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

Differentiate between strict and rigorous two phase locking, Differentiate ...

Differentiate between strict two-phase and rigorous two-phase with conversion protocol Ans:  Strict two-phase locking holds all its exclusive that is write locks until commit t

Which model is used to store data in tree structures, 1. Which model is use...

1. Which model is used to store data in tree structures Ans: Hierarchical model is used to store data in tree structures

Database Management System, please give me introduction to full data in D B...

please give me introduction to full data in D B M S in a short assignment

Describe deductive databases and relational databases, Problem : (b) A ...

Problem : (b) A deductive database system is essentially the outcome of applying mathematics logic to database management, where logic is used for both data representation and

What is recovery management component, What is recovery management componen...

What is recovery management component? Ensuring durability is the responsibility of a software component of the base system known as the recovery management component.

Functional dependency in entities, FDs in Entities : Student entity : ...

FDs in Entities : Student entity :                                                Enrolment number →  Student name, Address Course Entity :

Explain group by clause in sql, Explain group By clause in SQL? Group B...

Explain group By clause in SQL? Group By clause in SQL: The GROUP BY clause can be used in a SELECT statement to collect data across multiple records and group the results thro

Text mining, Text Processing: Use readLines to read SOU.txt into R. Cr...

Text Processing: Use readLines to read SOU.txt into R. Create a vector called Pres containing the names of the presidents giving each speech. To do this, rst identify the lin

Which element in the database can modified by changing, Which element in th...

Which element in the database can modified by changing the data dictionary? Data elements in the database can be changed or modified through changing the data dictionary.

Describes the several relationship constraints, Describes the several relat...

Describes the several relationship constraints through giving suitable example? Constraints on relationships: There are two kinds of constraints on relationships. 1) Mapping

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