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rocksdb/db/version_set.h

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43 KiB

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root 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.
//
// The representation of a DBImpl consists of a set of Versions. The
// newest version is called "current". Older versions may be kept
// around to provide a consistent view to live iterators.
//
// Each Version keeps track of a set of Table files per level. The
// entire set of versions is maintained in a VersionSet.
//
// Version,VersionSet are thread-compatible, but require external
// synchronization on all accesses.
#pragma once
#include <atomic>
#include <deque>
#include <limits>
#include <map>
#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "db/column_family.h"
#include "db/compaction.h"
#include "db/compaction_picker.h"
#include "db/dbformat.h"
#include "db/file_indexer.h"
#include "db/log_reader.h"
#include "db/range_del_aggregator.h"
#include "db/read_callback.h"
#include "db/table_cache.h"
#include "db/version_builder.h"
#include "db/version_edit.h"
#include "db/write_controller.h"
#include "monitoring/instrumented_mutex.h"
#include "options/db_options.h"
#include "port/port.h"
#include "rocksdb/env.h"
namespace rocksdb {
namespace log {
class Writer;
}
class Compaction;
class LogBuffer;
class LookupKey;
class MemTable;
class Version;
class VersionSet;
class WriteBufferManager;
class MergeContext;
class ColumnFamilySet;
class TableCache;
class MergeIteratorBuilder;
// Return the smallest index i such that file_level.files[i]->largest >= key.
// Return file_level.num_files if there is no such file.
// REQUIRES: "file_level.files" contains a sorted list of
// non-overlapping files.
extern int FindFile(const InternalKeyComparator& icmp,
const LevelFilesBrief& file_level, const Slice& key);
// Returns true iff some file in "files" overlaps the user key range
// [*smallest,*largest].
// smallest==nullptr represents a key smaller than all keys in the DB.
// largest==nullptr represents a key largest than all keys in the DB.
// REQUIRES: If disjoint_sorted_files, file_level.files[]
// contains disjoint ranges in sorted order.
extern bool SomeFileOverlapsRange(const InternalKeyComparator& icmp,
bool disjoint_sorted_files,
const LevelFilesBrief& file_level,
const Slice* smallest_user_key,
const Slice* largest_user_key);
// Generate LevelFilesBrief from vector<FdWithKeyRange*>
// Would copy smallest_key and largest_key data to sequential memory
// arena: Arena used to allocate the memory
extern void DoGenerateLevelFilesBrief(LevelFilesBrief* file_level,
const std::vector<FileMetaData*>& files,
Arena* arena);
class VersionStorageInfo {
public:
VersionStorageInfo(const InternalKeyComparator* internal_comparator,
const Comparator* user_comparator, int num_levels,
CompactionStyle compaction_style,
VersionStorageInfo* src_vstorage,
bool _force_consistency_checks);
~VersionStorageInfo();
void Reserve(int level, size_t size) { files_[level].reserve(size); }
void AddFile(int level, FileMetaData* f, Logger* info_log = nullptr);
void SetFinalized();
// Update num_non_empty_levels_.
void UpdateNumNonEmptyLevels();
void GenerateFileIndexer() {
file_indexer_.UpdateIndex(&arena_, num_non_empty_levels_, files_);
}
// Update the accumulated stats from a file-meta.
void UpdateAccumulatedStats(FileMetaData* file_meta);
// Decrease the current stat from a to-be-deleted file-meta
void RemoveCurrentStats(FileMetaData* file_meta);
void ComputeCompensatedSizes();
// Updates internal structures that keep track of compaction scores
// We use compaction scores to figure out which compaction to do next
// REQUIRES: db_mutex held!!
// TODO find a better way to pass compaction_options_fifo.
void ComputeCompactionScore(const ImmutableCFOptions& immutable_cf_options,
const MutableCFOptions& mutable_cf_options);
// Estimate est_comp_needed_bytes_
void EstimateCompactionBytesNeeded(
const MutableCFOptions& mutable_cf_options);
// This computes files_marked_for_compaction_ and is called by
// ComputeCompactionScore()
void ComputeFilesMarkedForCompaction();
// This computes ttl_expired_files_ and is called by
// ComputeCompactionScore()
void ComputeExpiredTtlFiles(const ImmutableCFOptions& ioptions,
const uint64_t ttl);
// This computes bottommost_files_marked_for_compaction_ and is called by
// ComputeCompactionScore() or UpdateOldestSnapshot().
//
// Among bottommost files (assumes they've already been computed), marks the
// ones that have keys that would be eliminated if recompacted, according to
// the seqnum of the oldest existing snapshot. Must be called every time
// oldest snapshot changes as that is when bottom-level files can become
// eligible for compaction.
//
// REQUIRES: DB mutex held
void ComputeBottommostFilesMarkedForCompaction();
// Generate level_files_brief_ from files_
void GenerateLevelFilesBrief();
// Sort all files for this version based on their file size and
// record results in files_by_compaction_pri_. The largest files are listed
// first.
void UpdateFilesByCompactionPri(CompactionPri compaction_pri);
void GenerateLevel0NonOverlapping();
bool level0_non_overlapping() const {
return level0_non_overlapping_;
}
// Check whether each file in this version is bottommost (i.e., nothing in its
// key-range could possibly exist in an older file/level).
// REQUIRES: This version has not been saved
void GenerateBottommostFiles();
// Updates the oldest snapshot and related internal state, like the bottommost
// files marked for compaction.
// REQUIRES: DB mutex held
void UpdateOldestSnapshot(SequenceNumber oldest_snapshot_seqnum);
int MaxInputLevel() const;
int MaxOutputLevel(bool allow_ingest_behind) const;
// Return level number that has idx'th highest score
int CompactionScoreLevel(int idx) const { return compaction_level_[idx]; }
// Return idx'th highest score
double CompactionScore(int idx) const { return compaction_score_[idx]; }
void GetOverlappingInputs(
int level, const InternalKey* begin, // nullptr means before all keys
const InternalKey* end, // nullptr means after all keys
std::vector<FileMetaData*>* inputs,
int hint_index = -1, // index of overlap file
int* file_index = nullptr, // return index of overlap file
bool expand_range = true, // if set, returns files which overlap the
// range and overlap each other. If false,
// then just files intersecting the range
InternalKey** next_smallest = nullptr) // if non-null, returns the
const; // smallest key of next file not included
void GetCleanInputsWithinInterval(
int level, const InternalKey* begin, // nullptr means before all keys
const InternalKey* end, // nullptr means after all keys
std::vector<FileMetaData*>* inputs,
int hint_index = -1, // index of overlap file
int* file_index = nullptr) // return index of overlap file
const;
void GetOverlappingInputsRangeBinarySearch(
int level, // level > 0
const InternalKey* begin, // nullptr means before all keys
const InternalKey* end, // nullptr means after all keys
std::vector<FileMetaData*>* inputs,
int hint_index, // index of overlap file
int* file_index, // return index of overlap file
bool within_interval = false, // if set, force the inputs within interval
InternalKey** next_smallest = nullptr) // if non-null, returns the
const; // smallest key of next file not included
void ExtendFileRangeOverlappingInterval(
int level,
const InternalKey* begin, // nullptr means before all keys
const InternalKey* end, // nullptr means after all keys
unsigned int index, // start extending from this index
int* startIndex, // return the startIndex of input range
int* endIndex) // return the endIndex of input range
const;
void ExtendFileRangeWithinInterval(
int level,
const InternalKey* begin, // nullptr means before all keys
const InternalKey* end, // nullptr means after all keys
unsigned int index, // start extending from this index
int* startIndex, // return the startIndex of input range
int* endIndex) // return the endIndex of input range
const;
// Returns true iff some file in the specified level overlaps
// some part of [*smallest_user_key,*largest_user_key].
// smallest_user_key==NULL represents a key smaller than all keys in the DB.
// largest_user_key==NULL represents a key largest than all keys in the DB.
bool OverlapInLevel(int level, const Slice* smallest_user_key,
const Slice* largest_user_key);
// Returns true iff the first or last file in inputs contains
// an overlapping user key to the file "just outside" of it (i.e.
// just after the last file, or just before the first file)
// REQUIRES: "*inputs" is a sorted list of non-overlapping files
bool HasOverlappingUserKey(const std::vector<FileMetaData*>* inputs,
int level);
int num_levels() const { return num_levels_; }
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
int num_non_empty_levels() const {
assert(finalized_);
return num_non_empty_levels_;
}
// REQUIRES: This version has been finalized.
// (CalculateBaseBytes() is called)
// This may or may not return number of level files. It is to keep backward
// compatible behavior in universal compaction.
int l0_delay_trigger_count() const { return l0_delay_trigger_count_; }
void set_l0_delay_trigger_count(int v) { l0_delay_trigger_count_ = v; }
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
int NumLevelFiles(int level) const {
assert(finalized_);
return static_cast<int>(files_[level].size());
}
// Return the combined file size of all files at the specified level.
uint64_t NumLevelBytes(int level) const;
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
const std::vector<FileMetaData*>& LevelFiles(int level) const {
return files_[level];
}
const rocksdb::LevelFilesBrief& LevelFilesBrief(int level) const {
assert(level < static_cast<int>(level_files_brief_.size()));
return level_files_brief_[level];
}
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
const std::vector<int>& FilesByCompactionPri(int level) const {
assert(finalized_);
return files_by_compaction_pri_[level];
}
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
// REQUIRES: DB mutex held during access
const autovector<std::pair<int, FileMetaData*>>& FilesMarkedForCompaction()
const {
assert(finalized_);
return files_marked_for_compaction_;
}
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
// REQUIRES: DB mutex held during access
const autovector<std::pair<int, FileMetaData*>>& ExpiredTtlFiles() const {
assert(finalized_);
return expired_ttl_files_;
}
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
// REQUIRES: DB mutex held during access
const autovector<std::pair<int, FileMetaData*>>&
BottommostFilesMarkedForCompaction() const {
assert(finalized_);
return bottommost_files_marked_for_compaction_;
}
int base_level() const { return base_level_; }
double level_multiplier() const { return level_multiplier_; }
// REQUIRES: lock is held
// Set the index that is used to offset into files_by_compaction_pri_ to find
// the next compaction candidate file.
void SetNextCompactionIndex(int level, int index) {
next_file_to_compact_by_size_[level] = index;
}
// REQUIRES: lock is held
int NextCompactionIndex(int level) const {
return next_file_to_compact_by_size_[level];
}
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
const FileIndexer& file_indexer() const {
assert(finalized_);
return file_indexer_;
}
// Only the first few entries of files_by_compaction_pri_ are sorted.
// There is no need to sort all the files because it is likely
// that on a running system, we need to look at only the first
// few largest files because a new version is created every few
// seconds/minutes (because of concurrent compactions).
static const size_t kNumberFilesToSort = 50;
// Return a human-readable short (single-line) summary of the number
// of files per level. Uses *scratch as backing store.
struct LevelSummaryStorage {
char buffer[1000];
};
struct FileSummaryStorage {
char buffer[3000];
};
const char* LevelSummary(LevelSummaryStorage* scratch) const;
// Return a human-readable short (single-line) summary of files
// in a specified level. Uses *scratch as backing store.
const char* LevelFileSummary(FileSummaryStorage* scratch, int level) const;
// Return the maximum overlapping data (in bytes) at next level for any
// file at a level >= 1.
int64_t MaxNextLevelOverlappingBytes();
// Return a human readable string that describes this version's contents.
std::string DebugString(bool hex = false) const;
uint64_t GetAverageValueSize() const {
if (accumulated_num_non_deletions_ == 0) {
return 0;
}
assert(accumulated_raw_key_size_ + accumulated_raw_value_size_ > 0);
assert(accumulated_file_size_ > 0);
return accumulated_raw_value_size_ / accumulated_num_non_deletions_ *
accumulated_file_size_ /
(accumulated_raw_key_size_ + accumulated_raw_value_size_);
}
uint64_t GetEstimatedActiveKeys() const;
double GetEstimatedCompressionRatioAtLevel(int level) const;
// re-initializes the index that is used to offset into
// files_by_compaction_pri_
// to find the next compaction candidate file.
void ResetNextCompactionIndex(int level) {
next_file_to_compact_by_size_[level] = 0;
}
const InternalKeyComparator* InternalComparator() {
return internal_comparator_;
}
// Returns maximum total bytes of data on a given level.
uint64_t MaxBytesForLevel(int level) const;
// Must be called after any change to MutableCFOptions.
void CalculateBaseBytes(const ImmutableCFOptions& ioptions,
const MutableCFOptions& options);
// Returns an estimate of the amount of live data in bytes.
uint64_t EstimateLiveDataSize() const;
uint64_t estimated_compaction_needed_bytes() const {
return estimated_compaction_needed_bytes_;
}
void TEST_set_estimated_compaction_needed_bytes(uint64_t v) {
estimated_compaction_needed_bytes_ = v;
}
bool force_consistency_checks() const { return force_consistency_checks_; }
// Returns whether any key in [`smallest_key`, `largest_key`] could appear in
// an older L0 file than `last_l0_idx` or in a greater level than `last_level`
//
// @param last_level Level after which we check for overlap
// @param last_l0_idx If `last_level == 0`, index of L0 file after which we
// check for overlap; otherwise, must be -1
bool RangeMightExistAfterSortedRun(const Slice& smallest_user_key,
const Slice& largest_user_key,
int last_level, int last_l0_idx);
private:
const InternalKeyComparator* internal_comparator_;
const Comparator* user_comparator_;
int num_levels_; // Number of levels
int num_non_empty_levels_; // Number of levels. Any level larger than it
// is guaranteed to be empty.
// Per-level max bytes
std::vector<uint64_t> level_max_bytes_;
// A short brief metadata of files per level
autovector<rocksdb::LevelFilesBrief> level_files_brief_;
FileIndexer file_indexer_;
Arena arena_; // Used to allocate space for file_levels_
CompactionStyle compaction_style_;
// List of files per level, files in each level are arranged
// in increasing order of keys
std::vector<FileMetaData*>* files_;
// Level that L0 data should be compacted to. All levels < base_level_ should
// be empty. -1 if it is not level-compaction so it's not applicable.
int base_level_;
double level_multiplier_;
// A list for the same set of files that are stored in files_,
// but files in each level are now sorted based on file
// size. The file with the largest size is at the front.
// This vector stores the index of the file from files_.
std::vector<std::vector<int>> files_by_compaction_pri_;
// If true, means that files in L0 have keys with non overlapping ranges
bool level0_non_overlapping_;
// An index into files_by_compaction_pri_ that specifies the first
// file that is not yet compacted
std::vector<int> next_file_to_compact_by_size_;
// Only the first few entries of files_by_compaction_pri_ are sorted.
// There is no need to sort all the files because it is likely
// that on a running system, we need to look at only the first
// few largest files because a new version is created every few
// seconds/minutes (because of concurrent compactions).
static const size_t number_of_files_to_sort_ = 50;
// This vector contains list of files marked for compaction and also not
// currently being compacted. It is protected by DB mutex. It is calculated in
// ComputeCompactionScore()
autovector<std::pair<int, FileMetaData*>> files_marked_for_compaction_;
autovector<std::pair<int, FileMetaData*>> expired_ttl_files_;
// These files are considered bottommost because none of their keys can exist
// at lower levels. They are not necessarily all in the same level. The marked
// ones are eligible for compaction because they contain duplicate key
// versions that are no longer protected by snapshot. These variables are
// protected by DB mutex and are calculated in `GenerateBottommostFiles()` and
// `ComputeBottommostFilesMarkedForCompaction()`.
autovector<std::pair<int, FileMetaData*>> bottommost_files_;
autovector<std::pair<int, FileMetaData*>>
bottommost_files_marked_for_compaction_;
// Threshold for needing to mark another bottommost file. Maintain it so we
// can quickly check when releasing a snapshot whether more bottommost files
// became eligible for compaction. It's defined as the min of the max nonzero
// seqnums of unmarked bottommost files.
SequenceNumber bottommost_files_mark_threshold_ = kMaxSequenceNumber;
// Monotonically increases as we release old snapshots. Zero indicates no
// snapshots have been released yet. When no snapshots remain we set it to the
// current seqnum, which needs to be protected as a snapshot can still be
// created that references it.
SequenceNumber oldest_snapshot_seqnum_ = 0;
// Level that should be compacted next and its compaction score.
// Score < 1 means compaction is not strictly needed. These fields
// are initialized by Finalize().
// The most critical level to be compacted is listed first
// These are used to pick the best compaction level
std::vector<double> compaction_score_;
std::vector<int> compaction_level_;
int l0_delay_trigger_count_ = 0; // Count used to trigger slow down and stop
// for number of L0 files.
// the following are the sampled temporary stats.
// the current accumulated size of sampled files.
uint64_t accumulated_file_size_;
// the current accumulated size of all raw keys based on the sampled files.
uint64_t accumulated_raw_key_size_;
// the current accumulated size of all raw keys based on the sampled files.
uint64_t accumulated_raw_value_size_;
// total number of non-deletion entries
uint64_t accumulated_num_non_deletions_;
// total number of deletion entries
uint64_t accumulated_num_deletions_;
// current number of non_deletion entries
uint64_t current_num_non_deletions_;
// current number of deletion entries
uint64_t current_num_deletions_;
// current number of file samples
uint64_t current_num_samples_;
// Estimated bytes needed to be compacted until all levels' size is down to
// target sizes.
uint64_t estimated_compaction_needed_bytes_;
bool finalized_;
// If set to true, we will run consistency checks even if RocksDB
// is compiled in release mode
bool force_consistency_checks_;
friend class Version;
friend class VersionSet;
// No copying allowed
VersionStorageInfo(const VersionStorageInfo&) = delete;
void operator=(const VersionStorageInfo&) = delete;
};
class Version {
public:
// Append to *iters a sequence of iterators that will
// yield the contents of this Version when merged together.
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
void AddIterators(const ReadOptions&, const EnvOptions& soptions,
MergeIteratorBuilder* merger_iter_builder,
RangeDelAggregator* range_del_agg);
void AddIteratorsForLevel(const ReadOptions&, const EnvOptions& soptions,
MergeIteratorBuilder* merger_iter_builder,
int level, RangeDelAggregator* range_del_agg);
Status OverlapWithLevelIterator(const ReadOptions&, const EnvOptions&,
const Slice& smallest_user_key,
const Slice& largest_user_key,
int level, bool* overlap);
// Lookup the value for key. If found, store it in *val and
// return OK. Else return a non-OK status.
// Uses *operands to store merge_operator operations to apply later.
//
// If the ReadOptions.read_tier is set to do a read-only fetch, then
// *value_found will be set to false if it cannot be determined whether
// this value exists without doing IO.
//
// If the key is Deleted, *status will be set to NotFound and
// *key_exists will be set to true.
// If no key was found, *status will be set to NotFound and
// *key_exists will be set to false.
// If seq is non-null, *seq will be set to the sequence number found
// for the key if a key was found.
//
// REQUIRES: lock is not held
void Get(const ReadOptions&, const LookupKey& key, PinnableSlice* value,
Status* status, MergeContext* merge_context,
SequenceNumber* max_covering_tombstone_seq,
bool* value_found = nullptr, bool* key_exists = nullptr,
SequenceNumber* seq = nullptr, ReadCallback* callback = nullptr,
bool* is_blob = nullptr);
// Loads some stats information from files. Call without mutex held. It needs
// to be called before applying the version to the version set.
void PrepareApply(const MutableCFOptions& mutable_cf_options,
bool update_stats);
// Reference count management (so Versions do not disappear out from
// under live iterators)
void Ref();
// Decrease reference count. Delete the object if no reference left
// and return true. Otherwise, return false.
bool Unref();
// Add all files listed in the current version to *live.
void AddLiveFiles(std::vector<FileDescriptor>* live);
// Return a human readable string that describes this version's contents.
std::string DebugString(bool hex = false, bool print_stats = false) const;
// Returns the version number of this version
uint64_t GetVersionNumber() const { return version_number_; }
// REQUIRES: lock is held
// On success, "tp" will contains the table properties of the file
// specified in "file_meta". If the file name of "file_meta" is
// known ahead, passing it by a non-null "fname" can save a
// file-name conversion.
Status GetTableProperties(std::shared_ptr<const TableProperties>* tp,
const FileMetaData* file_meta,
const std::string* fname = nullptr) const;
// REQUIRES: lock is held
// On success, *props will be populated with all SSTables' table properties.
// The keys of `props` are the sst file name, the values of `props` are the
// tables' properties, represented as shared_ptr.
Status GetPropertiesOfAllTables(TablePropertiesCollection* props);
Status GetPropertiesOfAllTables(TablePropertiesCollection* props, int level);
Status GetPropertiesOfTablesInRange(const Range* range, std::size_t n,
TablePropertiesCollection* props) const;
// REQUIRES: lock is held
// On success, "tp" will contains the aggregated table property among
// the table properties of all sst files in this version.
Status GetAggregatedTableProperties(
std::shared_ptr<const TableProperties>* tp, int level = -1);
uint64_t GetEstimatedActiveKeys() {
return storage_info_.GetEstimatedActiveKeys();
}
size_t GetMemoryUsageByTableReaders();
ColumnFamilyData* cfd() const { return cfd_; }
// Return the next Version in the linked list. Used for debug only
Version* TEST_Next() const {
return next_;
}
int TEST_refs() const { return refs_; }
VersionStorageInfo* storage_info() { return &storage_info_; }
VersionSet* version_set() { return vset_; }
void GetColumnFamilyMetaData(ColumnFamilyMetaData* cf_meta);
uint64_t GetSstFilesSize();
MutableCFOptions GetMutableCFOptions() { return mutable_cf_options_; }
private:
Env* env_;
friend class VersionSet;
const InternalKeyComparator* internal_comparator() const {
return storage_info_.internal_comparator_;
}
const Comparator* user_comparator() const {
return storage_info_.user_comparator_;
}
bool PrefixMayMatch(const ReadOptions& read_options,
InternalIterator* level_iter,
const Slice& internal_prefix) const;
// Returns true if the filter blocks in the specified level will not be
// checked during read operations. In certain cases (trivial move or preload),
// the filter block may already be cached, but we still do not access it such
// that it eventually expires from the cache.
bool IsFilterSkipped(int level, bool is_file_last_in_level = false);
// The helper function of UpdateAccumulatedStats, which may fill the missing
// fields of file_meta from its associated TableProperties.
// Returns true if it does initialize FileMetaData.
bool MaybeInitializeFileMetaData(FileMetaData* file_meta);
// Update the accumulated stats associated with the current version.
// This accumulated stats will be used in compaction.
void UpdateAccumulatedStats(bool update_stats);
// Sort all files for this version based on their file size and
// record results in files_by_compaction_pri_. The largest files are listed
// first.
void UpdateFilesByCompactionPri();
ColumnFamilyData* cfd_; // ColumnFamilyData to which this Version belongs
Logger* info_log_;
Statistics* db_statistics_;
TableCache* table_cache_;
const MergeOperator* merge_operator_;
VersionStorageInfo storage_info_;
VersionSet* vset_; // VersionSet to which this Version belongs
Version* next_; // Next version in linked list
Version* prev_; // Previous version in linked list
int refs_; // Number of live refs to this version
const EnvOptions env_options_;
const MutableCFOptions mutable_cf_options_;
// A version number that uniquely represents this version. This is
// used for debugging and logging purposes only.
uint64_t version_number_;
Version(ColumnFamilyData* cfd, VersionSet* vset, const EnvOptions& env_opt,
MutableCFOptions mutable_cf_options, uint64_t version_number = 0);
~Version();
// No copying allowed
Version(const Version&);
void operator=(const Version&);
};
struct ObsoleteFileInfo {
FileMetaData* metadata;
std::string path;
ObsoleteFileInfo() noexcept : metadata(nullptr) {}
ObsoleteFileInfo(FileMetaData* f, const std::string& file_path)
: metadata(f), path(file_path) {}
ObsoleteFileInfo(const ObsoleteFileInfo&) = delete;
ObsoleteFileInfo& operator=(const ObsoleteFileInfo&) = delete;
ObsoleteFileInfo(ObsoleteFileInfo&& rhs) noexcept :
ObsoleteFileInfo() {
*this = std::move(rhs);
}
ObsoleteFileInfo& operator=(ObsoleteFileInfo&& rhs) noexcept {
path = std::move(rhs.path);
metadata = rhs.metadata;
rhs.metadata = nullptr;
return *this;
}
void DeleteMetadata() {
delete metadata;
metadata = nullptr;
}
};
namespace {
class BaseReferencedVersionBuilder;
}
class VersionSet {
public:
VersionSet(const std::string& dbname, const ImmutableDBOptions* db_options,
const EnvOptions& env_options, Cache* table_cache,
WriteBufferManager* write_buffer_manager,
WriteController* write_controller);
~VersionSet();
// Apply *edit to the current version to form a new descriptor that
// is both saved to persistent state and installed as the new
// current version. Will release *mu while actually writing to the file.
// column_family_options has to be set if edit is column family add
// REQUIRES: *mu is held on entry.
// REQUIRES: no other thread concurrently calls LogAndApply()
Status LogAndApply(
ColumnFamilyData* column_family_data,
const MutableCFOptions& mutable_cf_options, VersionEdit* edit,
InstrumentedMutex* mu, Directory* db_directory = nullptr,
bool new_descriptor_log = false,
const ColumnFamilyOptions* column_family_options = nullptr) {
autovector<ColumnFamilyData*> cfds;
cfds.emplace_back(column_family_data);
autovector<const MutableCFOptions*> mutable_cf_options_list;
mutable_cf_options_list.emplace_back(&mutable_cf_options);
autovector<autovector<VersionEdit*>> edit_lists;
autovector<VersionEdit*> edit_list;
edit_list.emplace_back(edit);
edit_lists.emplace_back(edit_list);
return LogAndApply(cfds, mutable_cf_options_list, edit_lists, mu,
db_directory, new_descriptor_log, column_family_options);
}
// The batch version. If edit_list.size() > 1, caller must ensure that
// no edit in the list column family add or drop
Status LogAndApply(
ColumnFamilyData* column_family_data,
const MutableCFOptions& mutable_cf_options,
const autovector<VersionEdit*>& edit_list, InstrumentedMutex* mu,
Directory* db_directory = nullptr, bool new_descriptor_log = false,
const ColumnFamilyOptions* column_family_options = nullptr) {
autovector<ColumnFamilyData*> cfds;
cfds.emplace_back(column_family_data);
autovector<const MutableCFOptions*> mutable_cf_options_list;
mutable_cf_options_list.emplace_back(&mutable_cf_options);
autovector<autovector<VersionEdit*>> edit_lists;
edit_lists.emplace_back(edit_list);
return LogAndApply(cfds, mutable_cf_options_list, edit_lists, mu,
db_directory, new_descriptor_log, column_family_options);
}
// The across-multi-cf batch version. If edit_lists contain more than
// 1 version edits, caller must ensure that no edit in the []list is column
// family manipulation.
Status LogAndApply(
const autovector<ColumnFamilyData*>& cfds,
const autovector<const MutableCFOptions*>& mutable_cf_options_list,
const autovector<autovector<VersionEdit*>>& edit_lists,
InstrumentedMutex* mu, Directory* db_directory = nullptr,
bool new_descriptor_log = false,
const ColumnFamilyOptions* new_cf_options = nullptr);
// Recover the last saved descriptor from persistent storage.
// If read_only == true, Recover() will not complain if some column families
// are not opened
Status Recover(const std::vector<ColumnFamilyDescriptor>& column_families,
bool read_only = false);
// Reads a manifest file and returns a list of column families in
// column_families.
static Status ListColumnFamilies(std::vector<std::string>* column_families,
const std::string& dbname, Env* env);
#ifndef ROCKSDB_LITE
// Try to reduce the number of levels. This call is valid when
// only one level from the new max level to the old
// max level containing files.
// The call is static, since number of levels is immutable during
// the lifetime of a RocksDB instance. It reduces number of levels
// in a DB by applying changes to manifest.
// For example, a db currently has 7 levels [0-6], and a call to
// to reduce to 5 [0-4] can only be executed when only one level
// among [4-6] contains files.
static Status ReduceNumberOfLevels(const std::string& dbname,
const Options* options,
const EnvOptions& env_options,
int new_levels);
// printf contents (for debugging)
Status DumpManifest(Options& options, std::string& manifestFileName,
bool verbose, bool hex = false, bool json = false);
#endif // ROCKSDB_LITE
// Return the current manifest file number
uint64_t manifest_file_number() const { return manifest_file_number_; }
uint64_t options_file_number() const { return options_file_number_; }
uint64_t pending_manifest_file_number() const {
return pending_manifest_file_number_;
}
uint64_t current_next_file_number() const { return next_file_number_.load(); }
uint64_t min_log_number_to_keep_2pc() const {
return min_log_number_to_keep_2pc_.load();
}
// Allocate and return a new file number
uint64_t NewFileNumber() { return next_file_number_.fetch_add(1); }
// Fetch And Add n new file number
uint64_t FetchAddFileNumber(uint64_t n) {
return next_file_number_.fetch_add(n);
}
// Return the last sequence number.
uint64_t LastSequence() const {
return last_sequence_.load(std::memory_order_acquire);
}
// Note: memory_order_acquire must be sufficient.
uint64_t LastAllocatedSequence() const {
return last_allocated_sequence_.load(std::memory_order_seq_cst);
}
// Note: memory_order_acquire must be sufficient.
uint64_t LastPublishedSequence() const {
return last_published_sequence_.load(std::memory_order_seq_cst);
}
// Set the last sequence number to s.
void SetLastSequence(uint64_t s) {
assert(s >= last_sequence_);
// Last visible sequence must always be less than last written seq
assert(!db_options_->two_write_queues || s <= last_allocated_sequence_);
last_sequence_.store(s, std::memory_order_release);
}
// Note: memory_order_release must be sufficient
void SetLastPublishedSequence(uint64_t s) {
assert(s >= last_published_sequence_);
last_published_sequence_.store(s, std::memory_order_seq_cst);
}
// Note: memory_order_release must be sufficient
void SetLastAllocatedSequence(uint64_t s) {
assert(s >= last_allocated_sequence_);
last_allocated_sequence_.store(s, std::memory_order_seq_cst);
}
// Note: memory_order_release must be sufficient
uint64_t FetchAddLastAllocatedSequence(uint64_t s) {
return last_allocated_sequence_.fetch_add(s, std::memory_order_seq_cst);
}
// Mark the specified file number as used.
// REQUIRED: this is only called during single-threaded recovery or repair.
void MarkFileNumberUsed(uint64_t number);
// Mark the specified log number as deleted
// REQUIRED: this is only called during single-threaded recovery or repair, or
// from ::LogAndApply where the global mutex is held.
void MarkMinLogNumberToKeep2PC(uint64_t number);
// Return the log file number for the log file that is currently
// being compacted, or zero if there is no such log file.
uint64_t prev_log_number() const { return prev_log_number_; }
// Returns the minimum log number which still has data not flushed to any SST
// file.
// In non-2PC mode, all the log numbers smaller than this number can be safely
// deleted.
uint64_t MinLogNumberWithUnflushedData() const {
return PreComputeMinLogNumberWithUnflushedData(nullptr);
}
// Returns the minimum log number which still has data not flushed to any SST
// file, except data from `cfd_to_skip`.
uint64_t PreComputeMinLogNumberWithUnflushedData(
const ColumnFamilyData* cfd_to_skip) const {
uint64_t min_log_num = std::numeric_limits<uint64_t>::max();
for (auto cfd : *column_family_set_) {
if (cfd == cfd_to_skip) {
continue;
}
// It's safe to ignore dropped column families here:
// cfd->IsDropped() becomes true after the drop is persisted in MANIFEST.
if (min_log_num > cfd->GetLogNumber() && !cfd->IsDropped()) {
min_log_num = cfd->GetLogNumber();
}
}
return min_log_num;
}
// Create an iterator that reads over the compaction inputs for "*c".
// The caller should delete the iterator when no longer needed.
InternalIterator* MakeInputIterator(
const Compaction* c, RangeDelAggregator* range_del_agg,
const EnvOptions& env_options_compactions);
// Add all files listed in any live version to *live.
void AddLiveFiles(std::vector<FileDescriptor>* live_list);
// Return the approximate size of data to be scanned for range [start, end)
// in levels [start_level, end_level). If end_level == 0 it will search
// through all non-empty levels
uint64_t ApproximateSize(Version* v, const Slice& start, const Slice& end,
int start_level = 0, int end_level = -1);
// Return the size of the current manifest file
uint64_t manifest_file_size() const { return manifest_file_size_; }
// verify that the files that we started with for a compaction
// still exist in the current version and in the same original level.
// This ensures that a concurrent compaction did not erroneously
// pick the same files to compact.
bool VerifyCompactionFileConsistency(Compaction* c);
Status GetMetadataForFile(uint64_t number, int* filelevel,
FileMetaData** metadata, ColumnFamilyData** cfd);
// This function doesn't support leveldb SST filenames
void GetLiveFilesMetaData(std::vector<LiveFileMetaData> *metadata);
void GetObsoleteFiles(std::vector<ObsoleteFileInfo>* files,
std::vector<std::string>* manifest_filenames,
uint64_t min_pending_output);
ColumnFamilySet* GetColumnFamilySet() { return column_family_set_.get(); }
const EnvOptions& env_options() { return env_options_; }
void ChangeEnvOptions(const MutableDBOptions& new_options) {
env_options_.writable_file_max_buffer_size =
new_options.writable_file_max_buffer_size;
}
const ImmutableDBOptions* db_options() const { return db_options_; }
static uint64_t GetNumLiveVersions(Version* dummy_versions);
static uint64_t GetTotalSstFilesSize(Version* dummy_versions);
private:
struct ManifestWriter;
friend class Version;
friend class DBImpl;
struct LogReporter : public log::Reader::Reporter {
Status* status;
virtual void Corruption(size_t /*bytes*/, const Status& s) override {
if (this->status->ok()) *this->status = s;
}
};
// ApproximateSize helper
uint64_t ApproximateSizeLevel0(Version* v, const LevelFilesBrief& files_brief,
const Slice& start, const Slice& end);
uint64_t ApproximateSize(Version* v, const FdWithKeyRange& f,
const Slice& key);
// Save current contents to *log
Status WriteSnapshot(log::Writer* log);
void AppendVersion(ColumnFamilyData* column_family_data, Version* v);
ColumnFamilyData* CreateColumnFamily(const ColumnFamilyOptions& cf_options,
VersionEdit* edit);
Status ApplyOneVersionEdit(
VersionEdit& edit,
const std::unordered_map<std::string, ColumnFamilyOptions>& name_to_opts,
std::unordered_map<int, std::string>& column_families_not_found,
std::unordered_map<uint32_t, BaseReferencedVersionBuilder*>& builders,
bool* have_log_number, uint64_t* log_number, bool* have_prev_log_number,
uint64_t* previous_log_number, bool* have_next_file, uint64_t* next_file,
bool* have_last_sequence, SequenceNumber* last_sequence,
uint64_t* min_log_number_to_keep, uint32_t* max_column_family);
Status ProcessManifestWrites(std::deque<ManifestWriter>& writers,
InstrumentedMutex* mu, Directory* db_directory,
bool new_descriptor_log,
const ColumnFamilyOptions* new_cf_options);
std::unique_ptr<ColumnFamilySet> column_family_set_;
Env* const env_;
const std::string dbname_;
const ImmutableDBOptions* const db_options_;
std::atomic<uint64_t> next_file_number_;
// Any log number equal or lower than this should be ignored during recovery,
// and is qualified for being deleted in 2PC mode. In non-2PC mode, this
// number is ignored.
std::atomic<uint64_t> min_log_number_to_keep_2pc_ = {0};
uint64_t manifest_file_number_;
uint64_t options_file_number_;
uint64_t pending_manifest_file_number_;
// The last seq visible to reads. It normally indicates the last sequence in
// the memtable but when using two write queues it could also indicate the
// last sequence in the WAL visible to reads.
std::atomic<uint64_t> last_sequence_;
// The last seq that is already allocated. It is applicable only when we have
// two write queues. In that case seq might or might not have appreated in
// memtable but it is expected to appear in the WAL.
// We have last_sequence <= last_allocated_sequence_
std::atomic<uint64_t> last_allocated_sequence_;
// The last allocated sequence that is also published to the readers. This is
// applicable only when last_seq_same_as_publish_seq_ is not set. Otherwise
// last_sequence_ also indicates the last published seq.
// We have last_sequence <= last_published_sequence_ <=
// last_allocated_sequence_
std::atomic<uint64_t> last_published_sequence_;
uint64_t prev_log_number_; // 0 or backing store for memtable being compacted
// Opened lazily
unique_ptr<log::Writer> descriptor_log_;
// generates a increasing version number for every new version
uint64_t current_version_number_;
// Queue of writers to the manifest file
std::deque<ManifestWriter*> manifest_writers_;
// Current size of manifest file
uint64_t manifest_file_size_;
std::vector<ObsoleteFileInfo> obsolete_files_;
std::vector<std::string> obsolete_manifests_;
// env options for all reads and writes except compactions
EnvOptions env_options_;
// No copying allowed
VersionSet(const VersionSet&);
void operator=(const VersionSet&);
void LogAndApplyCFHelper(VersionEdit* edit);
void LogAndApplyHelper(ColumnFamilyData* cfd, VersionBuilder* b, Version* v,
VersionEdit* edit, InstrumentedMutex* mu);
};
} // namespace rocksdb