Middleware%20Mediated%20Transactions%20

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Middleware Mediated Transactions Conditional
Messaging

• Expert Topic
• ECE1770 Spring 2003
• Tim Chen John C Wu
• Electrical and Computer Engineering
• University of Toronto

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Agenda

• John
• Middleware Mediated Transactions
• Middleware Mediation
• Transactions
• MMT
• Tim
• Conditional Messaging
• D-Spheres

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Introduction

• Middleware Mediated Transactions (MMT) integrate
  message-oriented transactions and distributed
  object transactions
• Supports reliable and flexible interactions
  between heterogeneous and autonomous components

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Middleware Mediation

• Implicit Explicit Mediation
• Component Connection and Interaction
• Topology (11, 1n, nm)
• Binding
• Life-cycle dependency
• Synchronicity
• Reliability
• Delivery
• Processing

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Transactions

• Database Transactions
• Distributed Object Transactions (DOT)
• Message-oriented Transactions (MOT)

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Middleware Mediated Transactions

• Sample Scenarios and Requirements

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Middleware Mediated Transactions

• Coupling Modes

Visibility Immediate, on commit, on abort, deferred
Context None, shared, separate
Forward Dependency None, commit, abort
Backward Dependency None, vital, mark-rollback
Production Transactional, independent
Consumption On delivery, on return, atomic, explicit
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Service Support for MMT

• Dependency-Spheres by IBM Research
• X2TS by Darmstadt University of Technology

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Traditional Middleware

• Objectoriented middleware(OOM)
• Software components rendered as distributed
  object with well defined interface
• Message-oriented middleware(MOM)
• Components are decoupled and use messages as
  method of integration
• The problem
• Distributed transaction across platform, system

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Conditional Messaging

• Standard Messaging
• Conditional Messaging
• Extension of standard messaging

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Presentation of Condition
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Conditional Messaging Architecture
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Dependency-Spheres(D-Sphere)

• The purpose of D-Sphere is to enable the
  integration of existing OOM and MOM
• D-Sphere provides a intervening layer to enable
  coordination with messaging
• D-Sphere messaging model is to provide the
  minimum requirements to integrate with OOM

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D-Sphere Service Architecture
Message Sender Transactional Client
Read Message
Send message
invocation
2PC
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D-Sphere Commit Protocol

• Acknowledgments
• Commit Protocol
• Compensation

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Non D-Sphere D-Sphere Solution
App1
App2
App1
App2
DS
DS
Tx1
Tx2
D-Sphere
CTx1
CTx2
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QA