1、Maximum Application Availabilitywith OracleDatabase12cKuassiMensahDirectorProduct ManagementThefollowing is intended to outlineour generalproductdirection. It is intended forinformationpurposesonly,andmay notbeincorporatedintoanycontract. It is nota commitmenttodeliveranymaterial, code, or functiona

2、lity, andshouldnot be reliedupon in makingpurchasing decisions.The development,release,andtiming of anyfeaturesorfunctionality describedforOracles products remainsatthe solediscretionofOracle.MyNext SessionOracleIn-DatabaseMapReduce:When HadoopMeetsExadata7/25/13,12:0013:00, Room431Program AgendaPro

3、blemstoSolveNewConceptsTransactionGuardApplicationContinuityApplicationDesignConsiderationsProblemstoSolveUpon Database OutageFour Problems ConfrontApplicationsHangErrorsOutcome of In-FlightWorkResubmissionofIn-Flight WorkHang-Fast Application Notification(FAN)ErrorsHandling?NotformalizedIn-FlightWo

4、rk?Lost!ResubmissionofIn-Flight Work?N/A!Current SituationProgram AgendaProblemstoSolveNewConceptsTransactionGuardApplicationContinuityApplicationDesignConsiderationsRecoverableErrorFormalizedOracleException.IsRecoverablepropertyApplicationsNolonger needtomaintainown listoferrorcodes(e.g., ora-1033,

5、ora-1034,ora-xxx)JDBC throwsSQLRecoverableExceptionDatabaseRequestUnit of WorkPoolDataSourcepds=GetPoolDataSource();Connection conn=getConnection(pds);PreparedStatementpstmt= SQL, PL/SQL,localcalls, RPCmit();conn.close();Request BeginsRequest BodyUsually endswithCOMMITRequest EndsProgram AgendaProbl

6、emstoSolveNewConceptsTransactionGuardApplicationContinuityApplicationDesignConsiderationsTransactionGuardTool thatsupportsknownoutcomeforeverytransactionWithout Transaction Guard,retrycancauselogicalcorruptionUsed by Application ContinuityCanbeusedindependently of Application Continuity4.Enforce Out

7、comeWorkRequest2.DBCalls12cORACLE Database3.Errors4.ReliableCommitOutcomeTransactionGuard TypicalUsageUpon database instance crashFANaborts deadsessionApplicationgets an errorPool removesorphan connectionfrompoolIf“recoverableerror”thenGetlastLTXIDfrom deadsessionObtainnew database sessionGettransac

8、tionstatusTransactionGuardInActiongetConnection()Txn.Commit();getLastLTXIDCommitoutcome?COMMIT/ROLLBACKstart transactionassignLTXIDCOMMIT?Return&PreserveCOMMITOUTCOMEClient/Mid-tierDatabaseTimeRecoverable ErrorCOMMITGetLogicalTXIDSQL, PL/SQL, RPCResultsTGinActionOnServiceCOMMIT_OUTCOMEValuesTRUE and

9、FALSEDefault FALSEApplies to newsessionsRETENTION_TIMEOUTUnits secondsDefault 24hours(86400)Maximum value 30days(2592000)TransactionGuardConfigurationTransactionGuardinOracledatabase12cJDBC-thin, ODP.NET, OCI,OCCICommitModelsLocalTXNAuto-commit,Commit on SuccessCommitembeddedinPL/SQLDDL, DCL,Paralle

10、lDDLRemote, DistributedExclusionsXAR/WDBLinksfrom ActiveData Guard or ReadOnlyProgram AgendaProblemstoSolveNewConceptsTransactionGuardApplicationContinuityDesignConsiderationsApplicationContinuityMask Database OutageWhen SuccessfulReplays in-flightwork onrecoverableerrorsMasksmany hardware,software,

11、network,storageerrorsand outageswhensuccessfulImprovesenduserexperience5.ResponseWorkRequest2.DBCalls12cORACLE Database4.Replay3.ErrorsPhasesinApplicationContinuity1-Capture 2-Reconnect 3-Replay Demarcates database requestHolds original calls with binds & validationManages queues Checks request has

12、replay enabledHandles timeoutsCreates a new connectionValidates target databaseUses Transaction Guard to enforce last commit Replays held callsContinues replay, if user visible results match, based on validations Continues requestApplicationContinuity In ActionCall 1Application Proxy 1 Proxy 2RAC Da

13、tabaseInstance1Instance2Instance3Call 2 Connection Replay ContextOracleJDBCDriverDEMOSolutionCoverageApplicationContinuity forJavaClientJDBC-ThindriverUCP, WebLogic ServerDatabaseSQL, PL/SQL,RPCSelect, ALTER SESSION, DML,DDL,COMMIT/ROLLBACK/SAVEPOINTTransactionmodels: Local,Parallel,Remote,Distribut

14、edMutable function supportHardwareaccelerationoncurrentIntel& SPARC chipsExclusionsGlobalRequestTarget DatabaseDo not use default database serviceExcludes XA For Java, deprecated concrete classes Restricted calls Alter System Alter DatabaseNot supported for Active Data Guard with read/write database

15、 links Does not support: Logical Standby Golden GateRestrictionsWhen DoesReplay NotOccur?Normal RuntimeReconnectReplayAny call in same requestafter successful commit in dynamic mode (default)a restricted call disableReplay API Error is not recoverable Reconnection failure Replay initiation timeout M

16、ax connection retries Max retries per incident Target database not valid for replay Last call committed in dynamic modeValidation detects different resultsProgram AgendaProblemstoSolveNewConceptsTransactionGuardApplicationContinuityApplicationDesignConsiderationsApplicationAssessmentDecideWhat to do

17、Request BoundariesMark Request Boundaries, if you are not using Oracle PoolsJDBC Concrete ClassesReplace deprecated concrete classes with Java interfacesSide EffectsUse disable API if a database request has an external call that should not be replayed CallbacksEnsure a callback is registered if stat

18、e changes outside any request (WLS/UCP labeling included by default) Mutable FunctionsGrant keeping mutable values if these are compatible with your applicationSide EffectsWhen Replayisenabled,some calls mayberepeated.Appsmay needtousedisableReplay()APItopreventthis:Autonomous transactionsUTL_HTTP,UTL_URLUTL_FILE,UTL_FILE_TRANSFER-filesoperationsUTL_SMPT,UTL_TCP,UTL_MAIL-sending messagesDBMS_PIPE, RPCs-toexternalsourcesDBMS_ALERT -emailorothernotificationsConfigureJDBCReplayDriverSetreplay datasource in property filedatasource=oracle.jdbc.replay.OracleDataSourceImplEnableApplicati