@Override
protected RelationPlan visitJoin(Join node, Void context) {
// TODO: translate the RIGHT join into a mirrored LEFT join when we refactor (@martint)
RelationPlan leftPlan = process(node.getLeft(), context);
// Convert CROSS JOIN UNNEST to an UnnestNode
if (node.getRight() instanceof Unnest
|| (node.getRight() instanceof AliasedRelation
&& ((AliasedRelation) node.getRight()).getRelation() instanceof Unnest)) {
Unnest unnest;
if (node.getRight() instanceof AliasedRelation) {
unnest = (Unnest) ((AliasedRelation) node.getRight()).getRelation();
} else {
unnest = (Unnest) node.getRight();
}
if (node.getType() != Join.Type.CROSS && node.getType() != Join.Type.IMPLICIT) {
throw new SemanticException(
NOT_SUPPORTED, unnest, "UNNEST only supported on the right side of CROSS JOIN");
}
return planCrossJoinUnnest(leftPlan, node, unnest);
}
RelationPlan rightPlan = process(node.getRight(), context);
PlanBuilder leftPlanBuilder = initializePlanBuilder(leftPlan);
PlanBuilder rightPlanBuilder = initializePlanBuilder(rightPlan);
TupleDescriptor outputDescriptor = analysis.getOutputDescriptor(node);
// NOTE: symbols must be in the same order as the outputDescriptor
List<Symbol> outputSymbols =
ImmutableList.<Symbol>builder()
.addAll(leftPlan.getOutputSymbols())
.addAll(rightPlan.getOutputSymbols())
.build();
ImmutableList.Builder<JoinNode.EquiJoinClause> equiClauses = ImmutableList.builder();
Expression postInnerJoinCriteria = new BooleanLiteral("TRUE");
if (node.getType() != Join.Type.CROSS && node.getType() != Join.Type.IMPLICIT) {
Expression criteria = analysis.getJoinCriteria(node);
TupleDescriptor left = analysis.getOutputDescriptor(node.getLeft());
TupleDescriptor right = analysis.getOutputDescriptor(node.getRight());
List<Expression> leftExpressions = new ArrayList<>();
List<Expression> rightExpressions = new ArrayList<>();
List<ComparisonExpression.Type> comparisonTypes = new ArrayList<>();
for (Expression conjunct : ExpressionUtils.extractConjuncts(criteria)) {
if (!(conjunct instanceof ComparisonExpression)) {
throw new SemanticException(
NOT_SUPPORTED, node, "Unsupported non-equi join form: %s", conjunct);
}
ComparisonExpression comparison = (ComparisonExpression) conjunct;
ComparisonExpression.Type comparisonType = comparison.getType();
if (comparison.getType() != EQUAL && node.getType() != INNER) {
throw new SemanticException(
NOT_SUPPORTED, node, "Non-equi joins only supported for inner join: %s", conjunct);
}
Set<QualifiedName> firstDependencies =
DependencyExtractor.extractNames(comparison.getLeft());
Set<QualifiedName> secondDependencies =
DependencyExtractor.extractNames(comparison.getRight());
Expression leftExpression;
Expression rightExpression;
if (Iterables.all(firstDependencies, left.canResolvePredicate())
&& Iterables.all(secondDependencies, right.canResolvePredicate())) {
leftExpression = comparison.getLeft();
rightExpression = comparison.getRight();
} else if (Iterables.all(firstDependencies, right.canResolvePredicate())
&& Iterables.all(secondDependencies, left.canResolvePredicate())) {
leftExpression = comparison.getRight();
rightExpression = comparison.getLeft();
comparisonType = flipComparison(comparisonType);
} else {
// must have a complex expression that involves both tuples on one side of the comparison
// expression (e.g., coalesce(left.x, right.x) = 1)
throw new SemanticException(
NOT_SUPPORTED, node, "Unsupported non-equi join form: %s", conjunct);
}
leftExpressions.add(leftExpression);
rightExpressions.add(rightExpression);
comparisonTypes.add(comparisonType);
}
Analysis.JoinInPredicates joinInPredicates = analysis.getJoinInPredicates(node);
// Add semi joins if necessary
if (joinInPredicates != null) {
leftPlanBuilder = appendSemiJoins(leftPlanBuilder, joinInPredicates.getLeftInPredicates());
rightPlanBuilder =
appendSemiJoins(rightPlanBuilder, joinInPredicates.getRightInPredicates());
}
// Add projections for join criteria
leftPlanBuilder = appendProjections(leftPlanBuilder, leftExpressions);
rightPlanBuilder = appendProjections(rightPlanBuilder, rightExpressions);
List<Expression> postInnerJoinComparisons = new ArrayList<>();
for (int i = 0; i < comparisonTypes.size(); i++) {
Symbol leftSymbol = leftPlanBuilder.translate(leftExpressions.get(i));
Symbol rightSymbol = rightPlanBuilder.translate(rightExpressions.get(i));
equiClauses.add(new JoinNode.EquiJoinClause(leftSymbol, rightSymbol));
Expression leftExpression = leftPlanBuilder.rewrite(leftExpressions.get(i));
Expression rightExpression = rightPlanBuilder.rewrite(rightExpressions.get(i));
postInnerJoinComparisons.add(
new ComparisonExpression(comparisonTypes.get(i), leftExpression, rightExpression));
}
postInnerJoinCriteria = ExpressionUtils.and(postInnerJoinComparisons);
}
PlanNode root;
if (node.getType() == INNER) {
root =
new JoinNode(
idAllocator.getNextId(),
JoinNode.Type.CROSS,
leftPlanBuilder.getRoot(),
rightPlanBuilder.getRoot(),
ImmutableList.<JoinNode.EquiJoinClause>of(),
Optional.empty(),
Optional.empty());
root = new FilterNode(idAllocator.getNextId(), root, postInnerJoinCriteria);
} else {
root =
new JoinNode(
idAllocator.getNextId(),
JoinNode.Type.typeConvert(node.getType()),
leftPlanBuilder.getRoot(),
rightPlanBuilder.getRoot(),
equiClauses.build(),
Optional.empty(),
Optional.empty());
}
Optional<Symbol> sampleWeight = Optional.empty();
if (leftPlanBuilder.getSampleWeight().isPresent()
|| rightPlanBuilder.getSampleWeight().isPresent()) {
Expression expression =
new ArithmeticBinaryExpression(
ArithmeticBinaryExpression.Type.MULTIPLY,
oneIfNull(leftPlanBuilder.getSampleWeight()),
oneIfNull(rightPlanBuilder.getSampleWeight()));
sampleWeight = Optional.of(symbolAllocator.newSymbol(expression, BIGINT));
ImmutableMap.Builder<Symbol, Expression> projections = ImmutableMap.builder();
projections.put(sampleWeight.get(), expression);
for (Symbol symbol : root.getOutputSymbols()) {
projections.put(symbol, new QualifiedNameReference(symbol.toQualifiedName()));
}
root = new ProjectNode(idAllocator.getNextId(), root, projections.build());
}
return new RelationPlan(root, outputDescriptor, outputSymbols, sampleWeight);
}