Datastax Cassandra Administrator Certification Questions and Answer (Pratice Questions and Dumps)

Question-: While monitoring the Cassandra cluster you found that it is showing slow performance for node repair, compaction etc. What would you think as first approach being Cassandra administrator?
A. You should immediately bring down one of the nodes form the Cluster
B. You should plan to add new node to the Cluster
C. You would be enabling GC logging
D. You would restart the entire Cassandra cluster

Answer: B

Explanation: In this question, it is clearly saying there are issues with the node repair and compaction operations. Which means Cluster is not getting enough resources which is required. There is no mention that, it was observed as a GC issue. Hence, the better solution is add new node to the cluster.



Question-: Which of the following is/are the reason for adding new node to the existing Cassandra cluster?
A. If cluster reached the Capacity of data storage and no further space is available for storing data.
B. You are seeing latency is increased a lot in your cluster.
C. You have observed that there are issues with the node repair and compaction operations.
D. When you see more GC pauses

Answer: A,B,C

Explanation: You must consider the adding new node in Cassandra cluster for the following situations.
A. If cluster reached the Capacity of data storage and no further space is available for storing data.
B. You are seeing latency is increased a lot in your cluster.
C. You have observed that there are issues with the node repair and compaction operations.
As you add more nodes, it gives you linear scaling for storing the data and even more CPU is available then read/write latency would be improved. If issues with the node repair and compaction operations. Which means Cluster is not getting enough resources which is required. There is no mention that, it was observed as a GC issue. Hence, the better solution is to add a new node to the cluster.



Question-: Which of the following functionalities can be accomplished by the snitch in the Cassandra cluster?
A. It helps in distributing the token for each node
B. It helps in routing the request in the cluster
C. It helps in spreading the replicas around the cluster
D. It helps in finding the failed nodes in the cluster

Answer: B,C

Explanation: In Cassandra cluster Snitch has following two functions
- It teaches the Cassandra enough about the network topology to route request efficiently.
- Similarly help in spreading the replica around the cluster and avoid correlated failures. This is achieved by grouping nodes or machines into datacenters and racks. Cassandra tries to have not more than one replica in the same rack.

Related Questions

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Question-: You have been given below sample data with the millions of the rows


While designing data model we have below requirement which needs to be satisfied.
- We should be able to query table which can return n newest users in the group.
- Data should be evenly stored across the nodes in the cluster.
- Each new day there should be a new partition.
- Analytics group has huge volume of data compare to any other group.
- Query should be something like below
SELECT * FROM he_group WHERE coursegroup = ? LIMIT ?

A. CREATE TABLE he_group (
coursegroup text,
subs_timeuuid timeuuid,
subscribed_date text,
username text,
email text,
first text,
last text,
location text,
PRIMARY KEY ( coursegroup , subs_timeuuid ), subscribed_date )
) WITH CLUSTERING ORDER BY subs_timeuuid DESC)


B.
CREATE TABLE he_group (
coursegroup text,
subs_timeuuid timeuuid,
subscribed_date text,
username text,
email text,
first text,
last text,
location text,
PRIMARY KEY (coursegroup ), subscribed_date , subs_timeuuid )
) WITH CLUSTERING ORDER BY subs_timeuuid DESC)

C.
CREATE TABLE he_group (
coursegroup text,
subs_timeuuid timeuuid,
subscribed_date text,
username text,
email text,
first text,
last text,
location text,
PRIMARY KEY ( coursegroup , subscribed_date ), subs_timeuuid )
) WITH CLUSTERING ORDER BY subs_timeuuid DESC)

D.
CREATE TABLE he_group (
coursegroup text,
subs_timeuuid timeuuid,
subscribed_date text,
username text,
email text,
first text,
last text,
location text,
PRIMARY KEY ( coursegroup , subscribed_date ), subs_timeuuid )
) WITH CLUSTERING ORDER BY subscribed_date DESC)



Question-: You are designing a table with the columns (A, B, C, D,E) and you defined key as below
PRIMARY KEY (A, B, C)
Which of the following statement is true?

A. Columns A, B are partition key
B. Column A is a partition key
C. Columns B, C is a composite clustering key
D. Column C is a clustering key


Question-: Which of the following should be taken care while designing the data model in Apache Cassandra?

A. Data should be evenly distributed across the node in the cluster.
B. While reading the data, we have to make sure that minimum partitions are read.
C. While reading the data, we have to make sure as much as possible partitions (try to maximize it) are read.
D. Data duplication is encouraged to avoid multiple table read.


Question-: You have been given below table design

CREATE TABLE he_food_chain(
country_code text,
state text,
city text,
cafe_name text,
PRIMARY KEY (country_code, state, city, cafe_name )
);

Which of the following statement is/are correct?

A. All café within a country, state and city reside in the same partition.
B. All café within a country reside in the same partition.
C. Within a country, state and city you would get result order by café name.
D. Within a country you would get result order by state, city and café name.


Question-: You have defined below table definition

CREATE TABLE he_food_chain(
country_code text,
state text,
city text,
cafe_name text,
opening_date timestamp,
PRIMARY KEY ((country_code, state, city) , opening_date, cafe_name )
) WITH CLUSTERING ORDER BY (opening_date ASC, cafe_name ASC ) ;

Which of the following is valid query?

A. SELECT * FROM he_food_chain WHERE country_code = 'IND' and state = 'RAJ' and city = 'UDAIPUR'
B. SELECT * FROM he_food_chain WHERE country_code = 'IND' and state = 'RAJ' and city = 'UDAIPUR' and opening_date < '2019-01-01 00:00:00+0200'
C. SELECT * FROM he_food_chain WHERE country_code = 'IND' and state = 'RAJ'
D. SELECT * FROM he_food_chain WHERE country_code = 'IND' and state = 'RAJ' and city = 'UDAIPUR' and cafe_name = 'PRATAP DHABA'



Question-: Which of the following are correct limitation for the Cassandra database?
A. You should set the ordering of data while table creation only.
B. All data for a single partition must fit on disk in a single node in the cluster.
C. A single column value is limited to 1 MB only.
D. No join or subquery support for aggregation.