Study of Locking Protocols in Database Management for Increasing Concurrency

Transaction performs lock and unlocking operations on the data items required in its execution. These operations on the data items are important in order to maintain consistency of the database as the data may be accessed by concurrently executing transactions. Designing locking and unlocking mechanism on the data items it involves fine tuning which involves the following factors a) level of granularity b) appropriate version to be locked c) supporting the compatibility mode. In this paper, two locking protocols are covered namely Multi version and Multi granularity locking protocol. The Multiple granularity locking protocol specify at which level locks can be applied, if the lock is applied on exact level of database, then definitely system performance can be improved and basically explore how can be increase the concurrency of MGL locking protocol by considering suitable example. An efficient locking technique is proposed by integrating multi version with multiple granularity in the hierarchical structure. This allows several requesting transactions to be executed in parallel by serving them an appropriate version to read while the write operation of some other transaction is in progress.