1. 1 Event Processing: An Academic Perspective Hans-Arno Jacobsen Bell University Laboratory Chair Middleware Systems Research Group University of Toronto MIDDLEWARE SYSTEMS RESEARCH GROUP http://www.padres.msrg.utoronto.ca

2. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 2 Querying the Future

3. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 3 Amazon to Chapters to You.... Monday, October 10th in Cyberspace Your book “...” is available at.... $10 off Thursday, November 15th, in Toronto

4. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 4 Location Constraint Matching d P1P1 P2P2 P3P3 P4P4 P5P5 A P4P4 P3P3 P2P2 P1P1 P5P5 dAdA

5. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 5 BPM & SLA Monitoring N Y Far? Get destination Validate request Find flight Find train cost < $0.02 service time < 3s Only trusted partners

6. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 6 The Common Denominator These applications are driven by asynchronous state transitions  Information becomes available  Change in state in the environment  Something happens These state transitions are events Events are disseminated and filtered against queries events queries

7. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 7 Agenda What abstractions to use? Our approach Overview of paradigm The PADRES project

8. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 8 What Abstractions are Best Suited to Support this Modus Operandi? Databases  Great for managing historic data  But what about future data Data streams  Great for managing structured streams of tuples  But what about un-structured, multi-typed, sporadic events from many sources Rule-based expert systems  Great for inference and reasoning  But what about managing large numbers of fined-grained filters in distributed envrionments Take this cum gran salis

9. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 9 Our Approach: Publish/Subscribe More specifically Content-based publish/subscribe  For fine-grained filtering Combined with content-based message routing  For selective data dissemination Extended with persistence et al.  For historic data access

10. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 10 Content-based Publish/Subscribe Publisher Subscriber Subscriptions Publications Notification IBM=84 MSFT=27 INTC=19 JNJ=58 ORCL=12 HON=24 AMGN=58 Stock markets NYSE NASDAQ TSX Subscriptions: IBM > 85 ORCL < 10 JNJ > 60 Broker(s)

11. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 11 data tuples subscriptions query publication Query and subscription are very similar. Data tuples and publication are very similar. However, the two problem statements are inverse. That’s Like Data Base Querying  !! sets of tuples About past About future sets of tuples

12. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 12 The Content-based Model Language and data model  Conjunctive Boolean functions over predicates  Predicates are attribute-operator-value triples [class,=,trigger]  Subscriptions are conjunctions of predicates [class,=,trigger],[appl,=,payroll],[gid,=,g001]  Publications are sets of attribute-value pairs [class,trigger],[appl,printer],[gid,g007] Matching semantic  A subscription matches if all its predicates are matched P/S events notifications

13. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 13 Publish/Subscribe Matching Problem Given a set of subscriptions, S, and a publication, e, return all s in S matched by e. e is referred to as event or publication Splitting hairs  Event is a state transition of interest in the environment  Publication is the information about e submitted to the publish/subscribe system Simple problem statement, widely applicable, and lots of open questions

14. MIDDLEWARE SYSTEMS RESEARCH GROUP Content-based Message Routing Publisher Subscriber 1. Advertise 2. Subscribe 3. Publish Event-Based Decoupled Flexible Responsive Content Routing Declarative A: [class, =, stock], [name, =, HP], [price, >, 50] S: [class, =, stock], [name, =, *], [price, >, 50] P: [class, stock], [name, HP], [price, 55]

15. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 15 ToPSS - The Toronto Publish/Subscribe System Family [2000 – present] Matching algorithms  Language expressiveness vs. efficient matching Routing protocols  Network architectures & scalability Higher level abstractions  Workflow execution  Monitoring S-ToPSS (semantic) X-ToPSS (XML matching) A-ToPSS (approximate) persistent-ToPSS (subject spaces) L-ToPSS (location-based) ToPSS (matching) M-ToPSS (mobile) Ad hoc-ToPSS (ad hoc networking) Federated-ToPSS (federation of ToPSS brokers) Rb-ToPSS (rule-based) P2P-ToPSS (peer-to-peer) LB-ToPSS (load balancing) FT-ToPSS (fault tolerance) Historic-ToPSS (historic data) CS-ToPSS (composite subs) BPEL-ToPSS (BPEL execution) JS-ToPSS (job scheduling)

16. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 16 PADRES Publish/Subscribe System Project [2003-present] http://www.padres.msrg.utoronto.ca Peng Alex David aRno Eli Serge, PAdres is Distributed REsource Scheduling Publish/subscribe Applied to Distributed Resource Scheduling

17. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 17 The PADRES ESB Stack Business Process Execution Layer

18. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 18 Subscription Language & Publication Data Model Subscriptions are conjuncts of predicates  [class,=,job_info], [workflow,=, foo_example], [instanceID,=,$x], [job,=,A], [status,=,succ] isPresent operator, $X (variable binding), composite subscriptions, string operators etc. Publications are sets of attribute value pairs  [class, trigger], [workflow, foo_example], [instanceID, 54]

19. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 19 Padres Broker Architecture QueueHandler BrokerCore Matching Engine Controller Lifecycle Manager Overlay Manager Publication / Subscription Routing Table JESS InputQueue … QueueHandler OutputQueues Broker_Control Message QueueHandler … RMITransport Handler JMS BrokerRMI ClientRMI DB

20. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 20 PADRES Features A BC D E F Composite Events Historic Access Management Robustness Load Balancing Security

21. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 21 Limitations of Acyclic Overlays Broker Publisher Subscriber P Sensitive to  Congestion  Imbalanced workloads  Broker failures  Overlay changes

22. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 22 Robustness Through Cycles PPP P Robust Self-healingAdaptive routing Flexible overlay Publisher Subscriber Congested Link

23. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 23 End to End Delay (preliminary results) 30 brokers on 15 machines (on LAN) 20 publishers (2400msg/min) 30 subscribers (2000 total) toplogy with average connection degree of 4 Fixed routing does not exploit cycles Dynamic routing does exploit cycles

24. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 24 Sub Load Balancing Framework Local Load Balancing Global Load Balancing Pub offloading broker load-accepting broker

25. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 25 Load Balancing Components DETECTOR PIE MEDIATOR PIE messages OFFLOAD ALGORITHMS InputMatchOutput LOAD ESTIMATION PRESS Mediation and migration protocols Subscribers to offload Target broker Load Balancer Establish and teardown of load balancing sessions between two brokers/clusters Coordinate transparent subscriber migration Calculates the set of subscribers to offload for balancing the performance metric in question based on load information about the subscriptions and load-accepting broker Estimates load of subscriptions Triggers load balancing if overload or uneven load distribution is detected by examining 3 performance metrics

26. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 26 Output Utilization Ratio (no LB) Overload! Edge broker dies

27. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 27 End to End Delivery Delay Edge broker dies Increasing delay due to output overload at BOTH edge broker and cluster- head broker

28. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 28 Output Utilization Ratio (LB) Overload! Load balancing converges

29. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 29 Composite Subscription AND OR S1S2 OR S3S4 AND S5 CS={{S1 OR S2} AND {S3 OR S4} AND S5} A composite event is the constellation of events being detected by the composite subscription. S are atomic subscriptions. I.e., they are satisfied by a single, multi-attribute event. Composite subscriptions (CS) are used for event correlation, in network filtering, and the detection of complex events, Applications: BMP, BAM (see Thursday’s talk)

30. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 30 Topology-based CS Routing Distributed Overlay Broker Network B3 && S1S2 hS3 S P2 Pk CS={{S1 AND S2} AND hS3} B2 B1 B6 B5 P1 CS’={S1 AND S2} P Publishers S Subscribers S2 S1 B4 CS’ hS3 CS hS3 DB

31. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 31 Composite Event Detection Distributed Overlay Broker Network B3 && S1S2 hS3 S P2 PkPk CS={{S1 AND S2} AND hS3} B2 B1 B6 B5 P1 CS’={S1 AND S2} P Publishers S Subscribers CS’ hS3 S2 S1 P1 P2 B4 CS P123 P12 P3 hS3 DB

32. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 32 Optimizations Dynamic composite subscription routing Runtime adjustments of CS joint points

33. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 33 Cost Model I Definition 1. Data set size of atomic subscription S R i is the message rate at the source ApjApj SpjSpj p/s P1P1 PnPn AiAi AjAj AkAk S AiAi AkAk S S = p 1 and … and p n

34. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 34 Cost Model II Definition 2. Data set size of composite subscription CS

35. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 35 CS Routing Optimization Objectives  Minimize network traffic  Minimize notification delay 2 13 Adv 1 Adv 2 CS={{S1 AND S2} 2 13 Adv 1 Adv 2 CS={{S1 AND S2} (a) (b)

36. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 36 Estimate CE Detection Costs Traffic-based model Traffic Cost (S1) = Delay Cost (S1) = 2 13 Adv 1 Adv 2 CS={{S1 AND S2}

37. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 37 Optimized Subscription Routing Determine joint points based on cost model Distributed Overlay Broker Network B3 S P2 PkPk B2 B1 B6 B5 P1 S2 S1 B7 B4 CS’ hS3 CS CS={{S1 AND S2} AND hS3} hS3 DB

38. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 38 Optimized Subscription Routing Dynamically maintain joint points Distributed Overlay Broker Network B3 S P2 PkPk B2 B1 B6 B5 P1 S2 S1 B7 B4 CS’ hS3 CS CS={{S1 AND S2} AND hS3} hS3 DB

39. MIDDLEWARE SYSTEMS RESEARCH GROUP 39 Summary Publish/Subscribe solves a problem inverse to database query processing Publish/Subscribe is well suited as abstraction for many event processing based applications Publish/Subscribe is a paradigm for data-centric networking & selective information dissemination PADRES realizes a distributed publish/subscribe system offering many novel features PADRES can serve as ESB and ISB (Internet Service Bus); more on this Thursday at 8AM There are plenty of open research questions

40. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 40 Asking EPTS and Industry for Data sets  Subscription data sets for various domains  Workload characteristics  For active research we are looking for SLA examples, business process examples Interesting and relevant problems  Challenges of tomorrow  Specific problems

41. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 41 Acknowledgements Graduate students, visitors, and PDFs currently working on PADRES. Alex Cheung Guoli Li Jian Li Vinod Muthusamy Alex Wun Songlin Hu Reza Sherafat Partner from CA directly involved in project Serge Mankovskii And many alumni visit us @ http://www.padres.msrg.utoronto.ca

42. 42 “A forum dedicated to the dissemination of original research, the discussion of practical insights, and the reporting on relevant experience relating to event-based computing previously scattered across several communities.” In cooperation with (approval pending): July 2 nd – 4 th, 2008 Roma, Italy http://debs08.dis.uniroma1.it Submission deadline: March 15 th, 2008 Location: Dipartimento di Informatica e Sistemistica “A. Ruberti” Sapienza Università di Roma www.debs.org

43. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 43 Questions? A D R E S P

44. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 44

45. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 45 Routing in Cyclic Networks

46. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 46 Limitations of Acyclic Overlays Broker Publisher Subscriber P Sensitive to  Congestion  Imbalanced workloads  Broker failures  Overlay changes

47. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 47 General Overlay PPP P Robust Self-healingAdaptive routing Flexible overlay Publisher Subscriber Congested Link

48. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 48 1 Routing in General Overlays I 2 Advertisement Tree 1 Duplicate Messages S S S S S Advertisement Tree 2

49. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 49 Routing in General Overlays II Scenario 1  Subscriptions are routing in loops  Brokers receive duplicated subscriptions 2 34 5 1 6 Adv 1 Adv 2 S X S S

50. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 50 Routing in General Overlays III Scenario 2  Subscriptions are multicasted to several destinations  Brokers receive duplicated subscriptions  Scenario 1 is exacerbated by duplicated subscriptions 2 34 5 1 6 Adv 1 Adv 2 S Y S S S S

51. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 51 Redundant Messages Problem

52. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 52 Routing in General Overlays Extends standard content-based routing protocol Maintain the same interface to pub/sub clients Requires changes to  Advertisement routing  Subscription routing Atomic subscriptions Composite subscriptions  Publication routing

53. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 53 Advertisement Routing Each advertisement forms a spanning advertisement tree Duplicated advertisements are discarded by brokers Each advertisement is assigned a unique tree identifier (TID)  e.g. a [class, eq, stock]……[TID, eq, adv_msg_id] SRT  A set of [advertisement, last hop]

54. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 54 Subscription Routing Each subscription has a TID predicate with a variable.  e.g. s [class,eq,stock]……[TID,eq,$X] The variable is bound to the TID of matching advertisement upon subscribing PRT  A set of [subscription, {TID, last hop of subscription }]

55. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 55 Subscription Routing Scenario 1 2 34 5 1 6 Adv 1 Adv 2 S X S S: [class,eq,stock][name,eq,*][price,>,50] [TID,eq,$Z ] At Broker 1: Adv1: [class,eq,stock][name,eq,IBM][price,>,60][TID,eq,Adv1] Adv2: [class,eq,stock][name,eq,HP][price,>,50][TID,eq,Adv2] S matching Adv1: [class,eq,stock][name,eq,*][price,>,50] [TID,eq,Adv1] S matching Adv2: [class,eq,stock][name,eq,*][price,>,50] [TID,eq,Adv2]

56. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 56 Subscription Routing Scenario 2 SRT(B4)Last hop Adv12 Adv26 2 34 5 1 6 Adv 1 Adv 2 S Y S S PRT(B4)TID Last hop SAdv1Y Adv2Y

57. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 57 Publication Routing Each publication is assigned the TID of its matching advertisement Publications are routed:  Fixed TID routing  Dynamic publication routing Lemma 1: No broker receives duplicated publication messages No subscriber receives duplicated publications according to Lemma 1

58. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 58 Fixed TID Routing 2 34 5 1 6 Adv 1 Adv 2 X P Sub P

59. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 59 Dynamic Publication Routing Publication’s TID is changeable Best path algorithms Lemma 2: Changing a publication p’s TID while in transit will not change the set of subscribers, N, notified of p. 2 34 5 1 6 Adv 1 Adv 2 X Sub P

60. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 60 Advantages of TID-based Approach Retains the publish/subscribe client interface Speeds up subscription and publication propagation Generates duplicated messages only at advertisement level Builds multiple subscription routing paths for publications Routes publications dynamically Delivers publications around failed brokers

61. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 61 Preliminary Experimental Results Setup  Five dual core servers CPU: 2.4GHz ~ 3.4GHz Memory: 1GB ~2GB  Cyclic broker overlays Number of nodes: 23 brokers Average connection degree: D = 5; D=3  Delay = D_queue + D_transmission + D_ propagation Metrics  Notification delay  CPU and memory usage  Bandwidth consumption

62. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 62 Notification Delay

63. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 63 Notification Delay

64. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 64 Notification Delay

65. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 65 Notification Delay

66. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 66 Overhead in terms of CPU Usage Average over all brokers

67. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 67 Overhead in terms of Memory Use Average over all brokers

68. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 68 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 queries and event management Achieves scalability with in-network filtering and processing

69. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 69 Adaptive CS Routing Setup  1 subscriber with composite subscriptions  4 publishers with unbalanced publication rates  Focus on behaviours of four particular brokers: The subscriber connects to Broker A Broker B is the joint point broker in Topology-based routing Broker C is the new joint point broker in adaptive CS routing The slower publishers connect to Broker D Compare  Simple routing  Topology-based routing  QoS-based adaptive routing

70. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 70 Traffic of CS Routing Simple Routing A B C D

71. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 71 Traffic of CS Routing Topology-based Routing A B C D

72. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 72 Traffic of CS Routing QoS-based Adaptive Routing A B C D

73. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 73 Notification Delay of CS

74. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 74 Adaptive CS Routing CSs may be split according to potential publication traffic, bandwidth, latency, etc. 2 13 Adv 1 Adv 2 CS={{S1 AND S2} 2 13 Adv 1 Adv 2 CS={{S1 AND S2} (a) (b)

75. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 75 Estimate Data Set Size Definition 1. Data set size of atomic subscription Definition 2. Data set size of composite subscription

76. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 76 Estimate CE Detection Costs Traffic-based model Traffic Cost (S1) = Delay Cost (S1) = QoS-based model Delay Cost (S1) = 2 13 Adv 1 Adv 2 CS={{S1 AND S2}

77. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 77 Adaptive CS Routing Algorithm Evaluate the cost model at each broker for composite subscriptions Choose the broker with minimum detection cost as the joint point Joint points are maintained dynamically according to the traffic and network condition

78. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 78 Example: Topology-based CS Routing 2 34 5 1 6 Adv 1 Adv 2 7 8 9 CS S2 S3 S1 CS’ Adv 3 CS’={S1 AND S2} AND S1S2 S3 CS={{S1 AND S2} ANDS3}

79. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 79 Example: Adaptive CS Routing 2 34 5 1 6 Adv 1 Adv 2 7 8 9 CS={{S1 AND S2} ANDS3} CS S2 S3 S1 CS’ Adv 3

80. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 80 Effect of Parallelism

81. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 81 3-body Constraint Matching d 1 <d satisfied d 2 >d unsatisfied d 3 <d satisfied d enclosing circle |green set| < d satisfied |red set| < d unsatisfied

82. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 82 Composite Subscription Routing Distributed Overlay Broker Network B4 B3 AND S1S2 S3 S P2 P3 CS={{S1 AND S2} ANDS3} B2 B1 B6 B5 P1 CS CS’={S1 AND S2} P Publishers S Subscribers CS’ S3S2 S1

83. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 83 Composite Event Detection Distributed Overlay Broker Network B4 B3 AND S1S2 S3 S P2 P3 CS={{S1 AND S2} ANDS3} B2 B1 B6 B5 P1 CS CS’={S1 AND S2} P Publishers S Subscribers CS’ S3 S2 S1 CS P1 P2 P12 P3 P123

84. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 84 Optimized Routing Algorithm Evaluate the cost model at each broker for composite subscriptions Choose the broker with minimum detection cost as the joint point Joint points are maintained dynamically according to the traffic and network condition

85. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 85 Publish/Subscribe in Industry Standards  CORBA Event Service  CORBA Notification Service  OMG Data Dissemination Service  Java Messaging Service  WS Eventing  WS Notification  WS Brokered Notifications  INFO-D (Grid Forum)  AMQP Emerging technologies (not complete)  RSS aggregators PubSub.com, FeedTree  Real-time data dissemination TIBCO, RTI Inc., Mantara Software  Application integration Softwired  Hardware-based brokers Sarvega (Intel), Solace Systems, DataPower (IBM)

86. MIDDLEWARE SYSTEMS RESEARCH GROUP EPTS Symposium, Orlando, 2007 86 P S = publisher / sensor = subscriber / doctor S S B B B B B P P medication = NoNameDrugX temperature = 40°C illness = diabetes B B heart rate = 150 bpm blood pressure = 60 mmHg P P [medication = NoNameDrugX] & [blood pressure > 100] & [heart rate > 130] [heart rate > 140 bpm] & [temperature > 39] & [illness != cold] S [temperature > 42] & [medication = Advil] P temperature = 38°C Historic Query with Event Correlation Monitoring patients who still have high blood pressure after taking NoNameDrugX Monitoring patients having a fever but not having a cold Monitoring patients who still have fever after taking Advil Medical records database [medication = NoNameDrugX] [blood pressure > 100] [heart rate > 130]