ClickHouse/dbms/include/DB/Storages/StorageMergeTree.h

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#pragma once
#include <ext/shared_ptr_helper.hpp>
#include <DB/Storages/MergeTree/MergeTreeData.h>
#include <DB/Storages/MergeTree/MergeTreeDataSelectExecutor.h>
#include <DB/Storages/MergeTree/MergeTreeDataWriter.h>
#include <DB/Storages/MergeTree/MergeTreeDataMerger.h>
#include <DB/Storages/MergeTree/DiskSpaceMonitor.h>
#include <DB/Storages/MergeTree/BackgroundProcessingPool.h>
#include <DB/Common/Increment.h>
namespace DB
{
/** См. описание структуры данных в MergeTreeData.
*/
class StorageMergeTree : private ext::shared_ptr_helper<StorageMergeTree>, public IStorage
{
friend class ext::shared_ptr_helper<StorageMergeTree>;
friend class MergeTreeBlockOutputStream;
public:
/** Подцепить таблицу с соответствующим именем, по соответствующему пути (с / на конце),
* (корректность имён и путей не проверяется)
* состоящую из указанных столбцов.
*
* primary_expr_ast - выражение для сортировки;
* date_column_name - имя столбца с датой;
* index_granularity - на сколько строчек пишется одно значение индекса.
*/
static StoragePtr create(
const String & path_,
const String & database_name_,
const String & table_name_,
NamesAndTypesListPtr columns_,
const NamesAndTypesList & materialized_columns_,
const NamesAndTypesList & alias_columns_,
const ColumnDefaults & column_defaults_,
Context & context_,
ASTPtr & primary_expr_ast_,
const String & date_column_name_,
const ASTPtr & sampling_expression_, /// nullptr, если семплирование не поддерживается.
size_t index_granularity_,
const MergeTreeData::MergingParams & merging_params_,
bool has_force_restore_data_flag,
const MergeTreeSettings & settings_);
void shutdown() override;
~StorageMergeTree() override;
std::string getName() const override
{
return data.merging_params.getModeName() + "MergeTree";
}
std::string getTableName() const override { return table_name; }
bool supportsSampling() const override { return data.supportsSampling(); }
bool supportsFinal() const override { return data.supportsFinal(); }
bool supportsPrewhere() const override { return data.supportsPrewhere(); }
bool supportsParallelReplicas() const override { return true; }
const NamesAndTypesList & getColumnsListImpl() const override { return data.getColumnsListNonMaterialized(); }
NameAndTypePair getColumn(const String & column_name) const override
{
return data.getColumn(column_name);
}
bool hasColumn(const String & column_name) const override
{
return data.hasColumn(column_name);
}
BlockInputStreams read(
const Names & column_names,
ASTPtr query,
const Context & context,
const Settings & settings,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size = DEFAULT_BLOCK_SIZE,
unsigned threads = 1) override;
BlockOutputStreamPtr write(ASTPtr query, const Settings & settings) override;
/** Выполнить очередной шаг объединения кусков.
*/
bool optimize(const String & partition, bool final, const Settings & settings) override
{
return merge(settings.min_bytes_to_use_direct_io, true, partition, final);
}
void dropPartition(ASTPtr query, const Field & partition, bool detach, bool unreplicated, const Settings & settings) override;
void attachPartition(ASTPtr query, const Field & partition, bool unreplicated, bool part, const Settings & settings) override;
void freezePartition(const Field & partition, const String & with_name, const Settings & settings) override;
void drop() override;
void rename(const String & new_path_to_db, const String & new_database_name, const String & new_table_name) override;
void alter(const AlterCommands & params, const String & database_name, const String & table_name, const Context & context) override;
bool supportsIndexForIn() const override { return true; }
MergeTreeData & getData() { return data; }
private:
String path;
String database_name;
String table_name;
String full_path;
Context & context;
BackgroundProcessingPool & background_pool;
MergeTreeData data;
MergeTreeDataSelectExecutor reader;
MergeTreeDataWriter writer;
MergeTreeDataMerger merger;
/// Для нумерации блоков.
SimpleIncrement increment;
MergeTreeData::DataParts currently_merging;
std::mutex currently_merging_mutex;
Logger * log;
std::atomic<bool> shutdown_called {false};
BackgroundProcessingPool::TaskHandle merge_task_handle;
friend struct CurrentlyMergingPartsTagger;
StorageMergeTree(
const String & path_,
const String & database_name_,
const String & table_name_,
NamesAndTypesListPtr columns_,
const NamesAndTypesList & materialized_columns_,
const NamesAndTypesList & alias_columns_,
const ColumnDefaults & column_defaults_,
Context & context_,
ASTPtr & primary_expr_ast_,
const String & date_column_name_,
const ASTPtr & sampling_expression_, /// nullptr, if sampling is not supported.
size_t index_granularity_,
const MergeTreeData::MergingParams & merging_params_,
bool has_force_restore_data_flag,
const MergeTreeSettings & settings_);
/** Определяет, какие куски нужно объединять, и объединяет их.
* Если aggressive - выбрать куски, не обращая внимание на соотношение размеров и их новизну (для запроса OPTIMIZE).
* Возвращает, получилось ли что-нибудь объединить.
*/
bool merge(size_t aio_threshold, bool aggressive, const String & partition, bool final);
bool mergeTask();
};
}