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

Question-: There are various types of partitioner provided for the Cassandra storage engine. What exactly this partitioner does?
A. It takes the partition key and then generate the partition token for that key.
B. It takes the clustering column values and then generate the partition token for that key.
C. It helps in updating the partition Key index regularly.
D. It helps in removing tombstone record from the SSTable

Answer: A
Exp: Partitioner is an algorithm or mechanism by which a consistent hash token would be generated for each partition key. It affects on which node data should be stored.

Admin and Dev both


Question-: Which of the following is/are correct?
A. Partition Key = Primary Key
B. Primary Key = Partition Key + Clustering Column
C. Clustering Column = Partition Key + Primary Key
D. Partition Key = Clustering Column + Primary Key

Answer: A,B

Explanation: Primary key is must in Cassandra data model. And Primary key usually made of two things
1. Partition key: This decide the physical location of the data in cluster.
2. Clustering Column: This decide by which the columns are sorted in a partition.
It is possible that you don’t have primary key without defining clustering columns.

Admin and Dev both


Question-: Either of the clustering or partition key columns are required?
A. True
B. False

Answer: B
Exp: Partition column is a must.

Admin only

Related Questions

---

Question-: In Cassandra cluster you should initiate the repair command for?
A. Adding or removing new nodes to the cluster.
B. if node goes out of the cluster then using repair command you can bring it back in the cluster.
C. using the repair command you can synchronize all the replicas in the Cassandra cluster.
D. using repair command client can reconnect with the Cassandra cluster if connection is broken.


Question-: You have set up a Cassandra cluster with nodes, three nodes in each datacenter. It was found that because of network disconnect for almost minutes one of the data center got disconnected. And you are worried that there were lot of write happening on the database during that time. What would you do in this case when network connectivity re-established?

A. You would execute it nodetool synchronize command.
B. you would execute nodetool repair command.
C. you would execute nodetool rejoin command
D. you would execute nodetool reconnect command


Question-: In Cassandra cluster to repair dropped writes, which of the following data structure is used to compare the data between two nodes?
A. B- tree
B. Merkel tree
C. Hashtable
D. Log data structure


Question-: You are trying to repair a table using nodetool repair command, but you have found that repair is not executed on that table. What could be the possible reason?
A. Because NodeSync is already enabled on the table
B. Repairing disable on that table
C. The node which is hosting the table is down.
D. This table was already repaired 6 hours before.


Question-: Which of the following is/are correct for repairing table on a particular node?
A. You should run when node was disconnected from the cluster for some time.
B. You should run repair command at least once before gc_grace_second expire
C. You have to make sure that your repair can finish before gc_grace_second window expire
D. You should run repair command when node is under high utilization.



Question-: Please map the following options for the Nodetool repair command.

A. - -par
B. - -pr
C. - - st
D. - - local

1. Parallel repair
2. Repairs only the primary token range
3. Access Mostly Uused Products by 50000+ Subscribers
4. Apply repairs only in the local datacenter.