Compaq Reliable Transaction Router manual Architectural Concepts, Three-Layer Model

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Architectural Concepts

This chapter introduces concepts on basic transaction processing and RTR architecture.

The Three-Layer Model

RTR is based on a three-layer architecture consisting of frontend (FE) roles, backend (BE) roles and router (TR) roles. The roles are shown in Figure 2–1. In this and subsequent diagrams, rectangles represent physical nodes, ovals represent application software, and DB represents the disks storing the database (and usually the database software that runs on the server).

Client processes run on nodes deﬁned to have the frontend role. This layer allows computing power to be provided locally at the end-user site for transaction acquisition and presentation.

Server processes (represented by ``Server'' in Figure 2–1) run on nodes deﬁned to have the backend role. This layer:

•Allows the database to be distributed geographically.

•Permits replication of servers to cope with either network, node or site failures.

•Allows computer resources to be added to meet performance requirements.

Architectural Concepts 2–1

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Contents Reliable Transaction Router Getting Started Page Contents Reliability Features Figures Page Document Structure PrefacePurpose of this Document For all users Related DocumentationReaders Comments Reading Path= Tutorial System Manager Application ProgrammerIf V2 to Reliable Transaction Router IntroductionRTR Continuous Computing Concepts RTR Continuous Computing ConceptsRTR Terminology RTR TerminologyClient Symbol Server Symbol Roles Symbols Components in the RTR Environment Nontransactional messaging Transaction ID Controller Business Logic Odbc Model Database ServerApplication Presentation RTR Frontend PC BrowserJournal Browser11 RTR Deployed on Three Nodes 12 Standby Server Conﬁguration 13 Transactional Shadowing Conﬁguration RTR Server Types RTR Server TypesStandby server Standby in a cluster 15 Standby Servers 16 Shadow Servers Server1 Server2 Server3 Server4 17 Concurrent ServersPartition a Transaction19 Bank Partitioning Example Standby Server Conﬁgurations Anonymous clients Tunnel RTR Networking Capabilities RTR Networking CapabilitiesPage Three-Layer Model Architectural ConceptsThree Layer Model Three-Layer ModelRTR Facilities Bridge the Gap RTR Facilities Bridge the GapBroadcasts Flexibility and GrowthFlexibility and Growth Transaction IntegrityPartitioned Data Model Partitioned Data ModelObject-Oriented Programming Partitioned Data Model Object-Oriented ProgrammingFunctional and Object-Oriented Programming Compared ObjectsExample 2-1 Objects-Deﬁned Sample Messages Class RelationshipsPolymorphism Object Implementation Beneﬁts XA Support XA SupportServers Reliability FeaturesFailover and Recovery Failover and RecoveryRecovery Scenarios Recovery Scenarios Backend Recovery Router Recovery Frontend RecoveryPage RTR Interfaces RTR Management Station RTR Management Station RTR Create Facility DESIGN/ALLROLES=NODEA RTR RTRRECEIVEMESSAGE/TIME=0 RTR RTRSTARTTX/CHAN=C Interface Application Programming InterfacesRTR Browser Interface Application Programming InterfacesRTR C Example of an open channel call in an RTR client program RTR System Management Environment RTR EnvironmentRtrcomserv RTR System Management EnvironmentManagement Station Running Browser Software RTR System Management EnvironmentMonitoring RTR RTR Runtime Environment Optional External Applet Not Running RTR Runtime EnvironmentClient Application Whats Next? Whats Next?Page Glossary Channel BranchBroadcast Callout serverData object Common classesConcurrent server Data marshallingEvent driven Fault tolerantEndian EventKey range FrontendInquorate JournalMultithreaded MessageMessage handler MultichannelProperty classes PrimaryProcess PropertiesRTR environment RollbackRouter RTR conﬁgurationTransaction controller ShadowStandby TransactionTransactional shadowing Two-phase commitTransactional message Index-1 IndexIndex-2