private boolean purgeOverlappingContexts(
Dependency egd, Repair repair, Set<AttributeRef> affectedAttributesSoFar) {
// Needed also for FDs due to the presence of cellgroups that can span different eq. classes,
// but only if some earlier dependencies has generated a cell group for this attribute
if (affectedAttributesSoFar.isEmpty()) {
return true;
}
if (logger.isDebugEnabled())
logger.debug("Checking independence of violation contexts for egd " + egd);
boolean consistent = true;
Map<AttributeRef, Set<CellRef>> changedCellMap = new HashMap<AttributeRef, Set<CellRef>>();
for (Iterator<ChangeDescription> it = repair.getChangeDescriptions().iterator();
it.hasNext(); ) {
ChangeDescription changeDescription = it.next();
Set<AttributeRef> changedAttributes =
ChaseUtility.extractAffectedAttributes(changeDescription);
if (LunaticUtility.hasEmptyIntersection(affectedAttributesSoFar, changedAttributes)) {
continue;
}
if (ChaseUtility.occurrencesOverlap(changeDescription, changedCellMap)
|| ChaseUtility.witnessOverlaps(changeDescription, changedCellMap)) {
if (logger.isDebugEnabled())
logger.debug("Violation context has overlaps: " + changeDescription);
it.remove();
consistent = false;
} else {
ChaseUtility.addChangedCellsToMap(
changeDescription.getCellGroup().getOccurrences(), changedCellMap);
}
}
return consistent;
}
@Override
public IValue generalizeNonAuthoritativeConstantCells(
Set<CellGroupCell> nonAuthoritativeCells, CellGroup cellGroup, Scenario scenario) {
IValue lubValue =
super.generalizeNonAuthoritativeConstantCells(nonAuthoritativeCells, cellGroup, scenario);
if (lubValue instanceof LLUNValue) {
throw new ChaseFailedException(
"Unable to equate cells " + LunaticUtility.printCollection(nonAuthoritativeCells));
}
return lubValue;
}
private List<BackwardAttribute> findAttributesForBackwardChasing(Dependency egd) {
List<BackwardAttribute> attributesForBackwardChasing = new ArrayList<BackwardAttribute>();
for (FormulaVariableOccurrence backwardAttributeOccurrence : egd.getBackwardAttributes()) {
AttributeRef occurrenceAttribute =
EquivalenceClassUtility.correctAttributeForSymmetricEGDs(
backwardAttributeOccurrence.getAttributeRef(), egd);
FormulaVariable variable =
LunaticUtility.findPremiseVariableInDepedency(backwardAttributeOccurrence, egd);
BackwardAttribute backwardAttribute = new BackwardAttribute(occurrenceAttribute, variable);
if (attributesForBackwardChasing.contains(backwardAttribute)) {
continue;
}
attributesForBackwardChasing.add(backwardAttribute);
}
return attributesForBackwardChasing;
}
@Override
public NewChaseSteps chaseDependency(
DeltaChaseStep currentNode,
Dependency egd,
IAlgebraOperator premiseQuery,
Scenario scenario,
IChaseState chaseState,
IDatabase databaseForStep) {
if (logger.isDebugEnabled())
logger.debug("***** Step: " + currentNode.getId() + " - Chasing dependency: " + egd);
if (logger.isTraceEnabled()) logger.trace(databaseForStep.printInstances());
this.lastTuple = null;
this.lastTupleHandled = false;
if (logger.isDebugEnabled()) logger.debug("Executing premise query: " + premiseQuery);
if (logger.isTraceEnabled())
logger.debug(
"Result:\n"
+ LunaticUtility.printIterator(
queryRunner.run(premiseQuery, scenario.getSource(), databaseForStep)));
long violationQueryStart = new Date().getTime();
ITupleIterator it = queryRunner.run(premiseQuery, scenario.getSource(), databaseForStep);
long violationQueryEnd = new Date().getTime();
ChaseStats.getInstance()
.addStat(ChaseStats.EGD_VIOLATION_QUERY_TIME, violationQueryEnd - violationQueryStart);
List<Repair> repairsForDependency = new ArrayList<Repair>();
try {
while (true) {
long equivalenceClassStart = new Date().getTime();
EquivalenceClassForSymmetricEGD equivalenceClass =
readNextEquivalenceClass(
it, egd, currentNode.getDeltaDB(), currentNode.getId(), chaseState, scenario);
long equivalenceClassEnd = new Date().getTime();
ChaseStats.getInstance()
.addStat(
ChaseStats.EGD_EQUIVALENCE_CLASS_TIME, equivalenceClassEnd - equivalenceClassStart);
if (equivalenceClass == null) {
break;
}
ICostManager costManager = CostManagerFactory.getCostManager(egd, scenario);
long choosingRepairStart = new Date().getTime();
List<Repair> repairsForEquivalenceClass =
costManager.chooseRepairStrategy(
new EquivalenceClassForEGDProxy(equivalenceClass),
currentNode.getRoot(),
repairsForDependency,
scenario,
currentNode.getId(),
occurrenceHandler);
long choosingRepairEnd = new Date().getTime();
ChaseStats.getInstance()
.addStat(ChaseStats.EGD_CHOOSING_REPAIR_TIME, choosingRepairEnd - choosingRepairStart);
if (logger.isDebugEnabled())
logger.debug(
"Repairs for equivalence class: "
+ LunaticUtility.printCollection(repairsForEquivalenceClass));
repairsForDependency =
ChaseUtility.accumulateRepairs(repairsForDependency, repairsForEquivalenceClass);
if (noMoreTuples(it)) {
break;
}
if (logger.isDebugEnabled())
logger.debug("Repairs for equivalence classes so far: " + repairsForDependency.size());
}
} catch (ChaseFailedException e) {
throw e;
} finally {
it.close();
}
if (logger.isDebugEnabled())
logger.debug(
"Total repairs for dependency: " + LunaticUtility.printCollection(repairsForDependency));
long repairStart = new Date().getTime();
NewChaseSteps newSteps = applyRepairs(currentNode, repairsForDependency, egd, scenario);
long repairEnd = new Date().getTime();
ChaseStats.getInstance().addStat(ChaseStats.EGD_REPAIR_TIME, repairEnd - repairStart);
return newSteps;
}