thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-17 21:24:28 +00:00
Code Issues Packages Projects Releases Wiki Activity
4e8bea397b
ClickHouse/src/Interpreters/ExpressionActions.cpp
Nikolai Kochetov 4e8bea397b
Update ExpressionActions.cpp
2020-10-26 15:10:16 +03:00

1818 lines
62 KiB
C++
Raw Blame History

#include <Interpreters/Set.h>
#include <Common/ProfileEvents.h>
#include <Common/SipHash.h>
#include <Interpreters/ArrayJoinAction.h>
#include <Interpreters/ExpressionActions.h>
#include <Interpreters/ExpressionJIT.h>
#include <Interpreters/TableJoin.h>
#include <Interpreters/Context.h>
#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnArray.h>
#include <Common/typeid_cast.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeNullable.h>
#include <Functions/IFunction.h>
#include <IO/Operators.h>
#include <optional>
#include <Columns/ColumnSet.h>
#include <queue>
#if !defined(ARCADIA_BUILD)
# include "config_core.h"
#endif
#include <common/defines.h>
#if defined(MEMORY_SANITIZER)
#include <sanitizer/msan_interface.h>
#endif
#if defined(ADDRESS_SANITIZER)
#include <sanitizer/asan_interface.h>
#endif
namespace ProfileEvents
{
extern const Event FunctionExecute;
extern const Event CompiledFunctionExecute;
}
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int DUPLICATE_COLUMN;
extern const int UNKNOWN_IDENTIFIER;
extern const int NOT_FOUND_COLUMN_IN_BLOCK;
extern const int TOO_MANY_TEMPORARY_COLUMNS;
extern const int TOO_MANY_TEMPORARY_NON_CONST_COLUMNS;
extern const int TYPE_MISMATCH;
}
/// Read comment near usage
static constexpr auto DUMMY_COLUMN_NAME = "_dummy";
Names ExpressionAction::getNeededColumns() const
{
Names res = argument_names;
if (table_join)
res.insert(res.end(), table_join->keyNamesLeft().begin(), table_join->keyNamesLeft().end());
for (const auto & column : projection)
res.push_back(column.first);
if (!source_name.empty())
res.push_back(source_name);
return res;
}
ExpressionAction ExpressionAction::applyFunction(
const FunctionOverloadResolverPtr & function_,
const std::vector<std::string> & argument_names_,
std::string result_name_)
{
if (result_name_.empty())
{
result_name_ = function_->getName() + "(";
for (size_t i = 0 ; i < argument_names_.size(); ++i)
{
if (i)
result_name_ += ", ";
result_name_ += argument_names_[i];
}
result_name_ += ")";
}
ExpressionAction a;
a.type = APPLY_FUNCTION;
a.result_name = result_name_;
a.function_builder = function_;
a.argument_names = argument_names_;
return a;
}
ExpressionAction ExpressionAction::addColumn(
const ColumnWithTypeAndName & added_column_)
{
ExpressionAction a;
a.type = ADD_COLUMN;
a.result_name = added_column_.name;
a.result_type = added_column_.type;
a.added_column = added_column_.column;
return a;
}
ExpressionAction ExpressionAction::removeColumn(const std::string & removed_name)
{
ExpressionAction a;
a.type = REMOVE_COLUMN;
a.source_name = removed_name;
return a;
}
ExpressionAction ExpressionAction::copyColumn(const std::string & from_name, const std::string & to_name, bool can_replace)
{
ExpressionAction a;
a.type = COPY_COLUMN;
a.source_name = from_name;
a.result_name = to_name;
a.can_replace = can_replace;
return a;
}
ExpressionAction ExpressionAction::project(const NamesWithAliases & projected_columns_)
{
ExpressionAction a;
a.type = PROJECT;
a.projection = projected_columns_;
return a;
}
ExpressionAction ExpressionAction::project(const Names & projected_columns_)
{
ExpressionAction a;
a.type = PROJECT;
a.projection.resize(projected_columns_.size());
for (size_t i = 0; i < projected_columns_.size(); ++i)
a.projection[i] = NameWithAlias(projected_columns_[i], "");
return a;
}
ExpressionAction ExpressionAction::addAliases(const NamesWithAliases & aliased_columns_)
{
ExpressionAction a;
a.type = ADD_ALIASES;
a.projection = aliased_columns_;
return a;
}
ExpressionAction ExpressionAction::arrayJoin(std::string source_name, std::string result_name)
{
if (source_name == result_name)
throw Exception("ARRAY JOIN action should have different source and result names", ErrorCodes::LOGICAL_ERROR);
ExpressionAction a;
a.type = ARRAY_JOIN;
a.source_name = std::move(source_name);
a.result_name = std::move(result_name);
return a;
}
void ExpressionAction::prepare(Block & sample_block, const Settings & settings, NameSet & names_not_for_constant_folding)
{
// std::cerr << "preparing: " << toString() << std::endl;
/** Constant expressions should be evaluated, and put the result in sample_block.
*/
switch (type)
{
case APPLY_FUNCTION:
{
if (sample_block.has(result_name))
throw Exception("Column '" + result_name + "' already exists", ErrorCodes::DUPLICATE_COLUMN);
bool all_const = true;
bool all_suitable_for_constant_folding = true;
ColumnsWithTypeAndName arguments(argument_names.size());
for (size_t i = 0; i < argument_names.size(); ++i)
{
arguments[i] = sample_block.getByName(argument_names[i]);
ColumnPtr col = arguments[i].column;
if (!col || !isColumnConst(*col))
all_const = false;
if (names_not_for_constant_folding.count(argument_names[i]))
all_suitable_for_constant_folding = false;
}
size_t result_position = sample_block.columns();
sample_block.insert({nullptr, result_type, result_name});
if (!function)
function = function_base->prepare(arguments);
function->createLowCardinalityResultCache(settings.max_threads);
bool compile_expressions = false;
#if USE_EMBEDDED_COMPILER
compile_expressions = settings.compile_expressions;
#endif
/// If all arguments are constants, and function is suitable to be executed in 'prepare' stage - execute function.
/// But if we compile expressions compiled version of this function maybe placed in cache,
/// so we don't want to unfold non deterministic functions
if (all_const && function_base->isSuitableForConstantFolding() && (!compile_expressions || function_base->isDeterministic()))
{
if (added_column)
sample_block.getByPosition(result_position).column = added_column;
else
sample_block.getByPosition(result_position).column = function->execute(arguments, result_type, sample_block.rows(), true);
/// If the result is not a constant, just in case, we will consider the result as unknown.
ColumnWithTypeAndName & col = sample_block.safeGetByPosition(result_position);
if (!isColumnConst(*col.column))
{
col.column = nullptr;
}
else
{
/// All constant (literal) columns in block are added with size 1.
/// But if there was no columns in block before executing a function, the result has size 0.
/// Change the size to 1.
if (col.column->empty())
col.column = col.column->cloneResized(1);
if (!all_suitable_for_constant_folding)
names_not_for_constant_folding.insert(result_name);
}
}
/// Some functions like ignore() or getTypeName() always return constant result even if arguments are not constant.
/// We can't do constant folding, but can specify in sample block that function result is constant to avoid
/// unnecessary materialization.
auto & res = sample_block.getByPosition(result_position);
if (!res.column && function_base->isSuitableForConstantFolding())
{
if (auto col = function_base->getResultIfAlwaysReturnsConstantAndHasArguments(arguments))
{
res.column = std::move(col);
names_not_for_constant_folding.insert(result_name);
}
}
break;
}
case ARRAY_JOIN:
{
ColumnWithTypeAndName current = sample_block.getByName(source_name);
sample_block.erase(source_name);
const DataTypeArray * array_type = typeid_cast<const DataTypeArray *>(&*current.type);
if (!array_type)
throw Exception("ARRAY JOIN requires array argument", ErrorCodes::TYPE_MISMATCH);
current.name = result_name;
current.type = array_type->getNestedType();
current.column = nullptr; /// Result is never const
sample_block.insert(std::move(current));
break;
}
case PROJECT:
{
Block new_block;
for (const auto & elem : projection)
{
const std::string & name = elem.first;
const std::string & alias = elem.second;
ColumnWithTypeAndName column = sample_block.getByName(name);
if (!alias.empty())
column.name = alias;
new_block.insert(std::move(column));
}
sample_block.swap(new_block);
break;
}
case ADD_ALIASES:
{
for (const auto & elem : projection)
{
const std::string & name = elem.first;
const std::string & alias = elem.second;
const ColumnWithTypeAndName & column = sample_block.getByName(name);
if (!alias.empty() && !sample_block.has(alias))
sample_block.insert({column.column, column.type, alias});
}
break;
}
case REMOVE_COLUMN:
{
sample_block.erase(source_name);
break;
}
case ADD_COLUMN:
{
if (sample_block.has(result_name))
throw Exception("Column '" + result_name + "' already exists", ErrorCodes::DUPLICATE_COLUMN);
sample_block.insert(ColumnWithTypeAndName(added_column, result_type, result_name));
break;
}
case COPY_COLUMN:
{
const auto & source = sample_block.getByName(source_name);
result_type = source.type;
if (sample_block.has(result_name))
{
if (can_replace)
{
auto & result = sample_block.getByName(result_name);
result.type = result_type;
result.column = source.column;
}
else
throw Exception("Column '" + result_name + "' already exists", ErrorCodes::DUPLICATE_COLUMN);
}
else
sample_block.insert(ColumnWithTypeAndName(source.column, result_type, result_name));
break;
}
}
}
void ExpressionAction::execute(Block & block, bool dry_run) const
{
size_t input_rows_count = block.rows();
if (type == REMOVE_COLUMN || type == COPY_COLUMN)
if (!block.has(source_name))
throw Exception("Not found column '" + source_name + "'. There are columns: " + block.dumpNames(), ErrorCodes::NOT_FOUND_COLUMN_IN_BLOCK);
if (type == ADD_COLUMN || (type == COPY_COLUMN && !can_replace) || type == APPLY_FUNCTION)
if (block.has(result_name))
throw Exception("Column '" + result_name + "' already exists", ErrorCodes::DUPLICATE_COLUMN);
switch (type)
{
case APPLY_FUNCTION:
{
ColumnsWithTypeAndName arguments(argument_names.size());
for (size_t i = 0; i < argument_names.size(); ++i)
arguments[i] = block.getByName(argument_names[i]);
size_t num_columns_without_result = block.columns();
block.insert({ nullptr, result_type, result_name});
ProfileEvents::increment(ProfileEvents::FunctionExecute);
if (is_function_compiled)
ProfileEvents::increment(ProfileEvents::CompiledFunctionExecute);
block.getByPosition(num_columns_without_result).column = function->execute(arguments, result_type, input_rows_count, dry_run);
break;
}
case ARRAY_JOIN:
{
auto source = block.getByName(source_name);
block.erase(source_name);
source.column = source.column->convertToFullColumnIfConst();
const ColumnArray * array = typeid_cast<const ColumnArray *>(source.column.get());
if (!array)
throw Exception("ARRAY JOIN of not array: " + source_name, ErrorCodes::TYPE_MISMATCH);
for (auto & column : block)
column.column = column.column->replicate(array->getOffsets());
source.column = array->getDataPtr();
source.type = assert_cast<const DataTypeArray &>(*source.type).getNestedType();
source.name = result_name;
block.insert(std::move(source));
break;
}
case PROJECT:
{
Block new_block;
for (const auto & elem : projection)
{
const std::string & name = elem.first;
const std::string & alias = elem.second;
ColumnWithTypeAndName column = block.getByName(name);
if (!alias.empty())
column.name = alias;
new_block.insert(std::move(column));
}
block.swap(new_block);
break;
}
case ADD_ALIASES:
{
for (const auto & elem : projection)
{
const std::string & name = elem.first;
const std::string & alias = elem.second;
const ColumnWithTypeAndName & column = block.getByName(name);
if (!alias.empty() && !block.has(alias))
block.insert({column.column, column.type, alias});
}
break;
}
case REMOVE_COLUMN:
block.erase(source_name);
break;
case ADD_COLUMN:
block.insert({ added_column->cloneResized(input_rows_count), result_type, result_name });
break;
case COPY_COLUMN:
if (can_replace && block.has(result_name))
{
auto & result = block.getByName(result_name);
const auto & source = block.getByName(source_name);
result.type = source.type;
result.column = source.column;
}
else
{
const auto & source_column = block.getByName(source_name);
block.insert({source_column.column, source_column.type, result_name});
}
break;
}
}
std::string ExpressionAction::toString() const
{
std::stringstream ss;
switch (type)
{
case ADD_COLUMN:
ss << "ADD " << result_name << " "
<< (result_type ? result_type->getName() : "(no type)") << " "
<< (added_column ? added_column->getName() : "(no column)");
break;
case REMOVE_COLUMN:
ss << "REMOVE " << source_name;
break;
case COPY_COLUMN:
ss << "COPY " << result_name << " = " << source_name;
if (can_replace)
ss << " (can replace)";
break;
case APPLY_FUNCTION:
ss << "FUNCTION " << result_name << " " << (is_function_compiled ? "[compiled] " : "")
<< (result_type ? result_type->getName() : "(no type)") << " = "
<< (function_base ? function_base->getName() : "(no function)") << "(";
for (size_t i = 0; i < argument_names.size(); ++i)
{
if (i)
ss << ", ";
ss << argument_names[i];
}
ss << ")";
break;
case ARRAY_JOIN:
ss << "ARRAY JOIN " << source_name << " -> " << result_name;
break;
case PROJECT: [[fallthrough]];
case ADD_ALIASES:
ss << (type == PROJECT ? "PROJECT " : "ADD_ALIASES ");
for (size_t i = 0; i < projection.size(); ++i)
{
if (i)
ss << ", ";
ss << projection[i].first;
if (!projection[i].second.empty() && projection[i].second != projection[i].first)
ss << " AS " << projection[i].second;
}
break;
}
return ss.str();
}
ExpressionActions::ExpressionActions(const NamesAndTypesList & input_columns_, const Context & context_)
: input_columns(input_columns_), settings(context_.getSettingsRef())
{
for (const auto & input_elem : input_columns)
sample_block.insert(ColumnWithTypeAndName(nullptr, input_elem.type, input_elem.name));
#if USE_EMBEDDED_COMPILER
compilation_cache = context_.getCompiledExpressionCache();
#endif
}
/// For constant columns the columns themselves can be contained in `input_columns_`.
ExpressionActions::ExpressionActions(const ColumnsWithTypeAndName & input_columns_, const Context & context_)
: settings(context_.getSettingsRef())
{
for (const auto & input_elem : input_columns_)
{
input_columns.emplace_back(input_elem.name, input_elem.type);
sample_block.insert(input_elem);
}
#if USE_EMBEDDED_COMPILER
compilation_cache = context_.getCompiledExpressionCache();
#endif
}
ExpressionActions::~ExpressionActions() = default;
void ExpressionActions::checkLimits(Block & block) const
{
if (settings.max_temporary_columns && block.columns() > settings.max_temporary_columns)
throw Exception("Too many temporary columns: " + block.dumpNames()
+ ". Maximum: " + settings.max_temporary_columns.toString(),
ErrorCodes::TOO_MANY_TEMPORARY_COLUMNS);
if (settings.max_temporary_non_const_columns)
{
size_t non_const_columns = 0;
for (size_t i = 0, size = block.columns(); i < size; ++i)
if (block.safeGetByPosition(i).column && !isColumnConst(*block.safeGetByPosition(i).column))
++non_const_columns;
if (non_const_columns > settings.max_temporary_non_const_columns)
{
std::stringstream list_of_non_const_columns;
for (size_t i = 0, size = block.columns(); i < size; ++i)
if (block.safeGetByPosition(i).column && !isColumnConst(*block.safeGetByPosition(i).column))
list_of_non_const_columns << "\n" << block.safeGetByPosition(i).name;
throw Exception("Too many temporary non-const columns:" + list_of_non_const_columns.str()
+ ". Maximum: " + settings.max_temporary_non_const_columns.toString(),
ErrorCodes::TOO_MANY_TEMPORARY_NON_CONST_COLUMNS);
}
}
}
void ExpressionActions::addInput(const ColumnWithTypeAndName & column)
{
input_columns.emplace_back(column.name, column.type);
sample_block.insert(column);
}
void ExpressionActions::addInput(const NameAndTypePair & column)
{
addInput(ColumnWithTypeAndName(nullptr, column.type, column.name));
}
void ExpressionActions::add(const ExpressionAction & action, Names & out_new_columns)
{
addImpl(action, out_new_columns);
}
void ExpressionActions::add(const ExpressionAction & action)
{
Names new_names;
addImpl(action, new_names);
}
void ExpressionActions::addImpl(ExpressionAction action, Names & new_names)
{
if (!action.result_name.empty())
new_names.push_back(action.result_name);
/// Compiled functions are custom functions and they don't need building
if (action.type == ExpressionAction::APPLY_FUNCTION && !action.is_function_compiled)
{
if (sample_block.has(action.result_name))
throw Exception("Column '" + action.result_name + "' already exists", ErrorCodes::DUPLICATE_COLUMN);
ColumnsWithTypeAndName arguments(action.argument_names.size());
for (size_t i = 0; i < action.argument_names.size(); ++i)
{
if (!sample_block.has(action.argument_names[i]))
throw Exception("Unknown identifier: '" + action.argument_names[i] + "'", ErrorCodes::UNKNOWN_IDENTIFIER);
arguments[i] = sample_block.getByName(action.argument_names[i]);
}
if (!action.function_base)
{
action.function_base = action.function_builder->build(arguments);
action.result_type = action.function_base->getResultType();
}
}
if (action.type == ExpressionAction::ADD_ALIASES)
for (const auto & name_with_alias : action.projection)
new_names.emplace_back(name_with_alias.second);
action.prepare(sample_block, settings, names_not_for_constant_folding);
actions.push_back(action);
}
void ExpressionActions::prependProjectInput()
{
actions.insert(actions.begin(), ExpressionAction::project(getRequiredColumns()));
}
void ExpressionActions::execute(Block & block, bool dry_run) const
{
for (const auto & action : actions)
{
try
{
action.execute(block, dry_run);
checkLimits(block);
}
catch (Exception & e)
{
#if defined(MEMORY_SANITIZER)
const auto & msg = e.message();
if (__msan_test_shadow(msg.data(), msg.size()) != -1)
{
LOG_FATAL(&Poco::Logger::get("ExpressionActions"), "Poisoned exception message (msan): {}", e.getStackTraceString());
}
#endif
#if defined(ADDRESS_SANITIZER)
const auto & msg = e.message();
if (__asan_region_is_poisoned(const_cast<char *>(msg.data()), msg.size()))
{
LOG_FATAL(&Poco::Logger::get("ExpressionActions"), "Poisoned exception message (asan): {}", e.getStackTraceString());
}
#endif
e.addMessage(fmt::format("while executing '{}'", action.toString()));
throw;
}
}
}
bool ExpressionActions::hasArrayJoin() const
{
for (const auto & action : actions)
if (action.type == ExpressionAction::ARRAY_JOIN)
return true;
return false;
}
std::string ExpressionActions::getSmallestColumn(const NamesAndTypesList & columns)
{
std::optional<size_t> min_size;
String res;
for (const auto & column : columns)
{
/// @todo resolve evil constant
size_t size = column.type->haveMaximumSizeOfValue() ? column.type->getMaximumSizeOfValueInMemory() : 100;
if (!min_size || size < *min_size)
{
min_size = size;
res = column.name;
}
}
if (!min_size)
throw Exception("No available columns", ErrorCodes::LOGICAL_ERROR);
return res;
}
void ExpressionActions::finalize(const Names & output_columns)
{
NameSet final_columns;
for (const auto & name : output_columns)
{
if (!sample_block.has(name))
throw Exception("Unknown column: " + name + ", there are only columns "
+ sample_block.dumpNames(), ErrorCodes::UNKNOWN_IDENTIFIER);
final_columns.insert(name);
}
#if USE_EMBEDDED_COMPILER
/// This has to be done before removing redundant actions and inserting REMOVE_COLUMNs
/// because inlining may change dependency sets.
if (settings.compile_expressions)
compileFunctions(actions, output_columns, sample_block, compilation_cache, settings.min_count_to_compile_expression);
#endif
/// Which columns are needed to perform actions from the current to the last.
NameSet needed_columns = final_columns;
/// Which columns nobody will touch from the current action to the last.
NameSet unmodified_columns;
{
NamesAndTypesList sample_columns = sample_block.getNamesAndTypesList();
for (const auto & sample_column : sample_columns)
unmodified_columns.insert(sample_column.name);
}
/// Let's go from the end and maintain set of required columns at this stage.
/// We will throw out unnecessary actions, although usually they are absent by construction.
for (int i = static_cast<int>(actions.size()) - 1; i >= 0; --i)
{
ExpressionAction & action = actions[i];
Names in = action.getNeededColumns();
if (action.type == ExpressionAction::PROJECT)
{
needed_columns = NameSet(in.begin(), in.end());
unmodified_columns.clear();
}
else if (action.type == ExpressionAction::ADD_ALIASES)
{
needed_columns.insert(in.begin(), in.end());
for (auto & name_wit_alias : action.projection)
{
auto it = unmodified_columns.find(name_wit_alias.second);
if (it != unmodified_columns.end())
unmodified_columns.erase(it);
}
}
else if (action.type == ExpressionAction::ARRAY_JOIN)
{
/// We need source anyway, in order to calculate number of rows correctly.
needed_columns.insert(action.source_name);
unmodified_columns.erase(action.result_name);
needed_columns.erase(action.result_name);
/// Note: technically, if result of arrayJoin is not needed,
/// we may remove all the columns and loose the number of rows here.
/// However, I cannot imagine how it is possible.
/// For "big" ARRAY JOIN it could have happened in query like
/// SELECT count() FROM table ARRAY JOIN x
/// Now, "big" ARRAY JOIN is moved to separate pipeline step,
/// and arrayJoin(x) is an expression which result can't be lost.
}
else
{
std::string out = action.result_name;
if (!out.empty())
{
/// If the result is not used and there are no side effects, throw out the action.
if (!needed_columns.count(out) &&
(action.type == ExpressionAction::APPLY_FUNCTION
|| action.type == ExpressionAction::ADD_COLUMN
|| action.type == ExpressionAction::COPY_COLUMN))
{
actions.erase(actions.begin() + i);
if (unmodified_columns.count(out))
{
sample_block.erase(out);
unmodified_columns.erase(out);
}
continue;
}
unmodified_columns.erase(out);
needed_columns.erase(out);
/** If the function is a constant expression, then replace the action by adding a column-constant - result.
* That is, we perform constant folding.
*/
if (action.type == ExpressionAction::APPLY_FUNCTION && sample_block.has(out))
{
auto & result = sample_block.getByName(out);
if (result.column && names_not_for_constant_folding.count(result.name) == 0)
{
action.type = ExpressionAction::ADD_COLUMN;
action.result_type = result.type;
action.added_column = result.column;
action.function_builder = nullptr;
action.function_base = nullptr;
action.function = nullptr;
action.argument_names.clear();
in.clear();
}
}
}
needed_columns.insert(in.begin(), in.end());
}
}
/// 1) Sometimes we don't need any columns to perform actions and sometimes actions doesn't produce any columns as result.
/// But Block class doesn't store any information about structure itself, it uses information from column.
/// If we remove all columns from input or output block we will lose information about amount of rows in it.
/// To avoid this situation we always leaving one of the columns in required columns (input)
/// and output column. We choose that "redundant" column by size with help of getSmallestColumn.
///
/// 2) Sometimes we have to read data from different Storages to execute query.
/// For example in 'remote' function which requires to read data from local table (for example MergeTree) and
/// remote table (doesn't know anything about it).
///
/// If we have combination of two previous cases, our heuristic from (1) can choose absolutely different columns,
/// so generated streams with these actions will have different headers. To avoid this we additionally rename our "redundant" column
/// to DUMMY_COLUMN_NAME with help of COPY_COLUMN action and consequent remove of original column.
/// It doesn't affect any logic, but all streams will have same "redundant" column in header called "_dummy".
/// Also, it seems like we will always have same type (UInt8) of "redundant" column, but it's not obvious.
bool dummy_column_copied = false;
/// We will not throw out all the input columns, so as not to lose the number of rows in the block.
if (needed_columns.empty() && !input_columns.empty())
{
auto colname = getSmallestColumn(input_columns);
needed_columns.insert(colname);
actions.insert(actions.begin(), ExpressionAction::copyColumn(colname, DUMMY_COLUMN_NAME, true));
dummy_column_copied = true;
}
/// We will not leave the block empty so as not to lose the number of rows in it.
if (final_columns.empty() && !input_columns.empty())
{
auto colname = getSmallestColumn(input_columns);
final_columns.insert(DUMMY_COLUMN_NAME);
if (!dummy_column_copied) /// otherwise we already have this column
actions.insert(actions.begin(), ExpressionAction::copyColumn(colname, DUMMY_COLUMN_NAME, true));
}
for (NamesAndTypesList::iterator it = input_columns.begin(); it != input_columns.end();)
{
NamesAndTypesList::iterator it0 = it;
++it;
if (!needed_columns.count(it0->name))
{
if (unmodified_columns.count(it0->name))
sample_block.erase(it0->name);
input_columns.erase(it0);
}
}
/* std::cerr << "\n";
for (const auto & action : actions)
std::cerr << action.toString() << "\n";
std::cerr << "\n";*/
/// Deletes unnecessary temporary columns.
/// If the column after performing the function `refcount = 0`, it can be deleted.
std::map<String, int> columns_refcount;
for (const auto & name : final_columns)
++columns_refcount[name];
for (const auto & action : actions)
{
if (!action.source_name.empty())
++columns_refcount[action.source_name];
for (const auto & name : action.argument_names)
++columns_refcount[name];
for (const auto & name_alias : action.projection)
++columns_refcount[name_alias.first];
}
Actions new_actions;
new_actions.reserve(actions.size());
for (const auto & action : actions)
{
new_actions.push_back(action);
auto process = [&] (const String & name)
{
auto refcount = --columns_refcount[name];
if (refcount <= 0 && action.type != ExpressionAction::ARRAY_JOIN)
{
new_actions.push_back(ExpressionAction::removeColumn(name));
if (sample_block.has(name))
sample_block.erase(name);
}
};
if (!action.source_name.empty())
process(action.source_name);
for (const auto & name : action.argument_names)
process(name);
/// For `projection`, there is no reduction in `refcount`, because the `project` action replaces the names of the columns, in effect, already deleting them under the old names.
}
actions.swap(new_actions);
/* std::cerr << "\n";
for (const auto & action : actions)
std::cerr << action.toString() << "\n";
std::cerr << "\n";*/
optimizeArrayJoin();
checkLimits(sample_block);
}
std::string ExpressionActions::dumpActions() const
{
std::stringstream ss;
ss << "input:\n";
for (const auto & input_column : input_columns)
ss << input_column.name << " " << input_column.type->getName() << "\n";
ss << "\nactions:\n";
for (const auto & action : actions)
ss << action.toString() << '\n';
ss << "\noutput:\n";
NamesAndTypesList output_columns = sample_block.getNamesAndTypesList();
for (const auto & output_column : output_columns)
ss << output_column.name << " " << output_column.type->getName() << "\n";
return ss.str();
}
void ExpressionActions::optimizeArrayJoin()
{
const size_t none = actions.size();
size_t first_array_join = none;
/// Columns that need to be evaluated for arrayJoin.
/// Actions for adding them can not be moved to the left of the arrayJoin.
NameSet array_joined_columns;
/// Columns needed to evaluate arrayJoin or those that depend on it.
/// Actions to delete them can not be moved to the left of the arrayJoin.
NameSet array_join_dependencies;
for (size_t i = 0; i < actions.size(); ++i)
{
/// Do not move the action to the right of the projection (the more that they are not usually there).
if (actions[i].type == ExpressionAction::PROJECT)
break;
bool depends_on_array_join = false;
Names needed;
if (actions[i].type == ExpressionAction::ARRAY_JOIN)
{
depends_on_array_join = true;
needed = actions[i].getNeededColumns();
}
else
{
if (first_array_join == none)
continue;
needed = actions[i].getNeededColumns();
for (const auto & elem : needed)
{
if (array_joined_columns.count(elem))
{
depends_on_array_join = true;
break;
}
}
}
if (depends_on_array_join)
{
if (first_array_join == none)
first_array_join = i;
if (!actions[i].result_name.empty())
array_joined_columns.insert(actions[i].result_name);
array_join_dependencies.insert(needed.begin(), needed.end());
}
else
{
bool can_move = false;
if (actions[i].type == ExpressionAction::REMOVE_COLUMN)
{
/// If you delete a column that is not needed for arrayJoin (and those who depend on it), you can delete it before arrayJoin.
can_move = !array_join_dependencies.count(actions[i].source_name);
}
else
{
/// If the action does not delete the columns and does not depend on the result of arrayJoin, you can make it until arrayJoin.
can_move = true;
}
/// Move the current action to the position just before the first arrayJoin.
if (can_move)
{
/// Move the i-th element to the position `first_array_join`.
std::rotate(actions.begin() + first_array_join, actions.begin() + i, actions.begin() + i + 1);
++first_array_join;
}
}
}
}
ExpressionActionsPtr ExpressionActions::splitActionsBeforeArrayJoin(const NameSet & array_joined_columns)
{
/// Create new actions.
/// Copy from this because we don't have context.
/// TODO: remove context from constructor?
auto split_actions = std::make_shared<ExpressionActions>(*this);
split_actions->actions.clear();
split_actions->sample_block.clear();
split_actions->input_columns.clear();
/// Expected chain:
/// Expression (this) -> ArrayJoin (array_joined_columns) -> Expression (split_actions)
/// We are going to move as many actions as we can from this to split_actions.
/// We can move all inputs which are not depend on array_joined_columns
/// (with some exceptions to PROJECT and REMOVE_COLUMN
/// Use the same inputs for split_actions, except array_joined_columns.
for (const auto & input_column : input_columns)
{
if (array_joined_columns.count(input_column.name) == 0)
{
split_actions->input_columns.emplace_back(input_column);
split_actions->sample_block.insert(ColumnWithTypeAndName(nullptr, input_column.type, input_column.name));
}
}
/// Do not split action if input depends only on array joined columns.
if (split_actions->input_columns.empty())
return nullptr;
/// Actions which depend on ARRAY JOIN result.
NameSet array_join_dependent_columns = array_joined_columns;
/// Arguments of actions which depend on ARRAY JOIN result.
/// This columns can't be deleted in split_actions.
NameSet array_join_dependent_columns_arguments;
/// We create new_actions list for `this`. Current actions are moved to new_actions nor added to split_actions.
Actions new_actions;
for (const auto & action : actions)
{
/// Exception for PROJECT.
/// It removes columns, so it will remove split_actions output which may be needed for actions from `this`.
/// So, we replace it ADD_ALIASES.
/// Usually, PROJECT is added to begin of actions in order to remove unused output of prev actions.
/// We skip it now, but will prependProjectInput at the end.
if (action.type == ExpressionAction::PROJECT)
{
/// Each alias has separate dependencies, so we split this action into two parts.
NamesWithAliases split_aliases;
NamesWithAliases depend_aliases;
for (const auto & pair : action.projection)
{
/// Skip if is not alias.
if (pair.second.empty())
continue;
if (array_join_dependent_columns.count(pair.first))
{
array_join_dependent_columns.insert(pair.second);
depend_aliases.emplace_back(std::move(pair));
}
else
split_aliases.emplace_back(std::move(pair));
}
if (!split_aliases.empty())
split_actions->add(ExpressionAction::addAliases(split_aliases));
if (!depend_aliases.empty())
new_actions.emplace_back(ExpressionAction::addAliases(depend_aliases));
continue;
}
bool depends_on_array_join = false;
for (auto & column : action.getNeededColumns())
if (array_join_dependent_columns.count(column) != 0)
depends_on_array_join = true;
if (depends_on_array_join)
{
/// Add result of this action to array_join_dependent_columns too.
if (!action.result_name.empty())
array_join_dependent_columns.insert(action.result_name);
/// Add arguments of this action to array_join_dependent_columns_arguments.
auto needed = action.getNeededColumns();
array_join_dependent_columns_arguments.insert(needed.begin(), needed.end());
new_actions.emplace_back(action);
}
else if (action.type == ExpressionAction::REMOVE_COLUMN)
{
/// Exception for REMOVE_COLUMN.
/// We cannot move it to split_actions if any argument from `this` needed that column.
if (array_join_dependent_columns_arguments.count(action.source_name))
new_actions.emplace_back(action);
else
split_actions->add(action);
}
else
split_actions->add(action);
}
/// Return empty actions if nothing was separated. Keep `this` unchanged.
if (split_actions->getActions().empty())
return nullptr;
std::swap(actions, new_actions);
/// Collect inputs from ARRAY JOIN.
NamesAndTypesList inputs_from_array_join;
for (auto & column : input_columns)
if (array_joined_columns.count(column.name))
inputs_from_array_join.emplace_back(std::move(column));
/// Fix inputs for `this`.
/// It is output of split_actions + inputs from ARRAY JOIN.
input_columns = split_actions->getSampleBlock().getNamesAndTypesList();
input_columns.insert(input_columns.end(), inputs_from_array_join.begin(), inputs_from_array_join.end());
return split_actions;
}
bool ExpressionActions::checkColumnIsAlwaysFalse(const String & column_name) const
{
/// Check has column in (empty set).
String set_to_check;
for (auto it = actions.rbegin(); it != actions.rend(); ++it)
{
const auto & action = *it;
if (action.type == action.APPLY_FUNCTION && action.function_base)
{
auto name = action.function_base->getName();
if ((name == "in" || name == "globalIn")
&& action.result_name == column_name
&& action.argument_names.size() > 1)
{
set_to_check = action.argument_names[1];
break;
}
}
}
if (!set_to_check.empty())
{
for (const auto & action : actions)
{
if (action.type == action.ADD_COLUMN && action.result_name == set_to_check)
{
// Constant ColumnSet cannot be empty, so we only need to check non-constant ones.
if (const auto * column_set = checkAndGetColumn<const ColumnSet>(action.added_column.get()))
{
if (column_set->getData()->isCreated() && column_set->getData()->getTotalRowCount() == 0)
return true;
}
}
}
}
return false;
}
/// It is not important to calculate the hash of individual strings or their concatenation
UInt128 ExpressionAction::ActionHash::operator()(const ExpressionAction & action) const
{
SipHash hash;
hash.update(action.type);
hash.update(action.is_function_compiled);
switch (action.type)
{
case ADD_COLUMN:
hash.update(action.result_name);
if (action.result_type)
hash.update(action.result_type->getName());
if (action.added_column)
hash.update(action.added_column->getName());
break;
case REMOVE_COLUMN:
hash.update(action.source_name);
break;
case COPY_COLUMN:
hash.update(action.result_name);
hash.update(action.source_name);
break;
case APPLY_FUNCTION:
hash.update(action.result_name);
if (action.result_type)
hash.update(action.result_type->getName());
if (action.function_base)
{
hash.update(action.function_base->getName());
for (const auto & arg_type : action.function_base->getArgumentTypes())
hash.update(arg_type->getName());
}
for (const auto & arg_name : action.argument_names)
hash.update(arg_name);
break;
case ARRAY_JOIN:
hash.update(action.result_name);
hash.update(action.source_name);
break;
case PROJECT:
for (const auto & pair_of_strs : action.projection)
{
hash.update(pair_of_strs.first);
hash.update(pair_of_strs.second);
}
break;
case ADD_ALIASES:
break;
}
UInt128 result;
hash.get128(result.low, result.high);
return result;
}
bool ExpressionAction::operator==(const ExpressionAction & other) const
{
if (result_type != other.result_type)
{
if (result_type == nullptr || other.result_type == nullptr)
return false;
else if (!result_type->equals(*other.result_type))
return false;
}
if (function_base != other.function_base)
{
if (function_base == nullptr || other.function_base == nullptr)
return false;
else if (function_base->getName() != other.function_base->getName())
return false;
const auto & my_arg_types = function_base->getArgumentTypes();
const auto & other_arg_types = other.function_base->getArgumentTypes();
if (my_arg_types.size() != other_arg_types.size())
return false;
for (size_t i = 0; i < my_arg_types.size(); ++i)
if (!my_arg_types[i]->equals(*other_arg_types[i]))
return false;
}
if (added_column != other.added_column)
{
if (added_column == nullptr || other.added_column == nullptr)
return false;
else if (added_column->getName() != other.added_column->getName())
return false;
}
return source_name == other.source_name
&& result_name == other.result_name
&& argument_names == other.argument_names
&& TableJoin::sameJoin(table_join.get(), other.table_join.get())
&& projection == other.projection
&& is_function_compiled == other.is_function_compiled;
}
void ExpressionActionsChain::addStep()
{
if (steps.empty())
throw Exception("Cannot add action to empty ExpressionActionsChain", ErrorCodes::LOGICAL_ERROR);
if (auto * step = typeid_cast<ExpressionActionsStep *>(steps.back().get()))
{
if (!step->actions)
step->actions = step->actions_dag->buildExpressions(context);
}
ColumnsWithTypeAndName columns = steps.back()->getResultColumns();
steps.push_back(std::make_unique<ExpressionActionsStep>(std::make_shared<ActionsDAG>(columns)));
}
void ExpressionActionsChain::finalize()
{
/// Finalize all steps. Right to left to define unnecessary input columns.
for (int i = static_cast<int>(steps.size()) - 1; i >= 0; --i)
{
Names required_output = steps[i]->required_output;
std::unordered_map<String, size_t> required_output_indexes;
for (size_t j = 0; j < required_output.size(); ++j)
required_output_indexes[required_output[j]] = j;
auto & can_remove_required_output = steps[i]->can_remove_required_output;
if (i + 1 < static_cast<int>(steps.size()))
{
const NameSet & additional_input = steps[i + 1]->additional_input;
for (const auto & it : steps[i + 1]->getRequiredColumns())
{
if (additional_input.count(it.name) == 0)
{
auto iter = required_output_indexes.find(it.name);
if (iter == required_output_indexes.end())
required_output.push_back(it.name);
else if (!can_remove_required_output.empty())
can_remove_required_output[iter->second] = false;
}
}
}
steps[i]->finalize(required_output);
}
/// Adding the ejection of unnecessary columns to the beginning of each step.
for (size_t i = 1; i < steps.size(); ++i)
{
size_t columns_from_previous = steps[i - 1]->getResultColumns().size();
/// If unnecessary columns are formed at the output of the previous step, we'll add them to the beginning of this step.
/// Except when we drop all the columns and lose the number of rows in the block.
if (!steps[i]->getResultColumns().empty()
&& columns_from_previous > steps[i]->getRequiredColumns().size())
steps[i]->prependProjectInput();
}
}
std::string ExpressionActionsChain::dumpChain() const
{
std::stringstream ss;
for (size_t i = 0; i < steps.size(); ++i)
{
ss << "step " << i << "\n";
ss << "required output:\n";
for (const std::string & name : steps[i]->required_output)
ss << name << "\n";
ss << "\n" << steps[i]->dump() << "\n";
}
return ss.str();
}
ExpressionActionsChain::ArrayJoinStep::ArrayJoinStep(ArrayJoinActionPtr array_join_, ColumnsWithTypeAndName required_columns_)
: Step({})
, array_join(std::move(array_join_))
, result_columns(std::move(required_columns_))
{
for (auto & column : result_columns)
{
required_columns.emplace_back(NameAndTypePair(column.name, column.type));
if (array_join->columns.count(column.name) > 0)
{
const auto * array = typeid_cast<const DataTypeArray *>(column.type.get());
column.type = array->getNestedType();
/// Arrays are materialized
column.column = nullptr;
}
}
}
void ExpressionActionsChain::ArrayJoinStep::finalize(const Names & required_output_)
{
NamesAndTypesList new_required_columns;
ColumnsWithTypeAndName new_result_columns;
NameSet names(required_output_.begin(), required_output_.end());
for (const auto & column : result_columns)
{
if (array_join->columns.count(column.name) != 0 || names.count(column.name) != 0)
new_result_columns.emplace_back(column);
}
for (const auto & column : required_columns)
{
if (array_join->columns.count(column.name) != 0 || names.count(column.name) != 0)
new_required_columns.emplace_back(column);
}
std::swap(required_columns, new_required_columns);
std::swap(result_columns, new_result_columns);
}
ExpressionActionsChain::JoinStep::JoinStep(
std::shared_ptr<TableJoin> analyzed_join_,
JoinPtr join_,
ColumnsWithTypeAndName required_columns_)
: Step({})
, analyzed_join(std::move(analyzed_join_))
, join(std::move(join_))
, result_columns(std::move(required_columns_))
{
for (const auto & column : result_columns)
required_columns.emplace_back(column.name, column.type);
analyzed_join->addJoinedColumnsAndCorrectNullability(result_columns);
}
void ExpressionActionsChain::JoinStep::finalize(const Names & required_output_)
{
/// We need to update required and result columns by removing unused ones.
NamesAndTypesList new_required_columns;
ColumnsWithTypeAndName new_result_columns;
/// That's an input columns we need.
NameSet required_names(required_output_.begin(), required_output_.end());
for (const auto & name : analyzed_join->keyNamesLeft())
required_names.emplace(name);
for (const auto & column : required_columns)
{
if (required_names.count(column.name) != 0)
new_required_columns.emplace_back(column);
}
/// Result will also contain joined columns.
for (const auto & column : analyzed_join->columnsAddedByJoin())
required_names.emplace(column.name);
for (const auto & column : result_columns)
{
if (required_names.count(column.name) != 0)
new_result_columns.emplace_back(column);
}
std::swap(required_columns, new_required_columns);
std::swap(result_columns, new_result_columns);
}
ActionsDAGPtr & ExpressionActionsChain::Step::actions()
{
return typeid_cast<ExpressionActionsStep *>(this)->actions_dag;
}
const ActionsDAGPtr & ExpressionActionsChain::Step::actions() const
{
return typeid_cast<const ExpressionActionsStep *>(this)->actions_dag;
}
ExpressionActionsPtr ExpressionActionsChain::Step::getExpression() const
{
return typeid_cast<const ExpressionActionsStep *>(this)->actions;
}
ActionsDAG::ActionsDAG(const NamesAndTypesList & inputs)
{
for (const auto & input : inputs)
addInput(input.name, input.type);
}
ActionsDAG::ActionsDAG(const ColumnsWithTypeAndName & inputs)
{
for (const auto & input : inputs)
addInput(input);
}
ActionsDAG::Node & ActionsDAG::addNode(Node node, bool can_replace)
{
auto it = index.find(node.result_name);
if (it != index.end() && !can_replace)
throw Exception("Column '" + node.result_name + "' already exists", ErrorCodes::DUPLICATE_COLUMN);
auto & res = nodes.emplace_back(std::move(node));
if (it != index.end())
it->second->renaming_parent = &res;
index[res.result_name] = &res;
return res;
}
ActionsDAG::Node & ActionsDAG::getNode(const std::string & name)
{
auto it = index.find(name);
if (it == index.end())
throw Exception("Unknown identifier: '" + name + "'", ErrorCodes::UNKNOWN_IDENTIFIER);
return *it->second;
}
const ActionsDAG::Node & ActionsDAG::addInput(std::string name, DataTypePtr type)
{
Node node;
node.type = Type::INPUT;
node.result_type = std::move(type);
node.result_name = std::move(name);
return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addInput(ColumnWithTypeAndName column)
{
Node node;
node.type = Type::INPUT;
node.result_type = std::move(column.type);
node.result_name = std::move(column.name);
node.column = std::move(column.column);
return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addColumn(ColumnWithTypeAndName column)
{
if (!column.column)
throw Exception("Cannot add column " + column.name + " because it is nullptr", ErrorCodes::LOGICAL_ERROR);
Node node;
node.type = Type::COLUMN;
node.result_type = std::move(column.type);
node.result_name = std::move(column.name);
node.column = std::move(column.column);
return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addAlias(const std::string & name, std::string alias, bool can_replace)
{
auto & child = getNode(name);
Node node;
node.type = Type::ALIAS;
node.result_type = child.result_type;
node.result_name = std::move(alias);
node.column = child.column;
node.allow_constant_folding = child.allow_constant_folding;
node.children.emplace_back(&child);
return addNode(std::move(node), can_replace);
}
const ActionsDAG::Node & ActionsDAG::addArrayJoin(
const std::string & source_name, std::string result_name, std::string unique_column_name)
{
auto & child = getNode(source_name);
const DataTypeArray * array_type = typeid_cast<const DataTypeArray *>(child.result_type.get());
if (!array_type)
throw Exception("ARRAY JOIN requires array argument", ErrorCodes::TYPE_MISMATCH);
Node node;
node.type = Type::ARRAY_JOIN;
node.result_type = array_type->getNestedType();
node.result_name = std::move(result_name);
node.unique_column_name_for_array_join = std::move(unique_column_name);
node.children.emplace_back(&child);
return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addFunction(
const FunctionOverloadResolverPtr & function,
const Names & argument_names,
std::string result_name,
bool compile_expressions [[maybe_unused]])
{
size_t num_arguments = argument_names.size();
Node node;
node.type = Type::FUNCTION;
node.function_builder = function;
node.children.reserve(num_arguments);
bool all_const = true;
ColumnsWithTypeAndName arguments(num_arguments);
for (size_t i = 0; i < num_arguments; ++i)
{
auto & child = getNode(argument_names[i]);
node.children.emplace_back(&child);
node.allow_constant_folding = node.allow_constant_folding && child.allow_constant_folding;
ColumnWithTypeAndName argument;
argument.column = child.column;
argument.type = child.result_type;
if (!argument.column || !isColumnConst(*argument.column))
all_const = false;
arguments[i] = std::move(argument);
}
node.function_base = function->build(arguments);
node.result_type = node.function_base->getResultType();
node.function = node.function_base->prepare(arguments);
bool do_compile_expressions = false;
#if USE_EMBEDDED_COMPILER
do_compile_expressions = compile_expressions;
#endif
/// If all arguments are constants, and function is suitable to be executed in 'prepare' stage - execute function.
/// But if we compile expressions compiled version of this function maybe placed in cache,
/// so we don't want to unfold non deterministic functions
if (all_const && node.function_base->isSuitableForConstantFolding() && (!do_compile_expressions || node.function_base->isDeterministic()))
{
size_t num_rows = arguments.empty() ? 0 : arguments.front().column->size();
auto col = node.function->execute(arguments, node.result_type, num_rows, true);
/// If the result is not a constant, just in case, we will consider the result as unknown.
if (isColumnConst(*col))
{
/// All constant (literal) columns in block are added with size 1.
/// But if there was no columns in block before executing a function, the result has size 0.
/// Change the size to 1.
if (col->empty())
col = col->cloneResized(1);
node.column = std::move(col);
}
}
/// Some functions like ignore() or getTypeName() always return constant result even if arguments are not constant.
/// We can't do constant folding, but can specify in sample block that function result is constant to avoid
/// unnecessary materialization.
if (!node.column && node.function_base->isSuitableForConstantFolding())
{
if (auto col = node.function_base->getResultIfAlwaysReturnsConstantAndHasArguments(arguments))
{
node.column = std::move(col);
node.allow_constant_folding = false;
}
}
if (result_name.empty())
{
result_name = function->getName() + "(";
for (size_t i = 0; i < argument_names.size(); ++i)
{
if (i)
result_name += ", ";
result_name += argument_names[i];
}
result_name += ")";
}
node.result_name = std::move(result_name);
return addNode(std::move(node));
}
ColumnsWithTypeAndName ActionsDAG::getResultColumns() const
{
ColumnsWithTypeAndName result;
result.reserve(index.size());
for (const auto & node : nodes)
if (!node.renaming_parent)
result.emplace_back(node.column, node.result_type, node.result_name);
return result;
}
NamesAndTypesList ActionsDAG::getNamesAndTypesList() const
{
NamesAndTypesList result;
for (const auto & node : nodes)
if (!node.renaming_parent)
result.emplace_back(node.result_name, node.result_type);
return result;
}
Names ActionsDAG::getNames() const
{
Names names;
names.reserve(index.size());
for (const auto & node : nodes)
if (!node.renaming_parent)
names.emplace_back(node.result_name);
return names;
}
std::string ActionsDAG::dumpNames() const
{
WriteBufferFromOwnString out;
for (auto it = nodes.begin(); it != nodes.end(); ++it)
{
if (it != nodes.begin())
out << ", ";
out << it->result_name;
}
return out.str();
}
ExpressionActionsPtr ActionsDAG::buildExpressions(const Context & context)
{
struct Data
{
Node * node = nullptr;
size_t num_created_children = 0;
size_t num_expected_children = 0;
std::vector<Node *> parents;
Node * renamed_child = nullptr;
};
std::vector<Data> data(nodes.size());
std::unordered_map<Node *, size_t> reverse_index;
for (auto & node : nodes)
{
size_t id = reverse_index.size();
data[id].node = &node;
reverse_index[&node] = id;
}
std::queue<Node *> ready_nodes;
std::queue<Node *> ready_array_joins;
for (auto & node : nodes)
{
data[reverse_index[&node]].num_expected_children += node.children.size();
for (const auto & child : node.children)
data[reverse_index[child]].parents.emplace_back(&node);
if (node.renaming_parent)
{
auto & cur = data[reverse_index[node.renaming_parent]];
cur.renamed_child = &node;
cur.num_expected_children += 1;
}
}
for (auto & node : nodes)
{
if (node.children.empty() && data[reverse_index[&node]].renamed_child == nullptr)
ready_nodes.emplace(&node);
}
auto update_parent = [&](Node * parent)
{
auto & cur = data[reverse_index[parent]];
++cur.num_created_children;
if (cur.num_created_children == cur.num_expected_children)
{
auto & push_stack = parent->type == Type::ARRAY_JOIN ? ready_array_joins : ready_nodes;
push_stack.push(parent);
}
};
auto expressions = std::make_shared<ExpressionActions>(NamesAndTypesList(), context);
while (!ready_nodes.empty() || !ready_array_joins.empty())
{
auto & stack = ready_nodes.empty() ? ready_array_joins : ready_nodes;
Node * node = stack.front();
stack.pop();
Names argument_names;
for (const auto & child : node->children)
argument_names.emplace_back(child->result_name);
auto & cur = data[reverse_index[node]];
switch (node->type)
{
case Type::INPUT:
expressions->addInput({node->column, node->result_type, node->result_name});
break;
case Type::COLUMN:
expressions->add(ExpressionAction::addColumn({node->column, node->result_type, node->result_name}));
break;
case Type::ALIAS:
expressions->add(ExpressionAction::copyColumn(argument_names.at(0), node->result_name, cur.renamed_child != nullptr));
break;
case Type::ARRAY_JOIN:
/// Here we copy argument because arrayJoin removes source column.
/// It makes possible to remove source column before arrayJoin if it won't be needed anymore.
/// It could have been possible to implement arrayJoin which keeps source column,
/// but in this case it will always be replicated (as many arrays), which is expensive.
expressions->add(ExpressionAction::copyColumn(argument_names.at(0), node->unique_column_name_for_array_join));
expressions->add(ExpressionAction::arrayJoin(node->unique_column_name_for_array_join, node->result_name));
break;
case Type::FUNCTION:
{
ExpressionAction action;
action.type = ExpressionAction::APPLY_FUNCTION;
action.result_name = node->result_name;
action.result_type = node->result_type;
action.function_builder = node->function_builder;
action.function_base = node->function_base;
action.function = node->function;
action.argument_names = std::move(argument_names);
action.added_column = node->column;
expressions->add(action);
break;
}
}
for (const auto & parent : cur.parents)
update_parent(parent);
if (node->renaming_parent)
update_parent(node->renaming_parent);
}
return expressions;
}
}
Reference in New Issue View Git Blame Copy Permalink