Optimistic concurrency control, Database Management System

Optimistic Concurrency Control

Is locking the only way to stop concurrency related problems? There exist some other ways too. One such way is known as an Optimistic Concurrency control.

The basic logic in optimistic concurrency control is to permit the concurrent transactions to update the data items supposing that the concurrency related trouble will not occur. Though, we require to reconfirm our view in the validation phase. Thus, the optimistic concurrency control algorithm has the following phases:

a)   READ Phase: In a read phase, transaction T reads the data items from the database into its private workspace. All the updates of the transaction can only alter the local copies of the data in the private workspace.

b)   VALIDATE Phase: Checking is performed to verify whether the read values have changed during the time transaction was updating the local values. This is performed by evaluating the current database values to the values that were read in the private workspace. In case, the values have altered the local copies are thrown away and the transaction aborts.

c)   WRITE Phase: In a write phase, if validation phase is successful the transaction is committed and updates are applied to the database, otherwise the transaction is rolled back.

 

Posted Date: 3/12/2013 3:12:05 AM | Location : United States







Related Discussions:- Optimistic concurrency control, Assignment Help, Ask Question on Optimistic concurrency control, Get Answer, Expert's Help, Optimistic concurrency control Discussions

Write discussion on Optimistic concurrency control
Your posts are moderated
Related Questions
In which format database schema is written ? Data base schema is written in the DDL format.

Consider the E/R schema with weak entity sets shown below. Come up with the SQL CREATE TABLE statements (with appropriate primary key, unique and foreign key constraints). Include

Types of Locks There are two necessary types of locks: Binary lock : This locking mechanism has two states for to a data item: locked or unlocked Multiple-mode loc

Describe different steps of the object-oriented design process.  The broad steps of the object-oriented design process are: a. Define context and modes of use of the system

Determine the minimal set of functional dependencies for the following data. This table is part of the OHSU database of extracurricular activities and tracks the DMICE band's co

can you create a database for me in oracle/sql

What is hashing file organization? In the hashing file organization, a hash function is computed on some attribute of every record. The result of the hash function specify in

Describe the static hash file with buckets and chaining and show how insertion, deletion and modification of a record can be performed. In static hash file organization, the wo

List two restrictions that are applied on the modification (updation, insertion or deletion) of base tables through view.  Ans: The two restrictions are: 1. If a view

Explain the Functional Mode with help of an example. Functional Model  The functional model shows a computation and functional derivation of data values in it without ind