1. Optimizing BPM Through SLAs & Event Monitoring
MIDDLEWARE SYSTEMS
RESEARCH GROUP
Optimizing BPM Through SLAs & Event Monitoring
Hans-Arno Jacobsen
Bell University Laboratory Chair
Middleware Systems Research Group
University of Toronto
An eQoSystem for declarative
distributed applications with SLAs

2. Gartner Event Processing Summit, 15-16 September 2008
Agenda
Business goals, SLAs & events
Enabler and approach: Content-based Pub/Sub
The PADRES ESB for event-based BPM
SLA enforcement example
Summary & take-away
Gartner Event Processing Summit, September 2008

3. Gartner Event Processing Summit, 15-16 September 2008
Currently, business goals must be manually considered at every stage of the business process development cycle
cost < $0.02
Only trusted partners
service time < 3s
Find flight
Find train
Far?
Get destination
Validate request N Y
Gartner Event Processing Summit, September 2008 3

4. Large-scale Business Processes
Vendor
Goods
selection
Goods delivery
Dispatch B
Packaging
Pick-up goods
Out-stock B
FedEx
Delivery
Pick up
Sale
prediction
Sign
Contract
Sale
Fill order
Determinate
plan
Process
Check order
CCC
administrate
Fill out-stock
bill
Check stock
Manufactory
Confirm
features
Design
Fill dispatch
bill
Control
Determinate
plan
Prototype
Out
Take
Raw
materials
Execute
plan
Warehouse
Material
Out-stock B
Pay
Credit card
Check
Assign
Audit
Process
control
Make plan
Target price
Signature
Raw
Check dealer
Check credit
Finance
Confirm
Approval
Approval
Monitoring
Feature
selection
Print receipt
Statistic
Monitor
Validate
Marketing
Requirement
collection
Feedback
Affirm order
Chart
Strategy
Design
Marketing
Manufactory
Order
Payment
Gartner Event Processing Summit, September 2008

5. Service Level Agreements
SLAs are a contract between service consumers and providers that specifies the expected behaviour of each party and the penalties of violating the contract.
SLAs specify business goals declaratively.
Layer
SLA Metric
Example
Business Process
Cost
Cost of search service < $0.02 per use
Fidelity, quality, utility
Map resolution > 300x300
Trust, reputation
Only use trusted payment services
Deployment & Operations
Service time
Execution time < 3s
Throughput
Throughput > 100/min
Availability
Uptime > 99.9%
Load balance
Server utilization delta < 10%
Network
Latency
Service RTT < 100ms
Bandwidth
Max bandwidth < 3Mbps
Jitter
Delay jitter < 10ms

6. Challenge: Enforcing SLAs
Enforcing SLAs is a monitoring & control
problem.
Analyze log files
Use a (business) process to monitor SLAs
Use events and event processing to monitor SLAs
Gartner Event Processing Summit, September 2008

7. Business Goals, SLAs & Events
Business processes are triggered and driven by instantaneous and asynchronous state transitions.
Instantaneous and asynchronous state transitions are events.
SLA enforcement amounts to listening, tracking, filtering, correlating, and responding to events of business processes.
SLA monitoring requires event processing.
Gartner Event Processing Summit, September 2008

8. What Abstractions Enable Effective Event Processing?
The afore-mentioned points can best be addressed by
The content-based publish/subscribe model
Realized by content-based message routing
Events are conveyed as publications.
Event listening, filtering and correlating is based on subscriptions managed by the pub/sub system.
Gartner Event Processing Summit, September 2008

9. Content-based Pub/Sub & Routing
1. Advertise
Publisher
3. Publish
Subscriber
Publish/Subscribe Model
Publish/subscribe is a communication paradigm in which the interaction between the information producer (publisher) and consumer (subscriber) is mediated by a set of brokers.
Publishers publish events (aka publications) to the broker network, and subscribers subscribe to interesting events by submitting subscriptions to the broker network. It is the responsibility of the brokers to route each event to interested subscribers.
In content-based publish/subscribe, subscribers can specify constraints on the content of the events, and the broker network is said to perform content-based routing of events.
The routing in the PADRES distributed content-based publish/subscribe system works as follows.
0) Publishers and subscribers connect to one of a set of brokers.
Publishers specify a template of their event space by submitting an advertisement message that is flooded through the broker network and creates a spanning tree rooted at the publisher.
Similarly, subscribers specify their interest by sending a subscription message that is forwarded along the reverse paths of intersecting advertisements, i.e., those with potentially interesting events.
Now publications from publishers are forwarded along the reverse paths of matching subscriptions to interested subscribers.
Publish/Subscribe benefits
It is event-based, so it is a natural fit for the event-driven applications in the previous slide.
It decouples clients through a declarative publish/subscribe interface.
It performs content-based routing to support expressive queries.
Interactions and queries are declarative (say what you want, not where/who to get it from).
Content-based addresses allow for flexible deployment environments.
It is responsive since events are pushed to clients immediately.
Conclusion: pub/sub is a sound model for these event-driven enterprise applications.
2. Subscribe
Event-Based
Content Routing
Flexible
Decoupled
Declarative
Responsive
Gartner Event Processing Summit, September 2008

10. Benefits of Content-based Publish/Subscribe
Simplifies IT development and maintenance by decoupling enterprise components
Supports sophisticated interactions among components using expressive subscription languages – going beyond the limits of topics
Allows fine-grained filtering based on content matching
Achieves scalability with in-network filtering and processing
Constitutes an Event Processing Network
Content-based publish/subscribe is a powerful coordination and interaction model. It goes far beyond what can be achieved by the earlier topic-based publish/subscribe model.
Content-based publish/subscribe is fully compatible with topic-based p/s (i.e., any topic-based system can be easily emulated by a content-based one.)
Content-based p/s offers message filtering capabilities that by far outperform topic-based ones, as content-based filters operate over the message content rather than the topic filed.
Content-based p/s is very efficient. We have shown that millions (10 million) content-based filters (i.e., 10 predicates over integers and strings) can be processed on current server technology (Dell Poweredge Small Business Model) in about 100 milliseconds for one event containing up to 50 attribute-value pairs.
Content-based routing can be used to coordinate activities (e.g., business processes) as we demonstrate later. It can be used for event correlation, suppressing unnecessary events from polluting the network infrastructure. This is only possible due to the fine-grained expressiveness over message content, not available in the topic-based model.
Of course, at the end it is a design decision of whether to use topic or content-based p/s. However, the choice for the more flexible content-based p/s can never be wrong as it is fully compatible with the less expressive and less flexible topic-based model.
Gartner Event Processing Summit, September 2008

11. The PADRES ESB for Declarative Event-based BPM with SLAs
First generation of students, when I looked away 
Peng Alex David aRno Eli Serge
PADRES is Publish/subscribe Applied to Distributed
Resource Scheduling
PAdres is Distributed REsource Scheduling
An eQoSystem for declarative distributed applications with SLAs
Gartner Event Processing Summit, September 2008

12. Gartner Event Processing Summit, 15-16 September 2008
The PADRES R&D Efforts
Prove & develop flexible BPM concept
With CA Labs, Sun Microsystems, OCE & NSERC
Prove & develop SLA-based autonomic BPM concept
With IBM and NSERC
Evaluate and experiment with the use of the PADRES ESB for application integration
With Bell Canada and Bell University Labs
Acknowledgements
Gartner Event Processing Summit, September 2008

13. The PADRES ESB Architecture13
Gartner Event Processing Summit, September 2008
2017/4/26

14. Gartner Event Processing Summit, 15-16 September 2008
The PADRES ESB
Consists of pub/sub message brokers
Content-based publish/subscribe interface
Content-based message routing
Store-and-forward message queuing
Comprised of a federation of brokers deployed as overlay
Offers a slim client library for applications
Soon available under an open source license model and as Apache Poloka incubation project
Gartner Event Processing Summit, September 2008

15. PADRES Pub/Sub Message Broker
dest1
dest2
dest3
subscription
dest
Matching Engine
Routing Table +
input queue
output queue dest2
output queue dest3
Publications
temperature > 37 dest2
temperature > 40 dest3
temperature = 36
temperature = 42
temperature = 38 P S
= publisher
= subscriber
Gartner Event Processing Summit, September 2008

16. Innovative PADRES Features
Historic Access
Management
Composite Events A B C D E F
Need more features from the infrastructure for effectively supporting enterprise apps.
Old features
Composite events – for complex (business) event correlation.
Historic queries– for auditing; also temporal joins. For extracting information published in the past.
Management – monitoring, control, configuration.
New features
Cyclic – gives robustness, load balance, ease of administration.
This refers to allowing content-based routing over arbitrary overlay network topologies.
Existing approaches are limited to acyclic topologies and to tree topologies, which are severely limiting especially in sight of load issues (e.g., a link / broker maybe overloaded and in an acyclic topology there is no way to get around the overloaded link, as it is the only one link connecting two entities.) Furthermore, node failures are detrimental in an acyclic topology, whereas with cycles in the topology a new route can be found easily.
LB – gives load balance, ease of administration.
Security – hard due to content-based routing; issues of privacy, authentication, authorization, immutability, non-repudiation, trusted domains, key management, etc.
Security
Robustness
Load Balancing
Gartner Event Processing Summit, September 2008

17. Modeling Business Processes
Dependency in processes and more complex process patterns requires event correlation.
Event correlation enabled by the detection of composite events.
Composite events are expressed via composite subscriptions.
Composite subscription consists of atomic subscriptions.
Example: D executes, if B and C
have completed (D depends on
B and C) B C D
Gartner Event Processing Summit, September 2008

18. Business Process Execution
Encode process as subscriptions
Deploy the transformed process
Trigger and execute process instances
Monitoring process execution
trigger multiple
instances concurrently
trigger
Exception & compensation A E F B C D
Gartner Event Processing Summit, September 2008

19. Gartner Event Processing Summit, 15-16 September 2008
Example SLA
Ensure that the average hourly response time of searches by VIP customers is less than 0.5 s.
Search Reply
User Request
Find flight
Find train
Far?
Get destination
Validate request N Y
Gartner Event Processing Summit, September 2008

20. Event Model for SLA Monitoring
Event model is concerned with the data flow.
Event
Handler
Event
Gartner Event Processing Summit, September 2008

21. Event Model in PADRES

22. Process Model for SLA Monitoring
Process model is concerned with the control flow.
Gartner Event Processing Summit, September 2008

23. Process Model in PADRES

24. Event and Process Realizations
Realization of event model
User Request
Search Reply
Compute Delay
Filter VIP Users
Compute Avg Delay
Log
Notify
Realization of process model
Get Request Time
Get Reply Time
Notify
Log
Compute Avg Delay
Get User Profile
Compute Delay
Same number of clients
Slight difference in names and functionality
Same flow of messages
Actual publications and subscriptions are different
Gartner Event Processing Summit, September 2008

25. The PADRES ESB Architecture25
Gartner Event Processing Summit, September 2008
2017/4/26

26. Gartner Event Processing Summit, 15-16 September 2008
Summary
SLAs specify business goals declaratively.
Enforcing SLAs is a monitoring & control problem.
Process-based & event-based monitoring solutions are both decoupled from actual business process.
Content-based pub/sub is a powerful event processing abstraction.
PADRES is content-based pub/sub.
PADRES can execute business processes, monitoring processes and event-based monitoring.
PADRES enables real-time business analytics and business activity monitoring through events.
Gartner Event Processing Summit, September 2008

27. References @ the University of Toronto The DEBS Conference
July 2009 at Vanderbilt U.
Everything events Portal
The PADRES ESB project home
An eQoSystem for declarative distributed applications with SLAs
The Micro-ToPSS event processing middleware for sensor networks
Mobile-ToPSS – publish/subscribe for mobile and location-based applications
ToPSS - the Toronto Publish/Subscribe System Family Portal
(coming soon  )
Quantifying events in software to increase modularity & customization in C-based systems and software-based product lines
(ACC - the AspeCt-oriented C compiler)
The Middleware Systems Research Group
Professor Jacobsen’s web site
@ the University
of Toronto
Gartner Event Processing Summit, September 2008

28. Gartner Event Processing Summit, 15-16 September 2008
Acknowledgements
Graduate students, visitors, and PDFs currently
working on PADRES.
PADRES Alumni
Alex Cheung
Guoli Li
Bala Maniymaran
Vinod Muthusamy
Reza Sherafat
Partners from CA
Serge Mankovskii & Kirk Wilson
Partners from IBM
Phil Coultard & Allen Chan
Partners from Bell
Bell Systems & Technology
Gartner Event Processing Summit, September 2008

29. Gartner Event Processing Summit, 15-16 September 2008
Questions?
A D R E S P
Gartner Event Processing Summit, September 2008

30. Gartner Event Processing Summit, 15-16 September 2008
Additional slides
Gartner Event Processing Summit, September 2008

31. Benefits of Content-based Publish/Subscribe for BPM
Naturally enables centralized and distributed business process coordination
Coordination can span administrative domains and physically distributed resources
Supports process orchestration and choreography
Monitoring & control is integral part of paradigm
Agile on the fly process adaptation and versioning
Correlation of application events with low-level infrastructure events
Gartner Event Processing Summit, September 2008

32. Automatic Model Generation
Ensure that the average hourly response time of searches by VIP customers is less than 0.5 s.
<metric name=“UserRequest”/>
<metric name=“UserReply”/>
<metric name=“Delay”> <function expr=“UserReply.time – UserRequest.time” /> </metric>
<metric name=“VIPDelay”> <function filter=“Delay.userType = VIP”/> </metric>
<metric name=“AvgVIPDelay”> <function expr=“avg(VIPDelay, 1hr)”/> </metric>
<objective name=“ShortAvgVIPDelay”> <function boolexpr=“AvgVIPDelay < 0.5s”/> </objective>
<action name=“Notify”> <condition name=“ShortAvgVIPDelay” value=“false”/> </action>
<action name=“Log”> <condition name=“ShortAvgVIPDelay” value=“true”/> </action>
Gartner Event Processing Summit, September 2008