private LogicalVariable getNewDecorVar(GroupByOperator g, LogicalVariable v) {
for (Pair<LogicalVariable, LogicalExpressionReference> p : g.getDecorList()) {
ILogicalExpression e = p.second.getExpression();
if (e.getExpressionTag() == LogicalExpressionTag.VARIABLE) {
LogicalVariable v2 = ((VariableReferenceExpression) e).getVariableReference();
if (v2 == v) {
return (p.first != null) ? p.first : v2;
}
}
}
return null;
}
@Override
public Void visitNestedTupleSourceOperator(NestedTupleSourceOperator op, IOptimizationContext ctx)
throws AlgebricksException {
AbstractLogicalOperator op1 =
(AbstractLogicalOperator) op.getDataSourceReference().getOperator();
ILogicalOperator inp1 = op1.getInputs().get(0).getOperator();
Map<LogicalVariable, EquivalenceClass> eqClasses = getOrComputeEqClasses(inp1, ctx);
ctx.putEquivalenceClassMap(op, eqClasses);
List<FunctionalDependency> fds =
new ArrayList<FunctionalDependency>(getOrComputeFDs(inp1, ctx));
if (op1.getOperatorTag() == LogicalOperatorTag.GROUP) {
GroupByOperator gby = (GroupByOperator) op1;
LinkedList<LogicalVariable> tail = new LinkedList<LogicalVariable>();
for (LogicalVariable v : gby.getGbyVarList()) {
tail.add(v);
// all values for gby vars. are the same
}
FunctionalDependency gbyfd =
new FunctionalDependency(new LinkedList<LogicalVariable>(), tail);
fds.add(gbyfd);
}
ctx.putFDList(op, fds);
return null;
}
@Override
public Void visitGroupByOperator(GroupByOperator op, IOptimizationContext ctx)
throws AlgebricksException {
Map<LogicalVariable, EquivalenceClass> equivalenceClasses =
new HashMap<LogicalVariable, EquivalenceClass>();
List<FunctionalDependency> functionalDependencies = new ArrayList<FunctionalDependency>();
ctx.putEquivalenceClassMap(op, equivalenceClasses);
ctx.putFDList(op, functionalDependencies);
List<FunctionalDependency> inheritedFDs = new ArrayList<FunctionalDependency>();
for (ILogicalPlan p : op.getNestedPlans()) {
for (LogicalOperatorReference r : p.getRoots()) {
ILogicalOperator op2 = r.getOperator();
equivalenceClasses.putAll(getOrComputeEqClasses(op2, ctx));
inheritedFDs.addAll(getOrComputeFDs(op2, ctx));
}
}
ILogicalOperator op0 = op.getInputs().get(0).getOperator();
inheritedFDs.addAll(getOrComputeFDs(op0, ctx));
Map<LogicalVariable, EquivalenceClass> inheritedEcs = getOrComputeEqClasses(op0, ctx);
for (FunctionalDependency inherited : inheritedFDs) {
boolean isCoveredByGbyOrDecorVars = true;
List<LogicalVariable> newHead = new ArrayList<LogicalVariable>(inherited.getHead().size());
for (LogicalVariable v : inherited.getHead()) {
LogicalVariable vnew = getNewGbyVar(op, v);
if (vnew == null) {
vnew = getNewDecorVar(op, v);
if (vnew == null) {
isCoveredByGbyOrDecorVars = false;
}
break;
}
newHead.add(vnew);
}
if (isCoveredByGbyOrDecorVars) {
List<LogicalVariable> newTail = new ArrayList<LogicalVariable>();
for (LogicalVariable v2 : inherited.getTail()) {
LogicalVariable v3 = getNewGbyVar(op, v2);
if (v3 != null) {
newTail.add(v3);
}
}
if (!newTail.isEmpty()) {
FunctionalDependency newFd = new FunctionalDependency(newHead, newTail);
functionalDependencies.add(newFd);
}
}
}
List<LogicalVariable> premiseGby = new LinkedList<LogicalVariable>();
List<Pair<LogicalVariable, LogicalExpressionReference>> gByList = op.getGroupByList();
for (Pair<LogicalVariable, LogicalExpressionReference> p : gByList) {
premiseGby.add(p.first);
}
List<Pair<LogicalVariable, LogicalExpressionReference>> decorList = op.getDecorList();
LinkedList<LogicalVariable> conclDecor = new LinkedList<LogicalVariable>();
for (Pair<LogicalVariable, LogicalExpressionReference> p : decorList) {
conclDecor.add(GroupByOperator.getDecorVariable(p));
}
if (!conclDecor.isEmpty()) {
functionalDependencies.add(new FunctionalDependency(premiseGby, conclDecor));
}
Set<LogicalVariable> gbySet = new HashSet<LogicalVariable>();
for (Pair<LogicalVariable, LogicalExpressionReference> p : gByList) {
ILogicalExpression expr = p.second.getExpression();
if (expr.getExpressionTag() == LogicalExpressionTag.VARIABLE) {
VariableReferenceExpression v = (VariableReferenceExpression) expr;
gbySet.add(v.getVariableReference());
}
}
LocalGroupingProperty lgp = new LocalGroupingProperty(gbySet);
lgp.normalizeGroupingColumns(inheritedEcs, inheritedFDs);
Set<LogicalVariable> normSet = lgp.getColumnSet();
List<Pair<LogicalVariable, LogicalExpressionReference>> newGbyList =
new ArrayList<Pair<LogicalVariable, LogicalExpressionReference>>();
boolean changed = false;
for (Pair<LogicalVariable, LogicalExpressionReference> p : gByList) {
ILogicalExpression expr = p.second.getExpression();
if (expr.getExpressionTag() == LogicalExpressionTag.VARIABLE) {
VariableReferenceExpression varRef = (VariableReferenceExpression) expr;
LogicalVariable v2 = varRef.getVariableReference();
EquivalenceClass ec2 = inheritedEcs.get(v2);
LogicalVariable v3;
if (ec2 != null && !ec2.representativeIsConst()) {
v3 = ec2.getVariableRepresentative();
} else {
v3 = v2;
}
if (normSet.contains(v3)) {
newGbyList.add(p);
} else {
changed = true;
decorList.add(p);
}
} else {
newGbyList.add(p);
}
}
if (changed) {
AlgebricksConfig.ALGEBRICKS_LOGGER.fine(
">>>> Group-by list changed from "
+ GroupByOperator.veListToString(gByList)
+ " to "
+ GroupByOperator.veListToString(newGbyList)
+ ".\n");
}
gByList.clear();
gByList.addAll(newGbyList);
return null;
}