What does Read Repair do in Cassandra?

Read Repair plays a crucial role in maintaining data consistency across replicas in Cassandra. It operates during read operations by checking whether the data read from the different replicas is consistent. If it finds discrepancies among the replicas, Read Repair will update the stale replicas with the correct data from the other replicas. This process helps ensure that any future read requests get the most accurate and up-to-date information.

By comparing data across replicas during a read request, Read Repair mitigates the risk of serving outdated information to users and addresses potential inconsistencies that might have occurred due to factors like network partitions or delayed writes. This feature is vital for ensuring that all replicas eventually converge to the same state, maintaining the integrity and reliability of the distributed database.