@Override
public Void visitAssignOperator(AssignOperator op, Pair<LogicalVariable, LogicalVariable> pair)
throws AlgebricksException {
List<LogicalVariable> variables = op.getVariables();
int n = variables.size();
for (int i = 0; i < n; i++) {
if (variables.get(i).equals(pair.first)) {
variables.set(i, pair.second);
} else {
op.getExpressions().get(i).getValue().substituteVar(pair.first, pair.second);
}
}
// Substitute variables stored in ordering property
if (op.getExplicitOrderingProperty() != null) {
List<OrderColumn> orderColumns = op.getExplicitOrderingProperty().getOrderColumns();
for (int i = 0; i < orderColumns.size(); i++) {
OrderColumn oc = orderColumns.get(i);
if (oc.getColumn().equals(pair.first)) {
orderColumns.set(i, new OrderColumn(pair.second, oc.getOrder()));
}
}
}
substVarTypes(op, pair);
return null;
}
private int removeFromAssigns(
AbstractLogicalOperator op, Set<LogicalVariable> toRemove, IOptimizationContext context)
throws AlgebricksException {
switch (op.getOperatorTag()) {
case ASSIGN:
{
AssignOperator assign = (AssignOperator) op;
if (removeUnusedVarsAndExprs(toRemove, assign.getVariables(), assign.getExpressions())) {
context.computeAndSetTypeEnvironmentForOperator(assign);
}
return assign.getVariables().size();
}
case AGGREGATE:
{
AggregateOperator agg = (AggregateOperator) op;
if (removeUnusedVarsAndExprs(toRemove, agg.getVariables(), agg.getExpressions())) {
context.computeAndSetTypeEnvironmentForOperator(agg);
}
return agg.getVariables().size();
}
case UNNEST:
{
UnnestOperator uOp = (UnnestOperator) op;
LogicalVariable pVar = uOp.getPositionalVariable();
if (pVar != null && toRemove.contains(pVar)) {
uOp.setPositionalVariable(null);
}
break;
}
case UNIONALL:
{
UnionAllOperator unionOp = (UnionAllOperator) op;
if (removeUnusedVarsFromUnionAll(unionOp, toRemove)) {
context.computeAndSetTypeEnvironmentForOperator(unionOp);
}
return unionOp.getVariableMappings().size();
}
}
return -1;
}
private void collectUnusedAssignedVars(
AbstractLogicalOperator op,
Set<LogicalVariable> toRemove,
boolean first,
IOptimizationContext context)
throws AlgebricksException {
if (!first) {
context.addToDontApplySet(this, op);
}
for (Mutable<ILogicalOperator> c : op.getInputs()) {
collectUnusedAssignedVars((AbstractLogicalOperator) c.getValue(), toRemove, false, context);
}
if (op.hasNestedPlans()) {
AbstractOperatorWithNestedPlans opWithNested = (AbstractOperatorWithNestedPlans) op;
for (ILogicalPlan plan : opWithNested.getNestedPlans()) {
for (Mutable<ILogicalOperator> r : plan.getRoots()) {
collectUnusedAssignedVars(
(AbstractLogicalOperator) r.getValue(), toRemove, false, context);
}
}
}
boolean removeUsedVars = true;
switch (op.getOperatorTag()) {
case ASSIGN:
{
AssignOperator assign = (AssignOperator) op;
toRemove.addAll(assign.getVariables());
break;
}
case AGGREGATE:
{
AggregateOperator agg = (AggregateOperator) op;
toRemove.addAll(agg.getVariables());
break;
}
case UNNEST:
{
UnnestOperator uOp = (UnnestOperator) op;
LogicalVariable pVar = uOp.getPositionalVariable();
if (pVar != null) {
toRemove.add(pVar);
}
break;
}
case UNIONALL:
{
UnionAllOperator unionOp = (UnionAllOperator) op;
for (Triple<LogicalVariable, LogicalVariable, LogicalVariable> varMapping :
unionOp.getVariableMappings()) {
toRemove.add(varMapping.third);
}
removeUsedVars = false;
break;
}
}
if (removeUsedVars) {
List<LogicalVariable> used = new LinkedList<LogicalVariable>();
VariableUtilities.getUsedVariables(op, used);
toRemove.removeAll(used);
}
}
@Override
public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
throws AlgebricksException {
if (!opRef.getValue().getOperatorTag().equals(LogicalOperatorTag.ASSIGN)) {
return false;
}
AssignOperator assignUnion = (AssignOperator) opRef.getValue();
if (assignUnion.getExpressions().get(0).getValue().getExpressionTag()
!= LogicalExpressionTag.FUNCTION_CALL) return false;
AbstractFunctionCallExpression u =
(AbstractFunctionCallExpression) assignUnion.getExpressions().get(0).getValue();
if (!AsterixBuiltinFunctions.UNION.equals(u.getFunctionIdentifier())) {
return false;
}
// Retrieving the logical variables for the union from the two aggregates which are inputs to
// the join
Mutable<ILogicalOperator> join = assignUnion.getInputs().get(0);
LogicalOperatorTag tag1 = join.getValue().getOperatorTag();
if (tag1 != LogicalOperatorTag.INNERJOIN && tag1 != LogicalOperatorTag.LEFTOUTERJOIN) {
return false;
}
AbstractBinaryJoinOperator join1 = (AbstractBinaryJoinOperator) join.getValue();
ILogicalExpression cond1 = join1.getCondition().getValue();
// don't try to push a product down
if (!OperatorPropertiesUtil.isAlwaysTrueCond(cond1)) {
return false;
}
List<Mutable<ILogicalOperator>> joinInputs = join.getValue().getInputs();
Mutable<ILogicalOperator> left_branch = joinInputs.get(0);
Mutable<ILogicalOperator> right_branch = joinInputs.get(1);
List<LogicalVariable> input1Var = new ArrayList<LogicalVariable>();
VariableUtilities.getProducedVariables(left_branch.getValue(), input1Var);
List<LogicalVariable> input2Var = new ArrayList<LogicalVariable>();
VariableUtilities.getProducedVariables(right_branch.getValue(), input2Var);
List<Triple<LogicalVariable, LogicalVariable, LogicalVariable>> varMap =
new ArrayList<Triple<LogicalVariable, LogicalVariable, LogicalVariable>>(1);
Triple<LogicalVariable, LogicalVariable, LogicalVariable> triple =
new Triple<LogicalVariable, LogicalVariable, LogicalVariable>(
input1Var.get(0), input2Var.get(0), assignUnion.getVariables().get(0));
varMap.add(triple);
UnionAllOperator unionOp = new UnionAllOperator(varMap);
unionOp.getInputs().add(left_branch);
unionOp.getInputs().add(right_branch);
context.computeAndSetTypeEnvironmentForOperator(unionOp);
opRef.setValue(unionOp);
return true;
}