12b6cdeed3
Summary: A framework for tracing and replaying RocksDB operations. A binary trace file is created by capturing the DB operations, and it can be replayed back at the same rate using db_bench. - Column-families are supported - Multi-threaded tracing is supported. - TraceReader and TraceWriter are exposed to the user, so that tracing to various destinations can be enabled (say, to other messaging/logging services). By default, a FileTraceReader and FileTraceWriter are implemented to capture to a file and replay from it. - This is not yet ideal to be enabled in production due to large performance overhead, but it can be safely tried out in a shadow setup, say, for analyzing RocksDB operations. Currently supported DB operations: - Writes: -- Put -- Merge -- Delete -- SingleDelete -- DeleteRange -- Write - Reads: -- Get (point lookups) Pull Request resolved: https://github.com/facebook/rocksdb/pull/3837 Differential Revision: D7974837 Pulled By: sagar0 fbshipit-source-id: 8ec65aaf336504bc1f6ed0feae67f6ed5ef97a72
92 lines
2.1 KiB
C++
92 lines
2.1 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. 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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#include <memory>
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#include <unordered_map>
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#include <utility>
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#include "rocksdb/env.h"
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#include "rocksdb/trace_reader_writer.h"
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namespace rocksdb {
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class ColumnFamilyHandle;
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class DB;
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class DBImpl;
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class Slice;
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class WriteBatch;
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const std::string kTraceMagic = "feedcafedeadbeef";
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const unsigned int kTraceTimestampSize = 8;
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const unsigned int kTraceTypeSize = 1;
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const unsigned int kTracePayloadLengthSize = 4;
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const unsigned int kTraceMetadataSize =
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kTraceTimestampSize + kTraceTypeSize + kTracePayloadLengthSize;
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enum TraceType : char {
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kTraceBegin = 1,
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kTraceEnd = 2,
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kTraceWrite = 3,
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kTraceGet = 4,
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kTraceMax,
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};
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// TODO: This should also be made part of public interface to help users build
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// custom TracerReaders and TraceWriters.
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struct Trace {
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uint64_t ts;
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TraceType type;
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std::string payload;
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void reset() {
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ts = 0;
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type = kTraceMax;
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payload.clear();
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}
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};
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// Trace RocksDB operations using a TraceWriter.
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class Tracer {
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public:
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Tracer(Env* env, std::unique_ptr<TraceWriter>&& trace_writer);
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~Tracer();
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Status Write(WriteBatch* write_batch);
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Status Get(ColumnFamilyHandle* cfname, const Slice& key);
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Status Close();
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private:
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Status WriteHeader();
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Status WriteFooter();
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Status WriteTrace(const Trace& trace);
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Env* env_;
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unique_ptr<TraceWriter> trace_writer_;
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};
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// Replay RocksDB operations from a trace.
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class Replayer {
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public:
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Replayer(DB* db, const std::vector<ColumnFamilyHandle*>& handles,
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std::unique_ptr<TraceReader>&& reader);
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~Replayer();
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Status Replay();
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private:
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Status ReadHeader(Trace* header);
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Status ReadFooter(Trace* footer);
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Status ReadTrace(Trace* trace);
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DBImpl* db_;
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std::unique_ptr<TraceReader> trace_reader_;
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std::unordered_map<uint32_t, ColumnFamilyHandle*> cf_map_;
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};
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} // namespace rocksdb
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