Cassandra Consistency Levels Explained

Cassandra’s consistency level refers to the degree to which the system guarantees data consistency when performing read and write operations on the database. Cassandra offers three consistency levels.

1. When a client initiates a write request, it only needs to write the data to at least one replica for the request to be successful. For read requests, data can be read from one replica without waiting for all replicas to synchronize.
2. QUORUM: When a client initiates a write request, the data must be written to at least more than half of the replicas to return a successful response. Similarly, read requests also need to retrieve data from at least more than half of the replicas to ensure data consistency.
3. For all client-initiated write requests, the data must be written to all replicas before returning success. Similarly, read requests must also read data from all replicas to ensure data consistency.

Different consistency levels have a trade-off between data consistency and performance, allowing users to choose the appropriate consistency level based on their own needs and system performance.