ClickHouse/src/Storages/MergeTree/MergedBlockOutputStream.h

73 lines
2.5 KiB
C++

#pragma once
#include <Storages/MergeTree/IMergedBlockOutputStream.h>
#include <Columns/ColumnArray.h>
namespace DB
{
/** To write one part.
* The data refers to one partition, and is written in one part.
*/
class MergedBlockOutputStream final : public IMergedBlockOutputStream
{
public:
MergedBlockOutputStream(
const MergeTreeDataPartPtr & data_part,
const StorageMetadataPtr & metadata_snapshot_,
const NamesAndTypesList & columns_list_,
const MergeTreeIndices & skip_indices,
CompressionCodecPtr default_codec_,
bool blocks_are_granules_size = false);
MergedBlockOutputStream(
const MergeTreeDataPartPtr & data_part,
const StorageMetadataPtr & metadata_snapshot_,
const NamesAndTypesList & columns_list_,
const MergeTreeIndices & skip_indices,
CompressionCodecPtr default_codec_,
const MergeTreeData::DataPart::ColumnToSize & merged_column_to_size,
size_t aio_threshold,
bool blocks_are_granules_size = false);
Block getHeader() const override { return metadata_snapshot->getSampleBlock(); }
/// If the data is pre-sorted.
void write(const Block & block) override;
/** If the data is not sorted, but we have previously calculated the permutation, that will sort it.
* This method is used to save RAM, since you do not need to keep two blocks at once - the original one and the sorted one.
*/
void writeWithPermutation(const Block & block, const IColumn::Permutation * permutation);
void writeSuffix() override;
/// Finilize writing part and fill inner structures
void writeSuffixAndFinalizePart(
MergeTreeData::MutableDataPartPtr & new_part,
bool sync = false,
const NamesAndTypesList * total_columns_list = nullptr,
MergeTreeData::DataPart::Checksums * additional_column_checksums = nullptr);
private:
/** If `permutation` is given, it rearranges the values in the columns when writing.
* This is necessary to not keep the whole block in the RAM to sort it.
*/
void writeImpl(const Block & block, const IColumn::Permutation * permutation);
void finalizePartOnDisk(
const MergeTreeData::MutableDataPartPtr & new_part,
NamesAndTypesList & part_columns,
MergeTreeData::DataPart::Checksums & checksums,
bool sync);
private:
NamesAndTypesList columns_list;
IMergeTreeDataPart::MinMaxIndex minmax_idx;
size_t rows_count = 0;
CompressionCodecPtr default_codec;
};
}