How do optimistic and pessimistic concurrency control differ?

What are the main differences between optimistic and pessimistic concurrency control?

Optimistic concurrency control (OCC) assumes that conflicts are rare and allows transactions to execute without locking resources. Pessimistic concurrency control, on the other hand, locks resources to prevent conflicts, assuming that they are likely to occur.

Can you give me an example of when to use each method?

Sure! Use OCC in scenarios with low contention, like read-heavy applications. Use pessimistic control in high contention environments, like banking systems where data integrity is critical.

What are the advantages and disadvantages of each approach?

OCC's advantage is better performance in low contention, but it can lead to rollbacks. Pessimistic control ensures data integrity but can cause delays due to locking.

How do these methods impact database performance?

OCC can improve performance by reducing wait times, while pessimistic control can lead to bottlenecks due to resource locking.