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

What are the drawbacks of shadow-paging technique, What are the drawbacks o...

What are the drawbacks of shadow-paging technique? The drawbacks of shadow paging is:- a) Commit Overhead b) Data fragmentation c)  Garbage collection

Explain hash file organization, Explain hash file organization? Hash fu...

Explain hash file organization? Hash functions a) The distribution is uniform Hash functions assign each bucket the similar number of search -key values from the set of a

Write the sql code, Express the following queries in SQL: (a) Write the...

Express the following queries in SQL: (a) Write the SQL code that will create ALL the four tables given in the appendix. Your answer should not contain the primary key and

Related Rates, All edges of a cube are expanding at a rate of 6 centimeters...

All edges of a cube are expanding at a rate of 6 centimeters per second. How fast is the surface area changing when each edge is (a) 2 centimeters and (b) 10 centimeters?

Draw the precedence graph, Draw the precedence graph of the following sched...

Draw the precedence graph of the following schedule and determine whether the schedule is serializable. (Note that all instructions, except lock and unlock, are omitted. We assume

Command line interfaces, Command Line Interfaces: These are interactive int...

Command Line Interfaces: These are interactive interfaces, character-based that let you use the complete power and functionality of the DBMS query language directly. They permit yo

Database manager, Database Manager It is the interface among low-leve...

Database Manager It is the interface among low-level data, queries and application programs. Databases typically need a large amount of storage space. It is kept on disks, as

Explain the advantages of dbms over file oriented system, Explain the main ...

Explain the main advantages of DBMS over File Oriented System ?

Reflects organisational structure, Reflects organisational structure: Many ...

Reflects organisational structure: Many organizations are distributed over various locations. If an organisation has many offices in dissimilar cities, databases used in such an ap

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