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

What is database trigger, What is database Trigger? A database trigger ...

What is database Trigger? A database trigger is a PL/SQL block that can explained to automatically execute for insert, update, and delete statements against a table. The trigge

Approach to implement traffic data management, There are many simple and co...

There are many simple and complex approaches to implement. These reports are based on some views or certain query. The following number of reports can be built. 1. The averag

Dataware house, ) Define a job scheduling strategy that will meet business ...

) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a picto

Difference between operating system and database security, Difference betwe...

Difference between Operating System and Database Security Security within the operating system can be executed at various levels ranging from passwords for access to system, t

Define hot swapping, Define hot swapping? Hot swapping permits the remo...

Define hot swapping? Hot swapping permits the removal of faulty disks and changes it by new ones without turning power off. Hot swapping decreases the mean time to repair.

Differance between ddl and sdl, Differance between DDL and SDL? DDL and...

Differance between DDL and SDL? DDL and SDL - The data definition language (DDL) is used through DBA and database designers to describe internal schema, conceptual schema, and

MYSQL, write an SQL statement to create the database in MYSQL server

write an SQL statement to create the database in MYSQL server

What is thread splitting, What is Thread splitting A thread of cont...

What is Thread splitting A thread of control is a path by which a set of state diagrams on that a single object is active at a time. Objects are shared between threads

What is multivalued attribute, What is Multivalued Attribute? Multival...

What is Multivalued Attribute? Multivalued Attribute - Multivalued attribute might have more than one value for an entity. For instance, PreviousDegrees of a STUDENT.

Example on relational database schema, Question: The following relation...

Question: The following relational database schema corresponds to a part of a database used by the Registry Department of a university. DEPARTMENT (d#, d-name, head-of-dept)

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