Define Thomas write rule

Thomas' write rule: The Thomas' write rule is a modification of timestamp-ordering protocol for concurrency control. Assume that transaction T_i issues write (Q) and T_S (T_i) is its timestamp after that the subsequent actions are taken depending on T_S(T ) and the read-write timestamps of the data item Q:

• If T_S (T_i) i is generating was previously needed, and it had been assumed that the value would never be produced. Therefore, the system rejects the write operation and rolls Ti back.
• If T_S (T_i) < W-timestamp (Q), after that Ti is attempting to write an obsolete value of Q. Therefore, this write operation can be ignored otherwise, the system carries out the write operation and sets W-timestamp (Q) to T_s(T_i).

Posted Date: 5/3/2013 7:00:27 AM | Location : United States

Ask an Expert

Related Discussions:- Define thomas write rule, Assignment Help, Ask Question on Define thomas write rule, Get Answer, Expert's Help, Define thomas write rule Discussions

Write discussion on Define thomas write rule
Your posts are moderated

Write your message here..

Related Questions

Example database application, We will explain here an example database appl... We will explain here an example database application having COLLEGE database and use it in showing several E-R modelling concepts. College database remains track of faculty, Stu

Determine Which is not a consequence of concurrent operation, Determine Whi... Determine Which is not a consequence of concurrent operations? Ans: Update anomaly.

List the string operations supported by sql, List the string operations sup... List the string operations supported by SQL? 1) Pattern matching Operation 2) Concatenation 3) Extracting character strings 4) Converting among uppercase and lower cas

Explain the two types of participation constraint, Explain the two types of... Explain the two types of participation constraint.  Total: The participation of an entity set E in a relationship set R is said to be total if each entity in E participates i

Goals, what are the purposes of dbms in details what are the purposes of dbms in details

Designing a Human Resources Database LASA1, Scenario: You are a freelance ... Scenario: You are a freelance database designer who has just been contacted by a small software development company named Altair Software. The president of the company has asked

What is meant by the degree of relationship set, What is meant by the degre... What is meant by the degree of relationship set? The degree of relationship type is the number of participating entity types.

What is hash file organization, What is hash file organization? What are t... What is hash file organization? What are the causes of bucket overflow within a hash file organization? What can be completed to decrease the occurrence of bucket overflow?

Concatenation operator-data manipulation language, Concatenation operator ... Concatenation operator Example : Printing name and job as one string as column name employees: SELECT ENAME||JOB "EMPLOYEES" FROM EMP;

What is meant by normalization of data, What is meant by normalization of d... What is meant by normalization of data? It is a process of examining the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the prop