Distributed Databases Questions Medium
A distributed data concurrency control protocol in distributed databases is a mechanism that ensures the consistency and correctness of data access and modification in a distributed environment where multiple users or processes concurrently access and modify the data. It manages the coordination and synchronization of concurrent transactions to prevent conflicts and maintain data integrity.
Concurrency control protocols in distributed databases typically involve techniques such as locking, timestamp ordering, and optimistic concurrency control. These protocols aim to provide isolation and serializability of transactions, ensuring that the execution of concurrent transactions does not lead to data inconsistencies or conflicts.
Lock-based protocols involve acquiring and releasing locks on data items to control access. This ensures that only one transaction can access a particular data item at a time, preventing conflicts. However, it can lead to issues such as deadlocks and reduced concurrency.
Timestamp ordering protocols assign unique timestamps to transactions and use these timestamps to determine the order of execution. Transactions are allowed to proceed only if their timestamps do not conflict with the timestamps of other transactions. This approach ensures serializability and avoids conflicts.
Optimistic concurrency control protocols assume that conflicts are rare and allow transactions to proceed without acquiring locks initially. However, before committing, the protocol checks for conflicts and rolls back transactions if conflicts are detected. This approach reduces the overhead of acquiring and releasing locks but requires additional validation steps.
Overall, a distributed data concurrency control protocol plays a crucial role in ensuring data consistency and integrity in distributed databases by managing concurrent access and modification of data.