ClickHouse/dbms/include/DB/Storages/MergeTree/MergeTreeThreadBlockInputStream.h
2017-03-09 07:26:17 +03:00

75 lines
2.1 KiB
C++

#pragma once
#include <DB/DataStreams/IProfilingBlockInputStream.h>
#include <DB/Storages/MergeTree/MergeTreeData.h>
namespace DB
{
class MergeTreeReader;
class MergeTreeReadPool;
struct MergeTreeReadTask;
class UncompressedCache;
class MarkCache;
/** Used in conjunction with MergeTreeReadPool, asking it for more work to do and performing whatever reads it is asked
* to perform.
*/
class MergeTreeThreadBlockInputStream : public IProfilingBlockInputStream
{
/// "thread" index (there are N threads and each thread is assigned index in interval [0..N-1])
std::size_t thread;
public:
MergeTreeThreadBlockInputStream(
const std::size_t thread,
const std::shared_ptr<MergeTreeReadPool> & pool, const std::size_t min_marks_to_read, const std::size_t block_size,
MergeTreeData & storage, const bool use_uncompressed_cache, const ExpressionActionsPtr & prewhere_actions,
const String & prewhere_column, const Settings & settings, const Names & virt_column_names);
~MergeTreeThreadBlockInputStream() override;
String getName() const override { return "MergeTreeThread"; }
String getID() const override;
protected:
/// Будем вызывать progressImpl самостоятельно.
void progress(const Progress & value) override {}
Block readImpl() override;
private:
/// Requests read task from MergeTreeReadPool and signals whether it got one
bool getNewTask();
Block readFromPart();
void injectVirtualColumns(Block & block);
std::shared_ptr<MergeTreeReadPool> pool;
const std::size_t block_size_marks;
const std::size_t min_marks_to_read;
MergeTreeData & storage;
const bool use_uncompressed_cache;
ExpressionActionsPtr prewhere_actions;
const String prewhere_column;
const std::size_t min_bytes_to_use_direct_io;
const std::size_t max_read_buffer_size;
const Names virt_column_names;
Logger * log;
using MergeTreeReaderPtr = std::unique_ptr<MergeTreeReader>;
std::shared_ptr<UncompressedCache> owned_uncompressed_cache;
std::shared_ptr<MarkCache> owned_mark_cache;
std::shared_ptr<MergeTreeReadTask> task;
MergeTreeReaderPtr reader;
MergeTreeReaderPtr pre_reader;
};
}