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

What is trigger, What is Trigger? Trigger: A database trigger is proced...

What is Trigger? Trigger: A database trigger is procedural code which is automatically executed in response to specific events on a particular table in a database. Triggers can

ER diegrams, How to draw an ER diagram to a finance companz

How to draw an ER diagram to a finance companz

Entity identifier key attributes, An entity type usually has an attribute w...

An entity type usually has an attribute whose values are distinct for every individual entity in the collection. Such an attribute is known as a key attribute and its values can be

Write a short note on temporary tables, Write A short note on temporary tab...

Write A short note on temporary tables? Temporary Tables - Temporary tables exists solely for a particular session, or whose data persists for the duration of the transaction

Heap files (unordered file), Heap files (unordered file) Mostly these f...

Heap files (unordered file) Mostly these files are unordered files. It is the easiest and most basic type. These files having of randomly ordered records. The records will have

Relationships, Let us first describe the term relationships. What Are Re...

Let us first describe the term relationships. What Are Relationships? A relationship can be defined as: A set of associations or connection, or A rule for communic

Develop motel point of sale software, Project Description: I need a poin...

Project Description: I need a point of sale for motels. It needs to run on windows and requires being network able so that we can have more than one computer using it at once.

What is catalog in dbms, What is catalog in DBMS? Catalog - A relationa...

What is catalog in DBMS? Catalog - A relational DBMS maintains information about every table and index in which it contains. A catalog is a collection of special tables that st

Derived horizontal fragmentation, Derived horizontal fragmentation: Some ap...

Derived horizontal fragmentation: Some applications may include a join of two or more relations. If the relations are stored at dissimilar locations, there may be a major overhead

What is the use of a slotted-page structure, What is the use of a slotted-p...

What is the use of a slotted-page structure and what is the information are there in the header? The slotted-page structure is used for organizing records within a one block.

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