25-07-2012, 01:29 PM
A STUDY OF KANGAROO TRANSACTION MODEL FOR MOBILE
TRANSACTION MANAGEMENT
[attachment=28880]
INTRODUCTION
Advances in portable computing devices, computer technology and wireless
communication networks have lead to the emergence of mobile computing systems that
have provided users the opportunity to access information and services regardless of
their physical location or movement behavior [1].
Mobile computing enables enterprises to increase employee productivity, improve
customer service and reduce costs. Many organizations deploy mobile solutions, by
extending their existing applications or building new ones [5].
Wireless technology offers enterprises two fundamental opportunities – to run a
company more efficiently using the wireless Internet, and to exploit new business
opportunities that arise by providing customers, partners, suppliers, and employees with
expanded access to the Internet from a variety of wireless devices. Early adopters of
wireless technology are transforming their business and seeing competitive advantages
in their respective industries in the form of cost reduction and productivity.
Problem Statement
In Kangaroo Transaction model each time a mobile host connects to a different
base station, communication will take place with the previous base stations in order to
transfer transaction information to the new base station. Then, a new JT (Joey
transaction) will be created in the new base station.
Each Kangaroo Transactions use either the “compensating mode” or the” split
mode”. In split mode if a JT fails, no extra operation is needed on previously committed
JTs. n compensating mode, however all of the previously executed (and committed) JTs
must be compensated for by using compensating transactions. This requires a linked list
of all these JTs to be maintained by keeping the previous “base station id” at each JT
site. However, when/if a base station fails/ (or is disconnected) it will not be possible to
find out the preceding JTs.
Transactions
A common element of all mobile computing systems is the use of a transaction. A
transaction is defined as a collection of database operations that form a single, logical
unit of work. A traditional relational database management system is responsible to
maintain four key properties for all transactions. The properties are Atomicity,
Consistency, Isolation, and Durability. The meaning of each is provided below.
• Atomicity: All operations occur or none at all.
• Consistency: Relations and constraints among data elements must
preserve consistency of the data.
Mobile Transactions Characteristics
The access to the future information systems through mobile computers will be
performed with the help of mobile transactions.
However, a transaction in this environment is different from the transactions in the
centralized or distributed databases in the following ways.
• The mobile transactions might have to split their computations into sets of
operations, some of which execute on mobile host while others on
stationary host. A mobile transaction share their states and partial results
with other transactions due to disconnection and mobility.
• The mobile transactions require computations and communications to be
supported by stationary hosts.
• As the mobile hosts move from one cell to another, the states of
transaction, states of accessed data objects, and the location information
also move.
• The mobile transactions are long-lived transactions due to the mobility of
both the data and users, and due to the frequent disconnections.
• The mobile transactions should support and handle concurrency, recovery,
disconnection and mutual consistency of the replicated data objects [4].
TRANSACTION MANAGEMENT
[attachment=28880]
INTRODUCTION
Advances in portable computing devices, computer technology and wireless
communication networks have lead to the emergence of mobile computing systems that
have provided users the opportunity to access information and services regardless of
their physical location or movement behavior [1].
Mobile computing enables enterprises to increase employee productivity, improve
customer service and reduce costs. Many organizations deploy mobile solutions, by
extending their existing applications or building new ones [5].
Wireless technology offers enterprises two fundamental opportunities – to run a
company more efficiently using the wireless Internet, and to exploit new business
opportunities that arise by providing customers, partners, suppliers, and employees with
expanded access to the Internet from a variety of wireless devices. Early adopters of
wireless technology are transforming their business and seeing competitive advantages
in their respective industries in the form of cost reduction and productivity.
Problem Statement
In Kangaroo Transaction model each time a mobile host connects to a different
base station, communication will take place with the previous base stations in order to
transfer transaction information to the new base station. Then, a new JT (Joey
transaction) will be created in the new base station.
Each Kangaroo Transactions use either the “compensating mode” or the” split
mode”. In split mode if a JT fails, no extra operation is needed on previously committed
JTs. n compensating mode, however all of the previously executed (and committed) JTs
must be compensated for by using compensating transactions. This requires a linked list
of all these JTs to be maintained by keeping the previous “base station id” at each JT
site. However, when/if a base station fails/ (or is disconnected) it will not be possible to
find out the preceding JTs.
Transactions
A common element of all mobile computing systems is the use of a transaction. A
transaction is defined as a collection of database operations that form a single, logical
unit of work. A traditional relational database management system is responsible to
maintain four key properties for all transactions. The properties are Atomicity,
Consistency, Isolation, and Durability. The meaning of each is provided below.
• Atomicity: All operations occur or none at all.
• Consistency: Relations and constraints among data elements must
preserve consistency of the data.
Mobile Transactions Characteristics
The access to the future information systems through mobile computers will be
performed with the help of mobile transactions.
However, a transaction in this environment is different from the transactions in the
centralized or distributed databases in the following ways.
• The mobile transactions might have to split their computations into sets of
operations, some of which execute on mobile host while others on
stationary host. A mobile transaction share their states and partial results
with other transactions due to disconnection and mobility.
• The mobile transactions require computations and communications to be
supported by stationary hosts.
• As the mobile hosts move from one cell to another, the states of
transaction, states of accessed data objects, and the location information
also move.
• The mobile transactions are long-lived transactions due to the mobility of
both the data and users, and due to the frequent disconnections.
• The mobile transactions should support and handle concurrency, recovery,
disconnection and mutual consistency of the replicated data objects [4].