Zero Downtime for Java Applications: Use Cases ... - Oracle...Connection Manager –No Single Point...

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ZeroDowntimeforJavaApplications:UseCasesandSolutions

Nirmala Sundarappa,Kuassi Mensah,JeanDeLavareneJDBCandUCPTeam


SafeHarborStatement

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


ProgramAgenda

BuildingBlocksofHighAvailability

PlannedMaintenance:UsecasesandSolutions

UnplannedOutage:UsecasesandSolutions

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ProgramAgenda

HighAvailabilityBuildingBlocks

PlannedMaintenance:Usecases&Solutions

UnplannedOutage:Usecases&Solutions

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HighAvailabilityBuildingBlocks• FastApplicationNotification(FAN)• StandardRequestboundary• RecommendedConnectionURL• TransparentApplicationContinuity(TAC)• OracleConnectionManagerinTrafficDirectorMode• JavaintheDatabase(OJVM)RollingUpgrade


FastApplicationNotification(FAN)

• TheFastApplicationNotification(FAN)allowsapplicationstobenotifiedinstantaneouslyofOracleDatabaseevents

• SupportedFANeventsarementionedbelow– NodeEvents:NodeDown,PublicNetworkDown– InstanceEvents:InstanceDown,InstanceUp– ServiceEvents:ServicememberDown,ServicememberUp,ServiceDown,Service

Up– DatabaseEvents:DatabaseDown,DatabaseUp

• TheSimplefan.jar furnishestheJavaAPIsformanagingFANevents• TheUniversalConnectionPool(UCP)andJDBCsupportFAN

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UniversalConnectionPool(UCP)• ucp.jar availableonOTN,OracleMavenand$ORACLE_HOME/ucp/lib• Forusestand-aloneorwithJavaapplicationcontainers

– Tomcat,WebSphere,JBOSS,WLS(ActiveGridLink)

• TightintegrationwithRAC,ADG,andGDS• Built-insupportforFastApplicationNotification(FAN)events• Built-insupportforTransparentApplicationContinuity


StandardRequestBoundary

PoolDataSource pds = getPoolDataSource();Connection conn = pds.getConnection();conn.beginRequest()PreparedStatement pstmt = …

…SQLstmt,localcalls,RPC…

conn.commit();conn.endRequest();conn.close();

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BeginRequest

RequestBody

EndRequest

JDK9


RecommendedConnectionURL

alias =(DESCRIPTION =

(CONNECT_TIMEOUT=90)(RETRY_COUNT=20)(RETRY_DELAY=3)

(TRANSPORT_CONNECT_TIMEOUT=3)

(ADDRESS_LIST =

(LOAD_BALANCE=on)

(ADDRESS = (PROTOCOL = TCP)(HOST=primary-scan)(PORT=1521)))

(ADDRESS_LIST =

(LOAD_BALANCE=on)

(ADDRESS = (PROTOCOL = TCP)(HOST=secondary-scan)(PORT=1521)))

(CONNECT_DATA=(SERVICE_NAME = gold-cloud)))

DB12.2

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SingledescriptionAutomaticRetries

NorelianceonDNSconfig

NeverusetheDefaultService(DBorPDBName)


ApplicationContinuityDB18c

• Supportsapplicationswithsimplestate,orhavelogintriggerorcallbacktorestoretheircomplexstates,orthatcleantheircomplexstates(egDBMS_SESSION.RESET_PACKAGE,freetemplobs)

• Checksthatstateisrestorableatconnectioncheckout– Notallstateschecked–Won’treplayside-effects(stuffoutsidethesession,eg UTL_HTTP)

• Firstcallfailure:need18cclient• Applicationsw/oourpools:implicitboundaries(JDBC18c;OCI20c)

– Requiresoptionalclientsetting

Server-side


ConnectionManager(CMAN)- TrafficDirectorMode

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C++

CMAN- TrafficDirectorMode

C

Databases

Copyright©2018, Oracleand/oritsaffiliates.Allrightsreserved.| 12

ZeroApplicationDowntime

• Automaticallyredirectandreestablishdatabaseconnections– Hidedatabaseplanned/unplannedoutagesandPDBrelocationsfromapplications

• SupportmultipleinstancesofConnectionManager– NoSinglePointofFailure

OracleDatabase

CMAN– TrafficDirectorMode

Eventnotification

Connection isre-directedtoanewinstanceorPDB

C++C


ProgramAgendawithHighlight




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PlannedMaintenance:Usecases&Solutions• NodeMaintenance• DatacenterMaintenance• PDBrelocation• PlannedMaintenancewithCMAN-TDM• ConditionalRAC-RollingofOJVMPatching

PlannedMaintenance

PatchesRepairs

UpgradesChanges


PlannedNodeMaintenance

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InstanceA

InstanceB

Application

DrainSession

MAINTENANCE

FANDOWN

FANUP

BOTHINSTANCES ONEINSTANCE BOTHINSTANCES


PlannedNodeMaintenanceJavaRequirements (classpath)• DB12.2+ojdbc8.jar

• DB12.2+ucp.jar• DB12.2+ ons.jar

• Simplefan.jar ifnotusingUCP

ServerSideConfiguration• Auto-draining(12.2)srvctl stop service -node . -drain_timeout.. –stopoption[immediate|transactional]

• SetFAILOVER_RESTOREtolevel1srvctl modify service –db <db_name> -service <svc_name> -failover_restorelevel1

• EnableRuntimeLoadBalancing– Set –rlbgoal to SERVICE_TIME or THROUGHPUT

– Set –clbgoal to SHORT

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PlannedNodeMaintenancewithJDBCDB12.2JDBCdriver(ojdbc8.jar)

• Driverclosesthedatabasesessionsata“SafePlace”(Seeconnectionvalidationoptions)• Applicationmustuseoneofthesafedrainingmethods

– ValidationSQLwithahint/*+CLIENT_CONNECTION_VALIDATION*/SELECT1FROMDUAL– isValid(),pingDatabase(),isUsable(),endRequest()methods

• Requiressimplefan.jar andons.jar intheclasspath

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ConnectionValidationOptionsforContainersJavaConnectionPool ConnectionValidationOptions

OracleWebLogicGenericandMDSdatasources TestConnectionsOnReserve,TestConnectionsOnRelease,TestConnectionsOnCreate

IBMWebSphere PreTest Connection

WildFly /RedHat JBoss check-valid-connection-sql

ApacheTomCat TestonBorrow, TestonRelease


NECUseCase:DataCenterMaintenanceusingRAC+DataGuard

FAN

WebLogic

FAN

StartServices

TNSconnectionretry

Primary

Standby Primary

Standby

Swichover wait

RAC#1

RAC#2

Upgrade

Maintenance

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DrainSession

:requestandresponse

120sec

Confirmnoimpacttoclients

NoImpact!!!


DataCenterMaintenanceJavaRequirements• DB12.2+ojdbc8.jar


• SetRETRY_COUNT, RETRY_DELAY,longenoughtosustainswitchoverE.g.,RETRY_COUNT=30 andRETRY_DELAY=10

ServerSideConfiguration• UseRAC+DataGuard

• Auto-drainingsrvctl stop service -node . -drain_timeout.. –stopoption[immediate|transactional]

• EnableRLBontheserverside

• Killlongrunningsessions(enableAConJavaside)

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REDOsync

NECUseCase:PDB OnlineRelocate

Other PDBs

Other PDBs

Migration PDB

requestandresponse

CDB#1

WebLogic

…

CDB#2

(1) Relocate

OnlineCopy

(2)Open &Start Service

Confirmednoerrorstoalltenant’sclients

Application Continuityenablesnoerrorreplay


PDBRelocateJavaRequirements• DB12.2+ojdbc8.jar


• Drainsatsafeplaces

ServerSideConfiguration• Auto-drainingsrvctl stop service -node . -drain_timeout.. –stopoption[immediate|transactional]

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CMANTDMPlannedOutages&PDBRelocation

• Non-pooledConnections- Anyclient(11.2.0.4+)– Norequestboundaryinformationfromtheclient– Servicestopped/startedappropriatelyonServer– 11.2.0.4+Server:StopServiceatTransactionBoundary– 18Server:StopServiceatRequestBoundary,basedonSQLcommands(Cont.AC)

• PooledConnections- JDBC(12.1+),– Servicerelocationforplannedoutage(11.2.0.4+Server)– SupportPDBrelocationevenwhenONSisnotconfigured(18.1+Serveronly)– ConnectionMultiplexingatrequestboundary– PDBRelocation:CMAN-TDMrespondstoin-bandnotificationswhenaPDBisrelocatedi.e.,evenwhenONSisnotconfigured(18.1+Serveronly)


DB18.4OJVMPatching(planned)• Nofunctionalchange• Non-Javaserviceavailablealltime (atleastoneinstance)• Javaserviceavailablealltime,except~10secbrown-out• Noerrorreportedduringbrown-out• CDB/PDBssupported(mayincurlongerbrown-out)• Lookingintoback-portingto11.2and12.1(plannotfinalized)

OJVM Rolling Upgrade- Planned MaintenanceOverview

~10secstallJavaService

(OJVMunpatched)

NonJavaService

Clusterwide

JavaService(OJVMpatched)






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Copyright©2018, Oracleand/oritsaffiliates.Allrightsreserved.| 26

S#@$%

UnplannedOutages

UnpredictableResponse&Throughput

SiteDisasters

DataCorruption

Whichoutageclassesdoesyourbusinessneedtohandle?

HumanErrors

Whatkindofoutages?


UnplannedOutages:Usecases&Solutions• NetworkOutage• DatabaseInstanceOutage• NodeDown• DatacenterDown• UnplannedOutagewithCMAN-TDM


SolutionsforhandlingUnplannedOutage

• UseUCPwithreplaydatasource(oracle.jdbc.replay.OracleDataSourceImpl)• EnableApplicationContinuity(AC)ontheserverside• UseAPIstochecktheACstatistics

– OracleDataSource.getReplayStatistics(StatisticsReportType) and OracleDataSource.getReplayStatistics()

• AlignApplicationandServerTimeouts– http_request_timeout shouldbehigherthanREAD_TIMEOUTontheconnURL

• DisableAUTOCOMMIT

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NECUseCase:PublicNetworkDown

Applicationwait1s

FAN

:requestandresponse

…RACNode#1

WebLogic

RACNode#2

PDBservicesPDBs

PDBservicesPDBs

PublicNetworkdown

NoErrors!!!


Reconnect

ApplicationContinuity


NECUseCase:DBInstanceDown

ApplicationwaitsmaxFAST_START_MTTR_TARGET

Reconnect

FAN

:requestandresponse

…RACNode#1

WebLogic

RACNode#2

PDBservicesPDBs

PDBservicesPDBs

DB Reconfig & Recovery

instancedown

NoErrors!!!




NECUseCase:DBNodeDown

ApplicationwaitMisscount+FSMT (max)

FAN

:requestandresponse

…RACNode#1

WebLogic

RACNode#2

PDBservicesPDBs

PDBservicesPDBs

GRID + DB Reconfig & Recovery

Nodedown

NoErrors!!!


Reconnect



UnplannedOutage:TimerAlignment• Applicationtimeout(READ_TIMEOUT)shouldbehigherthanthedetectionandrecoverytimesfortheunderlyingsystems.

• AligntheapplicationtimeoutswithRACandDataGuardfailovertimers.– Read_timeout >>EXADATAspecialnodeeviction(2secondsin12.1.0.2)– Read_timeout >>Misscount (default30sec,modifiable)– Read_timeout >>DataGuardObserver,FastStartFailoverThreshold(default30sec,modifiable)AndFastStartFailoverThreshold>>>Misscount (atleasttwice)

– Read_timeout >>FAST_START_MTTR_TARGET– Read_timeout >>NETlevel(RETRY_COUNT+1)*RETRY_DELAY– Read_timeout << Replay_Initiation_Timeout (modifiableontheservice,default300second)


CMAN-TDMTransparentUnplannedOutages

• Non-PooledConnections- Anyclient(11.2.0.4+)– Simplesessionstateandcursorstatearere-established– SELECTSandfirstDMLsarereplayed– SupportsPlannedOutageformanyapplications(solongasonlysimplesessionstateandcursorstateneedtobepreservedacrosstherequest/transactionboundaries)

– SupportsUnplannedOutageforreadmostlyapplications

• PooledConnections- JDBC(12.1+)– LeverageTAF“FailoverRestore”featureonCMAN-TDMtoreconnectandrestoresimplestate

– LeverageApplicationContinuity(planned)






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Resources

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JDBC&UCPLandingpage– oracle.com/jdbc

JDBC&UCPBlogs- https://blogs.oracle.com/dev2dev

JDBCwithDBCloud- https://bit.ly/2MP1NIE

JDBCDownloadPage- https://bit.ly/2wccOdB

Date post:	11-Aug-2020
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Zero Downtime for Java Applications: Use Cases ... - Oracle...Connection Manager –No Single Point...

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