ceph/src/rocksdb/db/wal_manager.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 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
   7 // Use of this source code is governed by a BSD-style license that can be
   8 // found in the LICENSE file. See the AUTHORS file for names of contributors.
   9 #pragma once
  10
  11 #include <atomic>
  12 #include <deque>
  13 #include <limits>
  14 #include <set>
  15 #include <utility>
  16 #include <vector>
  17 #include <string>
  18 #include <memory>
  19
  20 #include "db/version_set.h"
  21 #include "file/file_util.h"
  22 #include "options/db_options.h"
  23 #include "port/port.h"
  24 #include "rocksdb/env.h"
  25 #include "rocksdb/status.h"
  26 #include "rocksdb/transaction_log.h"
  27 #include "rocksdb/types.h"
  28
  29 namespace ROCKSDB_NAMESPACE {
  30
  31 #ifndef ROCKSDB_LITE
  32
  33 // WAL manager provides the abstraction for reading the WAL files as a single
  34 // unit. Internally, it opens and reads the files using Reader or Writer
  35 // abstraction.
  36 class WalManager {
  37  public:
  38   WalManager(const ImmutableDBOptions& db_options,
  39              const FileOptions& file_options,
  40              const std::shared_ptr<IOTracer>& io_tracer,
  41              const bool seq_per_batch = false)
  42       : db_options_(db_options),
  43         file_options_(file_options),
  44         env_(db_options.env),
  45         fs_(db_options.fs, io_tracer),
  46         purge_wal_files_last_run_(0),
  47         seq_per_batch_(seq_per_batch),
  48         wal_in_db_path_(IsWalDirSameAsDBPath(&db_options)),
  49         io_tracer_(io_tracer) {}
  50
  51   Status GetSortedWalFiles(VectorLogPtr& files);
  52
  53   // Allow user to tail transaction log to find all recent changes to the
  54   // database that are newer than `seq_number`.
  55   Status GetUpdatesSince(
  56       SequenceNumber seq_number, std::unique_ptr<TransactionLogIterator>* iter,
  57       const TransactionLogIterator::ReadOptions& read_options,
  58       VersionSet* version_set);
  59
  60   void PurgeObsoleteWALFiles();
  61
  62   void ArchiveWALFile(const std::string& fname, uint64_t number);
  63
  64   Status DeleteFile(const std::string& fname, uint64_t number);
  65
  66   Status GetLiveWalFile(uint64_t number, std::unique_ptr<LogFile>* log_file);
  67
  68   Status TEST_ReadFirstRecord(const WalFileType type, const uint64_t number,
  69                               SequenceNumber* sequence) {
  70     return ReadFirstRecord(type, number, sequence);
  71   }
  72
  73   Status TEST_ReadFirstLine(const std::string& fname, const uint64_t number,
  74                             SequenceNumber* sequence) {
  75     return ReadFirstLine(fname, number, sequence);
  76   }
  77
  78  private:
  79   Status GetSortedWalsOfType(const std::string& path, VectorLogPtr& log_files,
  80                              WalFileType type);
  81   // Requires: all_logs should be sorted with earliest log file first
  82   // Retains all log files in all_logs which contain updates with seq no.
  83   // Greater Than or Equal to the requested SequenceNumber.
  84   Status RetainProbableWalFiles(VectorLogPtr& all_logs,
  85                                 const SequenceNumber target);
  86
  87   Status ReadFirstRecord(const WalFileType type, const uint64_t number,
  88                          SequenceNumber* sequence);
  89
  90   Status ReadFirstLine(const std::string& fname, const uint64_t number,
  91                        SequenceNumber* sequence);
  92
  93   // ------- state from DBImpl ------
  94   const ImmutableDBOptions& db_options_;
  95   const FileOptions file_options_;
  96   Env* env_;
  97   const FileSystemPtr fs_;
  98
  99   // ------- WalManager state -------
 100   // cache for ReadFirstRecord() calls
 101   std::unordered_map<uint64_t, SequenceNumber> read_first_record_cache_;
 102   port::Mutex read_first_record_cache_mutex_;
 103
 104   // last time when PurgeObsoleteWALFiles ran.
 105   uint64_t purge_wal_files_last_run_;
 106
 107   bool seq_per_batch_;
 108
 109   bool wal_in_db_path_;
 110
 111   // obsolete files will be deleted every this seconds if ttl deletion is
 112   // enabled and archive size_limit is disabled.
 113   static const uint64_t kDefaultIntervalToDeleteObsoleteWAL = 600;
 114
 115   std::shared_ptr<IOTracer> io_tracer_;
 116 };
 117
 118 #endif  // ROCKSDB_LITE
 119 }  // namespace ROCKSDB_NAMESPACE