ceph/src/rocksdb/util/trace_replay.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 #pragma once
   7
   8 #include <memory>
   9 #include <unordered_map>
  10 #include <utility>
  11
  12 #include "rocksdb/env.h"
  13 #include "rocksdb/trace_reader_writer.h"
  14
  15 namespace rocksdb {
  16
  17 class ColumnFamilyHandle;
  18 class ColumnFamilyData;
  19 class DB;
  20 class DBImpl;
  21 class Slice;
  22 class WriteBatch;
  23
  24 const std::string kTraceMagic = "feedcafedeadbeef";
  25 const unsigned int kTraceTimestampSize = 8;
  26 const unsigned int kTraceTypeSize = 1;
  27 const unsigned int kTracePayloadLengthSize = 4;
  28 const unsigned int kTraceMetadataSize =
  29     kTraceTimestampSize + kTraceTypeSize + kTracePayloadLengthSize;
  30
  31 enum TraceType : char {
  32   kTraceBegin = 1,
  33   kTraceEnd = 2,
  34   kTraceWrite = 3,
  35   kTraceGet = 4,
  36   kTraceIteratorSeek = 5,
  37   kTraceIteratorSeekForPrev = 6,
  38   kTraceMax,
  39 };
  40
  41 // TODO: This should also be made part of public interface to help users build
  42 // custom TracerReaders and TraceWriters.
  43 struct Trace {
  44   uint64_t ts;
  45   TraceType type;
  46   std::string payload;
  47
  48   void reset() {
  49     ts = 0;
  50     type = kTraceMax;
  51     payload.clear();
  52   }
  53 };
  54
  55 // Trace RocksDB operations using a TraceWriter.
  56 class Tracer {
  57  public:
  58   Tracer(Env* env, std::unique_ptr<TraceWriter>&& trace_writer);
  59   ~Tracer();
  60
  61   Status Write(WriteBatch* write_batch);
  62   Status Get(ColumnFamilyHandle* cfname, const Slice& key);
  63   Status IteratorSeek(const uint32_t& cf_id, const Slice& key);
  64   Status IteratorSeekForPrev(const uint32_t& cf_id, const Slice& key);
  65
  66   Status Close();
  67
  68  private:
  69   Status WriteHeader();
  70   Status WriteFooter();
  71   Status WriteTrace(const Trace& trace);
  72
  73   Env* env_;
  74   unique_ptr<TraceWriter> trace_writer_;
  75 };
  76
  77 // Replay RocksDB operations from a trace.
  78 class Replayer {
  79  public:
  80   Replayer(DB* db, const std::vector<ColumnFamilyHandle*>& handles,
  81            std::unique_ptr<TraceReader>&& reader);
  82   ~Replayer();
  83
  84   Status Replay();
  85
  86  private:
  87   Status ReadHeader(Trace* header);
  88   Status ReadFooter(Trace* footer);
  89   Status ReadTrace(Trace* trace);
  90
  91   DBImpl* db_;
  92   std::unique_ptr<TraceReader> trace_reader_;
  93   std::unordered_map<uint32_t, ColumnFamilyHandle*> cf_map_;
  94 };
  95
  96 }  // namespace rocksdb