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

Product adder required for ecommerce website, Product adder required for Ec...

Product adder required for Ecommerce website Project Description: Want a product adder for 500 products I have a magento website and need products pulled from site A to my si

What do you mean by atomicity and aggregation, What do you mean by atomicit...

What do you mean by atomicity and aggregation? Atomicity : Either all actions are carried out or none are. Users should not have to worry about the effect of incomplete trans

Deletion anomalies-data redundancy, Deletion Anomalies: Loss of important ...

Deletion Anomalies: Loss of important Information: In some cases, useful information may be lost when a tuple is deleted. For instance, if we delete the tuple corresponding to stu

Skills required, wrie a report on whether a BSc n information systems devel...

wrie a report on whether a BSc n information systems develops the skills required by employers in Database administration

State the step- implement software control designer, Implementing software ...

Implementing software control To implement software control designer must redesign strategy of state event model which is present in dynamic model. There are three basic ap

Using literal character string-data manipulation language, Using Literal Ch...

Using Literal Character String Example: To print IS A as one string with column name employee SELECT ENAME || ' IS A ' || JOB AS "EMPLOYEE" FROM EMP;

Relational schema, crete a data base relationship model Entity: ...

crete a data base relationship model Entity: Students; Professors; Dormitories buildings; Attributes of students: Name; Address; Dorm;

Query evolution, what is query processing ,query optimization and performan...

what is query processing ,query optimization and performance turring?

Assignment, Birla Institute of Technology & Science, Pilani Work-Integrated...

Birla Institute of Technology & Science, Pilani Work-Integrated Learning Programmes Division Second Semester 2012-2013 EC-1 Assignment 2 (7.5% of the grade) Course No. : SS ZG

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