Cassandra Practice Test

What does the read_repair_chance setting influence in Cassandra?

1. Controls the time for transactions

2. Sets the cost of storage

3. Sets the probability of performing a read repair

4. Determines the replication factor

The correct answer is: Sets the probability of performing a read repair

The read_repair_chance setting in Cassandra specifically influences the likelihood that a read repair will be executed during a read operation. Read repair is a mechanism used by Cassandra to ensure data consistency across replicas. When a read request is made, if Cassandra detects that the data across different replicas is inconsistent, it can correct this discrepancy through read repair. By adjusting the read_repair_chance, a developer can control the probability that such a repair will happen. A higher value increases the likelihood of inconsistency repairs being made during read operations, which can enhance data accuracy but may also introduce latency due to the additional overhead involved. Conversely, a lower value reduces the chance of read repairs, which might lead to slightly better performance but at the risk of serving outdated or inconsistent data. In contrast, the other options refer to different configurations or concepts within Cassandra. The time for transactions, storage costs, and replication factors are managed through separate settings and do not relate to the operational behavior of read repairs. Hence, the focus of the read_repair_chance setting makes it a crucial aspect of maintaining data consistency and integrity in a distributed database environment.