Transaction states, Database Management System

The following variant of the primary copy asynchronous-update replication protocol has been proposed for totally replicated systems.

(a)  A transaction executing at site A updates only the replicas at A before it commits (it needed to access no other site since replication is total).

(b)  After the transaction commits, a second transaction is initiated to update the primary copies of all items updated at A.

(c)  After the transaction in step (b) has completed, each primary site propagates the update made at that site to all secondaries (including the one at site A). Updates made to a primary copy by several transactions are propagated to secondaries in the order in which the primary was updated.

Explain why, in step (b), all primaries must be updated in a single transaction and, in step (c), the update is propagated to site A.

 

Posted Date: 3/11/2013 1:18:10 AM | Location : United States







Related Discussions:- Transaction states, Assignment Help, Ask Question on Transaction states, Get Answer, Expert's Help, Transaction states Discussions

Write discussion on Transaction states
Your posts are moderated
Related Questions
Define Aggregate functions and what aggregate functions supported by the MySQL To calculate a summary value from a set of individual values and uses one of the functions known

DDL Compiler The DDL compiler changes the data definition statements (such as CREATE TABLE .... in SQL) into a set of tables having metadata tables. These tables have infor

Consider the entity type dependent related to employee entity, which is used to keep track of the dependents of every employee. The attributes of dependents are: name, sex, birth d

Explain the two types of participation constraint. 1. 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

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

Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole t

Information about films holds information about movies, stars and studios. Movies have a title, year of production, length and the film type. Stars have a name and address. Studi

Which database object does not physically exist? A view database object does not physically exist.

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;

In an organisation various projects are undertaken. Each projects can employ one or more employees. Every employee can work on one or more projects. Each project is undertaken on