ClickHouse/dbms/src/Storages/MergeTree/MergeTreeBlockInputStream.h
2017-09-08 00:04:48 +03:00

76 lines
2.2 KiB
C++

#pragma once
#include <DataStreams/IProfilingBlockInputStream.h>
#include <Storages/MergeTree/MergeTreeThreadBlockInputStream.h>
#include <Storages/MergeTree/MergeTreeData.h>
#include <Storages/MergeTree/MarkRange.h>
#include <Storages/MergeTree/MergeTreeBlockReadUtils.h>
namespace DB
{
/// Used to read data from single part.
/// To read data from multiple parts, a Storage creates multiple such objects.
/// TODO: Make special lightweight version of the reader for merges and other utilites, remove this from SelectExecutor.
class MergeTreeBlockInputStream : public MergeTreeBaseBlockInputStream
{
public:
MergeTreeBlockInputStream(
MergeTreeData & storage,
const MergeTreeData::DataPartPtr & owned_data_part,
size_t max_block_size_rows,
size_t preferred_block_size_bytes,
size_t preferred_max_column_in_block_size_bytes,
Names column_names,
const MarkRanges & mark_ranges,
bool use_uncompressed_cache,
ExpressionActionsPtr prewhere_actions,
String prewhere_column,
bool check_columns,
size_t min_bytes_to_use_direct_io,
size_t max_read_buffer_size,
bool save_marks_in_cache,
const Names & virt_column_names = {},
size_t part_index_in_query = 0,
bool quiet = false);
~MergeTreeBlockInputStream() override;
String getName() const override { return "MergeTree"; }
String getID() const override;
/// Closes readers and unlock part locks
void finish();
protected:
bool getNewTask() override;
private:
/// Used by Task
Names ordered_names;
NameSet column_name_set;
NamesAndTypesList columns;
NamesAndTypesList pre_columns;
/// Data part will not be removed if the pointer owns it
MergeTreeData::DataPartPtr data_part;
/// Forbids to change columns list of the part during reading
std::shared_lock<std::shared_mutex> part_columns_lock;
/// Mark ranges we should read (in ascending order)
MarkRanges all_mark_ranges;
/// Value of _part_index virtual column (used only in SelectExecutor)
size_t part_index_in_query = 0;
bool check_columns;
String path;
bool is_first_task = true;
Logger * log = &Logger::get("MergeTreeBlockInputStream");
};
}