ClickHouse/src/Storages/MergeTree/MergeTreeDataPartCompact.h
2021-10-29 20:21:02 +03:00

78 lines
3.0 KiB
C++

#pragma once
#include <Storages/MergeTree/IMergeTreeDataPart.h>
namespace DB
{
/** In compact format all columns are stored in one file (`data.bin`).
* Data is split in granules and columns are serialized sequentially in one granule.
* Granules are written one by one in data file.
* Marks are also stored in single file (`data.mrk3`).
* In compact format one mark is an array of marks for every column and a number of rows in granule.
* Format of other data part files is not changed.
* It's considered to store only small parts in compact format (up to 10M).
* NOTE: Compact parts aren't supported for tables with non-adaptive granularity.
* NOTE: In compact part compressed and uncompressed size of single column is unknown.
*/
class MergeTreeDataPartCompact : public IMergeTreeDataPart
{
public:
static constexpr auto DATA_FILE_NAME = "data";
static constexpr auto DATA_FILE_NAME_WITH_EXTENSION = "data.bin";
MergeTreeDataPartCompact(
const MergeTreeData & storage_,
const String & name_,
const MergeTreePartInfo & info_,
const VolumePtr & volume_,
const std::optional<String> & relative_path_ = {},
const IMergeTreeDataPart * parent_part_ = nullptr);
MergeTreeDataPartCompact(
MergeTreeData & storage_,
const String & name_,
const VolumePtr & volume_,
const std::optional<String> & relative_path_ = {},
const IMergeTreeDataPart * parent_part_ = nullptr);
MergeTreeReaderPtr getReader(
const NamesAndTypesList & columns,
const StorageMetadataPtr & metadata_snapshot,
const MarkRanges & mark_ranges,
UncompressedCache * uncompressed_cache,
MarkCache * mark_cache,
const MergeTreeReaderSettings & reader_settings_,
const ValueSizeMap & avg_value_size_hints,
const ReadBufferFromFileBase::ProfileCallback & profile_callback) const override;
MergeTreeWriterPtr getWriter(
const NamesAndTypesList & columns_list,
const StorageMetadataPtr & metadata_snapshot,
const std::vector<MergeTreeIndexPtr> & indices_to_recalc,
const CompressionCodecPtr & default_codec_,
const MergeTreeWriterSettings & writer_settings,
const MergeTreeIndexGranularity & computed_index_granularity) const override;
bool isStoredOnDisk() const override { return true; }
bool isStoredOnRemoteDisk() const override;
bool hasColumnFiles(const NameAndTypePair & column) const override;
String getFileNameForColumn(const NameAndTypePair & /* column */) const override { return DATA_FILE_NAME; }
~MergeTreeDataPartCompact() override;
private:
void checkConsistency(bool require_part_metadata) const override;
/// Loads marks index granularity into memory
void loadIndexGranularity() override;
/// Compact parts doesn't support per column size, only total size
void calculateEachColumnSizes(ColumnSizeByName & each_columns_size, ColumnSize & total_size) const override;
};
}