Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
locking mechanism
In databases and transaction processing, two-phase locking (2PL) is a concurrency control method that guarantees serializability.
It is also the name of the resulting set of database transaction schedules (histories). The protocol uses locks, applied by a transaction to data, which may block (interpreted as signals to stop) other transactions from accessing the same data during the transaction's life.
By the 2PL protocol, locks are applied and removed in two phases:
Expanding phase: locks are acquired and no locks are released.
Shrinking phase: locks are released and no locks are acquired.Two types of locks are used by the basic protocol: Shared and Exclusive locks. Refinements of the basic protocol may use more lock types. Using locks that block processes, 2PL may be subject to deadlocks that result from the mutual blocking of two or more transactions.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.