ClickHouse/src/IO/WriteBufferFromFile.h
Azat Khuzhin a25dd1d348 Add ability to throttle local IO on per-query/server basis
Server settings:
- max_local_read_bandwidth_for_server
- max_local_write_bandwidth_for_server

Query settings:
- max_local_read_bandwidth
- max_local_write_bandwidth

This is the preparation for adding ability to throttle BACKUPs

Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
2023-04-05 09:39:15 +02:00

65 lines
1.5 KiB
C++

#pragma once
#include <sys/types.h>
#include <Common/CurrentMetrics.h>
#include <Common/Throttler_fwd.h>
#include <IO/WriteBufferFromFileDescriptor.h>
namespace CurrentMetrics
{
extern const Metric OpenFileForWrite;
}
#ifndef O_DIRECT
#define O_DIRECT 00040000
#endif
namespace DB
{
/** Accepts path to file and opens it, or pre-opened file descriptor.
* Closes file by himself (thus "owns" a file descriptor).
*/
class WriteBufferFromFile : public WriteBufferFromFileDescriptor
{
protected:
CurrentMetrics::Increment metric_increment{CurrentMetrics::OpenFileForWrite};
public:
explicit WriteBufferFromFile(
const std::string & file_name_,
size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
int flags = -1,
ThrottlerPtr throttler_ = {},
mode_t mode = 0666,
char * existing_memory = nullptr,
size_t alignment = 0);
/// Use pre-opened file descriptor.
explicit WriteBufferFromFile(
int & fd, /// Will be set to -1 if constructor didn't throw and ownership of file descriptor is passed to the object.
const std::string & original_file_name = {},
size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
ThrottlerPtr throttler_ = {},
char * existing_memory = nullptr,
size_t alignment = 0);
~WriteBufferFromFile() override;
/// Close file before destruction of object.
void close();
std::string getFileName() const override
{
return file_name;
}
private:
void finalizeImpl() override;
};
}