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/options.h"
  14 #include "rocksdb/trace_reader_writer.h"
  15
  16 namespace rocksdb {
  17
  18 class ColumnFamilyHandle;
  19 class ColumnFamilyData;
  20 class DB;
  21 class DBImpl;
  22 class Slice;
  23 class WriteBatch;
  24
  25 extern const std::string kTraceMagic;
  26 const unsigned int kTraceTimestampSize = 8;
  27 const unsigned int kTraceTypeSize = 1;
  28 const unsigned int kTracePayloadLengthSize = 4;
  29 const unsigned int kTraceMetadataSize =
  30     kTraceTimestampSize + kTraceTypeSize + kTracePayloadLengthSize;
  31
  32 enum TraceType : char {
  33   kTraceBegin = 1,
  34   kTraceEnd = 2,
  35   kTraceWrite = 3,
  36   kTraceGet = 4,
  37   kTraceIteratorSeek = 5,
  38   kTraceIteratorSeekForPrev = 6,
  39   kTraceMax,
  40 };
  41
  42 // TODO: This should also be made part of public interface to help users build
  43 // custom TracerReaders and TraceWriters.
  44 struct Trace {
  45   uint64_t ts;
  46   TraceType type;
  47   std::string payload;
  48
  49   void reset() {
  50     ts = 0;
  51     type = kTraceMax;
  52     payload.clear();
  53   }
  54 };
  55
  56 // Trace RocksDB operations using a TraceWriter.
  57 class Tracer {
  58  public:
  59   Tracer(Env* env, const TraceOptions& trace_options,
  60          std::unique_ptr<TraceWriter>&& trace_writer);
  61   ~Tracer();
  62
  63   Status Write(WriteBatch* write_batch);
  64   Status Get(ColumnFamilyHandle* cfname, const Slice& key);
  65   Status IteratorSeek(const uint32_t& cf_id, const Slice& key);
  66   Status IteratorSeekForPrev(const uint32_t& cf_id, const Slice& key);
  67   bool IsTraceFileOverMax();
  68
  69   Status Close();
  70
  71  private:
  72   Status WriteHeader();
  73   Status WriteFooter();
  74   Status WriteTrace(const Trace& trace);
  75   bool ShouldSkipTrace(const TraceType& type);
  76
  77   Env* env_;
  78   TraceOptions trace_options_;
  79   std::unique_ptr<TraceWriter> trace_writer_;
  80   uint64_t trace_request_count_;
  81 };
  82
  83 // Replay RocksDB operations from a trace.
  84 class Replayer {
  85  public:
  86   Replayer(DB* db, const std::vector<ColumnFamilyHandle*>& handles,
  87            std::unique_ptr<TraceReader>&& reader);
  88   ~Replayer();
  89
  90   Status Replay();
  91
  92  private:
  93   Status ReadHeader(Trace* header);
  94   Status ReadFooter(Trace* footer);
  95   Status ReadTrace(Trace* trace);
  96
  97   DBImpl* db_;
  98   std::unique_ptr<TraceReader> trace_reader_;
  99   std::unordered_map<uint32_t, ColumnFamilyHandle*> cf_map_;
 100 };
 101
 102 }  // namespace rocksdb