Line data Source code
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 <deque>
9 : #include <set>
10 : #include "db/dbformat.h"
11 : #include "db/log_writer.h"
12 : #include "db/snapshot.h"
13 : #include "leveldb/db.h"
14 : #include "leveldb/env.h"
15 : #include "port/port.h"
16 : #include "port/thread_annotations.h"
17 :
18 : namespace leveldb {
19 :
20 : class MemTable;
21 : class TableCache;
22 : class Version;
23 : class VersionEdit;
24 : class VersionSet;
25 :
26 : class DBImpl : public DB {
27 : public:
28 : DBImpl(const Options& options, const std::string& dbname);
29 : virtual ~DBImpl();
30 :
31 : // Implementations of the DB interface
32 : virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value);
33 : virtual Status Delete(const WriteOptions&, const Slice& key);
34 : virtual Status Write(const WriteOptions& options, WriteBatch* updates);
35 : virtual Status Get(const ReadOptions& options,
36 : const Slice& key,
37 : std::string* value);
38 : virtual Iterator* NewIterator(const ReadOptions&);
39 : virtual const Snapshot* GetSnapshot();
40 : virtual void ReleaseSnapshot(const Snapshot* snapshot);
41 : virtual bool GetProperty(const Slice& property, std::string* value);
42 : virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
43 : virtual void CompactRange(const Slice* begin, const Slice* end);
44 :
45 : // Extra methods (for testing) that are not in the public DB interface
46 :
47 : // Compact any files in the named level that overlap [*begin,*end]
48 : void TEST_CompactRange(int level, const Slice* begin, const Slice* end);
49 :
50 : // Force current memtable contents to be compacted.
51 : Status TEST_CompactMemTable();
52 :
53 : // Return an internal iterator over the current state of the database.
54 : // The keys of this iterator are internal keys (see format.h).
55 : // The returned iterator should be deleted when no longer needed.
56 : Iterator* TEST_NewInternalIterator();
57 :
58 : // Return the maximum overlapping data (in bytes) at next level for any
59 : // file at a level >= 1.
60 : int64_t TEST_MaxNextLevelOverlappingBytes();
61 :
62 : // Record a sample of bytes read at the specified internal key.
63 : // Samples are taken approximately once every config::kReadBytesPeriod
64 : // bytes.
65 : void RecordReadSample(Slice key);
66 :
67 : private:
68 : friend class DB;
69 : struct CompactionState;
70 : struct Writer;
71 :
72 : Iterator* NewInternalIterator(const ReadOptions&,
73 : SequenceNumber* latest_snapshot,
74 : uint32_t* seed);
75 :
76 : Status NewDB();
77 :
78 : // Recover the descriptor from persistent storage. May do a significant
79 : // amount of work to recover recently logged updates. Any changes to
80 : // be made to the descriptor are added to *edit.
81 : Status Recover(VersionEdit* edit) EXCLUSIVE_LOCKS_REQUIRED(mutex_);
82 :
83 : void MaybeIgnoreError(Status* s) const;
84 :
85 : // Delete any unneeded files and stale in-memory entries.
86 : void DeleteObsoleteFiles();
87 :
88 : // Compact the in-memory write buffer to disk. Switches to a new
89 : // log-file/memtable and writes a new descriptor iff successful.
90 : // Errors are recorded in bg_error_.
91 : void CompactMemTable() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
92 :
93 : Status RecoverLogFile(uint64_t log_number,
94 : VersionEdit* edit,
95 : SequenceNumber* max_sequence)
96 : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
97 :
98 : Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base)
99 : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
100 :
101 : Status MakeRoomForWrite(bool force /* compact even if there is room? */)
102 : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
103 : WriteBatch* BuildBatchGroup(Writer** last_writer);
104 :
105 : void RecordBackgroundError(const Status& s);
106 :
107 : void MaybeScheduleCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
108 : static void BGWork(void* db);
109 : void BackgroundCall();
110 : void BackgroundCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
111 : void CleanupCompaction(CompactionState* compact)
112 : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
113 : Status DoCompactionWork(CompactionState* compact)
114 : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
115 :
116 : Status OpenCompactionOutputFile(CompactionState* compact);
117 : Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
118 : Status InstallCompactionResults(CompactionState* compact)
119 : EXCLUSIVE_LOCKS_REQUIRED(mutex_);
120 :
121 : // Constant after construction
122 : Env* const env_;
123 : const InternalKeyComparator internal_comparator_;
124 : const InternalFilterPolicy internal_filter_policy_;
125 : const Options options_; // options_.comparator == &internal_comparator_
126 : bool owns_info_log_;
127 : bool owns_cache_;
128 : const std::string dbname_;
129 :
130 : // table_cache_ provides its own synchronization
131 : TableCache* table_cache_;
132 :
133 : // Lock over the persistent DB state. Non-NULL iff successfully acquired.
134 : FileLock* db_lock_;
135 :
136 : // State below is protected by mutex_
137 : port::Mutex mutex_;
138 : port::AtomicPointer shutting_down_;
139 : port::CondVar bg_cv_; // Signalled when background work finishes
140 : MemTable* mem_;
141 : MemTable* imm_; // Memtable being compacted
142 : port::AtomicPointer has_imm_; // So bg thread can detect non-NULL imm_
143 : WritableFile* logfile_;
144 : uint64_t logfile_number_;
145 : log::Writer* log_;
146 : uint32_t seed_; // For sampling.
147 :
148 : // Queue of writers.
149 : std::deque<Writer*> writers_;
150 : WriteBatch* tmp_batch_;
151 :
152 : SnapshotList snapshots_;
153 :
154 : // Set of table files to protect from deletion because they are
155 : // part of ongoing compactions.
156 : std::set<uint64_t> pending_outputs_;
157 :
158 : // Has a background compaction been scheduled or is running?
159 : bool bg_compaction_scheduled_;
160 :
161 : // Information for a manual compaction
162 0 : struct ManualCompaction {
163 : int level;
164 : bool done;
165 : const InternalKey* begin; // NULL means beginning of key range
166 : const InternalKey* end; // NULL means end of key range
167 : InternalKey tmp_storage; // Used to keep track of compaction progress
168 : };
169 : ManualCompaction* manual_compaction_;
170 :
171 : VersionSet* versions_;
172 :
173 : // Have we encountered a background error in paranoid mode?
174 : Status bg_error_;
175 :
176 : // Per level compaction stats. stats_[level] stores the stats for
177 : // compactions that produced data for the specified "level".
178 : struct CompactionStats {
179 : int64_t micros;
180 : int64_t bytes_read;
181 : int64_t bytes_written;
182 :
183 1830 : CompactionStats() : micros(0), bytes_read(0), bytes_written(0) { }
184 :
185 : void Add(const CompactionStats& c) {
186 122 : this->micros += c.micros;
187 7 : this->bytes_read += c.bytes_read;
188 122 : this->bytes_written += c.bytes_written;
189 : }
190 : };
191 : CompactionStats stats_[config::kNumLevels];
192 :
193 : // No copying allowed
194 : DBImpl(const DBImpl&);
195 : void operator=(const DBImpl&);
196 :
197 : const Comparator* user_comparator() const {
198 1821 : return internal_comparator_.user_comparator();
199 : }
200 : };
201 :
202 : // Sanitize db options. The caller should delete result.info_log if
203 : // it is not equal to src.info_log.
204 : extern Options SanitizeOptions(const std::string& db,
205 : const InternalKeyComparator* icmp,
206 : const InternalFilterPolicy* ipolicy,
207 : const Options& src);
208 :
209 : } // namespace leveldb
210 :
211 : #endif // STORAGE_LEVELDB_DB_DB_IMPL_H_
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