Question : Map the below, components
A. Node
B. Data center
C. Cluster

1. It can span Physical locations
2. Where you store your data. It is the basic infrastructure component of Cassandra
3. A collection of related machines and can be physical as well as virtual

: Map the below, components
1. A-2 , B-3 , C-1

2. A-1 , B-2 , C-3
3. A-1 , B-3 , C-2
4. A-3 , B-1 , C-2

Correct Answer : 1
Explanation: Node
Where you store your data. It is the basic infrastructure component of Cassandra.

Data center
A collection of related nodes. A data center can be a physical data center or virtual data center. Different
workloads should use separate data centers, either physical or virtual.
Replication is set by data center. Using separate data centers prevents Cassandra transactions from being
impacted by other workloads and keeps requests close to each other for lower latency.
Depending on the replication factor, data can be written to multiple data centers. Data centers must
never span physical locations.

Cluster
A cluster contains one or more data centers. It can span physical locations.





Question : Map the followings
A. Commit log
B. SSTable
C. CQL Table

1. Consists of columns and has a primary key
2. All data is written first to this for durability.
3. Maintained for each Cassandra table

: Map the followings
1. A-1 B-2 C-3

2. A-3 B-2 C-1
3. A-1 B-3 C-2
4. A-2 B-3 C-1

Correct Answer : 4
Explanation: Commit log
All data is written first to the commit log for durability.
After all its data has been flushed to SSTables, it can be archived, deleted, or recycled.

SSTable
A sorted string table (SSTable) is an immutable data file to which Cassandra writes memtables periodically.
SSTables are append only and stored on disk sequentially and maintained for each Cassandra table.

CQL Table
A collection of ordered columns fetched by table row. A table consists of columns and has a primary key.





Question : Select correct statements, with regards to Gossip protocol.
A. Using Gossip protocol nodes periodically exchange state information about themselves and about other nodes they know about.
B. The gossip process runs every 5 seconds and exchanges state messages with as many other nodes in the cluster as possible.
C. The nodes exchange information about themselves and about the other nodes that they have gossiped about,
so all nodes quickly learn about all other nodes in the cluster.
D. A gossip message has a version associated with it

: Select correct statements, with regards to Gossip protocol.
1. A,B,C
2. B,C,D
3. A,C,D
4. A,B,C,D

Correct Answer : 3
Explanation: Gossip is a peer-to-peer communication protocol in which nodes periodically
exchange state information about themselves and about other nodes they know about.
The gossip process runs every second and exchanges state messages with up to three other nodes in the cluster.
The nodes exchange information about themselves and about the other nodes that they have gossiped about,
so all nodes quickly learn about all other nodes in the cluster.
A gossip message has a version associated with it, so that during a gossip exchange, older information
is overwritten with the most current state for a particular node.



Related 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


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


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


Question : Last column in a primary key represent partition key
 : Last column in a primary key represent partition key
1. True
2. False


Question : Which of the following is true, with regards to Cassandra clustering columns
 : Which of the following is true, with regards to Cassandra clustering columns
1. Itas not mandatory to define

2. It helps to define sort order on a particular column

3. You can change ordering either ascending or descending using WITH CLUSTERING ORDER BY while creating table

4. 1 and 3

5. 2 and 3



Question : You are doing development using Python programming language, now you need to execute some select query on the
data stored in Cassandra, hence you will be using driver for that. Which of the following are correct statement with regards
to driver?



 : You are doing development using Python programming language, now you need to execute some select query on the
1. Cassandra does not support driver for Python, you must have to use Java for this.

2. Cassandra requires new driver class instance for each Cassandra select query

3. Cassandra requires new Cluster class instance for each Cassandra select query

4. You will typically have one instance of Cluster for each Cassandra cluster you want to interact with