Cassandra Partitioners

• A partitioner determines how data is distributed across the nodes in the cluster (including replicas)
• Basically, a partitioners is a function for deriving a token (a representating a row from its partition key, typically by hasing)
• Each row of data is distiributed across the cluster by the value of the token.

 

Strategies

• Murmur3Partitioner (default, from v1.2)
  • uniformly distributes data across thre cluster based on MurmurHash hash value.
• RandomPartitioner
  • uniformly distributes data across thre cluster based on MD5 hash values
• ByteOrderedPartitioner
  • keeps an ordered distributed of data lexcially by key bytes.

 

• if using vnodes, don’t need to calculate the tokens
• if not using vnodes, must calculate the tokens to assign to the initial_token parameter in the cassandra.yaml