ClickHouse/dbms/src/Functions/IFunction.cpp
2019-12-17 13:19:21 +03:00

641 lines
24 KiB
C++

#include <Functions/IFunctionAdaptors.h>
#include <Common/config.h>
#include <Common/typeid_cast.h>
#include <Common/assert_cast.h>
#include <Common/LRUCache.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnNullable.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnTuple.h>
#include <Columns/ColumnLowCardinality.h>
#include <DataTypes/DataTypeNothing.h>
#include <DataTypes/DataTypeNullable.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/Native.h>
#include <DataTypes/DataTypeLowCardinality.h>
#include <DataTypes/getLeastSupertype.h>
#include <Functions/FunctionHelpers.h>
#include <Interpreters/ExpressionActions.h>
#include <IO/WriteHelpers.h>
#include <ext/range.h>
#include <ext/collection_cast.h>
#include <cstdlib>
#include <memory>
#include <optional>
#if USE_EMBEDDED_COMPILER
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#include <llvm/IR/IRBuilder.h>
#pragma GCC diagnostic pop
#endif
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int ILLEGAL_COLUMN;
}
/// Cache for functions result if it was executed on low cardinality column.
/// It's LRUCache which stores function result executed on dictionary and index mapping.
/// It's expected that cache_size is a number of reading streams (so, will store single cached value per thread).
class ExecutableFunctionLowCardinalityResultCache
{
public:
/// Will assume that dictionaries with same hash has the same keys.
/// Just in case, check that they have also the same size.
struct DictionaryKey
{
UInt128 hash;
UInt64 size;
bool operator== (const DictionaryKey & other) const { return hash == other.hash && size == other.size; }
};
struct DictionaryKeyHash
{
size_t operator()(const DictionaryKey & key) const
{
SipHash hash;
hash.update(key.hash.low);
hash.update(key.hash.high);
hash.update(key.size);
return hash.get64();
}
};
struct CachedValues
{
/// Store ptr to dictionary to be sure it won't be deleted.
ColumnPtr dictionary_holder;
ColumnUniquePtr function_result;
/// Remap positions. new_pos = index_mapping->index(old_pos);
ColumnPtr index_mapping;
};
using CachedValuesPtr = std::shared_ptr<CachedValues>;
explicit ExecutableFunctionLowCardinalityResultCache(size_t cache_size) : cache(cache_size) {}
CachedValuesPtr get(const DictionaryKey & key) { return cache.get(key); }
void set(const DictionaryKey & key, const CachedValuesPtr & mapped) { cache.set(key, mapped); }
CachedValuesPtr getOrSet(const DictionaryKey & key, const CachedValuesPtr & mapped)
{
return cache.getOrSet(key, [&]() { return mapped; }).first;
}
private:
using Cache = LRUCache<DictionaryKey, CachedValues, DictionaryKeyHash>;
Cache cache;
};
void ExecutableFunctionAdaptor::createLowCardinalityResultCache(size_t cache_size)
{
if (!low_cardinality_result_cache)
low_cardinality_result_cache = std::make_shared<ExecutableFunctionLowCardinalityResultCache>(cache_size);
}
ColumnPtr wrapInNullable(const ColumnPtr & src, const Block & block, const ColumnNumbers & args, size_t result, size_t input_rows_count)
{
ColumnPtr result_null_map_column;
/// If result is already nullable.
ColumnPtr src_not_nullable = src;
if (src->onlyNull())
return src;
else if (auto * nullable = checkAndGetColumn<ColumnNullable>(*src))
{
src_not_nullable = nullable->getNestedColumnPtr();
result_null_map_column = nullable->getNullMapColumnPtr();
}
for (const auto & arg : args)
{
const ColumnWithTypeAndName & elem = block.getByPosition(arg);
if (!elem.type->isNullable())
continue;
/// Const Nullable that are NULL.
if (elem.column->onlyNull())
{
auto result_type = block.getByPosition(result).type;
assert(result_type->isNullable());
return result_type->createColumnConstWithDefaultValue(input_rows_count);
}
if (isColumnConst(*elem.column))
continue;
if (auto * nullable = checkAndGetColumn<ColumnNullable>(*elem.column))
{
const ColumnPtr & null_map_column = nullable->getNullMapColumnPtr();
if (!result_null_map_column)
{
result_null_map_column = null_map_column;
}
else
{
MutableColumnPtr mutable_result_null_map_column = (*std::move(result_null_map_column)).mutate();
NullMap & result_null_map = assert_cast<ColumnUInt8 &>(*mutable_result_null_map_column).getData();
const NullMap & src_null_map = assert_cast<const ColumnUInt8 &>(*null_map_column).getData();
for (size_t i = 0, size = result_null_map.size(); i < size; ++i)
if (src_null_map[i])
result_null_map[i] = 1;
result_null_map_column = std::move(mutable_result_null_map_column);
}
}
}
if (!result_null_map_column)
return makeNullable(src);
return ColumnNullable::create(src_not_nullable->convertToFullColumnIfConst(), result_null_map_column);
}
namespace
{
struct NullPresence
{
bool has_nullable = false;
bool has_null_constant = false;
};
NullPresence getNullPresense(const Block & block, const ColumnNumbers & args)
{
NullPresence res;
for (const auto & arg : args)
{
const auto & elem = block.getByPosition(arg);
if (!res.has_nullable)
res.has_nullable = elem.type->isNullable();
if (!res.has_null_constant)
res.has_null_constant = elem.type->onlyNull();
}
return res;
}
NullPresence getNullPresense(const ColumnsWithTypeAndName & args)
{
NullPresence res;
for (const auto & elem : args)
{
if (!res.has_nullable)
res.has_nullable = elem.type->isNullable();
if (!res.has_null_constant)
res.has_null_constant = elem.type->onlyNull();
}
return res;
}
bool allArgumentsAreConstants(const Block & block, const ColumnNumbers & args)
{
for (auto arg : args)
if (!isColumnConst(*block.getByPosition(arg).column))
return false;
return true;
}
}
bool ExecutableFunctionAdaptor::defaultImplementationForConstantArguments(
Block & block, const ColumnNumbers & args, size_t result, size_t input_rows_count, bool dry_run)
{
ColumnNumbers arguments_to_remain_constants = impl->getArgumentsThatAreAlwaysConstant();
/// Check that these arguments are really constant.
for (auto arg_num : arguments_to_remain_constants)
if (arg_num < args.size() && !isColumnConst(*block.getByPosition(args[arg_num]).column))
throw Exception("Argument at index " + toString(arg_num) + " for function " + getName() + " must be constant", ErrorCodes::ILLEGAL_COLUMN);
if (args.empty() || !impl->useDefaultImplementationForConstants() || !allArgumentsAreConstants(block, args))
return false;
Block temporary_block;
bool have_converted_columns = false;
size_t arguments_size = args.size();
for (size_t arg_num = 0; arg_num < arguments_size; ++arg_num)
{
const ColumnWithTypeAndName & column = block.getByPosition(args[arg_num]);
if (arguments_to_remain_constants.end() != std::find(arguments_to_remain_constants.begin(), arguments_to_remain_constants.end(), arg_num))
{
temporary_block.insert({column.column->cloneResized(1), column.type, column.name});
}
else
{
have_converted_columns = true;
temporary_block.insert({ assert_cast<const ColumnConst *>(column.column.get())->getDataColumnPtr(), column.type, column.name });
}
}
/** When using default implementation for constants, the function requires at least one argument
* not in "arguments_to_remain_constants" set. Otherwise we get infinite recursion.
*/
if (!have_converted_columns)
throw Exception("Number of arguments for function " + getName() + " doesn't match: the function requires more arguments",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
temporary_block.insert(block.getByPosition(result));
ColumnNumbers temporary_argument_numbers(arguments_size);
for (size_t i = 0; i < arguments_size; ++i)
temporary_argument_numbers[i] = i;
executeWithoutLowCardinalityColumns(temporary_block, temporary_argument_numbers, arguments_size, temporary_block.rows(), dry_run);
ColumnPtr result_column;
/// extremely rare case, when we have function with completely const arguments
/// but some of them produced by non isDeterministic function
if (temporary_block.getByPosition(arguments_size).column->size() > 1)
result_column = temporary_block.getByPosition(arguments_size).column->cloneResized(1);
else
result_column = temporary_block.getByPosition(arguments_size).column;
block.getByPosition(result).column = ColumnConst::create(result_column, input_rows_count);
return true;
}
bool ExecutableFunctionAdaptor::defaultImplementationForNulls(
Block & block, const ColumnNumbers & args, size_t result, size_t input_rows_count, bool dry_run)
{
if (args.empty() || !impl->useDefaultImplementationForNulls())
return false;
NullPresence null_presence = getNullPresense(block, args);
if (null_presence.has_null_constant)
{
auto & result_column = block.getByPosition(result).column;
auto result_type = block.getByPosition(result).type;
// Default implementation for nulls returns null result for null arguments,
// so the result type must be nullable.
assert(result_type->isNullable());
result_column = result_type->createColumnConstWithDefaultValue(input_rows_count);
return true;
}
if (null_presence.has_nullable)
{
Block temporary_block = createBlockWithNestedColumns(block, args, result);
executeWithoutLowCardinalityColumns(temporary_block, args, result, temporary_block.rows(), dry_run);
block.getByPosition(result).column = wrapInNullable(temporary_block.getByPosition(result).column, block, args,
result, input_rows_count);
return true;
}
return false;
}
void ExecutableFunctionAdaptor::executeWithoutLowCardinalityColumns(
Block & block, const ColumnNumbers & args, size_t result, size_t input_rows_count, bool dry_run)
{
if (defaultImplementationForConstantArguments(block, args, result, input_rows_count, dry_run))
return;
if (defaultImplementationForNulls(block, args, result, input_rows_count, dry_run))
return;
if (dry_run)
impl->executeDryRun(block, args, result, input_rows_count);
else
impl->execute(block, args, result, input_rows_count);
}
static const ColumnLowCardinality * findLowCardinalityArgument(const Block & block, const ColumnNumbers & args)
{
const ColumnLowCardinality * result_column = nullptr;
for (auto arg : args)
{
const ColumnWithTypeAndName & column = block.getByPosition(arg);
if (auto * low_cardinality_column = checkAndGetColumn<ColumnLowCardinality>(column.column.get()))
{
if (result_column)
throw Exception("Expected single dictionary argument for function.", ErrorCodes::LOGICAL_ERROR);
result_column = low_cardinality_column;
}
}
return result_column;
}
static ColumnPtr replaceLowCardinalityColumnsByNestedAndGetDictionaryIndexes(
Block & block, const ColumnNumbers & args, bool can_be_executed_on_default_arguments, size_t input_rows_count)
{
size_t num_rows = input_rows_count;
ColumnPtr indexes;
/// Find first LowCardinality column and replace it to nested dictionary.
for (auto arg : args)
{
ColumnWithTypeAndName & column = block.getByPosition(arg);
if (auto * low_cardinality_column = checkAndGetColumn<ColumnLowCardinality>(column.column.get()))
{
/// Single LowCardinality column is supported now.
if (indexes)
throw Exception("Expected single dictionary argument for function.", ErrorCodes::LOGICAL_ERROR);
auto * low_cardinality_type = checkAndGetDataType<DataTypeLowCardinality>(column.type.get());
if (!low_cardinality_type)
throw Exception("Incompatible type for low cardinality column: " + column.type->getName(),
ErrorCodes::LOGICAL_ERROR);
if (can_be_executed_on_default_arguments)
{
/// Normal case, when function can be executed on values's default.
column.column = low_cardinality_column->getDictionary().getNestedColumn();
indexes = low_cardinality_column->getIndexesPtr();
}
else
{
/// Special case when default value can't be used. Example: 1 % LowCardinality(Int).
/// LowCardinality always contains default, so 1 % 0 will throw exception in normal case.
auto dict_encoded = low_cardinality_column->getMinimalDictionaryEncodedColumn(0, low_cardinality_column->size());
column.column = dict_encoded.dictionary;
indexes = dict_encoded.indexes;
}
num_rows = column.column->size();
column.type = low_cardinality_type->getDictionaryType();
}
}
/// Change size of constants.
for (auto arg : args)
{
ColumnWithTypeAndName & column = block.getByPosition(arg);
if (auto * column_const = checkAndGetColumn<ColumnConst>(column.column.get()))
{
column.column = column_const->removeLowCardinality()->cloneResized(num_rows);
column.type = removeLowCardinality(column.type);
}
}
#ifndef NDEBUG
block.checkNumberOfRows(true);
#endif
return indexes;
}
static void convertLowCardinalityColumnsToFull(Block & block, const ColumnNumbers & args)
{
for (auto arg : args)
{
ColumnWithTypeAndName & column = block.getByPosition(arg);
column.column = recursiveRemoveLowCardinality(column.column);
column.type = recursiveRemoveLowCardinality(column.type);
}
}
void ExecutableFunctionAdaptor::execute(Block & block, const ColumnNumbers & args, size_t result, size_t input_rows_count, bool dry_run)
{
if (impl->useDefaultImplementationForLowCardinalityColumns())
{
auto & res = block.safeGetByPosition(result);
Block block_without_low_cardinality = block.cloneWithoutColumns();
for (auto arg : args)
block_without_low_cardinality.safeGetByPosition(arg).column = block.safeGetByPosition(arg).column;
if (auto * res_low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(res.type.get()))
{
const auto * low_cardinality_column = findLowCardinalityArgument(block, args);
bool can_be_executed_on_default_arguments = impl->canBeExecutedOnDefaultArguments();
bool use_cache = low_cardinality_result_cache && can_be_executed_on_default_arguments
&& low_cardinality_column && low_cardinality_column->isSharedDictionary();
ExecutableFunctionLowCardinalityResultCache::DictionaryKey key;
if (use_cache)
{
const auto & dictionary = low_cardinality_column->getDictionary();
key = {dictionary.getHash(), dictionary.size()};
auto cached_values = low_cardinality_result_cache->get(key);
if (cached_values)
{
auto indexes = cached_values->index_mapping->index(low_cardinality_column->getIndexes(), 0);
res.column = ColumnLowCardinality::create(cached_values->function_result, indexes, true);
return;
}
}
block_without_low_cardinality.safeGetByPosition(result).type = res_low_cardinality_type->getDictionaryType();
ColumnPtr indexes = replaceLowCardinalityColumnsByNestedAndGetDictionaryIndexes(
block_without_low_cardinality, args, can_be_executed_on_default_arguments, input_rows_count);
executeWithoutLowCardinalityColumns(block_without_low_cardinality, args, result, block_without_low_cardinality.rows(), dry_run);
auto keys = block_without_low_cardinality.safeGetByPosition(result).column->convertToFullColumnIfConst();
auto res_mut_dictionary = DataTypeLowCardinality::createColumnUnique(*res_low_cardinality_type->getDictionaryType());
ColumnPtr res_indexes = res_mut_dictionary->uniqueInsertRangeFrom(*keys, 0, keys->size());
ColumnUniquePtr res_dictionary = std::move(res_mut_dictionary);
if (indexes)
{
if (use_cache)
{
auto cache_values = std::make_shared<ExecutableFunctionLowCardinalityResultCache::CachedValues>();
cache_values->dictionary_holder = low_cardinality_column->getDictionaryPtr();
cache_values->function_result = res_dictionary;
cache_values->index_mapping = res_indexes;
cache_values = low_cardinality_result_cache->getOrSet(key, cache_values);
res_dictionary = cache_values->function_result;
res_indexes = cache_values->index_mapping;
}
res.column = ColumnLowCardinality::create(res_dictionary, res_indexes->index(*indexes, 0), use_cache);
}
else
{
res.column = ColumnLowCardinality::create(res_dictionary, res_indexes);
}
}
else
{
convertLowCardinalityColumnsToFull(block_without_low_cardinality, args);
executeWithoutLowCardinalityColumns(block_without_low_cardinality, args, result, input_rows_count, dry_run);
res.column = block_without_low_cardinality.safeGetByPosition(result).column;
}
}
else
executeWithoutLowCardinalityColumns(block, args, result, input_rows_count, dry_run);
}
void FunctionOverloadResolverAdaptor::checkNumberOfArguments(size_t number_of_arguments) const
{
if (isVariadic())
return;
size_t expected_number_of_arguments = getNumberOfArguments();
if (number_of_arguments != expected_number_of_arguments)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
+ toString(number_of_arguments) + ", should be " + toString(expected_number_of_arguments),
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
}
DataTypePtr FunctionOverloadResolverAdaptor::getReturnTypeWithoutLowCardinality(const ColumnsWithTypeAndName & arguments) const
{
checkNumberOfArguments(arguments.size());
if (!arguments.empty() && impl->useDefaultImplementationForNulls())
{
NullPresence null_presence = getNullPresense(arguments);
if (null_presence.has_null_constant)
{
return makeNullable(std::make_shared<DataTypeNothing>());
}
if (null_presence.has_nullable)
{
Block nested_block = createBlockWithNestedColumns(Block(arguments), ext::collection_cast<ColumnNumbers>(ext::range(0, arguments.size())));
auto return_type = impl->getReturnType(ColumnsWithTypeAndName(nested_block.begin(), nested_block.end()));
return makeNullable(return_type);
}
}
return impl->getReturnType(arguments);
}
#if USE_EMBEDDED_COMPILER
static std::optional<DataTypes> removeNullables(const DataTypes & types)
{
for (const auto & type : types)
{
if (!typeid_cast<const DataTypeNullable *>(type.get()))
continue;
DataTypes filtered;
for (const auto & sub_type : types)
filtered.emplace_back(removeNullable(sub_type));
return filtered;
}
return {};
}
bool IFunction::isCompilable(const DataTypes & arguments) const
{
if (useDefaultImplementationForNulls())
if (auto denulled = removeNullables(arguments))
return isCompilableImpl(*denulled);
return isCompilableImpl(arguments);
}
llvm::Value * IFunction::compile(llvm::IRBuilderBase & builder, const DataTypes & arguments, ValuePlaceholders values) const
{
if (useDefaultImplementationForNulls())
{
if (auto denulled = removeNullables(arguments))
{
/// FIXME: when only one column is nullable, this can actually be slower than the non-jitted version
/// because this involves copying the null map while `wrapInNullable` reuses it.
auto & b = static_cast<llvm::IRBuilder<> &>(builder);
auto * fail = llvm::BasicBlock::Create(b.GetInsertBlock()->getContext(), "", b.GetInsertBlock()->getParent());
auto * join = llvm::BasicBlock::Create(b.GetInsertBlock()->getContext(), "", b.GetInsertBlock()->getParent());
auto * zero = llvm::Constant::getNullValue(toNativeType(b, makeNullable(getReturnTypeImpl(*denulled))));
for (size_t i = 0; i < arguments.size(); i++)
{
if (!arguments[i]->isNullable())
continue;
/// Would be nice to evaluate all this lazily, but that'd change semantics: if only unevaluated
/// arguments happen to contain NULLs, the return value would not be NULL, though it should be.
auto * value = values[i]();
auto * ok = llvm::BasicBlock::Create(b.GetInsertBlock()->getContext(), "", b.GetInsertBlock()->getParent());
b.CreateCondBr(b.CreateExtractValue(value, {1}), fail, ok);
b.SetInsertPoint(ok);
values[i] = [value = b.CreateExtractValue(value, {0})]() { return value; };
}
auto * result = b.CreateInsertValue(zero, compileImpl(builder, *denulled, std::move(values)), {0});
auto * result_block = b.GetInsertBlock();
b.CreateBr(join);
b.SetInsertPoint(fail);
auto * null = b.CreateInsertValue(zero, b.getTrue(), {1});
b.CreateBr(join);
b.SetInsertPoint(join);
auto * phi = b.CreatePHI(result->getType(), 2);
phi->addIncoming(result, result_block);
phi->addIncoming(null, fail);
return phi;
}
}
return compileImpl(builder, arguments, std::move(values));
}
#endif
DataTypePtr FunctionOverloadResolverAdaptor::getReturnType(const ColumnsWithTypeAndName & arguments) const
{
if (impl->useDefaultImplementationForLowCardinalityColumns())
{
bool has_low_cardinality = false;
size_t num_full_low_cardinality_columns = 0;
size_t num_full_ordinary_columns = 0;
ColumnsWithTypeAndName args_without_low_cardinality(arguments);
for (ColumnWithTypeAndName & arg : args_without_low_cardinality)
{
bool is_const = arg.column && isColumnConst(*arg.column);
if (is_const)
arg.column = assert_cast<const ColumnConst &>(*arg.column).removeLowCardinality();
if (auto * low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(arg.type.get()))
{
arg.type = low_cardinality_type->getDictionaryType();
has_low_cardinality = true;
if (!is_const)
++num_full_low_cardinality_columns;
}
else if (!is_const)
++num_full_ordinary_columns;
}
for (auto & arg : args_without_low_cardinality)
{
arg.column = recursiveRemoveLowCardinality(arg.column);
arg.type = recursiveRemoveLowCardinality(arg.type);
}
auto type_without_low_cardinality = getReturnTypeWithoutLowCardinality(args_without_low_cardinality);
if (impl->canBeExecutedOnLowCardinalityDictionary() && has_low_cardinality
&& num_full_low_cardinality_columns <= 1 && num_full_ordinary_columns == 0
&& type_without_low_cardinality->canBeInsideLowCardinality())
return std::make_shared<DataTypeLowCardinality>(type_without_low_cardinality);
else
return type_without_low_cardinality;
}
return getReturnTypeWithoutLowCardinality(arguments);
}
}