Failures and recovery, Database Management System

Assignment Help:

Failures and Recovery

In practice various things might occur to prevent a transaction from completing. Recovery methods are used to bring database, which does not satisfy consistency needs, into a consistent state.  If a transaction finishes normally and commits then all the alters made by the transaction on the database are permanently registered in the database. They should not be lost. But, if a transaction does not finish normally and terminates abnormally then all the changes made by it should be discarded.  An abnormal termination of a transaction may be because of various causes, including:

a)  User may decide to terminate the transaction issued by him/ her

 b)  There may be a deadlock in the system

c)   There may be a system failure.

The recovery mechanisms must make sure that a consistent state of database can be restored under all circumstances.  In case of transaction terminate or deadlock, the system remains in control and can deal with the failure but in case of a system failure the system loses control because the computer itself has failed. Will the results of such type of failure be catastrophic? A database has a vast amount of useful information and any system failure should be recognised on the restart of the system. The DBMS should recover from some such failures.

 


Related Discussions:- Failures and recovery

Determine the method of choosing algorithms, Determine the method of Choosi...

Determine the method of Choosing Algorithms In general, most of operations are easy and have a satisfactory algorithm since description of what is to be done also shows how i

Explain discretionary access control, Problem: (a) Given the following ...

Problem: (a) Given the following relation: Stats(Name,Sex,Children, Occupation, Salary, Tax, Audits) Write SQL code to define the following security constraints: (i) User

Higher normal forms, Higher Normal Forms Is there more normal forms beyond...

Higher Normal Forms Is there more normal forms beyond BCNF? Yes, though, these normal forms are not based on the concept of functional dependence. More normalisation is needed if

Abstract data structures, The C_Artist  application will be developed using...

The C_Artist  application will be developed using the C language (C99 standards) and will be able to compile without warnings and link and run in the Swinburne computer laboratorie

Explain the disadvantages of creating a temporary table, Explain the disadv...

Explain the disadvantages of creating a temporary table? If you have already created a temporary table with a shown name and attempting to create a second one with that nam

Data management, Develop a database broker framework to implement a persist...

Develop a database broker framework to implement a persistence mechanism for the domain objects involved in the use case dealt with in Question 2.  a. Specify the attribute type

Explain a data dictionary, What is a data dictionary? Data Dictionary ...

What is a data dictionary? Data Dictionary is a main source of data in a data management system.  Its major function is to carry the creation and management of data definition

Goals, what are the purposes of dbms in details

what are the purposes of dbms in details

Explain the data access protocol, (a) Explain the three types of potentia...

(a) Explain the three types of potential mistake which could occur if concurrency control is not properly enforced in the database system. Support your answer with appropriate ex

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