Wound-wait scheme-deadlock prevention, Database Management System

Assignment Help:

"Wound-wait" scheme: It is based on a preemptive method. It is based on a simple rule:

                  If Ti requests a database resource that is held by Tj

                   then if Ti has a larger timestamp (Ti is younger) than that of Tj 

                    it is allowed to wait;

     else Tj is wounded up by Ti.

For example, suppose that 3 transactions T1, T2 and T3 were generated in that series, then if T1requests for a data item which is presently held by transaction T2, then T2 is rolled back and data item is allotted to T1 as T1 has a smaller time stamping than that of T2. Though, if T3 requests for a data item which is presently held by transaction T2, then T3 is permitted to wait.

                                    2389_Wound-wait scheme-deadlock prevention.png

                                                   Figure: Wound-wait Scheme of Deadlock prevention

It is vital to see that whenever any transaction is rolled back, it would not make a starvation condition, i.e., no transaction gets rolled back repeatedly and is never permitted to make progress. Also both "wait-die" & "wound-wait" idea avoid starvation. The number of aborts & rollbacks will be higher in wait-die scheme than in the wound-wait idea. But one main problem with both of these ideas is that these ideas may result in unnecessary rollbacks.


Related Discussions:- Wound-wait scheme-deadlock prevention

Explain the two constraints check and foreign key in sql, Explain the two c...

Explain the two constraints, check and foreign key in SQL along with an example for each. Give the syntax. CHECK constraint - CHECK constraint specifies an expression which

What is nested relational model, What is nested relational model? The n...

What is nested relational model? The nested relational model is an extension of relational model in which domains might be either atomic or relation valued.

Database Models, Benefits and Limitations od Data Models?

Benefits and Limitations od Data Models?

Design a gennalization and specialization hierarchy for an a, Design a genn...

Design a gennalization and specialization hierarchy for an automobile sales company

Distributed transaction atomic-consistent-isolated, A distributed transacti...

A distributed transaction consists of subtransactions that execute at different sites and access local DBMSs at those sites. For example, a distributed transaction that transfers m

Database tables design and test queries, Load sample data into the database...

Load sample data into the database tables design and test queries to return the following information • All rows and columns for employees • All rows and columns for customers •

Explain the object-oriented decomposition, Explain the Object-oriented deco...

Explain the Object-oriented decomposition Object-oriented decomposition targets at identifying individual sovereign objects that encapsulate both a state and certain behavio

Compare three clustering algorithms in weka, Compare three clustering algor...

Compare three clustering algorithms in Weka. For this comparison, you will need to use at least two different datasets. Run the algorithms on the datasets, and use the visual

What is the function of a domain, What is the function of a Domain? A d...

What is the function of a Domain? A domain defines the technical settings of a table field. A domain describes a value range, which sets the permissible data values for the

Discuss along with examples about several types of er model, Discuss along ...

Discuss along with examples about several types of attributes present in the ER model? Types of Attributes are: • SIMPLE attributes are attributes which are drawn from the ato

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