5OracleDatabase12c最大化应用程序的可用性

1、Maximum Application Availability with Oracle Database 12cKuassi MensahDirector Product ManagementThe following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any mate

2、rial, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracles products remains at the sole discretion of Oracle.My Next SessionOracle In-Database MapReduce: When Hadoop Meets Exa

3、data7/25/13, 12:00 13:00, Room 431Program AgendaProblems to SolveNew ConceptsTransaction GuardApplication ContinuityApplication Design ConsiderationsProblems to SolveUpon Database Outage Four Problems ConfrontApplicationsHangErrors Outcome of In-Flight WorkResubmission of In-Flight WorkHang- Fast Ap

4、plication Notification (FAN) Errors Handling? Not formalized In-Flight Work? Lost! Resubmission of In-Flight Work? N/A!Current SituationProgram AgendaProblems to SolveNew ConceptsTransaction Guard Application ContinuityApplication Design ConsiderationsRecoverable Error FormalizedOracleException.IsRe

5、coverable property Applications No longer need to maintain own list of error codes (e.g., ora-1033, ora-1034, ora-xxx) JDBC throws SQLRecoverableException Database RequestUnit of Work PoolDataSource pds = GetPoolDataSource();Connection conn = getConnection(pds); PreparedStatement pstmt = SQL, PL/SQL

6、, local calls, RPCmit();conn.close();Request BeginsRequest Body Usually ends with COMMITRequest EndsProgram AgendaProblems to SolveNew ConceptsTransaction Guard Application ContinuityApplication Design ConsiderationsTransaction GuardTool that supports known outcome for every transactionWithout Trans

7、action Guard, retry can cause logical corruptionUsed by Application ContinuityCan be used independently of Application Continuity4. Enforce OutcomeWork Request2. DB Calls12c ORACLE Database3. Errors4. Reliable Commit OutcomeTransaction Guard Typical UsageUpon database instance crash FAN aborts dead

8、session Application gets an error Pool removes orphan connection from pool If “recoverable error” thenGet last LTXID from dead session Obtain new database session Get transaction statusTransaction Guard In ActiongetConnection()Txn.Commit();get Last LTXIDCommit outcome?COMMIT/ROLLBACKstart transactio

9、nassign LTXIDCOMMIT?Return & Preserve COMMIT OUTCOMEClient/Mid-tierDatabaseTimeRecoverable ErrorCOMMITGet Logical TX IDSQL, PL/SQL, RPCResultsTG in Action On Service COMMIT_OUTCOMEValues TRUE and FALSE Default FALSEApplies to new sessions RETENTION_TIMEOUTUnits secondsDefault 24 hours (86400)Maximum

10、 value 30 days (2592000) Transaction Guard ConfigurationTransaction Guard in Oracle database 12cJDBC-thin, ODP.NET, OCI, OCCICommit Models Local TXN Auto-commit, Commit on Success Commit embedded in PL/SQL DDL, DCL, Parallel DDL Remote, DistributedExclusionsXAR/W DBLinks from Active Data Guard or Re

11、ad OnlyProgram AgendaProblems to SolveNew ConceptsTransaction Guard Application ContinuityDesign ConsiderationsApplication ContinuityMask Database Outage When SuccessfulReplays in-flight work on recoverable errorsMasks many hardware, software, network, storage errors and outages when successfulImpro

12、ves end user experience 5. ResponseWork Request2. DB Calls12c ORACLE Database4. Replay3. ErrorsPhases in Application Continuity1-Capture 2-Reconnect 3-Replay Demarcates database requestHolds original calls with binds & validationManages queues Checks request has replay enabledHandles timeoutsCreates

13、 a new connectionValidates target databaseUses Transaction Guard to enforce last commit Replays held callsContinues replay, if user visible results match, based on validations Continues requestApplication Continuity In Action Call 1 Application Proxy 1 Proxy 2RAC DatabaseInstance1Instance2Instance3

14、Call 2 Connection Replay ContextOracle JDBC DriverDEMOSolution CoverageApplication Continuity for JavaClient JDBC-Thin driver UCP, WebLogic ServerDatabaseSQL, PL/SQL, RPCSelect, ALTER SESSION, DML, DDL, COMMIT/ROLLBACK/SAVEPOINT Transaction models: Local, Parallel, Remote, Distributed Mutable functi

15、on support Hardware acceleration on current Intel & SPARC chipsExclusions GlobalRequestTarget 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 links Do

16、es not support: Logical Standby Golden GateRestrictionsWhen Does Replay Not Occur? 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 Max con

17、nection retries Max retries per incident Target database not valid for replay Last call committed in dynamic modeValidation detects different resultsProgram AgendaProblems to SolveNew ConceptsTransaction Guard Application ContinuityApplication Design ConsiderationsApplication AssessmentDecideWhat to

18、 doRequest 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 s

19、tate changes outside any request (WLS/UCP labeling included by default) Mutable FunctionsGrant keeping mutable values if these are compatible with your applicationSide EffectsWhen Replay is enabled, some calls may be repeated. Apps may need to use disableReplay() API to prevent this:Autonomous trans

20、actionsUTL_HTTP , UTL_URL UTL_FILE, UTL_FILE_TRANSFER - files operationsUTL_SMPT, UTL_TCP, UTL_MAIL - sending messagesDBMS_PIPE, RPCs - to external sourcesDBMS_ALERT - email or other notificationsConfigure JDBC Replay Driver Set replay data source in property file datasource=oracle.jdbc.replay.OracleDataSourceImplEnable Application Continuity on Service Set FAILOV