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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 [ # # ]: 0 : 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 [ + - + - ]: 22007 : CompactionStats() : micros(0), bytes_read(0), bytes_written(0) {}
92 : :
93 : 2029 : void Add(const CompactionStats& c) {
94 : 2029 : this->micros += c.micros;
95 : 2029 : this->bytes_read += c.bytes_read;
96 [ + + ]: 2029 : this->bytes_written += c.bytes_written;
97 : : }
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 : 125857 : const Comparator* user_comparator() const {
155 [ - + + - ]: 125857 : return internal_comparator_.user_comparator();
156 : : }
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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