Advantages of Locking
- Data Consistency: Locking can help ensure data consistency by preventing multiple users from modifying the same data simultaneously. By controlling access to shared resources, locking can help prevent data conflicts and ensure that the database remains in a consistent state.
- Isolation: Locking can ensure that transactions are executed in isolation from other transactions, preventing interference between transactions and reducing the risk of data inconsistencies.
- Granularity: Locking can be implemented at different levels of granularity, allowing for more precise control over shared resources. For example, row-level locking can be used to lock individual rows in a table, while table-level locking can be used to lock entire tables.
- Availability: Locking can help ensure the availability of shared resources by preventing users from monopolizing resources or causing resource starvation.
Implementation of Locking in DBMS
Locking protocols are used in database management systems as a means of concurrency control. Multiple transactions may request a lock on a data item simultaneously. Hence, we require a mechanism to manage the locking requests made by transactions. Such a mechanism is called a Lock Manager. It relies on the process of message passing where transactions and lock manager exchange messages to handle the locking and unlocking of data items.