Explain the concept of two-phase locking, Database Management System

Assignment Help:

Explain the Concept of Two-phase Locking

It concerns the positions of locking and unlocking operations in each transaction.  In this protocol every transaction issue lock and unlock requests in two phases. 

Growing Phase:  In this phase a transaction might acquire locks but may not release any lock. Here the of locks rises from zero to the maximum for the transaction. 

Shrinking Phase:  In this phase a transaction might release locks but may not obtain any new locks. Here the number of locks reduces from maximum to zero. 

The major concept of this protocol is that, all the locks are first obtained before any of the locks released. No new locks can be granted later than the releasing of any lock.


Related Discussions:- Explain the concept of two-phase locking

Which is another name for weak entity, Which is another name for weak entit...

Which is another name for weak entity? Child is another name of weak entity.

What is a database graph, What is a database graph? The partial orderin...

What is a database graph? The partial ordering implies that the set D may now be viewed as a directed acyclic graph, known as a database graph.

Vertical fragmentation, Vertical Fragmentation- Vertical fragmentation grou...

Vertical Fragmentation- Vertical fragmentation groups together only those attributes in a relation that are used jointly by various important transactions. A vertical fragment is d

State the meaning of self-transition, What is self-transition? ...

What is self-transition? If there is a transition which goes back to same state, it is known as "self- transition." With a trigger action exit action would be executed f

Dependency preservation, Dependency Preservation It is obvious that the...

Dependency Preservation It is obvious that the decomposition must be lossless so that we do not lose any information from the relation that is decomposed. Dependency preservati

EER models, Ask question #MinimThe Georgia Tech Library (GTL) has approxima...

Ask question #MinimThe Georgia Tech Library (GTL) has approximately 16,000 members, 100,000 titles, and 250,000 volumes (an average of 2.5 copies per book). About 10 percent of the

What are the kinds of strings, What are the kinds of Strings?  -A binar...

What are the kinds of Strings?  -A binary string in MySQL is one that MySQL treats as case sensitive in comparisons. -A non binary string in MySQL is one that MySQL does'nt

Determine the statement- state as location within a program, State as Locat...

State as Location within a Program In this traditional approach, location of control inside a program totally defines the program state. Any finite state machine may be implem

Explain weak and strong entity type, Explain weak and strong entity type ? ...

Explain weak and strong entity type ? Weak and Strong entity type: An entity set which does not have a primary key is referred to as a weak entity set. The existence of a wea

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd