ClickHouse/src/Interpreters/ActionsVisitor.cpp

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#include "Common/quoteString.h"
#include <Common/typeid_cast.h>
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#include <Common/PODArray.h>
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#include <Core/Row.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionsMiscellaneous.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <DataTypes/DataTypeSet.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeFunction.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypeTuple.h>
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#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeLowCardinality.h>
#include <DataTypes/FieldToDataType.h>
#include <DataStreams/LazyBlockInputStream.h>
#include <Columns/ColumnSet.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnsNumber.h>
#include <Storages/StorageSet.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSubquery.h>
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Interpreters/Context.h>
#include <Interpreters/ExpressionActions.h>
#include <Interpreters/misc.h>
#include <Interpreters/ActionsVisitor.h>
#include <Interpreters/InterpreterSelectWithUnionQuery.h>
#include <Interpreters/Set.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Interpreters/convertFieldToType.h>
#include <Interpreters/interpretSubquery.h>
#include <Interpreters/DatabaseAndTableWithAlias.h>
#include <Interpreters/IdentifierSemantic.h>
namespace DB
{
namespace ErrorCodes
{
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extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int UNKNOWN_IDENTIFIER;
extern const int NOT_AN_AGGREGATE;
extern const int UNEXPECTED_EXPRESSION;
extern const int TYPE_MISMATCH;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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extern const int INCORRECT_ELEMENT_OF_SET;
}
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static NamesAndTypesList::iterator findColumn(const String & name, NamesAndTypesList & cols)
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{
return std::find_if(cols.begin(), cols.end(),
[&](const NamesAndTypesList::value_type & val) { return val.name == name; });
}
static size_t getTypeDepth(const DataTypePtr & type)
{
if (const auto * array_type = typeid_cast<const DataTypeArray *>(type.get()))
return 1 + getTypeDepth(array_type->getNestedType());
else if (const auto * tuple_type = typeid_cast<const DataTypeTuple *>(type.get()))
return 1 + (tuple_type->getElements().empty() ? 0 : getTypeDepth(tuple_type->getElements().at(0)));
return 0;
}
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template<typename Collection>
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static Block createBlockFromCollection(const Collection & collection, const DataTypes & types, const Context & context)
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{
size_t columns_num = types.size();
MutableColumns columns(columns_num);
for (size_t i = 0; i < columns_num; ++i)
columns[i] = types[i]->createColumn();
Row tuple_values;
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for (const auto & value : collection)
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{
if (columns_num == 1)
{
auto field = convertFieldToType(value, *types[0]);
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if (!field.isNull() || context.getSettingsRef().transform_null_in)
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columns[0]->insert(std::move(field));
}
else
{
if (value.getType() != Field::Types::Tuple)
throw Exception("Invalid type in set. Expected tuple, got "
+ String(value.getTypeName()), ErrorCodes::INCORRECT_ELEMENT_OF_SET);
const auto & tuple = DB::get<const Tuple &>(value);
size_t tuple_size = tuple.size();
if (tuple_size != columns_num)
throw Exception("Incorrect size of tuple in set: " + toString(tuple_size)
+ " instead of " + toString(columns_num), ErrorCodes::INCORRECT_ELEMENT_OF_SET);
if (tuple_values.empty())
tuple_values.resize(tuple_size);
size_t i = 0;
for (; i < tuple_size; ++i)
{
tuple_values[i] = convertFieldToType(tuple[i], *types[i]);
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if (tuple_values[i].isNull() && !context.getSettingsRef().transform_null_in)
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break;
}
if (i == tuple_size)
for (i = 0; i < tuple_size; ++i)
columns[i]->insert(std::move(tuple_values[i]));
}
}
Block res;
for (size_t i = 0; i < columns_num; ++i)
res.insert(ColumnWithTypeAndName{std::move(columns[i]), types[i], "_" + toString(i)});
return res;
}
static Field extractValueFromNode(const ASTPtr & node, const IDataType & type, const Context & context)
{
if (const auto * lit = node->as<ASTLiteral>())
{
return convertFieldToType(lit->value, type);
}
else if (node->as<ASTFunction>())
{
std::pair<Field, DataTypePtr> value_raw = evaluateConstantExpression(node, context);
return convertFieldToType(value_raw.first, type, value_raw.second.get());
}
else
throw Exception("Incorrect element of set. Must be literal or constant expression.", ErrorCodes::INCORRECT_ELEMENT_OF_SET);
}
static Block createBlockFromAST(const ASTPtr & node, const DataTypes & types, const Context & context)
{
/// Will form a block with values from the set.
Block header;
size_t num_columns = types.size();
for (size_t i = 0; i < num_columns; ++i)
header.insert(ColumnWithTypeAndName(types[i]->createColumn(), types[i], "_" + toString(i)));
MutableColumns columns = header.cloneEmptyColumns();
DataTypePtr tuple_type;
Row tuple_values;
const auto & list = node->as<ASTExpressionList &>();
for (const auto & elem : list.children)
{
if (num_columns == 1)
{
Field value = extractValueFromNode(elem, *types[0], context);
if (!value.isNull() || context.getSettingsRef().transform_null_in)
columns[0]->insert(value);
}
else if (elem->as<ASTFunction>() || elem->as<ASTLiteral>())
{
Field function_result;
const Tuple * tuple = nullptr;
auto * func = elem->as<ASTFunction>();
if (func && func->name != "tuple")
{
if (!tuple_type)
tuple_type = std::make_shared<DataTypeTuple>(types);
function_result = extractValueFromNode(elem, *tuple_type, context);
if (function_result.getType() != Field::Types::Tuple)
throw Exception("Invalid type of set. Expected tuple, got " + String(function_result.getTypeName()),
ErrorCodes::INCORRECT_ELEMENT_OF_SET);
tuple = &function_result.get<Tuple>();
}
auto * literal = elem->as<ASTLiteral>();
if (literal)
{
if (literal->value.getType() != Field::Types::Tuple)
throw Exception("Invalid type in set. Expected tuple, got "
+ String(literal->value.getTypeName()), ErrorCodes::INCORRECT_ELEMENT_OF_SET);
tuple = &literal->value.get<Tuple>();
}
size_t tuple_size = tuple ? tuple->size() : func->arguments->children.size();
if (tuple_size != num_columns)
throw Exception("Incorrect size of tuple in set: " + toString(tuple_size) + " instead of " + toString(num_columns),
ErrorCodes::INCORRECT_ELEMENT_OF_SET);
if (tuple_values.empty())
tuple_values.resize(tuple_size);
size_t i = 0;
for (; i < tuple_size; ++i)
{
Field value = tuple ? (*tuple)[i]
: extractValueFromNode(func->arguments->children[i], *types[i], context);
/// If at least one of the elements of the tuple has an impossible (outside the range of the type) value, then the entire tuple too.
if (value.isNull() && !context.getSettings().transform_null_in)
break;
tuple_values[i] = value;
}
if (i == tuple_size)
for (i = 0; i < tuple_size; ++i)
columns[i]->insert(tuple_values[i]);
}
else
throw Exception("Incorrect element of set", ErrorCodes::INCORRECT_ELEMENT_OF_SET);
}
return header.cloneWithColumns(std::move(columns));
}
/** Create a block for set from literal.
* 'set_element_types' - types of what are on the left hand side of IN.
* 'right_arg' - Literal - Tuple or Array.
*/
static Block createBlockForSet(
const DataTypePtr & left_arg_type,
const std::shared_ptr<ASTLiteral> & right_arg,
const DataTypes & set_element_types,
const Context & context)
{
auto [right_arg_value, right_arg_type] = evaluateConstantExpression(right_arg, context);
const size_t left_type_depth = getTypeDepth(left_arg_type);
const size_t right_type_depth = getTypeDepth(right_arg_type);
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auto throw_unsupported_type = [](const auto & type)
{
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throw Exception("Unsupported value type at the right-side of IN: "
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+ type->getName() + ".", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
};
Block block;
/// 1 in 1; (1, 2) in (1, 2); identity(tuple(tuple(tuple(1)))) in tuple(tuple(tuple(1))); etc.
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if (left_type_depth == right_type_depth)
{
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Array array{right_arg_value};
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block = createBlockFromCollection(array, set_element_types, context);
}
/// 1 in (1, 2); (1, 2) in ((1, 2), (3, 4)); etc.
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else if (left_type_depth + 1 == right_type_depth)
{
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auto type_index = right_arg_type->getTypeId();
if (type_index == TypeIndex::Tuple)
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block = createBlockFromCollection(DB::get<const Tuple &>(right_arg_value), set_element_types, context);
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else if (type_index == TypeIndex::Array)
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block = createBlockFromCollection(DB::get<const Array &>(right_arg_value), set_element_types, context);
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else
throw_unsupported_type(right_arg_type);
}
else
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throw_unsupported_type(right_arg_type);
return block;
}
/** Create a block for set from expression.
* 'set_element_types' - types of what are on the left hand side of IN.
* 'right_arg' - list of values: 1, 2, 3 or list of tuples: (1, 2), (3, 4), (5, 6).
*
* We need special implementation for common AST, because in case, when we interpret tuple or array
* as function, `evaluateConstantExpression` works extremely slow.
*/
static Block createBlockForSet(
const DataTypePtr & left_arg_type,
const ASTPtr & right_arg,
const DataTypes & set_element_types,
const Context & context)
{
auto get_tuple_type_from_ast = [&context](const ASTPtr & tuple_ast) -> DataTypePtr
{
const auto * func = tuple_ast->as<ASTFunction>();
if (func && (func->name == "tuple" || func->name == "array") && !func->arguments->children.empty())
{
/// Won't parse all values of outer tuple.
auto element = func->arguments->children.at(0);
std::pair<Field, DataTypePtr> value_raw = evaluateConstantExpression(element, context);
return std::make_shared<DataTypeTuple>(DataTypes({value_raw.second}));
}
return evaluateConstantExpression(tuple_ast, context).second;
};
const DataTypePtr & right_arg_type = get_tuple_type_from_ast(right_arg);
size_t left_tuple_depth = getTypeDepth(left_arg_type);
size_t right_tuple_depth = getTypeDepth(right_arg_type);
ASTPtr elements_ast;
/// 1 in 1; (1, 2) in (1, 2); identity(tuple(tuple(tuple(1)))) in tuple(tuple(tuple(1))); etc.
if (left_tuple_depth == right_tuple_depth)
{
ASTPtr exp_list = std::make_shared<ASTExpressionList>();
exp_list->children.push_back(right_arg);
elements_ast = exp_list;
}
/// 1 in (1, 2); (1, 2) in ((1, 2), (3, 4)); etc.
else if (left_tuple_depth + 1 == right_tuple_depth)
{
const auto * set_func = right_arg->as<ASTFunction>();
if (!set_func || (set_func->name != "tuple" && set_func->name != "array"))
throw Exception("Incorrect type of 2nd argument for function 'in'"
". Must be subquery or set of elements with type " + left_arg_type->getName() + ".",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
elements_ast = set_func->arguments;
}
else
throw Exception("Invalid types for IN function: "
+ left_arg_type->getName() + " and " + right_arg_type->getName() + ".",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return createBlockFromAST(elements_ast, set_element_types, context);
}
SetPtr makeExplicitSet(
const ASTFunction * node, const Block & sample_block, bool create_ordered_set,
const Context & context, const SizeLimits & size_limits, PreparedSets & prepared_sets)
{
const IAST & args = *node->arguments;
if (args.children.size() != 2)
throw Exception("Wrong number of arguments passed to function in", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const ASTPtr & left_arg = args.children.at(0);
const ASTPtr & right_arg = args.children.at(1);
const DataTypePtr & left_arg_type = sample_block.getByName(left_arg->getColumnName()).type;
DataTypes set_element_types = {left_arg_type};
const auto * left_tuple_type = typeid_cast<const DataTypeTuple *>(left_arg_type.get());
if (left_tuple_type && left_tuple_type->getElements().size() != 1)
set_element_types = left_tuple_type->getElements();
for (auto & element_type : set_element_types)
if (const auto * low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(element_type.get()))
element_type = low_cardinality_type->getDictionaryType();
auto set_key = PreparedSetKey::forLiteral(*right_arg, set_element_types);
if (prepared_sets.count(set_key))
return prepared_sets.at(set_key); /// Already prepared.
Block block;
if (const auto & right_arg_literal = std::dynamic_pointer_cast<ASTLiteral>(right_arg))
block = createBlockForSet(left_arg_type, right_arg_literal, set_element_types, context);
else
block = createBlockForSet(left_arg_type, right_arg, set_element_types, context);
SetPtr set = std::make_shared<Set>(size_limits, create_ordered_set, context.getSettingsRef().transform_null_in);
set->setHeader(block.cloneEmpty());
set->insertFromBlock(block);
set->finishInsert();
prepared_sets[set_key] = set;
return set;
}
ScopeStack::ScopeStack(const ExpressionActionsPtr & actions, const Context & context_)
: context(context_)
{
stack.emplace_back();
stack.back().actions = actions;
const Block & sample_block = actions->getSampleBlock();
for (size_t i = 0, size = sample_block.columns(); i < size; ++i)
stack.back().new_columns.insert(sample_block.getByPosition(i).name);
}
void ScopeStack::pushLevel(const NamesAndTypesList & input_columns)
{
stack.emplace_back();
Level & prev = stack[stack.size() - 2];
ColumnsWithTypeAndName all_columns;
NameSet new_names;
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for (const auto & input_column : input_columns)
{
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all_columns.emplace_back(nullptr, input_column.type, input_column.name);
new_names.insert(input_column.name);
stack.back().new_columns.insert(input_column.name);
}
const Block & prev_sample_block = prev.actions->getSampleBlock();
for (size_t i = 0, size = prev_sample_block.columns(); i < size; ++i)
{
const ColumnWithTypeAndName & col = prev_sample_block.getByPosition(i);
if (!new_names.count(col.name))
all_columns.push_back(col);
}
stack.back().actions = std::make_shared<ExpressionActions>(all_columns, context);
}
size_t ScopeStack::getColumnLevel(const std::string & name)
{
for (int i = static_cast<int>(stack.size()) - 1; i >= 0; --i)
if (stack[i].new_columns.count(name))
return i;
throw Exception("Unknown identifier: " + name, ErrorCodes::UNKNOWN_IDENTIFIER);
}
void ScopeStack::addAction(const ExpressionAction & action)
{
size_t level = 0;
Names required = action.getNeededColumns();
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for (const auto & elem : required)
level = std::max(level, getColumnLevel(elem));
Names added;
stack[level].actions->add(action, added);
stack[level].new_columns.insert(added.begin(), added.end());
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for (const auto & elem : added)
{
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const ColumnWithTypeAndName & col = stack[level].actions->getSampleBlock().getByName(elem);
for (size_t j = level + 1; j < stack.size(); ++j)
stack[j].actions->addInput(col);
}
}
ExpressionActionsPtr ScopeStack::popLevel()
{
ExpressionActionsPtr res = stack.back().actions;
stack.pop_back();
return res;
}
const Block & ScopeStack::getSampleBlock() const
{
return stack.back().actions->getSampleBlock();
}
struct CachedColumnName
{
String cached;
const String & get(const ASTPtr & ast)
{
if (cached.empty())
cached = ast->getColumnName();
return cached;
}
};
bool ActionsMatcher::needChildVisit(const ASTPtr & node, const ASTPtr & child)
{
/// Visit children themself
if (node->as<ASTIdentifier>() ||
node->as<ASTFunction>() ||
node->as<ASTLiteral>())
return false;
/// Do not go to FROM, JOIN, UNION.
if (child->as<ASTTableExpression>() ||
child->as<ASTSelectQuery>())
return false;
return true;
}
void ActionsMatcher::visit(const ASTPtr & ast, Data & data)
{
if (const auto * identifier = ast->as<ASTIdentifier>())
visit(*identifier, ast, data);
else if (const auto * node = ast->as<ASTFunction>())
visit(*node, ast, data);
else if (const auto * literal = ast->as<ASTLiteral>())
visit(*literal, ast, data);
}
void ActionsMatcher::visit(const ASTIdentifier & identifier, const ASTPtr & ast, Data & data)
{
CachedColumnName column_name;
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if (data.hasColumn(column_name.get(ast)))
return;
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if (!data.only_consts)
{
/// The requested column is not in the block.
/// If such a column exists in the table, then the user probably forgot to surround it with an aggregate function or add it to GROUP BY.
bool found = false;
for (const auto & column_name_type : data.source_columns)
if (column_name_type.name == column_name.get(ast))
found = true;
if (found)
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throw Exception("Column " + backQuote(column_name.get(ast)) + " is not under aggregate function and not in GROUP BY",
ErrorCodes::NOT_AN_AGGREGATE);
/// Special check for WITH statement alias. Add alias action to be able to use this alias.
if (identifier.prefer_alias_to_column_name && !identifier.alias.empty())
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data.addAction(ExpressionAction::addAliases({{identifier.name, identifier.alias}}));
}
}
void ActionsMatcher::visit(const ASTFunction & node, const ASTPtr & ast, Data & data)
{
CachedColumnName column_name;
if (data.hasColumn(column_name.get(ast)))
return;
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if (node.name == "lambda")
throw Exception("Unexpected lambda expression", ErrorCodes::UNEXPECTED_EXPRESSION);
/// Function arrayJoin.
if (node.name == "arrayJoin")
{
if (node.arguments->children.size() != 1)
throw Exception("arrayJoin requires exactly 1 argument", ErrorCodes::TYPE_MISMATCH);
ASTPtr arg = node.arguments->children.at(0);
visit(arg, data);
if (!data.only_consts)
{
String result_name = column_name.get(ast);
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data.addAction(ExpressionAction::copyColumn(arg->getColumnName(), result_name));
NameSet joined_columns;
joined_columns.insert(result_name);
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data.addAction(ExpressionAction::arrayJoin(joined_columns, false, data.context));
}
return;
}
SetPtr prepared_set;
if (checkFunctionIsInOrGlobalInOperator(node))
{
/// Let's find the type of the first argument (then getActionsImpl will be called again and will not affect anything).
visit(node.arguments->children.at(0), data);
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if (!data.no_makeset && (prepared_set = makeSet(node, data, data.no_subqueries)))
{
/// Transform tuple or subquery into a set.
}
else
{
if (!data.only_consts)
{
/// We are in the part of the tree that we are not going to compute. You just need to define types.
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/// Do not subquery and create sets. We replace "in*" function to "in*IgnoreSet".
auto argument_name = node.arguments->children.at(0)->getColumnName();
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data.addAction(ExpressionAction::applyFunction(
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FunctionFactory::instance().get(node.name + "IgnoreSet", data.context),
{ argument_name, argument_name },
column_name.get(ast)));
}
return;
}
}
if (AggregateFunctionFactory::instance().isAggregateFunctionName(node.name))
return;
/// Context object that we pass to function should live during query.
const Context & function_context = data.context.hasQueryContext()
? data.context.getQueryContext()
: data.context;
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FunctionOverloadResolverPtr function_builder;
try
{
function_builder = FunctionFactory::instance().get(node.name, function_context);
}
catch (DB::Exception & e)
{
auto hints = AggregateFunctionFactory::instance().getHints(node.name);
if (!hints.empty())
e.addMessage("Or unknown aggregate function " + node.name + ". Maybe you meant: " + toString(hints));
e.rethrow();
}
Names argument_names;
DataTypes argument_types;
bool arguments_present = true;
/// If the function has an argument-lambda expression, you need to determine its type before the recursive call.
bool has_lambda_arguments = false;
for (size_t arg = 0; arg < node.arguments->children.size(); ++arg)
{
auto & child = node.arguments->children[arg];
const auto * lambda = child->as<ASTFunction>();
const auto * identifier = child->as<ASTIdentifier>();
if (lambda && lambda->name == "lambda")
{
/// If the argument is a lambda expression, just remember its approximate type.
if (lambda->arguments->children.size() != 2)
throw Exception("lambda requires two arguments", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const auto * lambda_args_tuple = lambda->arguments->children.at(0)->as<ASTFunction>();
if (!lambda_args_tuple || lambda_args_tuple->name != "tuple")
throw Exception("First argument of lambda must be a tuple", ErrorCodes::TYPE_MISMATCH);
has_lambda_arguments = true;
argument_types.emplace_back(std::make_shared<DataTypeFunction>(DataTypes(lambda_args_tuple->arguments->children.size())));
/// Select the name in the next cycle.
argument_names.emplace_back();
}
else if (checkFunctionIsInOrGlobalInOperator(node) && arg == 1 && prepared_set)
{
ColumnWithTypeAndName column;
column.type = std::make_shared<DataTypeSet>();
/// If the argument is a set given by an enumeration of values (so, the set was already built), give it a unique name,
/// so that sets with the same literal representation do not fuse together (they can have different types).
if (!prepared_set->empty())
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column.name = data.getUniqueName("__set");
else
column.name = child->getColumnName();
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if (!data.hasColumn(column.name))
{
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auto column_set = ColumnSet::create(1, prepared_set);
/// If prepared_set is not empty, we have a set made with literals.
/// Create a const ColumnSet to make constant folding work
if (!prepared_set->empty())
column.column = ColumnConst::create(std::move(column_set), 1);
else
column.column = std::move(column_set);
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data.addAction(ExpressionAction::addColumn(column));
}
argument_types.push_back(column.type);
argument_names.push_back(column.name);
}
else if (identifier && (functionIsJoinGet(node.name) || functionIsDictGet(node.name)) && arg == 0)
{
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auto table_id = IdentifierSemantic::extractDatabaseAndTable(*identifier);
table_id = data.context.resolveStorageID(table_id, Context::ResolveOrdinary);
auto column_string = ColumnString::create();
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column_string->insert(table_id.getDatabaseName() + "." + table_id.getTableName());
ColumnWithTypeAndName column(
ColumnConst::create(std::move(column_string), 1),
std::make_shared<DataTypeString>(),
data.getUniqueName("__" + node.name));
data.addAction(ExpressionAction::addColumn(column));
argument_types.push_back(column.type);
argument_names.push_back(column.name);
}
else
{
/// If the argument is not a lambda expression, call it recursively and find out its type.
visit(child, data);
// In the above visit() call, if the argument is a literal, we
// generated a unique column name for it. Use it instead of a generic
// display name.
auto child_column_name = child->getColumnName();
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const auto * as_literal = child->as<ASTLiteral>();
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if (as_literal)
{
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assert(!as_literal->unique_column_name.empty());
child_column_name = as_literal->unique_column_name;
}
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if (data.hasColumn(child_column_name))
{
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argument_types.push_back(data.getSampleBlock().getByName(child_column_name).type);
argument_names.push_back(child_column_name);
}
else
{
if (data.only_consts)
arguments_present = false;
else
throw Exception("Unknown identifier: " + child_column_name + " there are columns: " + data.getSampleBlock().dumpNames(),
ErrorCodes::UNKNOWN_IDENTIFIER);
}
}
}
if (data.only_consts && !arguments_present)
return;
if (has_lambda_arguments && !data.only_consts)
{
function_builder->getLambdaArgumentTypes(argument_types);
/// Call recursively for lambda expressions.
for (size_t i = 0; i < node.arguments->children.size(); ++i)
{
ASTPtr child = node.arguments->children[i];
const auto * lambda = child->as<ASTFunction>();
if (lambda && lambda->name == "lambda")
{
const DataTypeFunction * lambda_type = typeid_cast<const DataTypeFunction *>(argument_types[i].get());
const auto * lambda_args_tuple = lambda->arguments->children.at(0)->as<ASTFunction>();
const ASTs & lambda_arg_asts = lambda_args_tuple->arguments->children;
NamesAndTypesList lambda_arguments;
for (size_t j = 0; j < lambda_arg_asts.size(); ++j)
{
auto opt_arg_name = tryGetIdentifierName(lambda_arg_asts[j]);
if (!opt_arg_name)
throw Exception("lambda argument declarations must be identifiers", ErrorCodes::TYPE_MISMATCH);
lambda_arguments.emplace_back(*opt_arg_name, lambda_type->getArgumentTypes()[j]);
}
data.actions_stack.pushLevel(lambda_arguments);
visit(lambda->arguments->children.at(1), data);
ExpressionActionsPtr lambda_actions = data.actions_stack.popLevel();
String result_name = lambda->arguments->children.at(1)->getColumnName();
lambda_actions->finalize(Names(1, result_name));
DataTypePtr result_type = lambda_actions->getSampleBlock().getByName(result_name).type;
Names captured;
Names required = lambda_actions->getRequiredColumns();
for (const auto & required_arg : required)
if (findColumn(required_arg, lambda_arguments) == lambda_arguments.end())
captured.push_back(required_arg);
/// We can not name `getColumnName()`,
/// because it does not uniquely define the expression (the types of arguments can be different).
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String lambda_name = data.getUniqueName("__lambda");
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auto function_capture = std::make_unique<FunctionCaptureOverloadResolver>(
lambda_actions, captured, lambda_arguments, result_type, result_name);
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auto function_capture_adapter = std::make_shared<FunctionOverloadResolverAdaptor>(std::move(function_capture));
data.addAction(ExpressionAction::applyFunction(function_capture_adapter, captured, lambda_name));
argument_types[i] = std::make_shared<DataTypeFunction>(lambda_type->getArgumentTypes(), result_type);
argument_names[i] = lambda_name;
}
}
}
if (data.only_consts)
{
for (const auto & argument_name : argument_names)
{
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if (!data.hasColumn(argument_name))
{
arguments_present = false;
break;
}
}
}
if (arguments_present)
{
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data.addAction(ExpressionAction::applyFunction(function_builder, argument_names, column_name.get(ast)));
}
}
void ActionsMatcher::visit(const ASTLiteral & literal, const ASTPtr & /* ast */,
Data & data)
{
DataTypePtr type = applyVisitor(FieldToDataType(), literal.value);
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const auto value = convertFieldToType(literal.value, *type);
// FIXME why do we have a second pass with a clean sample block over the same
// AST here? Anyway, do not modify the column name if it is set already.
if (literal.unique_column_name.empty())
{
const auto default_name = literal.getColumnName();
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const auto & block = data.getSampleBlock();
const auto * existing_column = block.findByName(default_name);
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/*
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* To approximate CSE, bind all identical literals to a single temporary
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* columns. We try to find the column by its default name, but after that
* we have to check that it contains the correct data. This might not be
* the case if it is a user-supplied column, or it is from under a join,
* etc.
* Overall, this is a hack around a generally poor name-based notion of
* column identity we currently use.
*/
if (existing_column
&& existing_column->column
&& isColumnConst(*existing_column->column)
&& existing_column->column->size() == 1
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&& existing_column->column->operator[](0) == value)
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{
const_cast<ASTLiteral &>(literal).unique_column_name = default_name;
}
else
{
const_cast<ASTLiteral &>(literal).unique_column_name
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= data.getUniqueName(default_name);
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}
}
if (data.hasColumn(literal.unique_column_name))
{
return;
}
ColumnWithTypeAndName column;
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column.name = literal.unique_column_name;
column.column = type->createColumnConst(1, value);
column.type = type;
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data.addAction(ExpressionAction::addColumn(column));
}
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SetPtr ActionsMatcher::makeSet(const ASTFunction & node, Data & data, bool no_subqueries)
{
/** You need to convert the right argument to a set.
* This can be a table name, a value, a value enumeration, or a subquery.
* The enumeration of values is parsed as a function `tuple`.
*/
const IAST & args = *node.arguments;
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const ASTPtr & left_in_operand = args.children.at(0);
const ASTPtr & right_in_operand = args.children.at(1);
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const Block & sample_block = data.getSampleBlock();
/// If the subquery or table name for SELECT.
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const auto * identifier = right_in_operand->as<ASTIdentifier>();
if (right_in_operand->as<ASTSubquery>() || identifier)
{
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if (no_subqueries)
return {};
auto set_key = PreparedSetKey::forSubquery(*right_in_operand);
if (data.prepared_sets.count(set_key))
return data.prepared_sets.at(set_key);
/// A special case is if the name of the table is specified on the right side of the IN statement,
/// and the table has the type Set (a previously prepared set).
if (identifier)
{
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auto table_id = data.context.resolveStorageID(right_in_operand);
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StoragePtr table = DatabaseCatalog::instance().tryGetTable(table_id, data.context);
if (table)
{
StorageSet * storage_set = dynamic_cast<StorageSet *>(table.get());
if (storage_set)
{
data.prepared_sets[set_key] = storage_set->getSet();
return storage_set->getSet();
}
}
}
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/// We get the stream of blocks for the subquery. Create Set and put it in place of the subquery.
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String set_id = right_in_operand->getColumnName();
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SubqueryForSet & subquery_for_set = data.subqueries_for_sets[set_id];
/// If you already created a Set with the same subquery / table.
if (subquery_for_set.set)
{
data.prepared_sets[set_key] = subquery_for_set.set;
return subquery_for_set.set;
}
SetPtr set = std::make_shared<Set>(data.set_size_limit, false, data.context.getSettingsRef().transform_null_in);
/** The following happens for GLOBAL INs:
* - in the addExternalStorage function, the IN (SELECT ...) subquery is replaced with IN _data1,
* in the subquery_for_set object, this subquery is set as source and the temporary table _data1 as the table.
* - this function shows the expression IN_data1.
*/
if (!subquery_for_set.source && data.no_storage_or_local)
{
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auto interpreter = interpretSubquery(right_in_operand, data.context, data.subquery_depth, {});
subquery_for_set.source = std::make_shared<LazyBlockInputStream>(
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interpreter->getSampleBlock(), [interpreter]() mutable { return interpreter->execute().getInputStream(); });
/** Why is LazyBlockInputStream used?
*
* The fact is that when processing a query of the form
* SELECT ... FROM remote_test WHERE column GLOBAL IN (subquery),
* if the distributed remote_test table contains localhost as one of the servers,
* the query will be interpreted locally again (and not sent over TCP, as in the case of a remote server).
*
* The query execution pipeline will be:
* CreatingSets
* subquery execution, filling the temporary table with _data1 (1)
* CreatingSets
* reading from the table _data1, creating the set (2)
* read from the table subordinate to remote_test.
*
* (The second part of the pipeline under CreateSets is a reinterpretation of the query inside StorageDistributed,
* the query differs in that the database name and tables are replaced with subordinates, and the subquery is replaced with _data1.)
*
* But when creating the pipeline, when creating the source (2), it will be found that the _data1 table is empty
* (because the query has not started yet), and empty source will be returned as the source.
* And then, when the query is executed, an empty set will be created in step (2).
*
* Therefore, we make the initialization of step (2) lazy
* - so that it does not occur until step (1) is completed, on which the table will be populated.
*
* Note: this solution is not very good, you need to think better.
*/
}
subquery_for_set.set = set;
data.prepared_sets[set_key] = set;
return set;
}
else
{
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if (sample_block.has(left_in_operand->getColumnName()))
/// An explicit enumeration of values in parentheses.
return makeExplicitSet(&node, sample_block, false, data.context, data.set_size_limit, data.prepared_sets);
else
return {};
}
}
}