rocksdb/include/rocksdb/concurrent_task_limiter.h
Peter Dillinger 82afa01815 Some API clarifications (#9080)
Summary:
* Clarify that RocksDB is not exception safe on many of our callback
and extension interfaces
* Clarify FSRandomAccessFile::MultiRead implementations must accept
non-sorted inputs (see https://github.com/facebook/rocksdb/issues/8953)
* Clarify ConcurrentTaskLimiter and SstFileManager are not (currently)
extensible interfaces
* Mark WriteBufferManager as `final`, so it is then clearly not a
callback interface, even though it smells like one
* Clarify TablePropertiesCollector Status returns are mostly ignored

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9080

Test Plan: comments only (except WriteBufferManager final)

Reviewed By: ajkr

Differential Revision: D31968782

Pulled By: pdillinger

fbshipit-source-id: 11b648ce3ce3c5e5bdc02d2eafc7ea4b864bd1d2
2021-11-02 20:30:07 -07:00

52 lines
1.8 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <stdint.h>
#include <string>
#include "rocksdb/rocksdb_namespace.h"
namespace ROCKSDB_NAMESPACE {
// This is NOT an extensible interface but a public interface for result of
// NewConcurrentTaskLimiter. Any derived classes must be RocksDB internal.
class ConcurrentTaskLimiter {
public:
virtual ~ConcurrentTaskLimiter() {}
// Returns a name that identifies this concurrent task limiter.
virtual const std::string& GetName() const = 0;
// Set max concurrent tasks.
// limit = 0 means no new task allowed.
// limit < 0 means no limitation.
virtual void SetMaxOutstandingTask(int32_t limit) = 0;
// Reset to unlimited max concurrent task.
virtual void ResetMaxOutstandingTask() = 0;
// Returns current outstanding task count.
virtual int32_t GetOutstandingTask() const = 0;
};
// Create a ConcurrentTaskLimiter that can be shared with multiple CFs
// across RocksDB instances to control concurrent tasks.
//
// @param name: Name of the limiter.
// @param limit: max concurrent tasks.
// limit = 0 means no new task allowed.
// limit < 0 means no limitation.
extern ConcurrentTaskLimiter* NewConcurrentTaskLimiter(const std::string& name,
int32_t limit);
} // namespace ROCKSDB_NAMESPACE