Compaq Reliable Transaction Router manual Backend Recovery Router Recovery Frontend Recovery

Page 47

Backend Recovery

Router Recovery

Frontend Recovery

Recovery Scenarios

If standby or shadow servers are available on another backend node, operation of the rest of the system will continue without interruption, using the standby or shadow server.

If a backend processor is lost, any transactions in progress are remembered by RTR and later recovered, either when the backend restarts, or by a standby if one is present. Thus, the distributed database is brought back to a transaction-consistent state.

If a router fails and another router node is available, all in- progress transactions are transparently re-routed by the other router. System operation will continue without interruption.

If a frontend is lost:

•All transactions committed but not completed on the frontend node at the time of failure will be completed.

•All transactions started but not committed on the frontend node at the time of failure will be aborted.

Reliability Features 3–3

Image 47

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