// Copyright (c) 2013, Facebook, Inc. All rights reserved. // This source code is licensed under the BSD-style license found in the // LICENSE file in the root directory of this source tree. An additional grant // of patent rights can be found in the PATENTS file in the same directory. // // Copyright (c) 2011 The LevelDB Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. See the AUTHORS file for names of contributors. #pragma once #include #include #include #include #include "db/dbformat.h" #include "db/log_writer.h" #include "db/snapshot.h" #include "rocksdb/db.h" #include "rocksdb/env.h" #include "rocksdb/memtablerep.h" #include "rocksdb/transaction_log.h" #include "port/port.h" #include "util/stats_logger.h" #include "memtablelist.h" namespace rocksdb { class MemTable; class TableCache; class Version; class VersionEdit; class VersionSet; class DBImpl : public DB { public: DBImpl(const Options& options, const std::string& dbname); virtual ~DBImpl(); // Implementations of the DB interface virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value); virtual Status Merge(const WriteOptions&, const Slice& key, const Slice& value); virtual Status Delete(const WriteOptions&, const Slice& key); virtual Status Write(const WriteOptions& options, WriteBatch* updates); virtual Status Get(const ReadOptions& options, const Slice& key, std::string* value); virtual std::vector MultiGet(const ReadOptions& options, const std::vector& keys, std::vector* values); // Returns false if key doesn't exist in the database and true if it may. // If value_found is not passed in as null, then return the value if found in // memory. On return, if value was found, then value_found will be set to true // , otherwise false. virtual bool KeyMayExist(const ReadOptions& options, const Slice& key, std::string* value, bool* value_found = nullptr); virtual Iterator* NewIterator(const ReadOptions&); virtual const Snapshot* GetSnapshot(); virtual void ReleaseSnapshot(const Snapshot* snapshot); virtual bool GetProperty(const Slice& property, std::string* value); virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes); virtual void CompactRange(const Slice* begin, const Slice* end, bool reduce_level = false, int target_level = -1); virtual int NumberLevels(); virtual int MaxMemCompactionLevel(); virtual int Level0StopWriteTrigger(); virtual Status Flush(const FlushOptions& options); virtual Status DisableFileDeletions(); virtual Status EnableFileDeletions(); virtual Status GetLiveFiles(std::vector&, uint64_t* manifest_file_size, bool flush_memtable = true); virtual Status GetSortedWalFiles(VectorLogPtr& files); virtual SequenceNumber GetLatestSequenceNumber(); virtual Status GetUpdatesSince(SequenceNumber seq_number, unique_ptr* iter); virtual Status DeleteFile(std::string name); virtual void GetLiveFilesMetaData( std::vector *metadata); // Extra methods (for testing) that are not in the public DB interface // Compact any files in the named level that overlap [*begin, *end] void TEST_CompactRange(int level, const Slice* begin, const Slice* end); // Force current memtable contents to be flushed. Status TEST_FlushMemTable(); // Wait for memtable compaction Status TEST_WaitForFlushMemTable(); // Wait for any compaction Status TEST_WaitForCompact(); // Return an internal iterator over the current state of the database. // The keys of this iterator are internal keys (see format.h). // The returned iterator should be deleted when no longer needed. Iterator* TEST_NewInternalIterator(); // Return the maximum overlapping data (in bytes) at next level for any // file at a level >= 1. int64_t TEST_MaxNextLevelOverlappingBytes(); // Simulate a db crash, no elegant closing of database. void TEST_Destroy_DBImpl(); // Return the current manifest file no. uint64_t TEST_Current_Manifest_FileNo(); // Trigger's a background call for testing. void TEST_PurgeObsoleteteWAL(); // get total level0 file size. Only for testing. uint64_t TEST_GetLevel0TotalSize() { return versions_->NumLevelBytes(0);} protected: Env* const env_; const std::string dbname_; unique_ptr versions_; const InternalKeyComparator internal_comparator_; const Options options_; // options_.comparator == &internal_comparator_ const Comparator* user_comparator() const { return internal_comparator_.user_comparator(); } MemTable* GetMemTable() { return mem_; } Iterator* NewInternalIterator(const ReadOptions&, SequenceNumber* latest_snapshot); private: friend class DB; struct CompactionState; struct Writer; struct DeletionState; Status NewDB(); // Recover the descriptor from persistent storage. May do a significant // amount of work to recover recently logged updates. Any changes to // be made to the descriptor are added to *edit. Status Recover(VersionEdit* edit, MemTable* external_table = nullptr, bool error_if_log_file_exist = false); void MaybeIgnoreError(Status* s) const; const Status CreateArchivalDirectory(); // Delete any unneeded files and stale in-memory entries. void DeleteObsoleteFiles(); // Flush the in-memory write buffer to storage. Switches to a new // log-file/memtable and writes a new descriptor iff successful. Status FlushMemTableToOutputFile(bool* madeProgress = nullptr); Status RecoverLogFile(uint64_t log_number, VersionEdit* edit, SequenceNumber* max_sequence, MemTable* external_table); // The following two methods are used to flush a memtable to // storage. The first one is used atdatabase RecoveryTime (when the // database is opened) and is heavyweight because it holds the mutex // for the entire period. The second method WriteLevel0Table supports // concurrent flush memtables to storage. Status WriteLevel0TableForRecovery(MemTable* mem, VersionEdit* edit); Status WriteLevel0Table(std::vector &mems, VersionEdit* edit, uint64_t* filenumber); uint64_t SlowdownAmount(int n, int top, int bottom); Status MakeRoomForWrite(bool force /* compact even if there is room? */); WriteBatch* BuildBatchGroup(Writer** last_writer); // Force current memtable contents to be flushed. Status FlushMemTable(const FlushOptions& options); // Wait for memtable flushed Status WaitForFlushMemTable(); void MaybeScheduleLogDBDeployStats(); static void BGLogDBDeployStats(void* db); void LogDBDeployStats(); void MaybeScheduleFlushOrCompaction(); static void BGWorkCompaction(void* db); static void BGWorkFlush(void* db); void BackgroundCallCompaction(); void BackgroundCallFlush(); Status BackgroundCompaction(bool* madeProgress,DeletionState& deletion_state); Status BackgroundFlush(bool* madeProgress); void CleanupCompaction(CompactionState* compact); Status DoCompactionWork(CompactionState* compact); Status OpenCompactionOutputFile(CompactionState* compact); Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input); Status InstallCompactionResults(CompactionState* compact); void AllocateCompactionOutputFileNumbers(CompactionState* compact); void ReleaseCompactionUnusedFileNumbers(CompactionState* compact); // Returns the list of live files in 'live' and the list // of all files in the filesystem in 'allfiles'. void FindObsoleteFiles(DeletionState& deletion_state); // Diffs the files listed in filenames and those that do not // belong to live files are posibly removed. If the removed file // is a sst file, then it returns the file number in files_to_evict. void PurgeObsoleteFiles(DeletionState& deletion_state); // Removes the file listed in files_to_evict from the table_cache void EvictObsoleteFiles(DeletionState& deletion_state); Status DeleteLogFile(uint64_t number); void PurgeObsoleteWALFiles(); Status AppendSortedWalsOfType(const std::string& path, VectorLogPtr& log_files, WalFileType type); // Requires: all_logs should be sorted with earliest log file first // Retains all log files in all_logs which contain updates with seq no. // Greater Than or Equal to the requested SequenceNumber. Status RetainProbableWalFiles(VectorLogPtr& all_logs, const SequenceNumber target); // return true if bool CheckWalFileExistsAndEmpty(const WalFileType type, const uint64_t number); Status ReadFirstRecord(const WalFileType type, const uint64_t number, WriteBatch* const result); Status ReadFirstLine(const std::string& fname, WriteBatch* const batch); void PrintStatistics(); // dump rocksdb.stats to LOG void MaybeDumpStats(); // Return the minimum empty level that could hold the total data in the // input level. Return the input level, if such level could not be found. int FindMinimumEmptyLevelFitting(int level); // Move the files in the input level to the target level. // If target_level < 0, automatically calculate the minimum level that could // hold the data set. void ReFitLevel(int level, int target_level = -1); // Constant after construction const InternalFilterPolicy internal_filter_policy_; bool owns_info_log_; // table_cache_ provides its own synchronization unique_ptr table_cache_; // Lock over the persistent DB state. Non-nullptr iff successfully acquired. FileLock* db_lock_; // State below is protected by mutex_ port::Mutex mutex_; port::AtomicPointer shutting_down_; port::CondVar bg_cv_; // Signalled when background work finishes std::shared_ptr mem_rep_factory_; MemTable* mem_; MemTableList imm_; // Memtable that are not changing uint64_t logfile_number_; unique_ptr log_; std::string host_name_; // Queue of writers. std::deque writers_; WriteBatch tmp_batch_; SnapshotList snapshots_; // Set of table files to protect from deletion because they are // part of ongoing compactions. std::set pending_outputs_; // count how many background compaction been scheduled or is running? int bg_compaction_scheduled_; // number of background memtable flush jobs, submitted to the HIGH pool int bg_flush_scheduled_; // Has a background stats log thread scheduled? bool bg_logstats_scheduled_; // Information for a manual compaction struct ManualCompaction { int level; bool done; bool in_progress; // compaction request being processed? const InternalKey* begin; // nullptr means beginning of key range const InternalKey* end; // nullptr means end of key range InternalKey tmp_storage; // Used to keep track of compaction progress }; ManualCompaction* manual_compaction_; // Have we encountered a background error in paranoid mode? Status bg_error_; std::unique_ptr logger_; int64_t volatile last_log_ts; // shall we disable deletion of obsolete files bool disable_delete_obsolete_files_; // last time when DeleteObsoleteFiles was invoked uint64_t delete_obsolete_files_last_run_; // last time when PurgeObsoleteWALFiles ran. uint64_t purge_wal_files_last_run_; // last time stats were dumped to LOG std::atomic last_stats_dump_time_microsec_; // These count the number of microseconds for which MakeRoomForWrite stalls. uint64_t stall_level0_slowdown_; uint64_t stall_memtable_compaction_; uint64_t stall_level0_num_files_; std::vector stall_leveln_slowdown_; uint64_t stall_level0_slowdown_count_; uint64_t stall_memtable_compaction_count_; uint64_t stall_level0_num_files_count_; std::vector stall_leveln_slowdown_count_; // Time at which this instance was started. const uint64_t started_at_; bool flush_on_destroy_; // Used when disableWAL is true. // Per level compaction stats. stats_[level] stores the stats for // compactions that produced data for the specified "level". struct CompactionStats { uint64_t micros; // Bytes read from level N during compaction between levels N and N+1 int64_t bytes_readn; // Bytes read from level N+1 during compaction between levels N and N+1 int64_t bytes_readnp1; // Total bytes written during compaction between levels N and N+1 int64_t bytes_written; // Files read from level N during compaction between levels N and N+1 int files_in_leveln; // Files read from level N+1 during compaction between levels N and N+1 int files_in_levelnp1; // Files written during compaction between levels N and N+1 int files_out_levelnp1; // Number of compactions done int count; CompactionStats() : micros(0), bytes_readn(0), bytes_readnp1(0), bytes_written(0), files_in_leveln(0), files_in_levelnp1(0), files_out_levelnp1(0), count(0) { } void Add(const CompactionStats& c) { this->micros += c.micros; this->bytes_readn += c.bytes_readn; this->bytes_readnp1 += c.bytes_readnp1; this->bytes_written += c.bytes_written; this->files_in_leveln += c.files_in_leveln; this->files_in_levelnp1 += c.files_in_levelnp1; this->files_out_levelnp1 += c.files_out_levelnp1; this->count += 1; } }; std::vector stats_; // Used to compute per-interval statistics struct StatsSnapshot { uint64_t bytes_read_; uint64_t bytes_written_; uint64_t bytes_new_; double seconds_up_; StatsSnapshot() : bytes_read_(0), bytes_written_(0), bytes_new_(0), seconds_up_(0) {} }; StatsSnapshot last_stats_; static const int KEEP_LOG_FILE_NUM = 1000; std::string db_absolute_path_; // count of the number of contiguous delaying writes int delayed_writes_; // store the last flushed sequence. // Used by transaction log iterator. SequenceNumber last_flushed_sequence_; // The options to access storage files const EnvOptions storage_options_; // A value of true temporarily disables scheduling of background work bool bg_work_gate_closed_; // Guard against multiple concurrent refitting bool refitting_level_; // No copying allowed DBImpl(const DBImpl&); void operator=(const DBImpl&); // dump the delayed_writes_ to the log file and reset counter. void DelayLoggingAndReset(); // Return the earliest snapshot where seqno is visible. // Store the snapshot right before that, if any, in prev_snapshot inline SequenceNumber findEarliestVisibleSnapshot( SequenceNumber in, std::vector& snapshots, SequenceNumber* prev_snapshot); // Function that Get and KeyMayExist call with no_io true or false // Note: 'value_found' from KeyMayExist propagates here Status GetImpl(const ReadOptions& options, const Slice& key, std::string* value, bool* value_found = nullptr); }; // Sanitize db options. The caller should delete result.info_log if // it is not equal to src.info_log. extern Options SanitizeOptions(const std::string& db, const InternalKeyComparator* icmp, const InternalFilterPolicy* ipolicy, const Options& src); // Determine compression type, based on user options, level of the output // file and whether compression is disabled. // If enable_compression is false, then compression is always disabled no // matter what the values of the other two parameters are. // Otherwise, the compression type is determined based on options and level. CompressionType GetCompressionType(const Options& options, int level, const bool enable_compression); } // namespace rocksdb