Transaction states, Database Management System

Assignment Help:

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.

 


Related Discussions:- Transaction states

I need automated trading engine for crypto currencies, Project Description:...

Project Description: Looking to prepare automated trading engine for alternate cyprto currencies starting with Cryptsy, finally integrating into other exchanges. Need to work wi

What is the function of a domain, What is the function of a Domain? A d...

What is the function of a Domain? A domain defines the technical settings of a table field. A domain describes a value range, which sets the permissible data values for the

Define union compatibility, Define union compatibility? Explain why INTERSE...

Define union compatibility? Explain why INTERSECTION of two relations cannot be performed if they are not union compatible? Two relations R(A1, A2,-------, An) and S(B1, B2,--

What is bcnf boyce-codd normal form, BCNF Boyce-Codd Normal Form A rel...

BCNF Boyce-Codd Normal Form A relation schema R is in BCNF if it is in 3NF and accepts an additional constraint that for every FD X A, X has to be a candidate key. If a relati

Explain function group, What is a function group? A function group is ...

What is a function group? A function group is a collection of logically related modules that share global data with every other.  All the modules in the group are contained in

Accounting and external reporting, List the internal controls that should b...

List the internal controls that should be in effect solely because a EDP system is employed, classifing them as (1) Those controls pertaining to input of information and (2) All ot

Determine the object-oriented design process, An object-oriented design pro...

An object-oriented design process  1. Define the context and modes 2. Designs the system architecture 3. Identifies the principal system objects 4. Identifies concurrency in

What is transaction, What is transaction? Transaction is a unit of prog...

What is transaction? Transaction is a unit of program implementation that accesses and possibly updated several data items.

Determine the statement- state as location within a program, State as Locat...

State as Location within a Program In this traditional approach, location of control inside a program totally defines the program state. Any finite state machine may be implem

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