RIAlizing Enterprise Applications

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The DSine Research CompanyThe DSine Research Company

RIAlizing Enterprise ApplicationsRIAlizing Enterprise Applications

ByBy

Sujoe BoseSujoe Bose

www.dsinedynamics.comwww.dsinedynamics.com

AJAX World 2009 Conference, USA, June ‘09 AJAX World 2009 Conference, USA, June ‘09

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AgendaAgenda

MotivationMotivation

The RIA ChallengeThe RIA Challenge

RIA MethodologyRIA Methodology

RIA Scalability ModelRIA Scalability Model

Model EvaluationModel Evaluation

Conclusion and Future WorkConclusion and Future Work

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AgendaAgenda







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RIA-Enabling Methodology for Existing RIA-Enabling Methodology for Existing

Enterprise ApplicationsEnterprise Applications

Predicting AJAX ScalabilityPredicting AJAX Scalability

Unavailability of Objective MethodUnavailability of Objective Method

Formal treatment of AJAX side-effects on Formal treatment of AJAX side-effects on

PerformancePerformance

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ContextContext

RIA-Enabling Existing Enterprise RIA-Enabling Existing Enterprise ApplicationApplication Reuse of investment and infrastructureReuse of investment and infrastructure Seamless changes to WorkflowSeamless changes to Workflow

Refactoring Interfaces Iteratively for Richer Refactoring Interfaces Iteratively for Richer User ExperienceUser ExperienceNeed for a repeatable methodNeed for a repeatable methodImpact on ScalabilityImpact on ScalabilityPrediction better than Trial-and-ErrorPrediction better than Trial-and-Error

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AgendaAgenda







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The AJAX ConundrumThe AJAX Conundrum

Page-based approachPage-based approach Large ObjectsLarge Objects Lower frequency of accessLower frequency of access

AJAX-basedAJAX-based Small ObjectsSmall Objects Higher frequency of accessHigher frequency of access

Which one is better as far as scalability is Which one is better as far as scalability is concerned?concerned?

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Scalability ConcernScalability Concern

TCP/IP – Slow Start AlgorithmTCP/IP – Slow Start Algorithm Congestion and Flow ControlCongestion and Flow Control

Round-trip overhead:Round-trip overhead: High for smaller requestsHigh for smaller requests Amortized for larger requests (pipelined Amortized for larger requests (pipelined

transfer)transfer)

Increase in Invocation Frequency and Increase in Invocation Frequency and Quantity (AJAX Factor)Quantity (AJAX Factor)

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Shorter reply/responses vs. Larger Shorter reply/responses vs. Larger reply/responsesreply/responses

Frequent reply/responses vs. InfrequentFrequent reply/responses vs. Infrequent

Page loading interspersed between AJAX Page loading interspersed between AJAX burstsbursts

Find the appropriate mix in a disciplined Find the appropriate mix in a disciplined approachapproach

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RIA TargetsRIA Targets

Look-and-feelLook-and-feel

ResponsivenessResponsiveness

Modified workflow that is more usable and Modified workflow that is more usable and naturalnatural Moving away from page-centric behaviorMoving away from page-centric behavior

Non-functional targets: Stability and Non-functional targets: Stability and Scalability with no Infrastructural upgradesScalability with no Infrastructural upgrades

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Advantages of Evolutionary RIAAdvantages of Evolutionary RIA

Find what works and what does notFind what works and what does not

Experiment without large impactExperiment without large impact User’s likes and dislikesUser’s likes and dislikes

System PerformanceSystem Performance Introducing AJAX has some System side-Introducing AJAX has some System side-

effectseffects

Seamless User experience and System Seamless User experience and System Performance impactsPerformance impacts

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RIAlizing PrimitivesRIAlizing Primitives

Three Basic Primitives for RIA-enablingThree Basic Primitives for RIA-enablingSplitSplit Split an interaction into multiple fine-grainedSplit an interaction into multiple fine-grained LiveControls: specialization of splitLiveControls: specialization of split

MergeMerge Merge multiple interactions into oneMerge multiple interactions into one

FoldFold Coalesce with SummaryCoalesce with Summary Zoom or Deep dive (with and without caching)Zoom or Deep dive (with and without caching)

CombinationsCombinations

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Web InteractionWeb Interaction

User Action

User Action

User Submit

User Action

User Submit

Web BrowserWeb Browser Web ServerWeb Server

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SplitSplit

User Action

User Action

User Submit

User Action

User Submit

Ajax Factor: Increase in Service InvocationAjax Factor: Increase in Service Invocation


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The DSine Research CompanyThe DSine Research CompanySplit ExampleSplit Example

Web ServerWeb Serverhttp://dsinedynamics.com/training.phphttp://dsinedynamics.com/training.php

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MergeMerge

User Action

User Action

User Action

User Action

User Action

Ajax Factor: Increase in Service InvocationAjax Factor: Increase in Service Invocation


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Merge: Macro and Micro-levelMerge: Macro and Micro-level

P1

P2

P3

P4

P1

P4

P23

P2

P3

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Merge/Fold ExampleMerge/Fold Example

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RIA PrimitivesRIA Primitives

Basic primitives:Basic primitives: Iterative implementation Iterative implementation Helps easily model the scalability problemHelps easily model the scalability problem

The Scalability ChallengeThe Scalability Challenge Quantify the impact from these primitivesQuantify the impact from these primitives Predict Scalability based on the derived modelPredict Scalability based on the derived model

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ScalabilityScalability

AJAX – side effectsAJAX – side effects Smaller requests have large relative overhead Smaller requests have large relative overhead

[8][8] Frequent requests can increase the overall Frequent requests can increase the overall

network loadnetwork load

Implement and Checkout PerformanceImplement and Checkout Performance Fix by Trial and Error?Fix by Trial and Error? Costly and time-consumingCostly and time-consuming

Need Predictive ScalabilityNeed Predictive Scalability

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AJAX done rightAJAX done right

Identify proper mix of:Identify proper mix of: Shorter frequent requests Shorter frequent requests Larger infrequent requestsLarger infrequent requests

HTMLHTML

Page submitsPage submits

AJAXAJAX

AJAX requestsAJAX requests

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TCP-IP Slow StartTCP-IP Slow Start

Upfront setup time on each transferUpfront setup time on each transfer

Three-way handshake prior to Three-way handshake prior to sustained transfersustained transfer

HTTP Transactions are smaller and HTTP Transactions are smaller and connection-lessconnection-less

Slow start algorithm Overhead for Slow start algorithm Overhead for smaller transactions is higher [8]smaller transactions is higher [8]

Ajax Transactions are even smaller Ajax Transactions are even smaller than regular HTTP requeststhan regular HTTP requests

Overhead on N/W more Overhead on N/W more pronouncedpronounced

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Design for AJAX ScalabilityDesign for AJAX Scalability

RIAlizing strategy to include Scalability RIAlizing strategy to include Scalability upfrontupfront

Predict Scalability and Design accordinglyPredict Scalability and Design accordingly

Disciplined approach to mitigate riskDisciplined approach to mitigate risk

Simple model resulting in net effect of Simple model resulting in net effect of increased AJAX factorincreased AJAX factor

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Model for PerformanceModel for Performance

Queuing SystemQueuing System NetworkNetwork Web ServerWeb Server

Simplified View for easier IllustrationSimplified View for easier Illustration

NetworkNetwork

AppClient

Arrival rate: Arrival rate: λλ11

Service rate: Service rate: μμ11

Arrival rate: Arrival rate: λλ2 2 → → λλ11


WebServerWebServer

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ParametersParameters

AJAX FactorAJAX Factor

Server Processing timeServer Processing time External and Internal Services (SOA)External and Internal Services (SOA) Mostly unaltered by introducing AJAX Mostly unaltered by introducing AJAX

Network OverheadNetwork Overhead Time taken in the networkTime taken in the network

AJAX Response Reduction Factor AJAX Response Reduction Factor

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AJAX FactorAJAX FactorIncrease in arrival rate of requests: fIncrease in arrival rate of requests: faa

Increase in service rate of requests: fIncrease in service rate of requests: fbb

NetworkNetwork

AppHTMLClient

Arrival rate: Arrival rate: λλ11


Arrival rate: Arrival rate: λλ2 2 → → λλ11


WebServerWebServer

NetworkNetwork

AppAJAXClient

Arrival rate: fArrival rate: faa λλ11

Service rate: fService rate: fbbμμ11

Arrival rate: fArrival rate: faa λλ2 2 (where (where λλ22 → → λλ1 1 ))


WebServerWebServer

Remains the same unless backend

changed accordingly

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AJAX FactorsAJAX Factors

HTMLHTML

Page submitsPage submits

AJAXAJAX

AJAX requestsAJAX requests

In this example: fIn this example: faa = 4 = 4

ffbb depends on request depends on request

Page GetPage Get

Page GetPage Get

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Our ModelOur Model

Simple Model:Simple Model: Useful for prediction and estimationUseful for prediction and estimation

Arrival rate: Arrival rate: λλ

Service rate: Service rate: μμ

AppHTMLClient

NetworkNetwork WebServerWebServer

For AJAX performing better than HTML

fa ≤ μ(fb – 1) + λ λ

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Estimated ValuesEstimated Values

10 concurrent users, using 2 page 10 concurrent users, using 2 page requests (submits) within 12srequests (submits) within 12s

Comparing with various AJAX Comparing with various AJAX configurationsconfigurations If fIf fbb=1.7 (approx), ie 70% increase in service =1.7 (approx), ie 70% increase in service

rate)rate) Using Using λ and μ from the page-based scenarios

λ = 2.328 x 10-3 reqs/ms, μ = 0.1798 reqs/ms

Arrive at: fa ≤ 53

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ComparisonComparison

Vs.Vs.

AJAXAJAX HTMLHTML

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1010 concurrent users running for concurrent users running for 5mins 5mins ramp time of ramp time of 10s10s

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ObservationsObservations

Ensuring proper design to handle scalability is Ensuring proper design to handle scalability is the keythe key Know how to estimateKnow how to estimate Know what to expectKnow what to expect

Modeling AJAX and HTML responses provides Modeling AJAX and HTML responses provides the answerthe answerWhen load increase beyond calculated value the When load increase beyond calculated value the response time did not scaleresponse time did not scalePredictive Scalability better than Trial-and-ErrorPredictive Scalability better than Trial-and-Error

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RIA Side-EffectsRIA Side-Effects

Any of the methods: merge, split and folds Any of the methods: merge, split and folds leads to increased arrival rateleads to increased arrival rate

Load overhead percentage higher on Load overhead percentage higher on smaller requests: less useful worksmaller requests: less useful work

Scalability affected due to increase rate Scalability affected due to increase rate and increased overheadand increased overhead

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Workarounds or ExtensionsWorkarounds or Extensions

Adding Client-side Caching Adding Client-side Caching Key to eliminate network bottleneckKey to eliminate network bottleneck Cache JavaScript and CSSCache JavaScript and CSS

AJAX requests only when necessaryAJAX requests only when necessary Minimize server requestsMinimize server requests

Adding superfluous AJAX requests will Adding superfluous AJAX requests will swamp the networks (and the servers too)swamp the networks (and the servers too) Fewer the betterFewer the better

Compress response dataCompress response data

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ConclusionConclusion


AJAX Scalability IssueAJAX Scalability Issue

Model for predicting performance and Model for predicting performance and scalabilityscalability

Designing for ScalabilityDesigning for Scalability

Current and Future WorkCurrent and Future Work

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Current and Future WorkCurrent and Future Work

Adobe Flex Scalability StudyAdobe Flex Scalability Study

Model Variations:Model Variations: Effect of Service time on responsesEffect of Service time on responses Effect of CachingEffect of Caching Effect of Network (congestion and errors)Effect of Network (congestion and errors)

Extend the model to study resource Extend the model to study resource utilizationutilization

Reverse AJAXReverse AJAX

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Related Work - MethodsRelated Work - Methods

[1] RUX-Model Approach:[1] RUX-Model Approach: Linaje, M., Preciado, J., Sanchez-Figueroa, F.: Linaje, M., Preciado, J., Sanchez-Figueroa, F.: "Engineering Rich Internet Application User Interfaces over Legacy Web Models", Internet Computing, IEEE, "Engineering Rich Internet Application User Interfaces over Legacy Web Models", Internet Computing, IEEE, Volume: 11, Issue: 6, pp. 53-59, Nov.-Dec. 2007.Volume: 11, Issue: 6, pp. 53-59, Nov.-Dec. 2007.

[2] Semi-Automatic Approach:[2] Semi-Automatic Approach: Mesbah, A., Van Deursen, A. "Migrating Mesbah, A., Van Deursen, A. "Migrating Multi-page Web Applications to Single-page AJAX Interfaces," csmr, pp. 181-190, 11th European Conference on Multi-page Web Applications to Single-page AJAX Interfaces," csmr, pp. 181-190, 11th European Conference on Software Maintenance and Reengineering (CSMR'07), 2007.Software Maintenance and Reengineering (CSMR'07), 2007.

[3] Web Model Refactoring: [3] Web Model Refactoring: Garrido, A., Rossi, G., Distante, D.: Model Garrido, A., Rossi, G., Distante, D.: Model Refactoring in Web Applications. In Proceedings of the 9th International Symposium on Web Site Evolution (WSE Refactoring in Web Applications. In Proceedings of the 9th International Symposium on Web Site Evolution (WSE 2007: Oct. 05-06, 2007; Paris, France). Los Alamitos, CA: IEEE Press, 2007.2007: Oct. 05-06, 2007; Paris, France). Los Alamitos, CA: IEEE Press, 2007.

[4] Abstract Data Views: [4] Abstract Data Views: Cowan, D. Pereira de Lucena, C.: Abstract Data Views: Cowan, D. Pereira de Lucena, C.: Abstract Data Views: An Interface Specification Concept to Enhance Design for Reuse. IEEE Trans. Software Eng. 21(3): 229-243 An Interface Specification Concept to Enhance Design for Reuse. IEEE Trans. Software Eng. 21(3): 229-243 (1995).(1995).

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Related Work - PerformanceRelated Work - Performance[5] High Performance Web Sites, [5] High Performance Web Sites, Steve Souders, ACM Queue, v.6 n.6, Steve Souders, ACM Queue, v.6 n.6, October 2008October 2008

[6] Implementation of asynchronous predictive fetch [6] Implementation of asynchronous predictive fetch to to improve the performance of AJAX-enabled web applications, Andy Ahmad Dahlan, Toshikazu improve the performance of AJAX-enabled web applications, Andy Ahmad Dahlan, Toshikazu Nishimura, iiWAS '08, November 2008Nishimura, iiWAS '08, November 2008

[7] A Model of Web Server Performance, [7] A Model of Web Server Performance, Louis P. SlothouberLouis P. Slothouber, , June, June, 1995, http://www.geocities.com/webserverperformance/modelpaper.html1995, http://www.geocities.com/webserverperformance/modelpaper.html

[8] Modeling the performance of HTTP over several [8] Modeling the performance of HTTP over several transport protocols. transport protocols. John S. Heidemann, Katia Obraczka, Joseph D. Touch: John S. Heidemann, Katia Obraczka, Joseph D. Touch: IEEE/ACM Transactions on Networks 5(5): 616-630 (1997) IEEE/ACM Transactions on Networks 5(5): 616-630 (1997)

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RIAlizing Enterprise Applications