[GitHub] incubator-quickstep pull request #229: Implement parser and resolver for UNI...

[zuyu]

Github user zuyu commented on a diff in the pull request:

    https://github.com/apache/incubator-quickstep/pull/229#discussion_r110304313
  
    --- Diff: query_optimizer/resolver/Resolver.cpp ---
    @@ -1350,16 +1351,172 @@ L::LogicalPtr Resolver::resolveSelect(
       return logical_plan;
     }
     
    +L::LogicalPtr Resolver::resolveSetOperations(
    +    const ParseSetOperation &parse_set_operations,
    +    const std::string &set_operation_name,
    +    const std::vector<const Type*> *type_hints,
    +    const NameResolver *parent_resolver) {
    +  std::vector<const ParseSetOperation*> operands;
    +  CollapseSetOperation(parse_set_operations, parse_set_operations, 
&operands);
    +
    +  DCHECK_LT(1u, operands.size());
    +  std::vector<L::LogicalPtr> resolved_operations;
    +  std::vector<std::vector<E::AttributeReferencePtr>> attribute_matrix;
    +
    +  // Resolve the first operation, and get the output attributes.
    +  auto iter = operands.begin();
    +  const ParseSetOperation &operation = static_cast<const 
ParseSetOperation&>(**iter);
    +  L::LogicalPtr operation_logical =
    +      resolveSetOperationDispatcher(operation, set_operation_name, 
type_hints, parent_resolver);
    +  const std::vector<E::AttributeReferencePtr> operation_attributes =
    +      operation_logical->getOutputAttributes();
    +  attribute_matrix.push_back(operation_attributes);
    +  resolved_operations.push_back(operation_logical);
    +
    +  // Resolve the rest operations, and check the size of output attributes.
    +  ++iter;
    +  for (; iter != operands.end(); ++iter) {
    +    const ParseSetOperation &current_operation =
    +        static_cast<const ParseSetOperation&>(**iter);
    +    L::LogicalPtr current_logical =
    +        resolveSetOperationDispatcher(current_operation, 
set_operation_name, type_hints, parent_resolver);
    +    attribute_matrix.emplace_back(current_logical->getOutputAttributes());
    +
    +    // Check output attributes size.
    +    // Detailed type check and type cast will perform later.
    +    if (attribute_matrix.back().size() != operation_attributes.size()) {
    +        THROW_SQL_ERROR_AT(&current_operation)
    +            << "Can not perform " << parse_set_operations.getName()
    +            << "opeartion between " << 
std::to_string(attribute_matrix.back().size())
    +            << "and " << std::to_string(operation_attributes.size())
    +            << "columns";
    +    }
    +
    +    resolved_operations.push_back(current_logical);
    +  }
    +
    +  // Get the possible output attributes that the attributes of all 
operands can cast to.
    +  std::vector<E::AttributeReferencePtr> possible_attributes;
    +  for (std::size_t aid = 0; aid < operation_attributes.size(); ++aid) {
    +    E::AttributeReferencePtr possible_attribute = attribute_matrix[0][aid];
    +    for (std::size_t opid = 1; opid < resolved_operations.size(); ++opid) {
    +      const Type &current_type = 
attribute_matrix[opid][aid]->getValueType();
    +      const Type &possible_type = possible_attribute->getValueType();
    +      if (!possible_type.equals(current_type)) {
    +        if (possible_type.getSuperTypeID() == Type::SuperTypeID::kNumeric 
&&
    +            current_type.getSuperTypeID() == Type::SuperTypeID::kNumeric) {
    +          if (possible_type.isSafelyCoercibleFrom(current_type)) {
    +            // Cast current_type to possible_type.
    +            // Possible_attribute remain the same, nothing needs to change.
    +          } else if (current_type.isSafelyCoercibleFrom(possible_type)) {
    +            // Cast possible_type to current_type.
    +            possible_attribute = attribute_matrix[opid][aid];
    +          } else {
    +            // Can not cast between possible_type and current_type.
    +            // Throw an SQL error.
    +            THROW_SQL_ERROR_AT(&parse_set_operations)
    +                << "There is not a safely coerce between "
    +                << current_type.getName()
    +                << "and " << possible_type.getName();
    +          }
    +        } else {
    +            THROW_SQL_ERROR_AT(&parse_set_operations)
    --- End diff --
    
    Reduce to two-whitespace-indentation.


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