rocksdb/monitoring/file_read_sample.h
sdong fdf882ded2 Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433

Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.

Differential Revision: D19977691

fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
2020-02-20 12:09:57 -08:00

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// 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).
//
#pragma once
#include "db/version_edit.h"
#include "util/random.h"
namespace ROCKSDB_NAMESPACE {
static const uint32_t kFileReadSampleRate = 1024;
extern bool should_sample_file_read();
extern void sample_file_read_inc(FileMetaData*);
inline bool should_sample_file_read() {
return (Random::GetTLSInstance()->Next() % kFileReadSampleRate == 307);
}
inline void sample_file_read_inc(FileMetaData* meta) {
meta->stats.num_reads_sampled.fetch_add(kFileReadSampleRate,
std::memory_order_relaxed);
}
} // namespace ROCKSDB_NAMESPACE