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ClickHouse/src/Storages/MergeTree/MergeTreeRangeReader.cpp
Anton Popov 612173e734 refactoring near alter conversions
2023-05-25 22:54:54 +00:00

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#include <Storages/MergeTree/MergeTreeRangeReader.h>
#include <Storages/MergeTree/IMergeTreeReader.h>
#include <Columns/FilterDescription.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnsCommon.h>
#include <Common/TargetSpecific.h>
#include <Common/logger_useful.h>
#include <Core/UUID.h>
#include <IO/WriteBufferFromString.h>
#include <IO/Operators.h>
#include <base/range.h>
#include <Interpreters/castColumn.h>
#include <DataTypes/DataTypeNothing.h>
#include <bit>
#include <boost/algorithm/string/replace.hpp>
#ifdef __SSE2__
#include <emmintrin.h>
#endif
#if defined(__aarch64__) && defined(__ARM_NEON)
# include <arm_neon.h>
# pragma clang diagnostic ignored "-Wreserved-identifier"
#endif
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int BAD_ARGUMENTS;
}
static void filterColumns(Columns & columns, const IColumn::Filter & filter, size_t filter_bytes)
{
for (auto & column : columns)
{
if (column)
{
if (column->size() != filter.size())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Size of column {} doesn't match size of filter {}",
column->size(), filter.size());
column = column->filter(filter, filter_bytes);
if (column->empty())
{
columns.clear();
return;
}
}
}
}
static void filterColumns(Columns & columns, const FilterWithCachedCount & filter)
{
if (filter.alwaysTrue())
return;
if (filter.alwaysFalse())
{
for (auto & col : columns)
if (col)
col = col->cloneEmpty();
return;
}
filterColumns(columns, filter.getData(), filter.countBytesInFilter());
}
size_t MergeTreeRangeReader::ReadResult::getLastMark(const MergeTreeRangeReader::ReadResult::RangesInfo & ranges)
{
size_t current_task_last_mark = 0;
for (const auto & mark_range : ranges)
current_task_last_mark = std::max(current_task_last_mark, mark_range.range.end);
return current_task_last_mark;
}
MergeTreeRangeReader::DelayedStream::DelayedStream(
size_t from_mark,
size_t current_task_last_mark_,
IMergeTreeReader * merge_tree_reader_)
: current_mark(from_mark), current_offset(0), num_delayed_rows(0)
, current_task_last_mark(current_task_last_mark_)
, merge_tree_reader(merge_tree_reader_)
, index_granularity(&(merge_tree_reader->data_part_info_for_read->getIndexGranularity()))
, continue_reading(false), is_finished(false)
{
}
size_t MergeTreeRangeReader::DelayedStream::position() const
{
size_t num_rows_before_current_mark = index_granularity->getMarkStartingRow(current_mark);
return num_rows_before_current_mark + current_offset + num_delayed_rows;
}
size_t MergeTreeRangeReader::DelayedStream::readRows(Columns & columns, size_t num_rows)
{
if (num_rows)
{
size_t rows_read = merge_tree_reader->readRows(
current_mark, current_task_last_mark, continue_reading, num_rows, columns);
continue_reading = true;
/// Zero rows_read maybe either because reading has finished
/// or because there is no columns we can read in current part (for example, all columns are default).
/// In the last case we can't finish reading, but it's also ok for the first case
/// because we can finish reading by calculation the number of pending rows.
if (0 < rows_read && rows_read < num_rows)
is_finished = true;
return rows_read;
}
return 0;
}
size_t MergeTreeRangeReader::DelayedStream::read(Columns & columns, size_t from_mark, size_t offset, size_t num_rows)
{
size_t num_rows_before_from_mark = index_granularity->getMarkStartingRow(from_mark);
/// We already stand accurately in required position,
/// so because stream is lazy, we don't read anything
/// and only increment amount delayed_rows
if (position() == num_rows_before_from_mark + offset)
{
num_delayed_rows += num_rows;
return 0;
}
else
{
size_t read_rows = finalize(columns);
continue_reading = false;
current_mark = from_mark;
current_offset = offset;
num_delayed_rows = num_rows;
return read_rows;
}
}
size_t MergeTreeRangeReader::DelayedStream::finalize(Columns & columns)
{
/// We need to skip some rows before reading
if (current_offset && !continue_reading)
{
for (size_t mark_num : collections::range(current_mark, index_granularity->getMarksCount()))
{
size_t mark_index_granularity = index_granularity->getMarkRows(mark_num);
if (current_offset >= mark_index_granularity)
{
current_offset -= mark_index_granularity;
current_mark++;
}
else
break;
}
/// Skip some rows from begin of granule.
/// We don't know size of rows in compressed granule,
/// so have to read them and throw out.
if (current_offset)
{
Columns tmp_columns;
tmp_columns.resize(columns.size());
readRows(tmp_columns, current_offset);
}
}
size_t rows_to_read = num_delayed_rows;
current_offset += num_delayed_rows;
num_delayed_rows = 0;
return readRows(columns, rows_to_read);
}
MergeTreeRangeReader::Stream::Stream(
size_t from_mark, size_t to_mark, size_t current_task_last_mark, IMergeTreeReader * merge_tree_reader_)
: current_mark(from_mark), offset_after_current_mark(0)
, last_mark(to_mark)
, merge_tree_reader(merge_tree_reader_)
, index_granularity(&(merge_tree_reader->data_part_info_for_read->getIndexGranularity()))
, current_mark_index_granularity(index_granularity->getMarkRows(from_mark))
, stream(from_mark, current_task_last_mark, merge_tree_reader)
{
size_t marks_count = index_granularity->getMarksCount();
if (from_mark >= marks_count)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Trying create stream to read from mark №{} but total marks count is {}",
toString(current_mark), toString(marks_count));
if (last_mark > marks_count)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Trying create stream to read to mark №{} but total marks count is {}",
toString(current_mark), toString(marks_count));
}
void MergeTreeRangeReader::Stream::checkNotFinished() const
{
if (isFinished())
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Cannot read out of marks range.");
}
void MergeTreeRangeReader::Stream::checkEnoughSpaceInCurrentGranule(size_t num_rows) const
{
if (num_rows + offset_after_current_mark > current_mark_index_granularity)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Cannot read from granule more than index_granularity.");
}
size_t MergeTreeRangeReader::Stream::readRows(Columns & columns, size_t num_rows)
{
size_t rows_read = stream.read(columns, current_mark, offset_after_current_mark, num_rows);
if (stream.isFinished())
finish();
return rows_read;
}
void MergeTreeRangeReader::Stream::toNextMark()
{
++current_mark;
size_t total_marks_count = index_granularity->getMarksCount();
if (current_mark < total_marks_count)
current_mark_index_granularity = index_granularity->getMarkRows(current_mark);
else if (current_mark == total_marks_count)
current_mark_index_granularity = 0; /// HACK?
else
throw Exception(ErrorCodes::LOGICAL_ERROR, "Trying to read from mark {}, but total marks count {}",
toString(current_mark), toString(total_marks_count));
offset_after_current_mark = 0;
}
size_t MergeTreeRangeReader::Stream::read(Columns & columns, size_t num_rows, bool skip_remaining_rows_in_current_granule)
{
checkEnoughSpaceInCurrentGranule(num_rows);
if (num_rows)
{
checkNotFinished();
size_t read_rows = readRows(columns, num_rows);
offset_after_current_mark += num_rows;
/// Start new granule; skipped_rows_after_offset is already zero.
if (offset_after_current_mark == current_mark_index_granularity || skip_remaining_rows_in_current_granule)
toNextMark();
return read_rows;
}
else
{
/// Nothing to read.
if (skip_remaining_rows_in_current_granule)
{
/// Skip the rest of the rows in granule and start new one.
checkNotFinished();
toNextMark();
}
return 0;
}
}
void MergeTreeRangeReader::Stream::skip(size_t num_rows)
{
if (num_rows)
{
checkNotFinished();
checkEnoughSpaceInCurrentGranule(num_rows);
offset_after_current_mark += num_rows;
if (offset_after_current_mark == current_mark_index_granularity)
{
/// Start new granule; skipped_rows_after_offset is already zero.
toNextMark();
}
}
}
size_t MergeTreeRangeReader::Stream::finalize(Columns & columns)
{
size_t read_rows = stream.finalize(columns);
if (stream.isFinished())
finish();
return read_rows;
}
void MergeTreeRangeReader::ReadResult::addGranule(size_t num_rows_)
{
rows_per_granule.push_back(num_rows_);
total_rows_per_granule += num_rows_;
}
void MergeTreeRangeReader::ReadResult::adjustLastGranule()
{
size_t num_rows_to_subtract = total_rows_per_granule - num_read_rows;
if (rows_per_granule.empty())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Can't adjust last granule because no granules were added");
if (num_rows_to_subtract > rows_per_granule.back())
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Can't adjust last granule because it has {} rows, but try to subtract {} rows.",
rows_per_granule.back(), num_rows_to_subtract);
rows_per_granule.back() -= num_rows_to_subtract;
total_rows_per_granule -= num_rows_to_subtract;
}
void MergeTreeRangeReader::ReadResult::clear()
{
/// Need to save information about the number of granules.
num_rows_to_skip_in_last_granule += rows_per_granule.back();
rows_per_granule.assign(rows_per_granule.size(), 0);
total_rows_per_granule = 0;
final_filter = FilterWithCachedCount();
num_rows = 0;
columns.clear();
additional_columns.clear();
}
void MergeTreeRangeReader::ReadResult::shrink(Columns & old_columns, const NumRows & rows_per_granule_previous) const
{
for (auto & column : old_columns)
{
if (!column)
continue;
if (const auto * column_const = typeid_cast<const ColumnConst *>(column.get()))
{
column = column_const->cloneResized(total_rows_per_granule);
continue;
}
LOG_TEST(log, "ReadResult::shrink() column size: {} total_rows_per_granule: {}",
column->size(), total_rows_per_granule);
auto new_column = column->cloneEmpty();
new_column->reserve(total_rows_per_granule);
for (size_t j = 0, pos = 0; j < rows_per_granule_previous.size(); pos += rows_per_granule_previous[j++])
{
if (rows_per_granule[j])
new_column->insertRangeFrom(*column, pos, rows_per_granule[j]);
}
column = std::move(new_column);
}
}
/// The main invariant of the data in the read result is that he number of rows is
/// either equal to total_rows_per_granule (if filter has not been applied) or to the number of
/// 1s in the filter (if filter has been applied).
void MergeTreeRangeReader::ReadResult::checkInternalConsistency() const
{
/// Check that filter size matches number of rows that will be read.
if (final_filter.present() && final_filter.size() != total_rows_per_granule)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Final filter size {} doesn't match total_rows_per_granule {}",
final_filter.size(), total_rows_per_granule);
/// Check that num_rows is consistent with final_filter and rows_per_granule.
if (final_filter.present() && final_filter.countBytesInFilter() != num_rows && total_rows_per_granule != num_rows)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Number of rows {} doesn't match neither filter 1s count {} nor total_rows_per_granule {}",
num_rows, final_filter.countBytesInFilter(), total_rows_per_granule);
/// Check that additional columns have the same number of rows as the main columns.
if (additional_columns && additional_columns.rows() != num_rows)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Number of rows in additional columns {} is not equal to number of rows in result columns {}",
additional_columns.rows(), num_rows);
for (const auto & column : columns)
{
if (column)
chassert(column->size() == num_rows);
}
}
std::string MergeTreeRangeReader::ReadResult::dumpInfo() const
{
WriteBufferFromOwnString out;
out << "num_rows: " << num_rows
<< ", columns: " << columns.size()
<< ", total_rows_per_granule: " << total_rows_per_granule;
if (final_filter.present())
{
out << ", filter size: " << final_filter.size()
<< ", filter 1s: " << final_filter.countBytesInFilter();
}
else
{
out << ", no filter";
}
for (size_t ci = 0; ci < columns.size(); ++ci)
{
out << ", column[" << ci << "]: ";
if (!columns[ci])
out << " nullptr";
else
{
out << " " << columns[ci]->dumpStructure();
}
}
if (additional_columns)
{
out << ", additional_columns: " << additional_columns.dumpStructure();
}
return out.str();
}
static std::string dumpNames(const NamesAndTypesList & columns)
{
WriteBufferFromOwnString out;
for (auto it = columns.begin(); it != columns.end(); ++it)
{
if (it != columns.begin())
out << ", ";
out << it->name;
}
return out.str();
}
void MergeTreeRangeReader::ReadResult::setFilterConstTrue()
{
/// Remove the filter, so newly read columns will not be filtered.
final_filter = FilterWithCachedCount();
}
static ColumnPtr andFilters(ColumnPtr c1, ColumnPtr c2)
{
if (c1->size() != c2->size())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Size of filters don't match: {} and {}",
c1->size(), c2->size());
// TODO: use proper vectorized implementation of AND?
auto res = ColumnUInt8::create(c1->size());
auto & res_data = res->getData();
const auto & c1_data = typeid_cast<const ColumnUInt8&>(*c1).getData();
const auto & c2_data = typeid_cast<const ColumnUInt8&>(*c2).getData();
const size_t size = c1->size();
const size_t step = 16;
size_t i = 0;
/// NOTE: '&&' must be used instead of '&' for 'AND' operation because UInt8 columns might contain any non-zero
/// value for true and we cannot bitwise AND them to get the correct result.
for (; i + step < size; i += step)
for (size_t j = 0; j < step; ++j)
res_data[i+j] = (c1_data[i+j] && c2_data[i+j]);
for (; i < size; ++i)
res_data[i] = (c1_data[i] && c2_data[i]);
return res;
}
static ColumnPtr combineFilters(ColumnPtr first, ColumnPtr second);
void MergeTreeRangeReader::ReadResult::applyFilter(const FilterWithCachedCount & filter)
{
if (filter.size() != num_rows)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Filter size {} doesn't match number of rows {}",
filter.size(), num_rows);
LOG_TEST(log, "ReadResult::applyFilter() num_rows before: {}", num_rows);
filterColumns(columns, filter);
{
auto tmp_columns = additional_columns.getColumns();
filterColumns(tmp_columns, filter);
if (!tmp_columns.empty())
additional_columns.setColumns(tmp_columns);
else
additional_columns.clear();
}
num_rows = filter.countBytesInFilter();
LOG_TEST(log, "ReadResult::applyFilter() num_rows after: {}", num_rows);
}
void MergeTreeRangeReader::ReadResult::optimize(const FilterWithCachedCount & current_filter, bool can_read_incomplete_granules)
{
checkInternalConsistency();
/// Combine new filter with the previous one if it is present.
/// This filter has the size of total_rows_per granule. It is applied after reading contiguous chunks from
/// the start of each granule.
FilterWithCachedCount filter = current_filter;
if (final_filter.present())
{
/// If current filter has the same size as the final filter, it means that the final filter has not been applied.
/// In this case we AND current filter with the existing final filter.
/// In other case, when the final filter has been applied, the size of current step filter will be equal to number of ones
/// in the final filter. In this case we combine current filter with the final filter.
ColumnPtr combined_filter;
if (current_filter.size() == final_filter.size())
combined_filter = andFilters(final_filter.getColumn(), current_filter.getColumn());
else
combined_filter = combineFilters(final_filter.getColumn(), current_filter.getColumn());
filter = FilterWithCachedCount(combined_filter);
}
if (total_rows_per_granule == 0 || !filter.present())
return;
NumRows zero_tails;
auto total_zero_rows_in_tails = countZeroTails(filter.getData(), zero_tails, can_read_incomplete_granules);
LOG_TEST(log, "ReadResult::optimize() before: {}", dumpInfo());
SCOPE_EXIT(
if (!std::uncaught_exceptions())
{
checkInternalConsistency();
LOG_TEST(log, "ReadResult::optimize() after: {}", dumpInfo());
}
);
if (total_zero_rows_in_tails == filter.size())
{
LOG_TEST(log, "ReadResult::optimize() combined filter is const False");
clear();
return;
}
else if (total_zero_rows_in_tails == 0 && filter.countBytesInFilter() == filter.size())
{
LOG_TEST(log, "ReadResult::optimize() combined filter is const True");
setFilterConstTrue();
return;
}
/// Just a guess. If only a few rows may be skipped, it's better not to skip at all.
else if (2 * total_zero_rows_in_tails > filter.size())
{
const NumRows rows_per_granule_previous = rows_per_granule;
const size_t total_rows_per_granule_previous = total_rows_per_granule;
for (auto i : collections::range(0, rows_per_granule.size()))
{
rows_per_granule[i] -= zero_tails[i];
}
num_rows_to_skip_in_last_granule += rows_per_granule_previous.back() - rows_per_granule.back();
total_rows_per_granule = total_rows_per_granule_previous - total_zero_rows_in_tails;
/// Check if const 1 after shrink.
/// We can apply shrink only if after the previous step the number of rows in the result
/// matches the rows_per_granule info. Otherwise we will not be able to match newly added zeros in granule tails.
if (num_rows == total_rows_per_granule_previous &&
filter.countBytesInFilter() + total_zero_rows_in_tails == total_rows_per_granule_previous) /// All zeros are in tails?
{
setFilterConstTrue();
/// If all zeros are in granule tails, we can use shrink to filter out rows.
shrink(columns, rows_per_granule_previous); /// shrink acts as filtering in such case
auto c = additional_columns.getColumns();
shrink(c, rows_per_granule_previous);
additional_columns.setColumns(c);
num_rows = total_rows_per_granule;
LOG_TEST(log, "ReadResult::optimize() after shrink {}", dumpInfo());
}
else
{
auto new_filter = ColumnUInt8::create(filter.size() - total_zero_rows_in_tails);
IColumn::Filter & new_data = new_filter->getData();
/// Shorten the filter by removing zeros from granule tails
collapseZeroTails(filter.getData(), rows_per_granule_previous, new_data);
if (total_rows_per_granule != new_filter->size())
throw Exception(ErrorCodes::LOGICAL_ERROR, "New filter size {} doesn't match number of rows to be read {}",
new_filter->size(), total_rows_per_granule);
/// Need to apply combined filter here before replacing it with shortened one because otherwise
/// the filter size will not match the number of rows in the result columns.
if (num_rows == total_rows_per_granule_previous)
{
/// Filter from the previous steps has not been applied yet, do it now.
applyFilter(filter);
}
else
{
/// Filter was applied before, so apply only new filter from the current step.
applyFilter(current_filter);
}
final_filter = FilterWithCachedCount(new_filter->getPtr());
if (num_rows != final_filter.countBytesInFilter())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Count of 1s in final filter {} doesn't match number of rows {}",
final_filter.countBytesInFilter(), num_rows);
LOG_TEST(log, "ReadResult::optimize() after colapseZeroTails {}", dumpInfo());
}
}
else
{
/// Check if we have rows already filtered at the previous step. In such case we must apply the filter because
/// otherwise num_rows doesn't match total_rows_per_granule and the next read step will not know how to filter
/// newly read columns to match the num_rows.
if (num_rows != total_rows_per_granule)
{
applyFilter(current_filter);
}
/// Another guess, if it's worth filtering at PREWHERE
else if (filter.countBytesInFilter() < 0.6 * filter.size())
{
applyFilter(filter);
}
final_filter = std::move(filter);
}
}
size_t MergeTreeRangeReader::ReadResult::countZeroTails(const IColumn::Filter & filter_vec, NumRows & zero_tails, bool can_read_incomplete_granules) const
{
zero_tails.resize(0);
zero_tails.reserve(rows_per_granule.size());
const auto * filter_data = filter_vec.data();
size_t total_zero_rows_in_tails = 0;
for (auto rows_to_read : rows_per_granule)
{
/// Count the number of zeros at the end of filter for rows were read from current granule.
size_t zero_tail = numZerosInTail(filter_data, filter_data + rows_to_read);
if (!can_read_incomplete_granules && zero_tail != rows_to_read)
zero_tail = 0;
zero_tails.push_back(zero_tail);
total_zero_rows_in_tails += zero_tails.back();
filter_data += rows_to_read;
}
return total_zero_rows_in_tails;
}
void MergeTreeRangeReader::ReadResult::collapseZeroTails(const IColumn::Filter & filter_vec, const NumRows & rows_per_granule_previous, IColumn::Filter & new_filter_vec) const
{
const auto * filter_data = filter_vec.data();
auto * new_filter_data = new_filter_vec.data();
for (auto i : collections::range(0, rows_per_granule.size()))
{
memcpySmallAllowReadWriteOverflow15(new_filter_data, filter_data, rows_per_granule[i]);
filter_data += rows_per_granule_previous[i];
new_filter_data += rows_per_granule[i];
}
new_filter_vec.resize(new_filter_data - new_filter_vec.data());
}
DECLARE_AVX512BW_SPECIFIC_CODE(
size_t numZerosInTail(const UInt8 * begin, const UInt8 * end)
{
size_t count = 0;
const __m512i zero64 = _mm512_setzero_epi32();
while (end - begin >= 64)
{
end -= 64;
const auto * pos = end;
UInt64 val = static_cast<UInt64>(_mm512_cmp_epi8_mask(
_mm512_loadu_si512(reinterpret_cast<const __m512i *>(pos)),
zero64,
_MM_CMPINT_EQ));
val = ~val;
if (val == 0)
count += 64;
else
{
count += std::countl_zero(val);
return count;
}
}
while (end > begin && *(--end) == 0)
{
++count;
}
return count;
}
) /// DECLARE_AVX512BW_SPECIFIC_CODE
DECLARE_AVX2_SPECIFIC_CODE(
size_t numZerosInTail(const UInt8 * begin, const UInt8 * end)
{
size_t count = 0;
const __m256i zero32 = _mm256_setzero_si256();
while (end - begin >= 64)
{
end -= 64;
const auto * pos = end;
UInt64 val =
(static_cast<UInt64>(_mm256_movemask_epi8(_mm256_cmpeq_epi8(
_mm256_loadu_si256(reinterpret_cast<const __m256i *>(pos)),
zero32))) & 0xffffffffu)
| (static_cast<UInt64>(_mm256_movemask_epi8(_mm256_cmpeq_epi8(
_mm256_loadu_si256(reinterpret_cast<const __m256i *>(pos + 32)),
zero32))) << 32u);
val = ~val;
if (val == 0)
count += 64;
else
{
count += std::countl_zero(val);
return count;
}
}
while (end > begin && *(--end) == 0)
{
++count;
}
return count;
}
) /// DECLARE_AVX2_SPECIFIC_CODE
size_t MergeTreeRangeReader::ReadResult::numZerosInTail(const UInt8 * begin, const UInt8 * end)
{
#if USE_MULTITARGET_CODE
/// check if cpu support avx512 dynamically, haveAVX512BW contains check of haveAVX512F
if (isArchSupported(TargetArch::AVX512BW))
return TargetSpecific::AVX512BW::numZerosInTail(begin, end);
else if (isArchSupported(TargetArch::AVX2))
return TargetSpecific::AVX2::numZerosInTail(begin, end);
#endif
size_t count = 0;
#if defined(__SSE2__)
const __m128i zero16 = _mm_setzero_si128();
while (end - begin >= 64)
{
end -= 64;
const auto * pos = end;
UInt64 val =
static_cast<UInt64>(_mm_movemask_epi8(_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(pos)),
zero16)))
| (static_cast<UInt64>(_mm_movemask_epi8(_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(pos + 16)),
zero16))) << 16u)
| (static_cast<UInt64>(_mm_movemask_epi8(_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(pos + 32)),
zero16))) << 32u)
| (static_cast<UInt64>(_mm_movemask_epi8(_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(pos + 48)),
zero16))) << 48u);
val = ~val;
if (val == 0)
count += 64;
else
{
count += std::countl_zero(val);
return count;
}
}
#elif defined(__aarch64__) && defined(__ARM_NEON)
const uint8x16_t bitmask = {0x01, 0x02, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80, 0x01, 0x02, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80};
while (end - begin >= 64)
{
end -= 64;
const auto * src = reinterpret_cast<const unsigned char *>(end);
const uint8x16_t p0 = vceqzq_u8(vld1q_u8(src));
const uint8x16_t p1 = vceqzq_u8(vld1q_u8(src + 16));
const uint8x16_t p2 = vceqzq_u8(vld1q_u8(src + 32));
const uint8x16_t p3 = vceqzq_u8(vld1q_u8(src + 48));
uint8x16_t t0 = vandq_u8(p0, bitmask);
uint8x16_t t1 = vandq_u8(p1, bitmask);
uint8x16_t t2 = vandq_u8(p2, bitmask);
uint8x16_t t3 = vandq_u8(p3, bitmask);
uint8x16_t sum0 = vpaddq_u8(t0, t1);
uint8x16_t sum1 = vpaddq_u8(t2, t3);
sum0 = vpaddq_u8(sum0, sum1);
sum0 = vpaddq_u8(sum0, sum0);
UInt64 val = vgetq_lane_u64(vreinterpretq_u64_u8(sum0), 0);
val = ~val;
if (val == 0)
count += 64;
else
{
count += std::countl_zero(val);
return count;
}
}
#endif
while (end > begin && *(--end) == 0)
{
++count;
}
return count;
}
MergeTreeRangeReader::MergeTreeRangeReader(
IMergeTreeReader * merge_tree_reader_,
MergeTreeRangeReader * prev_reader_,
const PrewhereExprStep * prewhere_info_,
bool last_reader_in_chain_,
const Names & non_const_virtual_column_names_)
: merge_tree_reader(merge_tree_reader_)
, index_granularity(&(merge_tree_reader->data_part_info_for_read->getIndexGranularity()))
, prev_reader(prev_reader_)
, prewhere_info(prewhere_info_)
, last_reader_in_chain(last_reader_in_chain_)
, is_initialized(true)
{
if (prev_reader)
result_sample_block = prev_reader->getSampleBlock();
for (const auto & name_and_type : merge_tree_reader->getColumns())
{
read_sample_block.insert({name_and_type.type->createColumn(), name_and_type.type, name_and_type.name});
result_sample_block.insert({name_and_type.type->createColumn(), name_and_type.type, name_and_type.name});
}
for (const auto & column_name : non_const_virtual_column_names_)
{
if (result_sample_block.has(column_name))
continue;
non_const_virtual_column_names.push_back(column_name);
if (column_name == "_part_offset" && !prev_reader)
{
/// _part_offset column is filled by the first reader.
read_sample_block.insert(ColumnWithTypeAndName(ColumnUInt64::create(), std::make_shared<DataTypeUInt64>(), column_name));
result_sample_block.insert(ColumnWithTypeAndName(ColumnUInt64::create(), std::make_shared<DataTypeUInt64>(), column_name));
}
}
if (prewhere_info)
{
const auto & step = *prewhere_info;
if (step.actions)
step.actions->execute(result_sample_block, true);
if (step.remove_filter_column)
result_sample_block.erase(step.filter_column_name);
}
}
bool MergeTreeRangeReader::isReadingFinished() const
{
return prev_reader ? prev_reader->isReadingFinished() : stream.isFinished();
}
size_t MergeTreeRangeReader::numReadRowsInCurrentGranule() const
{
return prev_reader ? prev_reader->numReadRowsInCurrentGranule() : stream.numReadRowsInCurrentGranule();
}
size_t MergeTreeRangeReader::numPendingRowsInCurrentGranule() const
{
if (prev_reader)
return prev_reader->numPendingRowsInCurrentGranule();
auto pending_rows = stream.numPendingRowsInCurrentGranule();
if (pending_rows)
return pending_rows;
return numRowsInCurrentGranule();
}
size_t MergeTreeRangeReader::numRowsInCurrentGranule() const
{
/// If pending_rows is zero, than stream is not initialized.
if (stream.current_mark_index_granularity)
return stream.current_mark_index_granularity;
/// We haven't read anything, return first
size_t first_mark = merge_tree_reader->getFirstMarkToRead();
return index_granularity->getMarkRows(first_mark);
}
size_t MergeTreeRangeReader::currentMark() const
{
return stream.currentMark();
}
size_t MergeTreeRangeReader::Stream::numPendingRows() const
{
size_t rows_between_marks = index_granularity->getRowsCountInRange(current_mark, last_mark);
return rows_between_marks - offset_after_current_mark;
}
UInt64 MergeTreeRangeReader::Stream::currentPartOffset() const
{
return index_granularity->getMarkStartingRow(current_mark) + offset_after_current_mark;
}
UInt64 MergeTreeRangeReader::Stream::lastPartOffset() const
{
return index_granularity->getMarkStartingRow(last_mark);
}
size_t MergeTreeRangeReader::Stream::ceilRowsToCompleteGranules(size_t rows_num) const
{
/// FIXME suboptimal
size_t result = 0;
size_t from_mark = current_mark;
while (result < rows_num && from_mark < last_mark)
result += index_granularity->getMarkRows(from_mark++);
return result;
}
bool MergeTreeRangeReader::isCurrentRangeFinished() const
{
return prev_reader ? prev_reader->isCurrentRangeFinished() : stream.isFinished();
}
/// When executing ExpressionActions on an empty block, it is not possible to determine the number of rows
/// in the block for the new columns so the result block will have 0 rows and it will not match the rest of
/// the columns in the ReadResult.
/// The dummy column is added to maintain the information about the number of rows in the block and to produce
/// the result block with the correct number of rows.
String addDummyColumnWithRowCount(Block & block, size_t num_rows)
{
bool has_columns = false;
for (const auto & column : block)
{
if (column.column)
{
assert(column.column->size() == num_rows);
has_columns = true;
break;
}
}
if (has_columns)
return {};
ColumnWithTypeAndName dummy_column;
dummy_column.column = DataTypeUInt8().createColumnConst(num_rows, Field(1));
dummy_column.type = std::make_shared<DataTypeUInt8>();
/// Generate a random name to avoid collisions with real columns.
dummy_column.name = "....dummy...." + toString(UUIDHelpers::generateV4());
block.insert(dummy_column);
return dummy_column.name;
}
MergeTreeRangeReader::ReadResult MergeTreeRangeReader::read(size_t max_rows, MarkRanges & ranges)
{
if (max_rows == 0)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Expected at least 1 row to read, got 0.");
ReadResult read_result(log);
SCOPE_EXIT(
if (!std::uncaught_exceptions())
LOG_TEST(log, "read() returned {}, sample block {}",
read_result.dumpInfo(), this->result_sample_block.dumpNames());
);
if (prev_reader)
{
read_result = prev_reader->read(max_rows, ranges);
size_t num_read_rows;
Columns columns = continueReadingChain(read_result, num_read_rows);
/// Nothing to do. Return empty result.
if (read_result.num_rows == 0)
return read_result;
/// Calculate and update read bytes
size_t total_bytes = 0;
for (auto & column : columns)
if (column)
total_bytes += column->byteSize();
read_result.addNumBytesRead(total_bytes);
if (!columns.empty())
{
/// If all requested columns are absent in part num_read_rows will be 0.
/// In this case we need to use number of rows in the result to fill the default values and don't filter block.
if (num_read_rows == 0)
num_read_rows = read_result.num_rows;
/// fillMissingColumns() must be called after reading but befoe any filterings because
/// some columns (e.g. arrays) might be only partially filled and thus not be valid and
/// fillMissingColumns() fixes this.
bool should_evaluate_missing_defaults;
merge_tree_reader->fillMissingColumns(columns, should_evaluate_missing_defaults, num_read_rows);
if (read_result.total_rows_per_granule == num_read_rows && read_result.num_rows != num_read_rows)
{
/// We have filter applied from the previous step
/// So we need to apply it to the newly read rows
if (!read_result.final_filter.present() || read_result.final_filter.countBytesInFilter() != read_result.num_rows)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Final filter is missing or has mistaching size, read_result: {}",
read_result.dumpInfo());
filterColumns(columns, read_result.final_filter);
}
/// If some columns absent in part, then evaluate default values
if (should_evaluate_missing_defaults)
{
Block additional_columns = prev_reader->getSampleBlock().cloneWithColumns(read_result.columns);
for (const auto & col : read_result.additional_columns)
additional_columns.insert(col);
addDummyColumnWithRowCount(additional_columns, read_result.num_rows);
merge_tree_reader->evaluateMissingDefaults(additional_columns, columns);
}
/// If columns not empty, then apply on-fly alter conversions if any required
if (!prewhere_info || prewhere_info->perform_alter_conversions)
merge_tree_reader->performRequiredConversions(columns);
}
read_result.columns.reserve(read_result.columns.size() + columns.size());
for (auto & column : columns)
read_result.columns.emplace_back(std::move(column));
}
else
{
read_result = startReadingChain(max_rows, ranges);
read_result.num_rows = read_result.numReadRows();
LOG_TEST(log, "First reader returned: {}, requested columns: {}",
read_result.dumpInfo(), dumpNames(merge_tree_reader->getColumns()));
if (read_result.num_rows == 0)
return read_result;
{
/// Physical columns go first and then some virtual columns follow
size_t physical_columns_count = merge_tree_reader->getColumns().size();
Columns physical_columns(read_result.columns.begin(), read_result.columns.begin() + physical_columns_count);
bool should_evaluate_missing_defaults;
merge_tree_reader->fillMissingColumns(physical_columns, should_evaluate_missing_defaults, read_result.num_rows);
/// If some columns absent in part, then evaluate default values
if (should_evaluate_missing_defaults)
merge_tree_reader->evaluateMissingDefaults({}, physical_columns);
/// If result not empty, then apply on-fly alter conversions if any required
if (!prewhere_info || prewhere_info->perform_alter_conversions)
merge_tree_reader->performRequiredConversions(physical_columns);
for (size_t i = 0; i < physical_columns.size(); ++i)
read_result.columns[i] = std::move(physical_columns[i]);
}
size_t total_bytes = 0;
for (auto & column : read_result.columns)
total_bytes += column->byteSize();
read_result.addNumBytesRead(total_bytes);
}
executePrewhereActionsAndFilterColumns(read_result);
read_result.checkInternalConsistency();
if (!read_result.can_return_prewhere_column_without_filtering && last_reader_in_chain)
{
if (!read_result.filterWasApplied())
{
/// TODO: another solution might be to set all 0s from final filter into the prewhere column and not filter all the columns here
/// but rely on filtering in WHERE.
read_result.applyFilter(read_result.final_filter);
read_result.checkInternalConsistency();
}
read_result.can_return_prewhere_column_without_filtering = true;
}
if (read_result.num_rows != 0 && read_result.columns.size() != getSampleBlock().columns())
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Number of columns in result doesn't match number of columns in sample block, read_result: {}, sample block: {}",
read_result.dumpInfo(), getSampleBlock().dumpStructure());
return read_result;
}
MergeTreeRangeReader::ReadResult MergeTreeRangeReader::startReadingChain(size_t max_rows, MarkRanges & ranges)
{
ReadResult result(log);
result.columns.resize(merge_tree_reader->getColumns().size());
size_t current_task_last_mark = getLastMark(ranges);
/// The stream could be unfinished by the previous read request because of max_rows limit.
/// In this case it will have some rows from the previously started range. We need to save their begin and
/// end offsets to properly fill _part_offset column.
UInt64 leading_begin_part_offset = 0;
UInt64 leading_end_part_offset = 0;
if (!stream.isFinished())
{
leading_begin_part_offset = stream.currentPartOffset();
leading_end_part_offset = stream.lastPartOffset();
}
/// Stream is lazy. result.num_added_rows is the number of rows added to block which is not equal to
/// result.num_rows_read until call to stream.finalize(). Also result.num_added_rows may be less than
/// result.num_rows_read if the last granule in range also the last in part (so we have to adjust last granule).
{
size_t space_left = max_rows;
while (space_left && (!stream.isFinished() || !ranges.empty()))
{
if (stream.isFinished())
{
result.addRows(stream.finalize(result.columns));
stream = Stream(ranges.front().begin, ranges.front().end, current_task_last_mark, merge_tree_reader);
result.addRange(ranges.front());
ranges.pop_front();
}
size_t current_space = space_left;
/// If reader can't read part of granule, we have to increase number of reading rows
/// to read complete granules and exceed max_rows a bit.
if (!merge_tree_reader->canReadIncompleteGranules())
current_space = stream.ceilRowsToCompleteGranules(space_left);
auto rows_to_read = std::min(current_space, stream.numPendingRowsInCurrentGranule());
bool last = rows_to_read == space_left;
result.addRows(stream.read(result.columns, rows_to_read, !last));
result.addGranule(rows_to_read);
space_left = (rows_to_read > space_left ? 0 : space_left - rows_to_read);
}
}
result.addRows(stream.finalize(result.columns));
/// Last granule may be incomplete.
if (!result.rows_per_granule.empty())
result.adjustLastGranule();
if (read_sample_block.has("_part_offset"))
fillPartOffsetColumn(result, leading_begin_part_offset, leading_end_part_offset);
return result;
}
void MergeTreeRangeReader::fillPartOffsetColumn(ReadResult & result, UInt64 leading_begin_part_offset, UInt64 leading_end_part_offset)
{
size_t num_rows = result.numReadRows();
auto column = ColumnUInt64::create(num_rows);
ColumnUInt64::Container & vec = column->getData();
UInt64 * pos = vec.data();
UInt64 * end = &vec[num_rows];
/// Fill the reamining part of the previous range (it was started in the previous read request).
while (pos < end && leading_begin_part_offset < leading_end_part_offset)
*pos++ = leading_begin_part_offset++;
const auto & start_ranges = result.started_ranges;
/// Fill the ranges which were started in the current read request.
for (const auto & start_range : start_ranges)
{
UInt64 start_part_offset = index_granularity->getMarkStartingRow(start_range.range.begin);
UInt64 end_part_offset = index_granularity->getMarkStartingRow(start_range.range.end);
while (pos < end && start_part_offset < end_part_offset)
*pos++ = start_part_offset++;
}
result.columns.emplace_back(std::move(column));
}
Columns MergeTreeRangeReader::continueReadingChain(const ReadResult & result, size_t & num_rows)
{
Columns columns;
num_rows = 0;
/// No columns need to be read at this step? (only more filtering)
if (merge_tree_reader->getColumns().empty())
return columns;
if (result.rows_per_granule.empty())
{
/// If zero rows were read on prev step, than there is no more rows to read.
/// Last granule may have less rows than index_granularity, so finish reading manually.
stream.finish();
return columns;
}
columns.resize(merge_tree_reader->numColumnsInResult());
const auto & rows_per_granule = result.rows_per_granule;
const auto & started_ranges = result.started_ranges;
size_t current_task_last_mark = ReadResult::getLastMark(started_ranges);
size_t next_range_to_start = 0;
auto size = rows_per_granule.size();
for (auto i : collections::range(0, size))
{
if (next_range_to_start < started_ranges.size()
&& i == started_ranges[next_range_to_start].num_granules_read_before_start)
{
num_rows += stream.finalize(columns);
const auto & range = started_ranges[next_range_to_start].range;
++next_range_to_start;
stream = Stream(range.begin, range.end, current_task_last_mark, merge_tree_reader);
}
bool last = i + 1 == size;
num_rows += stream.read(columns, rows_per_granule[i], !last);
}
stream.skip(result.num_rows_to_skip_in_last_granule);
num_rows += stream.finalize(columns);
/// added_rows may be zero if all columns were read in prewhere and it's ok.
if (num_rows && num_rows != result.total_rows_per_granule)
throw Exception(ErrorCodes::LOGICAL_ERROR, "RangeReader read {} rows, but {} expected.",
num_rows, result.total_rows_per_granule);
return columns;
}
static void checkCombinedFiltersSize(size_t bytes_in_first_filter, size_t second_filter_size)
{
if (bytes_in_first_filter != second_filter_size)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Cannot combine filters because number of bytes in a first filter ({}) "
"does not match second filter size ({})", bytes_in_first_filter, second_filter_size);
}
/// Second filter size must be equal to number of 1s in the first filter.
/// The result has size equal to first filter size and contains 1s only where both filters contain 1s.
static ColumnPtr combineFilters(ColumnPtr first, ColumnPtr second)
{
ConstantFilterDescription first_const_descr(*first);
if (first_const_descr.always_true)
{
checkCombinedFiltersSize(first->size(), second->size());
return second;
}
if (first_const_descr.always_false)
{
checkCombinedFiltersSize(0, second->size());
return first;
}
FilterDescription first_descr(*first);
size_t bytes_in_first_filter = countBytesInFilter(*first_descr.data);
checkCombinedFiltersSize(bytes_in_first_filter, second->size());
ConstantFilterDescription second_const_descr(*second);
if (second_const_descr.always_true)
return first;
if (second_const_descr.always_false)
return second->cloneResized(first->size());
FilterDescription second_descr(*second);
MutableColumnPtr mut_first;
if (first_descr.data_holder)
mut_first = IColumn::mutate(std::move(first_descr.data_holder));
else
mut_first = IColumn::mutate(std::move(first));
auto & first_data = typeid_cast<ColumnUInt8 *>(mut_first.get())->getData();
const auto * second_data = second_descr.data->data();
for (auto & val : first_data)
{
if (val)
{
val = *second_data;
++second_data;
}
}
return mut_first;
}
void MergeTreeRangeReader::executePrewhereActionsAndFilterColumns(ReadResult & result) const
{
result.checkInternalConsistency();
if (!prewhere_info)
return;
const auto & header = read_sample_block;
size_t num_columns = header.columns();
/// Check that we have columns from previous steps and newly read required columns
if (result.columns.size() < num_columns)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Invalid number of columns passed to MergeTreeRangeReader. Expected {}, got {}",
num_columns, result.columns.size());
/// Restore block from columns list.
Block block;
size_t pos = 0;
if (prev_reader)
{
for (const auto & col : prev_reader->getSampleBlock())
{
block.insert({result.columns[pos], col.type, col.name});
++pos;
}
}
for (auto name_and_type = header.begin(); name_and_type != header.end() && pos < result.columns.size(); ++pos, ++name_and_type)
block.insert({result.columns[pos], name_and_type->type, name_and_type->name});
{
/// Columns might be projected out. We need to store them here so that default columns can be evaluated later.
Block additional_columns = block;
if (prewhere_info->actions)
{
const String dummy_column = addDummyColumnWithRowCount(block, result.num_rows);
LOG_TEST(log, "Executing prewhere actions on block: {}", block.dumpStructure());
prewhere_info->actions->execute(block);
if (!dummy_column.empty())
block.erase(dummy_column);
}
result.additional_columns.clear();
/// Additional columns might only be needed if there are more steps in the chain.
if (!last_reader_in_chain)
{
for (auto & col : additional_columns)
{
/// Exclude columns that are present in the result block to avoid storing them and filtering twice.
/// TODO: also need to exclude the columns that are not needed for the next steps.
if (block.has(col.name))
continue;
result.additional_columns.insert(col);
}
}
}
result.columns.clear();
result.columns.reserve(block.columns());
for (auto & col : block)
result.columns.emplace_back(std::move(col.column));
if (prewhere_info->type == PrewhereExprStep::Filter)
{
/// Filter computed at the current step. Its size is equal to num_rows which is <= total_rows_per_granule
size_t filter_column_pos = block.getPositionByName(prewhere_info->filter_column_name);
auto current_step_filter = result.columns[filter_column_pos];
/// In case when we are returning prewhere column the caller expects it to serve as a final filter:
/// it must contain 0s not only from the current step but also from all the previous steps.
/// One way to achieve this is to apply the final_filter if we know that the final_filter was not applied at
/// several previous steps but was accumulated instead.
result.can_return_prewhere_column_without_filtering = result.filterWasApplied();
if (prewhere_info->remove_filter_column)
result.columns.erase(result.columns.begin() + filter_column_pos);
FilterWithCachedCount current_filter(current_step_filter);
result.optimize(current_filter, merge_tree_reader->canReadIncompleteGranules());
if (prewhere_info->need_filter && !result.filterWasApplied())
{
/// Depending on whether the final filter was applied at the previous step or not we need to apply either
/// just the current step filter or the accumulated filter.
FilterWithCachedCount filter_to_apply =
current_filter.size() == result.total_rows_per_granule
? result.final_filter
: current_filter;
result.applyFilter(filter_to_apply);
}
}
LOG_TEST(log, "After execute prewhere {}", result.dumpInfo());
}
std::string PrewhereExprInfo::dump() const
{
WriteBufferFromOwnString s;
const char indent[] = "\n ";
for (size_t i = 0; i < steps.size(); ++i)
{
s << "STEP " << i << ":\n"
<< " ACTIONS: " << (steps[i]->actions ?
(indent + boost::replace_all_copy(steps[i]->actions->dumpActions(), "\n", indent)) :
"nullptr") << "\n"
<< " COLUMN: " << steps[i]->filter_column_name << "\n"
<< " REMOVE_COLUMN: " << steps[i]->remove_filter_column << "\n"
<< " NEED_FILTER: " << steps[i]->need_filter << "\n\n";
}
return s.str();
}
std::string PrewhereExprInfo::dumpConditions() const
{
WriteBufferFromOwnString s;
for (size_t i = 0; i < steps.size(); ++i)
s << (i == 0 ? "\"" : ", \"") << steps[i]->filter_column_name << "\"";
return s.str();
}
}
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