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SafeHarborStatement

Thefollowingisintendedtooutlineourgeneralproductdirection.Itisintendedforinformationpurposesonly,andmaynotbeincorporatedintoanycontract.Itisnotacommitmenttodeliveranymaterial,code,orfunctionality,andshouldnotberelieduponinmakingpurchasingdecisions.Thedevelopment,release,timing,andpricingofanyfeaturesorfunctionalitydescribedforOracle’sproductsmaychangeandremainsatthesolediscretionofOracleCorporation.

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Oracle(Active)DataGuardBestPracticesandNewFeaturesDeepDive

MaheshGirkar,SeniorDirector,DatabaseHADevelopmentNitinKarkhanis,Director,DataGuardBrokerDevelopmentOctober22,2018


IncludedwithOracleDatabaseEnterpriseEditionDataGuard:Real-timeDataProtectionandAvailability

PrimaryDataCenter DRDataCenter

AutomaticBlockRepair

DataGuardBroker(EnterpriseManagerCloudControlorDGMGRL)

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AlicensableoptiontotheOracleDatabaseEnterpriseEditionActiveDataGuard:AdvancedCapabilities

Zerodatalossatanydistance

PrimaryDataCenter DRDataCenter

AutomaticBlockRepair

DataGuardBroker(EnterpriseManagerCloudControlorDGMGRL)

OffloadFastIncrementalBackups

Offloadread-onlyworkloadtoopenstandbydatabase

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Agenda

What’snewwithOracle(Active)DataGuardin18c?

ApeekatthefutureofOracle(Active)DataGuard.

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Agenda



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(Active)DataGuardNewFeatures

• Multi-InstanceRedoApplyEnhancement•  ExtendActiveDataGuard(ADG)environmentsforDataWarehousing•  Fasterapplicationresponseafteraroletransition• ProtectPrimarydatabasefromlostwritestoragefailures•  ExtendthefootprintofActiveDataGuardapplications• Betterprotectionagainstfailedlogins

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Multi-InstanceRedoApplyEnhancements•  IntroducedinOracleDatabase12cRelease2

• Multi-InstanceRedoapplynowworkswithBlockChangeTrackingenabled– BlockChangeTrackingonastandbyrequiresanActiveDataGuardlicense

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DataGuardandDatabaseNologgingImprovements*

•  TwonewmodesareaddedasalternativestotheFORCELOGGINGmode:1.  StandbyNologgingforLoadPerformance•  Ensuresthatstandbyswillreceivethenonloggeddatachangeswithminimumimpacttothespeed

ofloadingattheprimary.•  Thestandbycantransientlyhavenonloggedblocks.Thesenonloggedblockswillbeautomatically

resolvedbymanagedstandbyrecovery.2.  StandbyNologgingforDataavailability•  Ensuresthatallstandbyshavethedatawhentheprimaryloadcommits,butatthecostof

throttlingthespeedofloadingdataattheprimary.•  Thestandbyswillneverhaveanynonloggedblocks.– ThesenewmodescauseMulti-InstanceRedoApplytoreturnanerror•  SingleInstanceRedoapplymustbemanuallyenabledtoproceedpastthenologgingoperation.

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*AvailableonEngineeredSystemsandOracleCloudonly


PreserveBufferCacheDuringRoleChange*

•  ThedatabasebuffercachestatewillbemaintainedonanADGstandbyduringarolechange• Automatic,nothingtosetup– ServicesneedtobeconfiguredcorrectlysothatuserswhostayconnectedareonaservicethatisvalidinbothPHYSICAL_STANDBYandPRIMARYroles.

*FirstReleaseCaveat:Onlyavailableonnon-RACActiveDataGuardstandbydatabases.

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Read/Write Read

Read/Write

ActiveDataGuardStandby

PrimaryFailedPrimary

Primary


LostwriteprotectiononPrimary•  Lostwritescauseseriouscorruptionsduetostaleblocksappearingasgood–  Applicationsrunningontheprimarycanget“incorrect”staledata.–  Priorfeaturesfocusedondetectionoflostwritesonthestandbyduringredoapply.•  Thiscausesdatalossdilemmas,iftimeelapsesbetweenoccurrenceoflostwriteanditsdetection.

•  Lostwritedetectiononprimarypreventsinconsistenciesfromspreading•  DatabaserecordsSCNofdatablockbeingwrittenina“shadowblock”– Requirestheconfigurationofanewtablespacetypecalled“shadowtablespace”thatcontainsshadowblocks–  TheSCNofdatablocksthatarereadintothebuffercachearevalidatedwithitsSCNsavedintheshadowblocks–  Designisefficientandhasminimaloverhead

•  Standbysremainintact!Applicationsdonotgetinconsistentresults!Noneedtofailover!

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CreatingPrivateTemporaryTablesonActiveDataGuard• CreatingPrivate(Local)TemporaryTablesissupportedonanActiveDataGuardstandbydatabase– Theyarestoredinmemoryonthestandby– Visibleonlytothesessionthatcreatedit– Droppedattheendofatransactionorsession

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ControlLogin-AttemptsonActiveDataGuard•  TheADG_ACCOUNT_INFO_TRACKINGparameterextendsthecontrolofuseraccountsecurityinformationandreaction– ‘LOCAL’(defaultvalue)continuestoenforcetheexistingbehavior• Maintainslocalcopyofusersaccountinformationinthestandby'sin-memoryview– Loginfailuresareonlytrackedlocallyonaperdatabasebasis– Loginsaredeniedwhenthefailuremaximumisreached

– ‘GLOBAL’triggersthenew,securebehavior• MaintainsasingleglobalcopyofusersaccountinformationacrossallDataGuarddatabases– LoginfailuresacrossalldatabasesintheDataGuardconfigurationcounttowardsthemaximumcount– Loginsanywherewillbedeniedwhenthecountisreached

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NewDataGuardBrokerCommands

•  EnhancedScriptingandExecutioncommands• NewVALIDATEcommands

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Copyright©2018,Oracleand/oritsaffiliates.Allrightsreserved.| 16

SHOWALL

DGMGRL> show all; debug OFF

echo OFF time OFF

observerconfigfile = observer.ora


SETDEBUGON|OFFDGMGRL> set debug on;

DGMGRL> connect sys/@boston;

Password:********

[W000 2018-09-28T10:07:10.924-04:00] Connecting to database using boston.

[W000 2018-09-28T10:07:10.924-04:00] Attempt logon as SYSDBA

[W000 2018-09-28T10:07:11.318-04:00] Successfully logged on as SYSDBA

.

.

.

Connected as SYSDBA.


SETECHOON|OFF

DGMGRL> set echo off; DGMGRL> edit database boston set property logxptmode=async;

Property "logxptmode" updated DGMGRL> set echo on; DGMGRL> edit database boston set property logxptmode=sync; edit database dgc2 set property logxptmode=sync; Property "logxptmode" updated

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SETTIMEON|OFF

DGMGRL> set time on; DGMGRL 10:21:04> failover to boston; Performing failover NOW, please wait… Failover succeeded, new primary is “Boston”

DGMGRL 10:21:25>

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DGMGRLScripting

Script File: commands.cli

set echo on connect /@boston;

edit database boston set property logxptmode=sync;

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DGMGRLScripting

DGMGRL> @commands.cli connect /@boston;

Connected to ”boston" Connected as SYSDG.

edit database boston set property logxptmode=sync; Property "logxptmode" updated

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VALIDATEDATABASESPFILE– Validatesparametersettingsbetweentheprimaryandastandbydatabase

– Goodresultànodifferences

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DGMGRL> validate database boston spfile ; Connecting to “boston”.

Connecting to “newyork”.

No parameter differences found.


VALIDATEDATABASESPFILE(Cont’d) DGMGRL> validate database newyork spfile ; Connecting to ”boston".

Connecting to ”newyork".

Parameter settings with different values: aq_tm_processes: boston (PRIMARY) : 8 newyork : 9

use_large_pages:

boston (PRIMARY) : TRUE newyork : NOT SPECIFIED


VALIDATENETWORKCONFIGURATION• Validatesthenetworksetupbetweenalldatabasesintheconfiguration

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DGMGRL> validate network configuration for boston; Connecting to instance ”bos" on database ”boston" ... Connected to ”boston"

Checking connectivity from instance ”bos" on database ”boston to instance ”den" on database ”denver"...

Succeeded. Connecting to instance ”den" on database ”denver" ...

Connected to ”denver" Checking connectivity from instance ”den" on database ”denver to instance ”bos" on database ”boston"...

Succeeded. Oracle Clusterware on database ”boston" is available for database restart.


VALIDATESTATICCONNECTIDENTIFIER• Validatesthestaticconnectidentifiersetupinunmanagedenvironments– AppliestodatabasesintheDataGuardconfigurationthatdonotuse•  OracleRAC•  RACOneNode•  OracleRestart

– RequiresastaticentrysothattheBrokercan•  Restartadatabaseduringswitchover•  ConvertfromSnapshotStandbybacktoPhysicalStandby•  Reinstateafailedprimaryasastandby

• AlsorunaspartofVALIDATENETWORKCONFIGURATION,ifnecessary

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Agenda



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(Active)DataGuardFeaturesfortheFuture

•  ImprovedDataGuardMulti-InstanceRedoApply• ActiveDataGuardDMLRedirection• NewParametersfortuningautomaticoutageresolutionwithDataGuard• BufferCacheonActiveDataGuardpreservedafterroletransitionforRAC•  FlashbackDatabaseenhancementswithDataGuard

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Documents

Copyright © 2018, Oracle and/or its affiliates. All … › technetwork › database › exadata › dg...• Maintains local copy of users account information in the standby's in-memory