0ed8cb666d
Summary: As a part of tiered storage, writing tempeature information to manifest is needed so that after DB recovery, RocksDB still has the tiering information, to implement some further necessary functionalities. Also fix some issues in simulated hybrid FS. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8284 Test Plan: Add a new unit test to validate that the information is indeed written and read back. Reviewed By: zhichao-cao Differential Revision: D28335801 fbshipit-source-id: 56aeb2e6ea090be0200181dd968c8a7278037def
92 lines
3.4 KiB
C++
92 lines
3.4 KiB
C++
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <utility>
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#include "rocksdb/file_system.h"
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namespace ROCKSDB_NAMESPACE {
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// A FileSystem simulates hybrid file system by ingesting latency and limit
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// IOPs.
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// This class is only used for development purpose and should not be used
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// in production.
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// Right now we ingest 15ms latency and allow 100 requests per second when
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// the file is for warm temperature.
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// When the object is destroyed, the list of warm files are written to a
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// file, which can be used to reopen a FileSystem and still recover the
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// list. This is to allow the information to preserve between db_bench
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// runs.
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class SimulatedHybridFileSystem : public FileSystemWrapper {
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public:
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// metadata_file_name stores metadata of the files, so that it can be
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// loaded after process restarts. If the file doesn't exist, create
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// one. The file is written when the class is destroyed.
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explicit SimulatedHybridFileSystem(const std::shared_ptr<FileSystem>& base,
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const std::string& metadata_file_name);
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~SimulatedHybridFileSystem() override;
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public:
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IOStatus NewRandomAccessFile(const std::string& fname,
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const FileOptions& file_opts,
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std::unique_ptr<FSRandomAccessFile>* result,
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IODebugContext* dbg) override;
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IOStatus NewWritableFile(const std::string& fname,
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const FileOptions& file_opts,
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std::unique_ptr<FSWritableFile>* result,
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IODebugContext* dbg) override;
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IOStatus DeleteFile(const std::string& fname, const IOOptions& options,
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IODebugContext* dbg) override;
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const char* Name() const override { return name_.c_str(); }
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private:
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// Limit 100 requests per second. Rate limiter is designed to byte but
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// we use it as fixed bytes is one request.
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std::shared_ptr<RateLimiter> rate_limiter_;
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std::mutex mutex_;
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std::unordered_set<std::string> warm_file_set_;
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std::string metadata_file_name_;
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std::string name_;
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};
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// Simulated random access file that can control IOPs and latency to simulate
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// specific storage media
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class SimulatedHybridRaf : public FSRandomAccessFileWrapper {
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public:
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SimulatedHybridRaf(FSRandomAccessFile* t,
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std::shared_ptr<RateLimiter> rate_limiter,
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Temperature temperature)
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: FSRandomAccessFileWrapper(t),
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rate_limiter_(rate_limiter),
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temperature_(temperature) {}
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~SimulatedHybridRaf() override {}
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IOStatus Read(uint64_t offset, size_t n, const IOOptions& options,
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Slice* result, char* scratch,
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IODebugContext* dbg) const override;
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IOStatus MultiRead(FSReadRequest* reqs, size_t num_reqs,
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const IOOptions& options, IODebugContext* dbg) override;
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IOStatus Prefetch(uint64_t offset, size_t n, const IOOptions& options,
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IODebugContext* dbg) override;
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private:
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std::shared_ptr<RateLimiter> rate_limiter_;
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Temperature temperature_;
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void RequestRateLimit(int64_t num_requests) const;
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};
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} // namespace ROCKSDB_NAMESPACE
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#endif // ROCKSDB_LITE
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