ClickHouse/src/Interpreters/sortBlock.cpp
2023-06-19 13:02:35 +03:00

338 lines
10 KiB
C++

#include <Interpreters/sortBlock.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnNullable.h>
#include <Columns/ColumnTuple.h>
#include <Functions/FunctionHelpers.h>
#ifdef __SSE2__
#include <emmintrin.h>
#endif
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_COLLATION;
}
/// Column with description for sort
struct ColumnWithSortDescription
{
const IColumn * column = nullptr;
SortColumnDescription description;
/// It means, that this column is ColumnConst
bool column_const = false;
};
using ColumnsWithSortDescriptions = std::vector<ColumnWithSortDescription>;
namespace
{
inline bool isCollationRequired(const SortColumnDescription & description)
{
return description.collator != nullptr;
}
template <bool check_collation>
struct PartialSortingLessImpl
{
const ColumnsWithSortDescriptions & columns;
explicit PartialSortingLessImpl(const ColumnsWithSortDescriptions & columns_) : columns(columns_) { }
ALWAYS_INLINE int compare(size_t lhs, size_t rhs) const
{
int res = 0;
for (const auto & elem : columns)
{
if (elem.column_const)
{
continue;
}
if constexpr (check_collation)
{
if (isCollationRequired(elem.description))
{
res = elem.column->compareAtWithCollation(lhs, rhs, *elem.column, elem.description.nulls_direction, *elem.description.collator);
}
else
{
res = elem.column->compareAt(lhs, rhs, *elem.column, elem.description.nulls_direction);
}
}
else
{
res = elem.column->compareAt(lhs, rhs, *elem.column, elem.description.nulls_direction);
}
res *= elem.description.direction;
if (res != 0)
break;
}
return res;
}
ALWAYS_INLINE bool operator()(size_t lhs, size_t rhs) const
{
int res = compare(lhs, rhs);
return res < 0;
}
};
using PartialSortingLess = PartialSortingLessImpl<false>;
using PartialSortingLessWithCollation = PartialSortingLessImpl<true>;
ColumnsWithSortDescriptions getColumnsWithSortDescription(const Block & block, const SortDescription & description)
{
size_t size = description.size();
ColumnsWithSortDescriptions result;
result.reserve(size);
for (size_t i = 0; i < size; ++i)
{
const auto & sort_column_description = description[i];
const IColumn * column = block.getByName(sort_column_description.column_name).column.get();
if (isCollationRequired(sort_column_description))
{
if (!column->isCollationSupported())
throw Exception(ErrorCodes::BAD_COLLATION, "Collations could be specified only for String, LowCardinality(String), "
"Nullable(String) or for Array or Tuple, containing them.");
}
result.emplace_back(ColumnWithSortDescription{column, sort_column_description, isColumnConst(*column)});
}
return result;
}
void getBlockSortPermutationImpl(const Block & block, const SortDescription & description, IColumn::PermutationSortStability stability, UInt64 limit, IColumn::Permutation & permutation)
{
if (!block)
return;
ColumnsWithSortDescriptions columns_with_sort_descriptions = getColumnsWithSortDescription(block, description);
bool all_const = true;
for (const auto & column : columns_with_sort_descriptions)
{
if (!column.column_const)
{
all_const = false;
break;
}
}
if (unlikely(all_const))
return;
/// If only one column to sort by
if (columns_with_sort_descriptions.size() == 1)
{
auto & column_with_sort_description = columns_with_sort_descriptions[0];
IColumn::PermutationSortDirection direction = column_with_sort_description.description.direction == -1 ? IColumn::PermutationSortDirection::Descending : IColumn::PermutationSortDirection::Ascending;
int nan_direction_hint = column_with_sort_description.description.nulls_direction;
const auto & column = column_with_sort_description.column;
if (isCollationRequired(column_with_sort_description.description))
column->getPermutationWithCollation(
*column_with_sort_description.description.collator, direction, stability, limit, nan_direction_hint, permutation);
else
column->getPermutation(direction, stability, limit, nan_direction_hint, permutation);
}
else
{
size_t size = block.rows();
permutation.resize(size);
for (size_t i = 0; i < size; ++i)
permutation[i] = i;
if (limit >= size)
limit = 0;
EqualRanges ranges;
ranges.emplace_back(0, permutation.size());
for (const auto & column_with_sort_description : columns_with_sort_descriptions)
{
while (!ranges.empty() && limit && limit <= ranges.back().first)
ranges.pop_back();
if (ranges.empty())
break;
if (column_with_sort_description.column_const)
continue;
bool is_collation_required = isCollationRequired(column_with_sort_description.description);
IColumn::PermutationSortDirection direction = column_with_sort_description.description.direction == -1 ? IColumn::PermutationSortDirection::Descending : IColumn::PermutationSortDirection::Ascending;
int nan_direction_hint = column_with_sort_description.description.nulls_direction;
const auto & column = column_with_sort_description.column;
if (is_collation_required)
{
column->updatePermutationWithCollation(
*column_with_sort_description.description.collator, direction, stability, limit, nan_direction_hint, permutation, ranges);
}
else
{
column->updatePermutation(direction, stability, limit, nan_direction_hint, permutation, ranges);
}
}
}
}
bool isIdentityPermutation(const IColumn::Permutation & permutation, size_t limit)
{
static_assert(sizeof(permutation[0]) == sizeof(UInt64), "Invalid permutation value size");
size_t permutation_size = permutation.size();
size_t size = limit == 0 ? permutation_size : std::min(limit, permutation_size);
if (size == 0)
return true;
if (permutation[0] != 0)
return false;
size_t i = 0;
#if defined(__SSE2__)
if (size >= 8)
{
static constexpr UInt64 compare_all_elements_equal_mask = (1UL << 16) - 1;
__m128i permutation_add_vector = { 8, 8 };
__m128i permutation_compare_values_vectors[4] { { 0, 1 }, { 2, 3 }, { 4, 5 }, { 6, 7 } };
const size_t * permutation_data = permutation.data();
static constexpr size_t unroll_count = 8;
size_t size_unrolled = (size / unroll_count) * unroll_count;
for (; i < size_unrolled; i += 8)
{
UInt64 permutation_equals_vector_mask = compare_all_elements_equal_mask;
for (size_t j = 0; j < 4; ++j)
{
__m128i permutation_data_vector = _mm_loadu_si128(reinterpret_cast<const __m128i *>(permutation_data + i + j * 2));
__m128i permutation_equals_vector = _mm_cmpeq_epi8(permutation_data_vector, permutation_compare_values_vectors[j]);
permutation_compare_values_vectors[j] = _mm_add_epi64(permutation_compare_values_vectors[j], permutation_add_vector);
permutation_equals_vector_mask &= _mm_movemask_epi8(permutation_equals_vector);
}
if (permutation_equals_vector_mask != compare_all_elements_equal_mask)
return false;
}
}
#endif
i = std::max(i, static_cast<size_t>(1));
for (; i < size; ++i)
if (permutation[i] != (permutation[i - 1] + 1))
return false;
return true;
}
template <typename Comparator>
bool isAlreadySortedImpl(size_t rows, Comparator compare)
{
/** If the rows are not too few, then let's make a quick attempt to verify that the block is not sorted.
* Constants - at random.
*/
static constexpr size_t num_rows_to_try = 10;
if (rows > num_rows_to_try * 5)
{
for (size_t i = 1; i < num_rows_to_try; ++i)
{
size_t prev_position = rows * (i - 1) / num_rows_to_try;
size_t curr_position = rows * i / num_rows_to_try;
if (compare(curr_position, prev_position))
return false;
}
}
for (size_t i = 1; i < rows; ++i)
if (compare(i, i - 1))
return false;
return true;
}
}
void sortBlock(Block & block, const SortDescription & description, UInt64 limit)
{
IColumn::Permutation permutation;
getBlockSortPermutationImpl(block, description, IColumn::PermutationSortStability::Unstable, limit, permutation);
if (permutation.empty())
return;
bool is_identity_permutation = isIdentityPermutation(permutation, limit);
if (is_identity_permutation && limit == 0)
return;
size_t columns = block.columns();
for (size_t i = 0; i < columns; ++i)
{
auto & column_to_sort = block.getByPosition(i).column;
if (is_identity_permutation)
column_to_sort = column_to_sort->cut(0, std::min(static_cast<size_t>(limit), permutation.size()));
else
column_to_sort = column_to_sort->permute(permutation, limit);
}
}
void stableGetPermutation(const Block & block, const SortDescription & description, IColumn::Permutation & out_permutation)
{
if (!block)
return;
getBlockSortPermutationImpl(block, description, IColumn::PermutationSortStability::Stable, 0, out_permutation);
}
bool isAlreadySorted(const Block & block, const SortDescription & description)
{
if (!block)
return true;
ColumnsWithSortDescriptions columns_with_sort_desc = getColumnsWithSortDescription(block, description);
bool is_collation_required = false;
for (auto & column_with_sort_desc : columns_with_sort_desc)
{
if (isCollationRequired(column_with_sort_desc.description))
{
is_collation_required = true;
break;
}
}
size_t rows = block.rows();
if (is_collation_required)
{
PartialSortingLessWithCollation less(columns_with_sort_desc);
return isAlreadySortedImpl(rows, less);
}
PartialSortingLess less(columns_with_sort_desc);
return isAlreadySortedImpl(rows, less);
}
}