185 lines
5.8 KiB

  1. // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file. See the AUTHORS file for names of contributors.
  4. #ifndef STORAGE_LEVELDB_DB_DB_IMPL_H_
  5. #define STORAGE_LEVELDB_DB_DB_IMPL_H_
  6. #include <set>
  7. #include "db/dbformat.h"
  8. #include "db/log_writer.h"
  9. #include "db/snapshot.h"
  10. #include "leveldb/db.h"
  11. #include "leveldb/env.h"
  12. #include "port/port.h"
  13. namespace leveldb {
  14. class MemTable;
  15. class TableCache;
  16. class Version;
  17. class VersionEdit;
  18. class VersionSet;
  19. class DBImpl : public DB {
  20. public:
  21. DBImpl(const Options& options, const std::string& dbname);
  22. virtual ~DBImpl();
  23. // Implementations of the DB interface
  24. virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value);
  25. virtual Status Delete(const WriteOptions&, const Slice& key);
  26. virtual Status Write(const WriteOptions& options, WriteBatch* updates);
  27. virtual Status Get(const ReadOptions& options,
  28. const Slice& key,
  29. std::string* value);
  30. virtual Iterator* NewIterator(const ReadOptions&);
  31. virtual const Snapshot* GetSnapshot();
  32. virtual void ReleaseSnapshot(const Snapshot* snapshot);
  33. virtual bool GetProperty(const Slice& property, std::string* value);
  34. virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
  35. // Extra methods (for testing) that are not in the public DB interface
  36. // Compact any files in the named level that overlap [begin,end]
  37. void TEST_CompactRange(
  38. int level,
  39. const std::string& begin,
  40. const std::string& end);
  41. // Force current memtable contents to be compacted.
  42. Status TEST_CompactMemTable();
  43. // Return an internal iterator over the current state of the database.
  44. // The keys of this iterator are internal keys (see format.h).
  45. // The returned iterator should be deleted when no longer needed.
  46. Iterator* TEST_NewInternalIterator();
  47. // Return the maximum overlapping data (in bytes) at next level for any
  48. // file at a level >= 1.
  49. int64_t TEST_MaxNextLevelOverlappingBytes();
  50. private:
  51. friend class DB;
  52. Iterator* NewInternalIterator(const ReadOptions&,
  53. SequenceNumber* latest_snapshot);
  54. Status NewDB();
  55. // Recover the descriptor from persistent storage. May do a significant
  56. // amount of work to recover recently logged updates. Any changes to
  57. // be made to the descriptor are added to *edit.
  58. Status Recover(VersionEdit* edit);
  59. void MaybeIgnoreError(Status* s) const;
  60. // Delete any unneeded files and stale in-memory entries.
  61. void DeleteObsoleteFiles();
  62. // Compact the in-memory write buffer to disk. Switches to a new
  63. // log-file/memtable and writes a new descriptor iff successful.
  64. Status CompactMemTable();
  65. Status RecoverLogFile(uint64_t log_number,
  66. VersionEdit* edit,
  67. SequenceNumber* max_sequence);
  68. Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base);
  69. Status MakeRoomForWrite(bool force /* compact even if there is room? */);
  70. struct CompactionState;
  71. void MaybeScheduleCompaction();
  72. static void BGWork(void* db);
  73. void BackgroundCall();
  74. void BackgroundCompaction();
  75. void CleanupCompaction(CompactionState* compact);
  76. Status DoCompactionWork(CompactionState* compact);
  77. Status OpenCompactionOutputFile(CompactionState* compact);
  78. Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
  79. Status InstallCompactionResults(CompactionState* compact);
  80. // Constant after construction
  81. Env* const env_;
  82. const InternalKeyComparator internal_comparator_;
  83. const Options options_; // options_.comparator == &internal_comparator_
  84. bool owns_info_log_;
  85. bool owns_cache_;
  86. const std::string dbname_;
  87. // table_cache_ provides its own synchronization
  88. TableCache* table_cache_;
  89. // Lock over the persistent DB state. Non-NULL iff successfully acquired.
  90. FileLock* db_lock_;
  91. // State below is protected by mutex_
  92. port::Mutex mutex_;
  93. port::AtomicPointer shutting_down_;
  94. port::CondVar bg_cv_; // Signalled when background work finishes
  95. MemTable* mem_;
  96. MemTable* imm_; // Memtable being compacted
  97. port::AtomicPointer has_imm_; // So bg thread can detect non-NULL imm_
  98. WritableFile* logfile_;
  99. uint64_t logfile_number_;
  100. log::Writer* log_;
  101. SnapshotList snapshots_;
  102. // Set of table files to protect from deletion because they are
  103. // part of ongoing compactions.
  104. std::set<uint64_t> pending_outputs_;
  105. // Has a background compaction been scheduled or is running?
  106. bool bg_compaction_scheduled_;
  107. // Information for a manual compaction
  108. struct ManualCompaction {
  109. int level;
  110. std::string begin;
  111. std::string end;
  112. };
  113. ManualCompaction* manual_compaction_;
  114. VersionSet* versions_;
  115. // Have we encountered a background error in paranoid mode?
  116. Status bg_error_;
  117. // Per level compaction stats. stats_[level] stores the stats for
  118. // compactions that produced data for the specified "level".
  119. struct CompactionStats {
  120. int64_t micros;
  121. int64_t bytes_read;
  122. int64_t bytes_written;
  123. CompactionStats() : micros(0), bytes_read(0), bytes_written(0) { }
  124. void Add(const CompactionStats& c) {
  125. this->micros += c.micros;
  126. this->bytes_read += c.bytes_read;
  127. this->bytes_written += c.bytes_written;
  128. }
  129. };
  130. CompactionStats stats_[config::kNumLevels];
  131. // No copying allowed
  132. DBImpl(const DBImpl&);
  133. void operator=(const DBImpl&);
  134. const Comparator* user_comparator() const {
  135. return internal_comparator_.user_comparator();
  136. }
  137. };
  138. // Sanitize db options. The caller should delete result.info_log if
  139. // it is not equal to src.info_log.
  140. extern Options SanitizeOptions(const std::string& db,
  141. const InternalKeyComparator* icmp,
  142. const Options& src);
  143. }
  144. #endif // STORAGE_LEVELDB_DB_DB_IMPL_H_