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

Urgent need tutoring in conjunction with help on assignment!, Hi is anyone ...

Hi is anyone well versed in accounting information systems available now to help me work through an important assignment due tomorrow at noon?

Explain the check clause, Explain the Check Clause The CHECK clause is ...

Explain the Check Clause The CHECK clause is employed to at the end of a CREATE TABLE statement specify table constraints. This is known as table-based constraint because it ap

Process of adjustment of inheritance, Process of Adjustment of inheritance ...

Process of Adjustment of inheritance During object design, inheritance is readjusted by rearranging classes and operations, and abstracting common behaviour.

Describe the benefits of OOD techniques, Describe the benefits of OOD techn...

Describe the benefits of OOD techniques OOD techniques are very useful for development of large and complex systems. It has been noted that large projects that are developed u

Create a database for store company details, You group has been hired by  T...

You group has been hired by  TrainingrUs.com to keeps track of training revenues. TrainingrUS.com wants you to keep scheduling. COURSE table contains following information:

DSS, WHAT IS DSS? WRITE ITS REQUIREMENTS.

WHAT IS DSS? WRITE ITS REQUIREMENTS.

What is theta join explain, What is theta join explain? Theta  Join  -...

What is theta join explain? Theta  Join  - The  theta  join  operation  is  an  extension  to  the  natural-join operation which permits us to merge selection and a Cartesian

Define tables students and teachers as sub tables of people, Write a query ...

Write a query to define tables students and teachers as sub tables of people? Create table students of student under people Create table teachers of teacher under people

Write a qbe query to display names of cs department, Consider a table stude...

Consider a table student (std_id, std_name, date_of_birth, percent_marks, dept_name). Write a QBE query to display names of Computer Science department students who have scored mo

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