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# 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 : :
# 5 : : #ifndef STORAGE_LEVELDB_DB_DB_IMPL_H_
# 6 : : #define STORAGE_LEVELDB_DB_DB_IMPL_H_
# 7 : :
# 8 : : #include <atomic>
# 9 : : #include <deque>
# 10 : : #include <set>
# 11 : : #include <string>
# 12 : :
# 13 : : #include "db/dbformat.h"
# 14 : : #include "db/log_writer.h"
# 15 : : #include "db/snapshot.h"
# 16 : : #include "leveldb/db.h"
# 17 : : #include "leveldb/env.h"
# 18 : : #include "port/port.h"
# 19 : : #include "port/thread_annotations.h"
# 20 : :
# 21 : : namespace leveldb {
# 22 : :
# 23 : : class MemTable;
# 24 : : class TableCache;
# 25 : : class Version;
# 26 : : class VersionEdit;
# 27 : : class VersionSet;
# 28 : :
# 29 : : class DBImpl : public DB {
# 30 : : public:
# 31 : : DBImpl(const Options& options, const std::string& dbname);
# 32 : :
# 33 : : DBImpl(const DBImpl&) = delete;
# 34 : : DBImpl& operator=(const DBImpl&) = delete;
# 35 : :
# 36 : : ~DBImpl() override;
# 37 : :
# 38 : : // Implementations of the DB interface
# 39 : : Status Put(const WriteOptions&, const Slice& key,
# 40 : : const Slice& value) override;
# 41 : : Status Delete(const WriteOptions&, const Slice& key) override;
# 42 : : Status Write(const WriteOptions& options, WriteBatch* updates) override;
# 43 : : Status Get(const ReadOptions& options, const Slice& key,
# 44 : : std::string* value) override;
# 45 : : Iterator* NewIterator(const ReadOptions&) override;
# 46 : : const Snapshot* GetSnapshot() override;
# 47 : : void ReleaseSnapshot(const Snapshot* snapshot) override;
# 48 : : bool GetProperty(const Slice& property, std::string* value) override;
# 49 : : void GetApproximateSizes(const Range* range, int n, uint64_t* sizes) override;
# 50 : : void CompactRange(const Slice* begin, const Slice* end) override;
# 51 : :
# 52 : : // Extra methods (for testing) that are not in the public DB interface
# 53 : :
# 54 : : // Compact any files in the named level that overlap [*begin,*end]
# 55 : : void TEST_CompactRange(int level, const Slice* begin, const Slice* end);
# 56 : :
# 57 : : // Force current memtable contents to be compacted.
# 58 : : Status TEST_CompactMemTable();
# 59 : :
# 60 : : // Return an internal iterator over the current state of the database.
# 61 : : // The keys of this iterator are internal keys (see format.h).
# 62 : : // The returned iterator should be deleted when no longer needed.
# 63 : : Iterator* TEST_NewInternalIterator();
# 64 : :
# 65 : : // Return the maximum overlapping data (in bytes) at next level for any
# 66 : : // file at a level >= 1.
# 67 : : int64_t TEST_MaxNextLevelOverlappingBytes();
# 68 : :
# 69 : : // Record a sample of bytes read at the specified internal key.
# 70 : : // Samples are taken approximately once every config::kReadBytesPeriod
# 71 : : // bytes.
# 72 : : void RecordReadSample(Slice key);
# 73 : :
# 74 : : private:
# 75 : : friend class DB;
# 76 : : struct CompactionState;
# 77 : : struct Writer;
# 78 : :
# 79 : : // Information for a manual compaction
# 80 : : struct ManualCompaction {
# 81 : : int level;
# 82 : : bool done;
# 83 : : const InternalKey* begin; // null means beginning of key range
# 84 : : const InternalKey* end; // null means end of key range
# 85 : : InternalKey tmp_storage; // Used to keep track of compaction progress
# 86 : : };
# 87 : :
# 88 : : // Per level compaction stats. stats_[level] stores the stats for
# 89 : : // compactions that produced data for the specified "level".
# 90 : : struct CompactionStats {
# 91 : 16427 : CompactionStats() : micros(0), bytes_read(0), bytes_written(0) {}
# 92 : :
# 93 : 1077 : void Add(const CompactionStats& c) {
# 94 : 1077 : this->micros += c.micros;
# 95 : 1077 : this->bytes_read += c.bytes_read;
# 96 : 1077 : this->bytes_written += c.bytes_written;
# 97 : 1077 : }
# 98 : :
# 99 : : int64_t micros;
# 100 : : int64_t bytes_read;
# 101 : : int64_t bytes_written;
# 102 : : };
# 103 : :
# 104 : : Iterator* NewInternalIterator(const ReadOptions&,
# 105 : : SequenceNumber* latest_snapshot,
# 106 : : uint32_t* seed);
# 107 : :
# 108 : : Status NewDB();
# 109 : :
# 110 : : // Recover the descriptor from persistent storage. May do a significant
# 111 : : // amount of work to recover recently logged updates. Any changes to
# 112 : : // be made to the descriptor are added to *edit.
# 113 : : Status Recover(VersionEdit* edit, bool* save_manifest)
# 114 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 115 : :
# 116 : : void MaybeIgnoreError(Status* s) const;
# 117 : :
# 118 : : // Delete any unneeded files and stale in-memory entries.
# 119 : : void DeleteObsoleteFiles() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 120 : :
# 121 : : // Compact the in-memory write buffer to disk. Switches to a new
# 122 : : // log-file/memtable and writes a new descriptor iff successful.
# 123 : : // Errors are recorded in bg_error_.
# 124 : : void CompactMemTable() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 125 : :
# 126 : : Status RecoverLogFile(uint64_t log_number, bool last_log, bool* save_manifest,
# 127 : : VersionEdit* edit, SequenceNumber* max_sequence)
# 128 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 129 : :
# 130 : : Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base)
# 131 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 132 : :
# 133 : : Status MakeRoomForWrite(bool force /* compact even if there is room? */)
# 134 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 135 : : WriteBatch* BuildBatchGroup(Writer** last_writer)
# 136 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 137 : :
# 138 : : void RecordBackgroundError(const Status& s);
# 139 : :
# 140 : : void MaybeScheduleCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 141 : : static void BGWork(void* db);
# 142 : : void BackgroundCall();
# 143 : : void BackgroundCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 144 : : void CleanupCompaction(CompactionState* compact)
# 145 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 146 : : Status DoCompactionWork(CompactionState* compact)
# 147 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 148 : :
# 149 : : Status OpenCompactionOutputFile(CompactionState* compact);
# 150 : : Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
# 151 : : Status InstallCompactionResults(CompactionState* compact)
# 152 : : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
# 153 : :
# 154 : 39863 : const Comparator* user_comparator() const {
# 155 : 39863 : return internal_comparator_.user_comparator();
# 156 : 39863 : }
# 157 : :
# 158 : : // Constant after construction
# 159 : : Env* const env_;
# 160 : : const InternalKeyComparator internal_comparator_;
# 161 : : const InternalFilterPolicy internal_filter_policy_;
# 162 : : const Options options_; // options_.comparator == &internal_comparator_
# 163 : : const bool owns_info_log_;
# 164 : : const bool owns_cache_;
# 165 : : const std::string dbname_;
# 166 : :
# 167 : : // table_cache_ provides its own synchronization
# 168 : : TableCache* const table_cache_;
# 169 : :
# 170 : : // Lock over the persistent DB state. Non-null iff successfully acquired.
# 171 : : FileLock* db_lock_;
# 172 : :
# 173 : : // State below is protected by mutex_
# 174 : : port::Mutex mutex_;
# 175 : : std::atomic<bool> shutting_down_;
# 176 : : port::CondVar background_work_finished_signal_ GUARDED_BY(mutex_);
# 177 : : MemTable* mem_;
# 178 : : MemTable* imm_ GUARDED_BY(mutex_); // Memtable being compacted
# 179 : : std::atomic<bool> has_imm_; // So bg thread can detect non-null imm_
# 180 : : WritableFile* logfile_;
# 181 : : uint64_t logfile_number_ GUARDED_BY(mutex_);
# 182 : : log::Writer* log_;
# 183 : : uint32_t seed_ GUARDED_BY(mutex_); // For sampling.
# 184 : :
# 185 : : // Queue of writers.
# 186 : : std::deque<Writer*> writers_ GUARDED_BY(mutex_);
# 187 : : WriteBatch* tmp_batch_ GUARDED_BY(mutex_);
# 188 : :
# 189 : : SnapshotList snapshots_ GUARDED_BY(mutex_);
# 190 : :
# 191 : : // Set of table files to protect from deletion because they are
# 192 : : // part of ongoing compactions.
# 193 : : std::set<uint64_t> pending_outputs_ GUARDED_BY(mutex_);
# 194 : :
# 195 : : // Has a background compaction been scheduled or is running?
# 196 : : bool background_compaction_scheduled_ GUARDED_BY(mutex_);
# 197 : :
# 198 : : ManualCompaction* manual_compaction_ GUARDED_BY(mutex_);
# 199 : :
# 200 : : VersionSet* const versions_ GUARDED_BY(mutex_);
# 201 : :
# 202 : : // Have we encountered a background error in paranoid mode?
# 203 : : Status bg_error_ GUARDED_BY(mutex_);
# 204 : :
# 205 : : CompactionStats stats_[config::kNumLevels] GUARDED_BY(mutex_);
# 206 : : };
# 207 : :
# 208 : : // Sanitize db options. The caller should delete result.info_log if
# 209 : : // it is not equal to src.info_log.
# 210 : : Options SanitizeOptions(const std::string& db,
# 211 : : const InternalKeyComparator* icmp,
# 212 : : const InternalFilterPolicy* ipolicy,
# 213 : : const Options& src);
# 214 : :
# 215 : : } // namespace leveldb
# 216 : :
# 217 : : #endif // STORAGE_LEVELDB_DB_DB_IMPL_H_
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