LongRunningTransactionsinServiceOriented Environments infm3::SR - - PowerPoint PPT Presentation

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LongRunningTransactionsinServiceOriented Environments infm3::SR - - PowerPoint PPT Presentation

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LongRunningTransactionsinServiceOriented Environments infm3::SR MartinGerlach martin.gerlach@informatik.hawhamburg.de 16.12.2005 Needforconsistencyofbusinesscriticaldata

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16.12.2005

LongRunningTransactionsinServiceOriented Environments

infm3::SR MartinGerlach martin.gerlach@informatik.hawhamburg.de

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 2

Needforconsistencyofbusinesscriticaldata

  • … asalways,acrossevolvingtechnologies
  • Combinationofcoordination/compositiontechniques

(workflow)[sinceearly90ies]withlooselycoupled services[thisdecade]

  • Distributedapplications[since"sometimelongago"]
  • Mobileapplications[moreandmore,recently]
  • EAI+B2B
  • Services/SOA/<insertmorebuzzwordshere>fitwell
  • Nothinggroundbreakingly new,butsuccessfulapplication

innumerousprojects

  • Manylessonslearnt
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 3

Noteworthyhistoricalfacts(1)

  • 6000yearsago,Sumer:

Royalinventoryoftaxes, land,grain,cattle,etc.on claytablets

  • Recordskeptforevery

transaction

  • …papyrus,…,paper…
  • 1890useofpunchcard

systemtoreportUScensus byHermanHollerith

  • From≈1950
  • Batch(offline)transactions
  • Followedbyonline

transactions(OLTP)

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 4

Noteworthyhistoricalfacts(2)

JimGray,1981: TheTransactionConcept– VirtuesandLimitations

  • Purpose:Thereareno"perfectsystems",soweneedtomake"almost

perfect"systemssafe(r),i.e.faulttolerant

  • ACIDTransactions:Activitiescomposedofactionsofdifferentcriticality
  • Realization:Updateinplace,TimeDomainAddressing,Loggingand

Locking,UNDO/REDO,etc.

  • Firstundo/redolog:Hänsel andGretel☺ … alsofirstlogfailure
  • Limitations
  • NestedTransactions
  • Transparentintegrationintoprogramminglanguages
  • PeterPrinciple:"Everyideaisgeneralizedtoitslevelofinapplicability"
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 5

Thesisoutline::Wherearewetoday?

  • Workingtitle
  • Outline
  • SOA:Fromobjectstocomponentstoservices:

Whyservices?

  • Distributedtransactionsincomponentframeworks
  • Whylong runningtransactions?
  • Existingspecsandongoingresearchwork
  • Conceptualdesignofaframeworkthatsupports

coordinationandlongrunningtransactions

  • Breakingdownthe(somewhatoverloaded)WebServices

relatedspecsandthedesigntotheessentialconcepts

  • Aimatperformance
  • Aimatlimitedresources(mobiledevices)
  • Prototyping(WebServices)

AW1

  • /PJ

PJ Thesis

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 6

SOA:Whyservices?

  • Whatisneeded?
  • Coarsegranulation
  • Loosecoupling
  • Asynchronous(andreliable)messaging
  • Abstractionfromunderlyingtransportandimplementation
  • Standards
  • Canpreviouslyexistingarchitecturesprovidethis?
  • Functionlibrariesandpackages
  • Classes/Objects
  • Components
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 7

SOA:Whyservices?::ClassesandComponents

Coarsegranulated Finegranulated CORBA,EJB,JavaBeans,.NET, COM MFC,STL,… ,separatefrom businesslogic,somewellknown Problemdomainspecific ,fewwellknown "Component– Contract– Container"runtimeenvironment Standalone Loosecoupling Tightcoupling "No"persistentstate Stateful (instancevars) NeednotbeOO Objectoriented Describedbyinterface, deploymentdescriptor,contract Describedbyinterface

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 8

SOA:Whyservices?::Conclusions

  • MappingofServicestoComponents
  • Interface
  • QoS requirements
  • Semantics
  • "Live"inmanagedenvironment(≈Container)
  • Servicesadditionallyprovide
  • Abstractionfromimplementation
  • Abstractionfromtransportandencoding
  • Interoperabilitythroughstandards
  • Atleastagoodidea

WebServicesarchitecturespecificationsprovidea frameworkforrealizationofSOAs

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 9

SOA:WebServicesFramework

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 10

Thesisoutline::Wherearewetoday?

  • Workingtitle
  • Outline
  • SOA:Fromobjectstocomponentstoservices:

Whyservices?

  • Distributedtransactionsincomponentframeworks
  • Whylong runningtransactions?
  • Existingspecsandongoingresearchwork
  • Conceptualdesignofaframeworkthatsupports

coordinationandlongrunningtransactions

  • Breakingdownthe(somewhatoverloaded)WebServices

relatedspecsandthedesigntotheessentialconcepts

  • Aimatperformance
  • Aimatlimitedresources(mobiledevices)
  • Prototyping(WebServices)

AW1

  • /PJ

PJ Thesis

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 11

TXmanagementfundamentals

  • Awholeapplication
  • Distributed(logically,physically,geographically)
  • Heterogeneous
  • WithstringentQoS requirements
  • !
  • Acollectionofoperationsonthephysicalandabstractapplication

state

  • SpecifiesfailuresemanticsforcomputationthroughACID

properties

  • ""!
  • Acollectionofcoreservicesthatmanageandcoordinate

transactions

  • TXmanager,"RPC"manager,[Logging,][Locking,]…
  • "
  • Data,code,processesprovidingaccesstoshareddata
  • ProvidesACIDoperations
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 12

Application Resource Manager Comm. Manager Transaction Manager Resource Manager Resource Manager Resource Manager Comm. Manager Server Transaction Manager App Data Begin, Commit Rollback Tx id leaving Prepare, Commit, Abort Requests Requests Prepare, Commit, Abort Start App Data Remote Requests prepare, commit, abort +ack, -ack, restart Tx id arriving TX [X/Open DTP] RM specific [various, e.g. SQL] "RPC..." "...RPC" RM specific [various, e.g. SQL] OSI/TP and CCR [ISO] XA XA [X/Open DTP] XA+ [X/Open DTP] Resource Manager Resource Manager Resource Manager Resource Manager Join tx Join tx

TXmanagementfundamentals::X/OpenDTP

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 13

TXmanagementfundamentals

  • TXmodels(AW1recap)
  • Flat
  • Flat,distributed(splitsintoTXoneachparticipatingnode)
  • Flatwithsavepoints (partialrollback)
  • Chained
  • Nested
  • Multilevel
  • Opennested
  • Longlivedwithcompensationandcontextmanagement
  • TXprocessingmodels
  • Direct,synchronous
  • Queued,asynchronous
  • Compensationbased,both,usingextramiddleware
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 14

CORBAObjectTransactionService(OTS)

  • ObjectManagementArchitecture(OMA)specifiessyntax

(IDL)andsemantics(Englishtext)for

  • ORB
  • CORBAservices
  • Naming,Event,,Security,…
  • CORBAfacilities
  • Vertical(industries)
  • Horizontal(utilities,internationalization,time,…)
  • OTS
  • DevelopedbygroupincludingeverymajorTPvendor
  • ExtendstransactionalsemanticstoOOapplications
  • Integrationofobjectandnonobjecttx systems
  • >12implementationsin2000
  • Flat(mandatory)andnested(optional)tx models
  • InteroperablewithX/OpenDTPmodel(TX,XA,OSI/TP)
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 15

OTS Implementation Transactional Client Resource Request incl. PropagationContext Available Interfaces Current TransactionFactory Control Terminator Coordinator Current Control Coordinator Resource SubtransactionAwareResource Transaction Context Transaction Context Associated with thread Associated with thread Transactional Object Recoverable Object Recoverable Server Transactional Server Begin, commit, rollback Register res. Participate TX XA

CORBAOTS::ArchitectureandAPI

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 16

OTS Implementation Transactional Client Resource Request incl. PropagationContext Available Interfaces Current TransactionFactory Control Terminator Coordinator Current Control Coordinator Resource SubtransactionAwareResource Transaction Context Transaction Context Associated with thread Associated with thread Transactional Object Recoverable Object Recoverable Server Transactional Server Begin, commit, rollback Register res. Participate TX XA

CORBAOTS::ArchitectureandAPI

interface Current : CORBA::Current { void begin(); void commit(); void rollback(); Status get_status(); void rollback_only(); Control get_control(); Control suspend(); void resume(Control); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 17

OTS Implementation Transactional Client Resource Request incl. PropagationContext Available Interfaces Current TransactionFactory Control Terminator Coordinator Current Control Coordinator Resource SubtransactionAwareResource Transaction Context Transaction Context Associated with thread Associated with thread Transactional Object Recoverable Object Recoverable Server Transactional Server Begin, commit, rollback Register res. Participate TX XA

CORBAOTS::ArchitectureandAPI

interface TransactionFactory { Control create(…); }; interface Terminator { void commit(); void rollback(); }; interface Control { Terminator get_terminator(); Coordinator get_coordinator(); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 18

OTS Implementation Transactional Client Resource Request incl. PropagationContext Available Interfaces Current TransactionFactory Control Terminator Coordinator Current Control Coordinator Resource SubtransactionAwareResource Transaction Context Transaction Context Associated with thread Associated with thread Transactional Object Recoverable Object Recoverable Server Transactional Server Begin, commit, rollback Register res. Participate TX XA

CORBAOTS::ArchitectureandAPI

interface Coordinator { Status get_status(); RecoveryCoordinator register_resource(Resource); void register_synchronization(Synchronization); Control create_subtransaction(…); void rollback_only(…); PropagationContext get_txcontext(); }; interface Synchronization : TransactionalObject { void before_completion(); void after_completion(Status); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 19

OTS Implementation Transactional Client Resource Request incl. PropagationContext Available Interfaces Current TransactionFactory Control Terminator Coordinator Current Control Coordinator Resource SubtransactionAwareResource Transaction Context Transaction Context Associated with thread Associated with thread Transactional Object Recoverable Object Recoverable Server Transactional Server Begin, commit, rollback Register res. Participate TX XA

CORBAOTS::ArchitectureandAPI

interface Resource { Vote prepare(); void rollback(); void commit(); void commit_one_phase(); void forget(); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 20

J2EEJavaTransactionService(JTS)

  • BasedonOTS1.1
  • TransactionalObject interfaceusedtodeclare

transactionality,notPOApolicies

  • UsesIIOPforRMI
  • PartofmostJ2EEApplicationServers
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 21

J2EEJTS::JavaTransactionAPI(JTA)

package javax.transaction package javax.transaction.xa

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 22

J2EEJTS::JavaTransactionAPI(JTA)

interface UserTransaction { void begin(); void commit(); int getStatus(); void rollback(); void setRollbackOnly(); void setTransactionTimeout(int); }; package javax.transaction package javax.transaction.xa

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 23

J2EEJTS::JavaTransactionAPI(JTA)

package javax.transaction package javax.transaction.xa interface TransactionManager { void begin(); void commit(); int getStatus(); Transaction getTransaction(); void resume(Transaction); void rollback(); void setRollbackOnly(); void setTransactionTimeout(int); Transaction suspend(); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 24

J2EEJTS::JavaTransactionAPI(JTA)

package javax.transaction package javax.transaction.xa interface Transaction { void begin(); void commit(); boolean delistResource(XAResource); boolean enlistResource(XAResource); int getStatus(); void registerSynchronization( Synchronization); void rollback(); void setRollbackOnly(); }; interface Synchronization { void beforeCompletion(); void afterCompletion(int status); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 25

J2EEJTS::JavaTransactionAPI(JTA)

package javax.transaction package javax.transaction.xa interface XAResource { void commit(Xid, boolean); void end(Xid); void forget(Xid); int getTransactionTimeout(); boolean isSameRM(XAResource); int prepare(Xid); Xid[] recover(); void rollback(Xid); boolean setTransactionTimeout(int); void start(Xid); };

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 26

J2EEJTS::TransactionalJ2EEcomponents

  • EJBs
  • SimilartobasiclevelCORBA3components
  • MethodsontheEJBinterfacecanbetransactional
  • Beanmanaged:ThroughJTAUserTransaction
  • Containermanaged:Throughdeploymentdescriptoratmethod

level

  • NotSupported

[none -> none][T1 -> none]

  • Required

[none -> T2 ][T1 -> T1 ]

  • Supports

[none -> none][T1 -> T1 ]

  • RequiresNew

[none -> T2 ][T1 -> T2 ]

  • Mandatory

[none -> ERR ][T1 -> T1 ]

  • Never

[none -> none][T1 -> ERR ]

  • EJBContainerdoesnotneedtouseaJTSimplementation,but

mustprovideJTA

  • JDBC+JMSproviders
  • Actasresourcemanagers
  • MustimplementJTAXAinterface
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 27

Thesisoutline::Wherearewetoday?

  • Workingtitle
  • Outline
  • …
  • Conceptualdesignofaframeworkthatsupports

coordinationandlongrunningtransactions

  • Whylongrunningtransactions?(AW1recap)
  • Requirements
  • Specs:WSC,WSBA
  • Relatedwork
  • Initialideas
  • Projectexperiences
  • Outlook
  • …

Thesis

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 28

Whylongrunningtransactions?(AW1recap)

  • SomeactivitiesintheTXcantakelong
  • NosatisfyingQoS guaranteescanbemade
  • Participantsareunabletoperform2PC
  • Participantsmustnotholdlocksfortoolong
  • ACIDistoorestrictive
  • Participatingresourcemanagersshouldcommitassoon

aspossible

  • #$…therentalcarshouldnotstaybookedifthe

restaurantissoldout…

  • Coordinationandcompensationhandlingrequired
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 29

Requirements

  • %&!
  • '
  • Heterogeneous
  • CompensationbasedTXprocessing(CTP)
  • Resourcemanagerlogging
  • But"no"locking
  • Commutativeactions
  • (
  • ')*(
  • +,-.
  • /
  • Idempotentactionsincaseofunreliablemessaging
  • …fromcontextinpersistentstorage
  • ")'-
  • AOP(injection,codegenerationatruntime)
  • vs Dynamic
  • Policiesandimplementedinterfaces
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 30

Requirements

  • %&!
  • '
  • Heterogeneous
  • CompensationbasedTXprocessing(CTP)
  • Resourcemanagerlogging
  • But"no"locking
  • Commutativeactions
  • (
  • ')*(
  • +,-.
  • /
  • Idempotentactionsincaseofunreliablemessaging
  • …fromcontextinpersistentstorage
  • ")'-
  • AOP(injection,codegenerationatruntime)
  • vs Dynamic
  • Policiesandimplementedinterfaces

complete Coordinator Participant cancel

!

"self-compensate"

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 31

Specifications

Generic,interop., sep.C/T,complete, nestedscopes Short,easy, generic,interoper., separationofC/T Complete,well formed

  • Prettylong;)

Incomplete,flat NolegacyTXintegr. "Bus./TXLogicMix"

  • OASISsince10/2003

OASISsince10/2005 (!) OASISsince03/2001, butalmostabandoned

  • &'

#& #'

1!

  • ACIDTransaction

(2PC)

AtomicTransaction

(3protocols,incl.2PC)

Atom

(Opentop2phasecompl.)

' (seenextslide) Coordinator, Participant Superior,Inferior

  • WSCTX(59),

WSCF(63), WSTXM(111) WSC(23), WSAT(21), WSBA(23) BTP(163) ! Arjuna,Fujitsu,IONA, Oracle,Sun IBM,Microsoft HP,Oracle,BEA

  • 2003

2002 2001

  • '2

, #

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 32

Specifications

Generic,interop., sep.C/T,complete, nestedscopes Short,easy, generic,interoper., separationofC/T Complete,well formed

  • Prettylong;)

Incomplete,flat NolegacyTXintegr. "Bus./TXLogicMix"

  • OASISsince10/2003

OASISsince10/2005 (!) OASISsince03/2001, butalmostabandoned

  • &'

#& #'

1!

  • ACIDTransaction

(2PC)

AtomicTransaction

(3protocols,incl.2PC)

Atom

(Opentop2phasecompl.)

' (Hierarchical) Coordinator, Participant Superior,Inferior

  • WSCTX(59),

WSCF(63), WSTXM(111) WSC(23), WSAT(21), WSBA(23) BTP(163) ! Arjuna,Fujitsu,IONA, Oracle,Sun IBM,Microsoft HP,Oracle,BEA

  • 2003

2002 2001

  • '2

, #

Participant CoordinatorParticipant ParticipantCoordinator ParticipantRespondant ServiceCoordinator ServiceRespondant ClientCoordinator ClientRespondant RecoveryCoordinator

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 33

WSCoordination

protocol Operation (w/ CoordinationContext) RegisterResponse Register CreateResponse protocol Coordinator Participant Registration Registration Activation Service Client Create Register Operation Response Coordination Service Coordination Service

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 34

WSCoordination

protocol Operation (w/ CoordinationContext) RegisterResponse Register CreateResponse protocol Coordinator Participant Registration Registration Activation Service Client Create Register Operation Response Coordination Service Coordination Service

<soap:Header> <wscoor:CoordinationContext soap:mustUnderstand="true"> <wscoor:Identifier> http://www.informatik.haw-hamburg.de/ws/#8237123801 </wscoor:Identifier> <wscoor:CoordinationType> http://schemas.xmlsoap.org/ws/2004/10/wsba/AtomicOutcome </wscoor:CoordinationType> <wscoor:RegistrationService> <wsa:Address> http://host/service </wsa:Address> </wscoor:RegistrationService> </wscoor:CoordinationContext> </soap:Header>

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 35

WSBusinessActivity

Completed Completed Close Close Close Completed Complete Exited Complete Complete Complete Participant 1 Participant 2 Participant 3 Coordinator Exit Participant 4 Closed Closed Closed

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 36

WSBusinessActivity withcompensation

Completed Completed Canceled Compensated Compensate Compensate Cancel Faulted Complete Complete Complete Participant 1 Participant 2 Participant 3 Coordinator Fault Participant 4 Compensated

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 37

Relatedwork

  • JSR95:J2EEActivityServiceforExtendedTransactions
  • "JTAforlongrunningtransactions"basedonOMGActivityService
  • Activities=unitsofwork,potentiallydistributed,neednotbe transactional
  • JSR156:JavaAPIforXMLTransactions(JAXTX)
  • SupportforJTA,J2EEActivityService,BTP,WST,WSTXM
  • Purpose:Providecommoninterfacefordifferenttx implemenations
  • ApacheKandula
  • BasedonApacheAxis2
  • SubversionBranchKandula_1(Early2005)
  • WSATonly
  • MappingofCoordinationContext identifiertoJTAUserTransaction inAxisHandler
  • TestedwithJBoss andJOTMtx managers
  • Subversiontrunk
  • Significantlychangedandchanging
  • NoJTAcodesofar
  • Seemstobearefactoring effortonKandula_1
  • StillnoWSBAcode
  • EJB2.1WebServiceEndpointEJBs
  • StatelessSessionBeans
  • TXsupportforlocalJTAtransactionsonly(Mandatory notallowed!)
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 38

Initialideas::Conceptualoverview/Architecture

Service1 PParticipant Service2 Coordinator QoS/Transaction Application TXMiddleware TXMiddleware Call implementation Service1 Skeleton Service2 Skeleton Service2 Stub Service1 Stub CParticipant

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 39

Initialideas::Conceptualoverview/Architecture

Service1 PParticipant Service2 Coordinator QoS/Transaction Application TXMiddleware TXMiddleware Call implementation Service1 Skeleton Service2 Skeleton Service2 Stub Service1 Stub CParticipant

create

Incoming call toService 1transactional operation

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 40

Initialideas::Conceptualoverview/Architecture

Service1 PParticipant Service2 Coordinator QoS/Transaction Application TXMiddleware TXMiddleware Call implementation Service1 Skeleton Service2 Skeleton Service2 Stub Service1 Stub CParticipant

(context) (context) (context)

Call from transactional

  • peration toService2
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 41

Initialideas::Conceptualoverview/Architecture

Service1 PParticipant Service2 Coordinator QoS/Transaction Application TXMiddleware TXMiddleware Call implementation Service1 Skeleton Service2 Skeleton Service2 Stub Service1 Stub CParticipant

register(context) create create regResp(context)

Service2registration at Service1

1 2 3 4 5 6 7 8 9(actual business method)

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 42

Initialideas::Conceptualoverview/Architecture

Service1 PParticipant Service2 Coordinator QoS/Transaction Application TXMiddleware TXMiddleware Call implementation Service1 Skeleton Service2 Skeleton Service2 Stub Service1 Stub CParticipant

(context) (context) (context)

Service2response to Service1

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 43

Initialideas::Conceptualoverview/Architecture

Service1 PParticipant Service2 Coordinator QoS/Transaction Application TXMiddleware TXMiddleware Call implementation Service1 Skeleton Service2 Skeleton Service2 Stub Service1 Stub CParticipant

complete complete/close(ctx) completed/closed(ctx) update update

Service1completes the transaction (2phases)

1 2 3,11 4,12 5 13 7,16 8,17 9,18 10,19 6,14 15 20

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 44

Initialideas::Notes

  • Asynchronouscallhandling
  • Modelservicesandprotocolsasstatemachines,persiststateafter

eachoperation

  • Registryforcontexts,coordinators,participants,operationcall

backs,…

  • Onestatemachineperserviceandpercoordinator/participantpair
  • Transparency
  • Hideasmuchprotocolprocessingaspossiblefromdevelopers
  • Somecompletionsemanticsmaydependonbusinesslogic
  • Needtoexposeoperationsoncoordinator/participantsforservice

managedtx

  • Use/extendcodegeneration(e.g.AxisWSDL2Java)
  • LikeEJB:Containermanagedtx,Servicemanagedtx
  • GeneratedcodecoulduseJAXTX
  • Generatedcode(possibly)differentforeachservicerole
  • Coordinator/participant/coordinationtype/protocoltype/operation
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 45

Projectexperiences/Outlook

  • Project:Theusualdifficulties
  • Technical
  • NewtoJBoss
  • Setupofdevelopmentenvironmentwithdebugging,SOAPmonitor,…
  • WebServicescontainer(Axis1.2.1)issues
  • Logistical
  • Notenoughtimetoproducemeaningfulresults
  • HadtorevisequiteafewTX/J2EE/WebServicesconcepts
  • Lowertargetswouldnothavemademuchsense,butmaybethreeto

fourmotivatedpeopleas"TXteam"

  • Project:Successes(by01/2006)
  • "Rapidly"(nettime)prototypedactivation,registration,participant

initiatedBAcompletionwithmixedoutcome

  • Foundationforaframeworkprototypewithcodegeneration
  • Outlook
  • Project:IntegrationconceptwithESBandSecurity
  • Thesis:Detailedframeworkdesign
  • Thesis:"TXLite"frameworkfordeviceswithlimitedresources
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 46

34

  • 35
  • Gray,Reuter,6

7,MorganKaufman,1993

  • Szyperski,*)6#89

,AddisonWesley,1998

  • Siegel,#':2,

OMGPress,2000

  • Pavlik,Maron,Little,;,

PrenticeHall,2004

  • Weerawarana,Curbera,Leymann,Storey,Ferguson,

8*',Pearson,2005

  • …plusseveralarticlesandpapers(seereport)
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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 47 public class MySessionEJB implements SessionBean { EJBContext ejbContext; public void someMethod(...) { javax.transaction.UserTransaction ut; DataSource ds; Connection dcon; Statement stmt; QueueConnectionFactory qcf; QueueConnection qcon; Queue q; QueueSession qsession; QueueSender qsender; Message message; // obtain db conn and queue session objects through JNDI InitialContext lookup ... // Now do a transaction that involves the two connections. ut = ejbContext.getUserTransaction(); // start the transaction ut.begin(); // Do database updates and send message. The container automatically enlists // dcon and qsession with the transaction. stmt.executeQuery(...); stmt.executeUpdate(...); stmt.executeUpdate(...); message = qsession.createTextMessage(); message.setText(“some message”); qsender.send(message); // commit the transaction ut.commit(); // release connections stmt.close(); qsender.close(); qsession.close(); dcon.close(); qcon.close(); } ... }

J2EEJTS::TransactionalJ2EEcomponents::EJBwith beanmanagedtransactioncodesample

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 48

J2EEJTS::TransactionalJ2EEcomponents

commit begin enlist XA Resource with Tx delist XA Resource from Tx close update dispatch to business method EJB Container TX Service EJB App Server Connection Proxy XA Resource XA Start XA End commit prepare

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16.12.2005 infm3::SR::LongRunningTransactions...::MartinGerlach 49

Excursus:Experiences@Techniker Krankenkasse

  • Formbasedcasemanagementsystem
  • Problems
  • 2PCnotsupportedbymanysystems(e.g.SAP)
  • Distributedtx notsupportedbymany(legacy)systems
  • TXmanageroverhead
  • ObjectTX(CORBAetc.):Traffic!
  • Atomiconlymanageablewithinonecompany/enterprise
  • DBtransactions:Shouldneverbelong
  • Solutions
  • Longtx oninmemoryobjectmodelsonly
  • O/Rmapping
  • Writeonce(≈ACID),failifconcurrentchangesoccurred
  • Optimisticlocking(changecounter,selectforupdate)
  • Timeframe:absolutemaxisseveralhours,butmostlyratherminutesfor
  • neworkitem
  • Sessiongroupslongrunningtx in"userinteraction"
  • Logicalsequenceofatomichighleveltx (workflow)
  • Onlymanageablewithcoarsergrainedhigherlevelcalls(services)
  • Designsystemsothatinconsistenciesarealsoavoidedbythenature
  • ftheworkflow
  • Compensation,etc.