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
tell me the functionality,advantages and disadvantages of student database

Improved availability: The data in a distributed system may be replicated so that it is at more than one site. Thus, the failure of a node or a communication link does not necessar

What do you understand by ACID? - ACID (Atomicity Consistency Isolation Durability) is a quality sought after in a reliable database. Here's the relevance of each quality:

what are the main characteristics of database

What is data independence? Data Independence: Techniques which permit data to be changed without affecting the applications in which procedure it. There are two types of data

Explain the function of Object model Object model describes the classes of objects in system, including their attributes and operations which they support. The analysis object

What is an E-R model? Draw an E-R Diagram for the company database with following Descriptions? The company is organized within departments. Each department has a unique name a

compare the features of oracle RDBMS with MySQL and Microsoft SQL server

What is Distributed system ? Distributed System - A distributed system consists of a number of processing parts in which are interconnected through a computer network and in

List the types of authorization. A) Read authorization B) Write authorization C) Update authorization D) Drop authorization