Download to read offline
Uploaded byZoltán Ujhelyi
Rete network slicing for Model Queries
The document presents an overview of the VIATRA framework, focusing on reactive event-driven transformations and incremental model queries. It discusses the concept of slicing within the context of rete networks for dynamically evaluating graph patterns and the transformation models associated with them. The key contribution is the formulation of a slicing algorithm that enables systematic tracking of dependencies and changes in production nodes within the framework.
Rete network slicing for Model Queries
- 1. Budapest University of Technology and Economics Department of Measurement and Information Systems Rete network slicing for model queries Zoltán Ujhelyi, Gábor Bergmann, Dániel Varró
- 2.
- 3. VIATRA: Reactive Transformation Framework Reactive Event DrivenTransformations Observed events Controlled events Notifications Messages Model
- 4. VIATRA: Reactive Transformation Framework Reactive Event DrivenTransformations Observed events Controlled events Notifications Messages Model Event What has happened? (external + internal) Condition When to react? (internal) Action What to do? (external+internal)
- 5. VIATRA: Reactive Transformation Framework Reactive Event DrivenTransformations Observed events Controlled events Notifications Messages Model • Model modified • Match of queryappeared • Event sequence identified • „Run” button pushed • Consistentstate reached after edit • Transaction committed • Modifymodel • Add error marker • Update view • Send e-mail • Regular model queries • Traceabilityinfo
- 6. VIATRA: Overview of Features •Display exec. state of MT (indebug mode) •Model + rule activations •Breakpoints (incl. conditional) •User selects next activation Debugger •Explore design model candidates •Satisfying multiple criteria •Rule based exploration •Optimization Design Space Exploration •Detect complex event sequences •Rule based reaction •Xtext based language Complex Event Processing § Reactive MT Platform o Query + MT Language • Language + API for queries and transformations – Query: DSL (VQL) – MT: Internal DSL over Xtend o Engine: • Event-driven VM (compiles to Java) • Local-search + incremental queries • Batch + Incremental MTs o Advanced GUI § Unified projects (April 2016) o EMF-IncQuery è VIATRA Query o Graduatedat Eclipse Foundation Tool integration with: Papyrus UML, Sirius, RMF, Capella, ARTOP, mbeddr Industrial users: Itemis, Ericsson, CERN Embraer, Thales, CEA ThyssenKrupp
- 7. Simple Graph Pattern in VIATRA pattern stateOfMachine(sm :StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } 7 7 sm: State Machine st: State member region r: Region
- 8. And a More Complex Example /** * A transitionbetween different state machines */ pattern differentStateMachine(tr : Transition) { State.outgoing(src, tr); Transition.target(tr, trg); find stateOfMachine(sm, src); neg find stateOfMachine(sm, trg); } pattern stateOfMachine(sm : StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } 8
- 9. And a More Complex Example /** * A transitionbetween different state machines */ pattern differentStateMachine(tr : Transition) { State.outgoing(src, tr); Transition.target(tr, trg); find stateOfMachine(sm, src); neg find stateOfMachine(sm, trg); } pattern stateOfMachine(sm : StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } 9 Pattern composition (for reuse) Negative composition (negation, quantification)
- 10.
- 11. Current VIATRA Debugger 11 • Display exec. stateof MT (in debug mode) • Model + rule activations • Breakpoints (incl. Conditional) • User selects next activation
- 12. Motivations Towards advanced debuggingby slicing
- 13.
- 14. Incorrect Query 14 Negation replaced with (positive) patterncomposition Incorrect query results found
- 15. Incorrect Query 15 Negation replaced with (positive) patterncomposition Incorrect query results found Why is a tuple (transition TI) incorrectly included in the results? Debugging graph patterns: • Manually removing constraints • Evaluating the result manually
- 16.
- 17.
- 18.
- 19.
- 20.
- 21.
- 22. Debugging the Faulty Pattern 22 All transition/target pairs correct Conclusion: thetwo compositionsneeds to be verified
- 23. Rete Networks forIncremental Graph Query Evaluation
- 24. Graph Pattern Matching with Rete networks § Rete network: complex cache structure o Model index oPattern matches o Partial matches § Graph pattern matching with Rete o Incremental approach: • Partial re-evaluation on model changes • Notifications on pattern match changes 24
- 25. Intermediate nodes pattern stateOfMachine(sm :StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } ∏ stateOfMachine StateMachine # region Region # member JOIN Rete Network – Simple Pattern Input nodes Production nodes
- 26. Intermediate nodes pattern stateOfMachine(sm :StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } ∏ stateOfMachine StateMachine # region Region # member JOIN Rete Network – Simple Pattern Input nodes Indexes model objects and links Production nodes
- 27. Intermediate nodes pattern stateOfMachine(sm :StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } ∏ stateOfMachine StateMachine # region Region # member JOIN Rete Network – Simple Pattern Input nodes Indexes model objects and links Production nodes
- 28. Intermediate nodes pattern stateOfMachine(sm :StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } ∏ stateOfMachine StateMachine # region Region # member JOIN Rete Network – Simple Pattern Input nodes Production nodes Caches partial matches
- 29. Intermediate nodes pattern stateOfMachine(sm :StateMachine, st : State) { StateMachine.region(sm, r); Region.member(r, st); } ∏ stateOfMachine StateMachine # region Region # member JOIN Rete Network – Simple Pattern Input nodes Production nodes Caches pattern matches
- 30.
- 31.
- 32.
- 33.
- 34. Rete Network – Cached Information 34 st = fr JOIN st= to NAC State # outgoingTransition Transition # targetState tr = tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TC1 S21 SM1 S12 TC2 FS ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS
- 35. Rete Network – Change Propagation 35 st = fr JOIN st= to NAC State # outgoingTransition Transition # targetState tr = tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TC1 S21 SM1 S12 TC2 FS ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS
- 36.
- 37. Slicing Model Transformations § Similar to program slicing o Systematic collection of dependencies oBUT: slicing of (input) models is also required Z. Ujhelyi et al: Dynamic Forward Slicing of Model Transformation Programs. ICST 2012. 37 Model transformation slicing Transformation Models Transformation Slice Model Slice Criterion
- 38. Slicing Rete Networks § Goals of thispaper: o Identify model changes resulting in a specific change in the production node o Explain the chain of operations connecting the model and the production node changes 38 Rete network Transformation Models Rete Operations Model Changes Criterion: production node change Rete network slicing
- 39. Slicing Algorithm § Inputs: o Match set M of Production node P oCriteria • An existing match in M to disappear, or • A non-existing match in M to appear § Output: Formula identifying matches in Rete nodes § For each evaluated term recursively o Calculate possible changes in parent § Recursion stops o Elementary changes in input nodes o A match already existing in a node to be added o A non-existing match to be deleted from a node 39
- 40. Slicing Rete Network 40 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN
- 41. Slicing Rete Network 41 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN Why is state S12 present in the match set? Criteria: remove tuple (0) from match set 0
- 42. Slicing Rete Network 42 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 Removing the other tuples cannot remove (0) Removing tuple (1) results in the removal of (0).
- 43. Slicing Rete Network 43 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 2 Removing tuple (2) results in the removal of (1).
- 44. Slicing Rete Network 44 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 2 3 Removing tuple (3) results in the removal of (2).
- 45. Slicing Rete Network 45 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 2 3 4 Removing tuple (4) results in the removal of (3).
- 46. Slicing Rete Network 46 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 2 3 4 5 Removing tuple (5) results in the removal of (1).
- 47. Slicing Rete Network 47 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 2 3 4 5 6 Removing tuple (6) results in the removal of (0).
- 48. Slicing Rete Network 48 st = fr JOIN st = to State # outgoingTransition Transition # targetState tr= tr JOIN sm st SM1 S11 SM1 S12 SM2 S21 SM2 FS st tr S11 TC1 S11 TI S12 TC2 tr to TC1 S21 TI S12 TC2 FS fr tr to S11 TC1 S21 S11 TI S12 S12 TC2 FS sm fr tr to SM1 S11 TI S12 ∏ stateOfMachine ∏ DSM sm fr tr to SM1 S11 TC1 S21 SM1 S11 TI S12 SM1 S12 TC2 FS JOIN 0 1 2 3 4 5 6
- 49. Formalization Overview § Slice Formalization o Basis: a chain of semantic mappings oMain contribution: the slice formula 49 Graph Patterns Rete Networks Terms Rel Alg Rete Changes Terms Query Alg Terms Change Alg Rete Slices Formula Graphs Terms Graph Alg matchedOn derivedFrom uses
- 50. Formalization Overview § Slice Formalization o Basis: a chain of semantic mappings oMain contribution: the slice formula 50 Graph Patterns Rete Networks Terms Rel Alg Rete Changes Terms Query Alg Terms Change Alg Rete Slices Formula Graphs Terms Graph Alg matchedOn derivedFrom uses Instance models & metamodels
- 51. Formalization Overview § Slice Formalization o Basis: a chain of semantic mappings oMain contribution: the slice formula 51 Graph Patterns Rete Networks Terms Rel Alg Rete Changes Terms Query Alg Terms Change Alg Rete Slices Formula Graphs Terms Graph Alg matchedOn derivedFrom uses Graph patterns & constraints
- 52. Formalization Overview § Slice Formalization o Basis: a chain of semantic mappings oMain contribution: the slice formula 52 Graph Patterns Rete Networks Terms Rel Alg Rete Changes Terms Query Alg Terms Change Alg Rete Slices Formula Graphs Terms Graph Alg matchedOn derivedFrom uses (Rete) Cache for relational algebra
- 53. Formalization Overview § Slice Formalization o Basis: a chain of semantic mappings oMain contribution: the slice formula 53 Graph Patterns Rete Networks Terms Rel Alg Rete Changes Terms Query Alg Terms Change Alg Rete Slices Formula Graphs Terms Graph Alg matchedOn derivedFrom uses Incremental update formula for Rete nodes
- 54. Formalization Overview § Slice Formalization o Basis: a chain of semantic mappings oMain contribution: the slice formula 54 Graph Patterns Rete Networks Terms Rel Alg Rete Changes Terms Query Alg Terms Change Alg Rete Slices Formula Graphs Terms Graph Alg matchedOn derivedFrom uses Formula derived for slicing criteria
- 55. The Slice Formula § Derived in Disjunctive NormalForm o Cases of disjunction represent possible changes o The conjunction describe the chain of operations § The resulting formula is easy to understand 55
- 56. The Slice Formula § Derived in Disjunctive NormalForm o Cases of disjunction represent possible changes o The conjunction describe the chain of operations § The resulting formula is easy to understand 56
- 57. The Slice Formula § Derived in Disjunctive NormalForm o Cases of disjunction represent possible changes o The conjunction describe the chain of operations § The resulting formula is easy to understand 57 We want to remove a tuple from node n6 where the 4th parameter is S12.
- 58. The Slice Formula § Derived in Disjunctive NormalForm o Cases of disjunction represent possible changes o The conjunction describe the chain of operations § The resulting formula is easy to understand 58 The slicer has found four possible changes.
- 59. The Slice Formula § Derived in Disjunctive NormalForm o Cases of disjunction represent possible changes o The conjunction describe the chain of operations § The resulting formula is easy to understand 59 By removing the input tuple <TI, S11>...
- 60. The Slice Formula § Derived in Disjunctive NormalForm o Cases of disjunction represent possible changes o The conjunction describe the chain of operations § The resulting formula is easy to understand 60 By removing the input tuple <TI, S11>... ... the followingoperations provide the removal of the expected tuple from n6.
- 61. Summary Context: Debugging of MT • Extensivesupport in VIATRA • Challenge: debugging graph patterns Background: MT Slicing • Compute dependencies based on a slicing condition • Model + MT program This paper: • Rete networks cache matches of patterns • Slicing Rete networks • Identify input changes resulting in a certain output change • Formalization by a chain of mappings 61