ClickHouse/src/Storages/MergeTree/MergeTreeReaderCompact.cpp
2021-09-18 22:34:54 +03:00

360 lines
12 KiB
C++

#include <Storages/MergeTree/MergeTreeReaderCompact.h>
#include <Storages/MergeTree/MergeTreeDataPartCompact.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/NestedUtils.h>
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_READ_ALL_DATA;
extern const int ARGUMENT_OUT_OF_BOUND;
extern const int MEMORY_LIMIT_EXCEEDED;
}
MergeTreeReaderCompact::MergeTreeReaderCompact(
DataPartCompactPtr data_part_,
NamesAndTypesList columns_,
const StorageMetadataPtr & metadata_snapshot_,
UncompressedCache * uncompressed_cache_,
MarkCache * mark_cache_,
MarkRanges mark_ranges_,
MergeTreeReaderSettings settings_,
ValueSizeMap avg_value_size_hints_,
const ReadBufferFromFileBase::ProfileCallback & profile_callback_,
clockid_t clock_type_)
: IMergeTreeReader(
std::move(data_part_),
std::move(columns_),
metadata_snapshot_,
uncompressed_cache_,
mark_cache_,
std::move(mark_ranges_),
std::move(settings_),
std::move(avg_value_size_hints_))
, marks_loader(
data_part->volume->getDisk(),
mark_cache,
data_part->index_granularity_info.getMarksFilePath(data_part->getFullRelativePath() + MergeTreeDataPartCompact::DATA_FILE_NAME),
data_part->getMarksCount(),
data_part->index_granularity_info,
settings.save_marks_in_cache,
data_part->getColumns().size())
{
try
{
size_t columns_num = columns.size();
column_positions.resize(columns_num);
read_only_offsets.resize(columns_num);
auto name_and_type = columns.begin();
for (size_t i = 0; i < columns_num; ++i, ++name_and_type)
{
auto column_from_part = getColumnFromPart(*name_and_type);
auto position = data_part->getColumnPosition(column_from_part.name);
if (!position && typeid_cast<const DataTypeArray *>(column_from_part.type.get()))
{
/// If array of Nested column is missing in part,
/// we have to read its offsets if they exist.
position = findColumnForOffsets(column_from_part.name);
read_only_offsets[i] = (position != std::nullopt);
}
column_positions[i] = std::move(position);
}
/// Do not use max_read_buffer_size, but try to lower buffer size with maximal size of granule to avoid reading much data.
auto buffer_size = getReadBufferSize(data_part, marks_loader, column_positions, all_mark_ranges);
if (buffer_size)
settings.read_settings = settings.read_settings.adjustBufferSize(buffer_size);
const String full_data_path = data_part->getFullRelativePath() + MergeTreeDataPartCompact::DATA_FILE_NAME_WITH_EXTENSION;
if (uncompressed_cache)
{
auto buffer = std::make_unique<CachedCompressedReadBuffer>(
fullPath(data_part->volume->getDisk(), full_data_path),
[this, full_data_path]()
{
return data_part->volume->getDisk()->readFile(
full_data_path,
settings.read_settings);
},
uncompressed_cache,
/* allow_different_codecs = */ true);
if (profile_callback_)
buffer->setProfileCallback(profile_callback_, clock_type_);
if (!settings.checksum_on_read)
buffer->disableChecksumming();
cached_buffer = std::move(buffer);
data_buffer = cached_buffer.get();
}
else
{
auto buffer =
std::make_unique<CompressedReadBufferFromFile>(
data_part->volume->getDisk()->readFile(
full_data_path,
settings.read_settings,
0),
/* allow_different_codecs = */ true);
if (profile_callback_)
buffer->setProfileCallback(profile_callback_, clock_type_);
if (!settings.checksum_on_read)
buffer->disableChecksumming();
non_cached_buffer = std::move(buffer);
data_buffer = non_cached_buffer.get();
}
}
catch (...)
{
storage.reportBrokenPart(data_part->name);
throw;
}
}
size_t MergeTreeReaderCompact::readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
{
if (continue_reading)
from_mark = next_mark;
size_t read_rows = 0;
size_t num_columns = columns.size();
checkNumberOfColumns(num_columns);
MutableColumns mutable_columns(num_columns);
auto column_it = columns.begin();
for (size_t i = 0; i < num_columns; ++i, ++column_it)
{
if (!column_positions[i])
continue;
if (res_columns[i] == nullptr)
res_columns[i] = getColumnFromPart(*column_it).type->createColumn();
}
while (read_rows < max_rows_to_read)
{
size_t rows_to_read = data_part->index_granularity.getMarkRows(from_mark);
auto name_and_type = columns.begin();
for (size_t pos = 0; pos < num_columns; ++pos, ++name_and_type)
{
auto column_from_part = getColumnFromPart(*name_and_type);
if (!res_columns[pos])
continue;
try
{
auto & column = res_columns[pos];
size_t column_size_before_reading = column->size();
readData(column_from_part, column, from_mark, *column_positions[pos], rows_to_read, read_only_offsets[pos]);
size_t read_rows_in_column = column->size() - column_size_before_reading;
if (read_rows_in_column < rows_to_read)
throw Exception("Cannot read all data in MergeTreeReaderCompact. Rows read: " + toString(read_rows_in_column) +
". Rows expected: " + toString(rows_to_read) + ".", ErrorCodes::CANNOT_READ_ALL_DATA);
}
catch (Exception & e)
{
if (e.code() != ErrorCodes::MEMORY_LIMIT_EXCEEDED)
storage.reportBrokenPart(data_part->name);
/// Better diagnostics.
e.addMessage("(while reading column " + column_from_part.name + ")");
throw;
}
catch (...)
{
storage.reportBrokenPart(data_part->name);
throw;
}
}
++from_mark;
read_rows += rows_to_read;
}
next_mark = from_mark;
return read_rows;
}
void MergeTreeReaderCompact::readData(
const NameAndTypePair & name_and_type, ColumnPtr & column,
size_t from_mark, size_t column_position, size_t rows_to_read, bool only_offsets)
{
const auto & [name, type] = name_and_type;
if (!isContinuousReading(from_mark, column_position))
seekToMark(from_mark, column_position);
auto buffer_getter = [&](const ISerialization::SubstreamPath & substream_path) -> ReadBuffer *
{
if (only_offsets && (substream_path.size() != 1 || substream_path[0].type != ISerialization::Substream::ArraySizes))
return nullptr;
return data_buffer;
};
ISerialization::DeserializeBinaryBulkStatePtr state;
ISerialization::DeserializeBinaryBulkSettings deserialize_settings;
deserialize_settings.getter = buffer_getter;
deserialize_settings.avg_value_size_hint = avg_value_size_hints[name];
if (name_and_type.isSubcolumn())
{
const auto & type_in_storage = name_and_type.getTypeInStorage();
ColumnPtr temp_column = type_in_storage->createColumn();
auto serialization = type_in_storage->getDefaultSerialization();
serialization->deserializeBinaryBulkStatePrefix(deserialize_settings, state);
serialization->deserializeBinaryBulkWithMultipleStreams(temp_column, rows_to_read, deserialize_settings, state, nullptr);
auto subcolumn = type_in_storage->getSubcolumn(name_and_type.getSubcolumnName(), *temp_column);
/// TODO: Avoid extra copying.
if (column->empty())
column = subcolumn;
else
column->assumeMutable()->insertRangeFrom(*subcolumn, 0, subcolumn->size());
}
else
{
auto serialization = type->getDefaultSerialization();
serialization->deserializeBinaryBulkStatePrefix(deserialize_settings, state);
serialization->deserializeBinaryBulkWithMultipleStreams(column, rows_to_read, deserialize_settings, state, nullptr);
}
/// The buffer is left in inconsistent state after reading single offsets
if (only_offsets)
last_read_granule.reset();
else
last_read_granule.emplace(from_mark, column_position);
}
void MergeTreeReaderCompact::seekToMark(size_t row_index, size_t column_index)
{
MarkInCompressedFile mark = marks_loader.getMark(row_index, column_index);
try
{
if (cached_buffer)
cached_buffer->seek(mark.offset_in_compressed_file, mark.offset_in_decompressed_block);
if (non_cached_buffer)
non_cached_buffer->seek(mark.offset_in_compressed_file, mark.offset_in_decompressed_block);
}
catch (Exception & e)
{
/// Better diagnostics.
if (e.code() == ErrorCodes::ARGUMENT_OUT_OF_BOUND)
e.addMessage("(while seeking to mark (" + toString(row_index) + ", " + toString(column_index) + ")");
throw;
}
}
bool MergeTreeReaderCompact::isContinuousReading(size_t mark, size_t column_position)
{
if (!last_read_granule)
return false;
const auto & [last_mark, last_column] = *last_read_granule;
return (mark == last_mark && column_position == last_column + 1)
|| (mark == last_mark + 1 && column_position == 0 && last_column == data_part->getColumns().size() - 1);
}
namespace
{
/// A simple class that helps to iterate over 2-dim marks of compact parts.
class MarksCounter
{
public:
MarksCounter(size_t rows_num_, size_t columns_num_)
: rows_num(rows_num_), columns_num(columns_num_) {}
struct Iterator
{
size_t row;
size_t column;
MarksCounter * counter;
Iterator(size_t row_, size_t column_, MarksCounter * counter_)
: row(row_), column(column_), counter(counter_) {}
Iterator operator++()
{
if (column + 1 == counter->columns_num)
{
++row;
column = 0;
}
else
{
++column;
}
return *this;
}
bool operator==(const Iterator & other) const { return row == other.row && column == other.column; }
bool operator!=(const Iterator & other) const { return !(*this == other); }
};
Iterator get(size_t row, size_t column) { return Iterator(row, column, this); }
Iterator end() { return get(rows_num, 0); }
private:
size_t rows_num;
size_t columns_num;
};
}
size_t MergeTreeReaderCompact::getReadBufferSize(
const DataPartPtr & part,
MergeTreeMarksLoader & marks_loader,
const ColumnPositions & column_positions,
const MarkRanges & mark_ranges)
{
size_t buffer_size = 0;
size_t columns_num = column_positions.size();
size_t file_size = part->getFileSizeOrZero(MergeTreeDataPartCompact::DATA_FILE_NAME_WITH_EXTENSION);
MarksCounter counter(part->getMarksCount(), part->getColumns().size());
for (const auto & mark_range : mark_ranges)
{
for (size_t mark = mark_range.begin; mark < mark_range.end; ++mark)
{
for (size_t i = 0; i < columns_num; ++i)
{
if (!column_positions[i])
continue;
auto it = counter.get(mark, *column_positions[i]);
size_t cur_offset = marks_loader.getMark(it.row, it.column).offset_in_compressed_file;
while (it != counter.end() && cur_offset == marks_loader.getMark(it.row, it.column).offset_in_compressed_file)
++it;
size_t next_offset = (it == counter.end() ? file_size : marks_loader.getMark(it.row, it.column).offset_in_compressed_file);
buffer_size = std::max(buffer_size, next_offset - cur_offset);
}
}
}
return buffer_size;
}
}