fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
64 lines
2.8 KiB
64 lines
2.8 KiB
// Copyright (c) 2014, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under the BSD-style license found in the
|
|
// LICENSE file in the root directory of this source tree. An additional grant
|
|
// of patent rights can be found in the PATENTS file in the same 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 "rocksdb/env.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
class RateLimiter {
|
|
public:
|
|
virtual ~RateLimiter() {}
|
|
|
|
// This API allows user to dynamically change rate limiter's bytes per second.
|
|
// REQUIRED: bytes_per_second > 0
|
|
virtual void SetBytesPerSecond(int64_t bytes_per_second) = 0;
|
|
|
|
// Request for token to write bytes. If this request can not be satisfied,
|
|
// the call is blocked. Caller is responsible to make sure
|
|
// bytes <= GetSingleBurstBytes()
|
|
virtual void Request(const int64_t bytes, const Env::IOPriority pri) = 0;
|
|
|
|
// Max bytes can be granted in a single burst
|
|
virtual int64_t GetSingleBurstBytes() const = 0;
|
|
|
|
// Total bytes that go though rate limiter
|
|
virtual int64_t GetTotalBytesThrough(
|
|
const Env::IOPriority pri = Env::IO_TOTAL) const = 0;
|
|
|
|
// Total # of requests that go though rate limiter
|
|
virtual int64_t GetTotalRequests(
|
|
const Env::IOPriority pri = Env::IO_TOTAL) const = 0;
|
|
};
|
|
|
|
// Create a RateLimiter object, which can be shared among RocksDB instances to
|
|
// control write rate of flush and compaction.
|
|
// @rate_bytes_per_sec: this is the only parameter you want to set most of the
|
|
// time. It controls the total write rate of compaction and flush in bytes per
|
|
// second. Currently, RocksDB does not enforce rate limit for anything other
|
|
// than flush and compaction, e.g. write to WAL.
|
|
// @refill_period_us: this controls how often tokens are refilled. For example,
|
|
// when rate_bytes_per_sec is set to 10MB/s and refill_period_us is set to
|
|
// 100ms, then 1MB is refilled every 100ms internally. Larger value can lead to
|
|
// burstier writes while smaller value introduces more CPU overhead.
|
|
// The default should work for most cases.
|
|
// @fairness: RateLimiter accepts high-pri requests and low-pri requests.
|
|
// A low-pri request is usually blocked in favor of hi-pri request. Currently,
|
|
// RocksDB assigns low-pri to request from compaciton and high-pri to request
|
|
// from flush. Low-pri requests can get blocked if flush requests come in
|
|
// continuouly. This fairness parameter grants low-pri requests permission by
|
|
// 1/fairness chance even though high-pri requests exist to avoid starvation.
|
|
// You should be good by leaving it at default 10.
|
|
extern RateLimiter* NewGenericRateLimiter(
|
|
int64_t rate_bytes_per_sec,
|
|
int64_t refill_period_us = 100 * 1000,
|
|
int32_t fairness = 10);
|
|
|
|
} // namespace rocksdb
|
|
|