@Override
protected RelationPlan visitUnnest(Unnest node, Void context) {
TupleDescriptor descriptor = analysis.getOutputDescriptor(node);
ImmutableList.Builder<Symbol> outputSymbolsBuilder = ImmutableList.builder();
for (Field field : descriptor.getVisibleFields()) {
Symbol symbol = symbolAllocator.newSymbol(field);
outputSymbolsBuilder.add(symbol);
}
List<Symbol> unnestedSymbols = outputSymbolsBuilder.build();
// If we got here, then we must be unnesting a constant, and not be in a join (where there could
// be column references)
ImmutableList.Builder<Symbol> argumentSymbols = ImmutableList.builder();
ImmutableList.Builder<Expression> values = ImmutableList.builder();
ImmutableMap.Builder<Symbol, List<Symbol>> unnestSymbols = ImmutableMap.builder();
Iterator<Symbol> unnestedSymbolsIterator = unnestedSymbols.iterator();
for (Expression expression : node.getExpressions()) {
Object constantValue =
evaluateConstantExpression(expression, analysis.getCoercions(), metadata, session);
Type type = analysis.getType(expression);
values.add(LiteralInterpreter.toExpression(constantValue, type));
Symbol inputSymbol = symbolAllocator.newSymbol(expression, type);
argumentSymbols.add(inputSymbol);
if (type instanceof ArrayType) {
unnestSymbols.put(inputSymbol, ImmutableList.of(unnestedSymbolsIterator.next()));
} else if (type instanceof MapType) {
unnestSymbols.put(
inputSymbol,
ImmutableList.of(unnestedSymbolsIterator.next(), unnestedSymbolsIterator.next()));
} else {
throw new IllegalArgumentException("Unsupported type for UNNEST: " + type);
}
}
Optional<Symbol> ordinalitySymbol =
node.isWithOrdinality() ? Optional.of(unnestedSymbolsIterator.next()) : Optional.empty();
checkState(
!unnestedSymbolsIterator.hasNext(),
"Not all output symbols were matched with input symbols");
ValuesNode valuesNode =
new ValuesNode(
idAllocator.getNextId(),
argumentSymbols.build(),
ImmutableList.<List<Expression>>of(values.build()));
UnnestNode unnestNode =
new UnnestNode(
idAllocator.getNextId(),
valuesNode,
ImmutableList.<Symbol>of(),
unnestSymbols.build(),
ordinalitySymbol);
return new RelationPlan(unnestNode, descriptor, unnestedSymbols, Optional.empty());
}
private RelationPlan planCrossJoinUnnest(RelationPlan leftPlan, Join joinNode, Unnest node) {
TupleDescriptor outputDescriptor = analysis.getOutputDescriptor(joinNode);
TupleDescriptor unnestOutputDescriptor = analysis.getOutputDescriptor(node);
// Create symbols for the result of unnesting
ImmutableList.Builder<Symbol> unnestedSymbolsBuilder = ImmutableList.builder();
for (Field field : unnestOutputDescriptor.getVisibleFields()) {
Symbol symbol = symbolAllocator.newSymbol(field);
unnestedSymbolsBuilder.add(symbol);
}
ImmutableList<Symbol> unnestedSymbols = unnestedSymbolsBuilder.build();
// Add a projection for all the unnest arguments
PlanBuilder planBuilder = initializePlanBuilder(leftPlan);
planBuilder = appendProjections(planBuilder, node.getExpressions());
TranslationMap translations = planBuilder.getTranslations();
ProjectNode projectNode =
checkType(planBuilder.getRoot(), ProjectNode.class, "planBuilder.getRoot()");
ImmutableMap.Builder<Symbol, List<Symbol>> unnestSymbols = ImmutableMap.builder();
UnmodifiableIterator<Symbol> unnestedSymbolsIterator = unnestedSymbols.iterator();
for (Expression expression : node.getExpressions()) {
Type type = analysis.getType(expression);
Symbol inputSymbol = translations.get(expression);
if (type instanceof ArrayType) {
unnestSymbols.put(inputSymbol, ImmutableList.of(unnestedSymbolsIterator.next()));
} else if (type instanceof MapType) {
unnestSymbols.put(
inputSymbol,
ImmutableList.of(unnestedSymbolsIterator.next(), unnestedSymbolsIterator.next()));
} else {
throw new IllegalArgumentException("Unsupported type for UNNEST: " + type);
}
}
Optional<Symbol> ordinalitySymbol =
node.isWithOrdinality() ? Optional.of(unnestedSymbolsIterator.next()) : Optional.empty();
checkState(
!unnestedSymbolsIterator.hasNext(),
"Not all output symbols were matched with input symbols");
UnnestNode unnestNode =
new UnnestNode(
idAllocator.getNextId(),
projectNode,
leftPlan.getOutputSymbols(),
unnestSymbols.build(),
ordinalitySymbol);
return new RelationPlan(
unnestNode, outputDescriptor, unnestNode.getOutputSymbols(), Optional.empty());
}