ClickHouse/dbms/Storages/MergeTree/MergedBlockOutputStream.h
Ivan 97f2a2213e
Move all folders inside /dbms one level up (#9974)
* Move some code outside dbms/src folder
* Fix paths
2020-04-02 02:51:21 +03:00

61 lines
2.0 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 NamesAndTypesList & columns_list_,
CompressionCodecPtr default_codec,
bool blocks_are_granules_size = false);
MergedBlockOutputStream(
const MergeTreeDataPartPtr & data_part,
const NamesAndTypesList & columns_list_,
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 storage.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,
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);
private:
NamesAndTypesList columns_list;
size_t rows_count = 0;
};
}