Question-12: Select the correct statement with regards to Partitioner?

1. It is the partitioner responsibility to distribute the data across the nodes in the cluster for load balancing.
2. It is the user who decide on which node first replica of the data should be placed and then partitioner decide how to distribute other replicas across other nodes in the cluster.
3. Partition key and primary key may be the same.
4. Murmur3Partitioner is decommissioned and should not be used in new version of Cassandra Cluster.

Ans: A, C

Exp: It is the partitioner responsibility to distribute the data evenly across all the nodes in the cluster for load balancing. Partitioner decides which node receives the first replica if a piece of data and how to distribute other replicas across other nodes in the cluster. Each row of data is uniquely identified by a primary key which may be same as its partition key. Even partition key can include other clustering columns. A partitioner is a hash function that derives a token from the primary key of that row. The partitioner uses the token value to determine which nodes in the cluster receive the replicas of that row. The Murmur3Partitioner is a valid partitioner strategy for Cassandra Cluster and even suitable for almost all cases.