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217 Zeilen
7.4 KiB
217 Zeilen
7.4 KiB
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#ifndef STORAGE_LEVELDB_DB_DB_IMPL_H_
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#define STORAGE_LEVELDB_DB_DB_IMPL_H_
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#include <atomic>
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#include <deque>
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#include <set>
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#include <string>
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#include "db/dbformat.h"
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#include "db/log_writer.h"
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#include "db/snapshot.h"
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#include "leveldb/db.h"
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#include "leveldb/env.h"
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#include "port/port.h"
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#include "port/thread_annotations.h"
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namespace leveldb {
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class MemTable;
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class TableCache;
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class Version;
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class VersionEdit;
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class VersionSet;
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class DBImpl : public DB {
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public:
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DBImpl(const Options& options, const std::string& dbname);
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DBImpl(const DBImpl&) = delete;
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DBImpl& operator=(const DBImpl&) = delete;
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~DBImpl() override;
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// Implementations of the DB interface
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Status Put(const WriteOptions&, const Slice& key,
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const Slice& value) override;
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Status Delete(const WriteOptions&, const Slice& key) override;
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Status Write(const WriteOptions& options, WriteBatch* updates) override;
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Status Get(const ReadOptions& options, const Slice& key,
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std::string* value) override;
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Iterator* NewIterator(const ReadOptions&) override;
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const Snapshot* GetSnapshot() override;
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void ReleaseSnapshot(const Snapshot* snapshot) override;
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bool GetProperty(const Slice& property, std::string* value) override;
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void GetApproximateSizes(const Range* range, int n, uint64_t* sizes) override;
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void CompactRange(const Slice* begin, const Slice* end) override;
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// Extra methods (for testing) that are not in the public DB interface
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// Compact any files in the named level that overlap [*begin,*end]
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void TEST_CompactRange(int level, const Slice* begin, const Slice* end);
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// Force current memtable contents to be compacted.
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Status TEST_CompactMemTable();
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// Return an internal iterator over the current state of the database.
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// The keys of this iterator are internal keys (see format.h).
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// The returned iterator should be deleted when no longer needed.
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Iterator* TEST_NewInternalIterator();
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// Return the maximum overlapping data (in bytes) at next level for any
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// file at a level >= 1.
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int64_t TEST_MaxNextLevelOverlappingBytes();
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// Record a sample of bytes read at the specified internal key.
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// Samples are taken approximately once every config::kReadBytesPeriod
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// bytes.
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void RecordReadSample(Slice key);
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private:
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friend class DB;
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struct CompactionState;
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struct Writer;
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// Information for a manual compaction
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struct ManualCompaction {
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int level;
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bool done;
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const InternalKey* begin; // null means beginning of key range
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const InternalKey* end; // null means end of key range
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InternalKey tmp_storage; // Used to keep track of compaction progress
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};
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// Per level compaction stats. stats_[level] stores the stats for
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// compactions that produced data for the specified "level".
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struct CompactionStats {
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CompactionStats() : micros(0), bytes_read(0), bytes_written(0) {}
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void Add(const CompactionStats& c) {
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this->micros += c.micros;
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this->bytes_read += c.bytes_read;
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this->bytes_written += c.bytes_written;
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}
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int64_t micros;
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int64_t bytes_read;
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int64_t bytes_written;
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};
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Iterator* NewInternalIterator(const ReadOptions&,
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SequenceNumber* latest_snapshot,
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uint32_t* seed);
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Status NewDB();
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// Recover the descriptor from persistent storage. May do a significant
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// amount of work to recover recently logged updates. Any changes to
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// be made to the descriptor are added to *edit.
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Status Recover(VersionEdit* edit, bool* save_manifest)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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void MaybeIgnoreError(Status* s) const;
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// Delete any unneeded files and stale in-memory entries.
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void RemoveObsoleteFiles() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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// Compact the in-memory write buffer to disk. Switches to a new
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// log-file/memtable and writes a new descriptor iff successful.
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// Errors are recorded in bg_error_.
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void CompactMemTable() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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Status RecoverLogFile(uint64_t log_number, bool last_log, bool* save_manifest,
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VersionEdit* edit, SequenceNumber* max_sequence)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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Status MakeRoomForWrite(bool force /* compact even if there is room? */)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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WriteBatch* BuildBatchGroup(Writer** last_writer)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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void RecordBackgroundError(const Status& s);
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void MaybeScheduleCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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static void BGWork(void* db);
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void BackgroundCall();
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void BackgroundCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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void CleanupCompaction(CompactionState* compact)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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Status DoCompactionWork(CompactionState* compact)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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Status OpenCompactionOutputFile(CompactionState* compact);
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Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
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Status InstallCompactionResults(CompactionState* compact)
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EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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const Comparator* user_comparator() const {
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return internal_comparator_.user_comparator();
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}
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// Constant after construction
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Env* const env_;
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const InternalKeyComparator internal_comparator_;
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const InternalFilterPolicy internal_filter_policy_;
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const Options options_; // options_.comparator == &internal_comparator_
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const bool owns_info_log_;
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const bool owns_cache_;
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const std::string dbname_;
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// table_cache_ provides its own synchronization
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TableCache* const table_cache_;
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// Lock over the persistent DB state. Non-null iff successfully acquired.
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FileLock* db_lock_;
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// State below is protected by mutex_
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port::Mutex mutex_;
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std::atomic<bool> shutting_down_;
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port::CondVar background_work_finished_signal_ GUARDED_BY(mutex_);
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MemTable* mem_;
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MemTable* imm_ GUARDED_BY(mutex_); // Memtable being compacted
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std::atomic<bool> has_imm_; // So bg thread can detect non-null imm_
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WritableFile* logfile_;
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uint64_t logfile_number_ GUARDED_BY(mutex_);
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log::Writer* log_;
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uint32_t seed_ GUARDED_BY(mutex_); // For sampling.
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// Queue of writers.
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std::deque<Writer*> writers_ GUARDED_BY(mutex_);
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WriteBatch* tmp_batch_ GUARDED_BY(mutex_);
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SnapshotList snapshots_ GUARDED_BY(mutex_);
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// Set of table files to protect from deletion because they are
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// part of ongoing compactions.
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std::set<uint64_t> pending_outputs_ GUARDED_BY(mutex_);
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// Has a background compaction been scheduled or is running?
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bool background_compaction_scheduled_ GUARDED_BY(mutex_);
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ManualCompaction* manual_compaction_ GUARDED_BY(mutex_);
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VersionSet* const versions_ GUARDED_BY(mutex_);
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// Have we encountered a background error in paranoid mode?
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Status bg_error_ GUARDED_BY(mutex_);
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CompactionStats stats_[config::kNumLevels] GUARDED_BY(mutex_);
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};
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// Sanitize db options. The caller should delete result.info_log if
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// it is not equal to src.info_log.
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Options SanitizeOptions(const std::string& db,
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const InternalKeyComparator* icmp,
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const InternalFilterPolicy* ipolicy,
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const Options& src);
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_DB_DB_IMPL_H_
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