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

Define the term multimedia database, Question : (a) Explain with the h...

Question : (a) Explain with the help of appropriate examples the difference between ‘Data' and ‘Information'. (b) A digital image is an array of pixels, where each pixel h

Write short notes on index structure of files, WRITE SHORT NOTES ON INDEX S...

WRITE SHORT NOTES ON INDEX STRUCTURE OF FILES? There are two basic parts of indices 1.   Ordered indices 2.   Hash indices Every technique must be evaluated on the bas

Mapping, How external/conceptual mapping and conceptual /internal mapping i...

How external/conceptual mapping and conceptual /internal mapping is performed

North indian plains, i am not clear with the climetic condition of the nort...

i am not clear with the climetic condition of the north indian plain. can u plz explain it for me

Horizontal Fragmentation, I want to fragment existing table using java code...

I want to fragment existing table using java code... help me..!!

What is the full form of ddl, What is the full form of DDL? DDL is stan...

What is the full form of DDL? DDL is stand for Data Definition Language.

What is association, What is association? Give an example of association ...

What is association? Give an example of association Association is used for establishing relationships among classes. Association describe links among/between classes. For exa

Relation and relational schema, A relation has: Relational Schema ...

A relation has: Relational Schema Relation instance Relational Schema: A relational schema shows the relation's name, its attributes and the domain of every a

E-r model uses this symbol to represent weak entity set, E-R model uses thi...

E-R model uses this symbol to represent weak entity set ? A Doubly outlined rectangle symbol is used to represent weak entity set.

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