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rocksdb/db/version_set.h

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// 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, as well as a
// set of blob files. 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 <optional>
#include <set>
#include <string>
#include <unordered_set>
#include <utility>
#include <vector>
#include "cache/cache_helpers.h"
#include "db/blob/blob_file_meta.h"
#include "db/blob/blob_index.h"
#include "db/column_family.h"
#include "db/compaction/compaction.h"
#include "db/compaction/compaction_picker.h"
#include "db/dbformat.h"
#include "db/error_handler.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 "env/file_system_tracer.h"
#if USE_COROUTINES
#include "folly/coro/BlockingWait.h"
#include "folly/coro/Collect.h"
#endif
#include "monitoring/instrumented_mutex.h"
#include "options/db_options.h"
#include "options/offpeak_time_info.h"
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/file_checksum.h"
#include "table/get_context.h"
#include "table/multiget_context.h"
#include "trace_replay/block_cache_tracer.h"
#include "util/autovector.h"
#include "util/coro_utils.h"
#include "util/hash_containers.h"
namespace ROCKSDB_NAMESPACE {
namespace log {
class Writer;
}
class BlobIndex;
class Compaction;
class LogBuffer;
class LookupKey;
class MemTable;
class Version;
class VersionSet;
class WriteBufferManager;
class MergeContext;
class ColumnFamilySet;
class MergeIteratorBuilder;
class SystemClock;
class ManifestTailer;
class FilePickerMultiGet;
// VersionEdit is always supposed to be valid and it is used to point at
// entries in Manifest. Ideally it should not be used as a container to
// carry around few of its fields as function params because it can cause
// readers to think it's a valid entry from Manifest. To avoid that confusion
// introducing VersionEditParams to simply carry around multiple VersionEdit
// params. It need not point to a valid record in Manifest.
using VersionEditParams = VersionEdit;
// 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.
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.
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
void DoGenerateLevelFilesBrief(LevelFilesBrief* file_level,
const std::vector<FileMetaData*>& files,
Arena* arena);
enum EpochNumberRequirement {
kMightMissing,
kMustPresent,
};
// Information of the storage associated with each Version, including number of
// levels of LSM tree, files information at each level, files marked for
// compaction, blob files, etc.
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,
EpochNumberRequirement epoch_number_requirement,
SystemClock* clock,
uint32_t bottommost_file_compaction_delay,
OffpeakTimeOption offpeak_time_option);
// No copying allowed
VersionStorageInfo(const VersionStorageInfo&) = delete;
void operator=(const VersionStorageInfo&) = delete;
~VersionStorageInfo();
void Reserve(int level, size_t size) { files_[level].reserve(size); }
void AddFile(int level, FileMetaData* f);
// Resize/Initialize the space for compact_cursor_
void ResizeCompactCursors(int level) {
compact_cursor_.resize(level, InternalKey());
}
const std::vector<InternalKey>& GetCompactCursors() const {
return compact_cursor_;
}
// REQUIRES: ResizeCompactCursors has been called
void AddCursorForOneLevel(int level,
const InternalKey& smallest_uncompacted_key) {
compact_cursor_[level] = smallest_uncompacted_key;
}
// REQUIRES: lock is held
// Update the compact cursor and advance the file index using increment
// so that it can point to the next cursor (increment means the number of
// input files in this level of the last compaction)
const InternalKey& GetNextCompactCursor(int level, size_t increment) {
int cmp_idx = next_file_to_compact_by_size_[level] + (int)increment;
assert(cmp_idx <= (int)files_by_compaction_pri_[level].size());
// TODO(zichen): may need to update next_file_to_compact_by_size_
// for parallel compaction.
InternalKey new_cursor;
if (cmp_idx >= (int)files_by_compaction_pri_[level].size()) {
cmp_idx = 0;
}
// TODO(zichen): rethink if this strategy gives us some good guarantee
return files_[level][files_by_compaction_pri_[level][cmp_idx]]->smallest;
}
void ReserveBlob(size_t size) { blob_files_.reserve(size); }
void AddBlobFile(std::shared_ptr<BlobFileMetaData> blob_file_meta);
void PrepareForVersionAppend(const ImmutableOptions& immutable_options,
const MutableCFOptions& mutable_cf_options);
// REQUIRES: PrepareForVersionAppend has been called
void SetFinalized();
// 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);
// 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 ImmutableOptions& immutable_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(int last_level);
// This computes ttl_expired_files_ and is called by
// ComputeCompactionScore()
void ComputeExpiredTtlFiles(const ImmutableOptions& ioptions,
const uint64_t ttl);
// This computes files_marked_for_periodic_compaction_ and is called by
// ComputeCompactionScore()
void ComputeFilesMarkedForPeriodicCompaction(
const ImmutableOptions& ioptions,
const uint64_t periodic_compaction_seconds, int last_level);
// 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(bool allow_ingest_behind);
// This computes files_marked_for_forced_blob_gc_ and is called by
// ComputeCompactionScore()
//
// REQUIRES: DB mutex held
void ComputeFilesMarkedForForcedBlobGC(
double blob_garbage_collection_age_cutoff,
double blob_garbage_collection_force_threshold,
bool enable_blob_garbage_collection);
bool level0_non_overlapping() const { return level0_non_overlapping_; }
// 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,
bool allow_ingest_behind);
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
// 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: PrepareForVersionAppend has been called
int num_non_empty_levels() const {
assert(finalized_);
return num_non_empty_levels_;
}
// REQUIRES: PrepareForVersionAppend has been 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 VersionBuilder::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 VersionBuilder::SaveTo)
const std::vector<FileMetaData*>& LevelFiles(int level) const {
return files_[level];
}
bool HasMissingEpochNumber() const;
uint64_t GetMaxEpochNumberOfFiles() const;
EpochNumberRequirement GetEpochNumberRequirement() const {
return epoch_number_requirement_;
}
void SetEpochNumberRequirement(
EpochNumberRequirement epoch_number_requirement) {
epoch_number_requirement_ = epoch_number_requirement;
}
// Ensure all files have epoch number set.
// If there is a file missing epoch number, all files' epoch number will be
// reset according to CF's epoch number. Otherwise, the CF will be updated
// with the max epoch number of the files.
//
// @param restart_epoch This CF's epoch number will be reset to start from 0.
// @param force Force resetting all files' epoch number.
void RecoverEpochNumbers(ColumnFamilyData* cfd, bool restart_epoch = true,
bool force = false);
class FileLocation {
public:
FileLocation() = default;
FileLocation(int level, size_t position)
: level_(level), position_(position) {}
int GetLevel() const { return level_; }
size_t GetPosition() const { return position_; }
bool IsValid() const { return level_ >= 0; }
bool operator==(const FileLocation& rhs) const {
return level_ == rhs.level_ && position_ == rhs.position_;
}
bool operator!=(const FileLocation& rhs) const { return !(*this == rhs); }
static FileLocation Invalid() { return FileLocation(); }
private:
int level_ = -1;
size_t position_ = 0;
};
// REQUIRES: PrepareForVersionAppend has been called
FileLocation GetFileLocation(uint64_t file_number) const {
const auto it = file_locations_.find(file_number);
if (it == file_locations_.end()) {
return FileLocation::Invalid();
}
assert(it->second.GetLevel() < num_levels_);
assert(it->second.GetPosition() < files_[it->second.GetLevel()].size());
assert(files_[it->second.GetLevel()][it->second.GetPosition()]);
assert(files_[it->second.GetLevel()][it->second.GetPosition()]
->fd.GetNumber() == file_number);
return it->second;
}
// REQUIRES: PrepareForVersionAppend has been called
FileMetaData* GetFileMetaDataByNumber(uint64_t file_number) const {
auto location = GetFileLocation(file_number);
if (!location.IsValid()) {
return nullptr;
}
return files_[location.GetLevel()][location.GetPosition()];
}
// REQUIRES: This version has been saved (see VersionBuilder::SaveTo)
using BlobFiles = std::vector<std::shared_ptr<BlobFileMetaData>>;
const BlobFiles& GetBlobFiles() const { return blob_files_; }
// REQUIRES: This version has been saved (see VersionBuilder::SaveTo)
BlobFiles::const_iterator GetBlobFileMetaDataLB(
uint64_t blob_file_number) const;
// REQUIRES: This version has been saved (see VersionBuilder::SaveTo)
std::shared_ptr<BlobFileMetaData> GetBlobFileMetaData(
uint64_t blob_file_number) const {
const auto it = GetBlobFileMetaDataLB(blob_file_number);
assert(it == blob_files_.end() || *it);
if (it != blob_files_.end() &&
(*it)->GetBlobFileNumber() == blob_file_number) {
return *it;
}
return std::shared_ptr<BlobFileMetaData>();
}
// REQUIRES: This version has been saved (see VersionBuilder::SaveTo)
struct BlobStats {
uint64_t total_file_size = 0;
uint64_t total_garbage_size = 0;
double space_amp = 0.0;
};
BlobStats GetBlobStats() const {
uint64_t total_file_size = 0;
uint64_t total_garbage_size = 0;
for (const auto& meta : blob_files_) {
assert(meta);
total_file_size += meta->GetBlobFileSize();
total_garbage_size += meta->GetGarbageBlobBytes();
}
double space_amp = 0.0;
if (total_file_size > total_garbage_size) {
space_amp = static_cast<double>(total_file_size) /
(total_file_size - total_garbage_size);
}
return BlobStats{total_file_size, total_garbage_size, space_amp};
}
const ROCKSDB_NAMESPACE::LevelFilesBrief& LevelFilesBrief(int level) const {
assert(level < static_cast<int>(level_files_brief_.size()));
return level_files_brief_[level];
}
// REQUIRES: PrepareForVersionAppend has been called
const std::vector<int>& FilesByCompactionPri(int level) const {
assert(finalized_);
return files_by_compaction_pri_[level];
}
// REQUIRES: ComputeCompactionScore has been called
// REQUIRES: DB mutex held during access
const autovector<std::pair<int, FileMetaData*>>& FilesMarkedForCompaction()
const {
assert(finalized_);
return files_marked_for_compaction_;
}
void TEST_AddFileMarkedForCompaction(int level, FileMetaData* f) {
f->marked_for_compaction = true;
files_marked_for_compaction_.emplace_back(level, f);
}
// REQUIRES: ComputeCompactionScore has been called
// REQUIRES: DB mutex held during access
// Used by Leveled Compaction only.
const autovector<std::pair<int, FileMetaData*>>& ExpiredTtlFiles() const {
assert(finalized_);
return expired_ttl_files_;
}
// REQUIRES: ComputeCompactionScore has been called
// REQUIRES: DB mutex held during access
// Used by Leveled and Universal Compaction.
const autovector<std::pair<int, FileMetaData*>>&
FilesMarkedForPeriodicCompaction() const {
assert(finalized_);
return files_marked_for_periodic_compaction_;
}
void TEST_AddFileMarkedForPeriodicCompaction(int level, FileMetaData* f) {
files_marked_for_periodic_compaction_.emplace_back(level, f);
}
// REQUIRES: PrepareForVersionAppend has been called
const autovector<std::pair<int, FileMetaData*>>& BottommostFiles() const {
assert(finalized_);
return bottommost_files_;
}
// REQUIRES: ComputeCompactionScore has been called
// REQUIRES: DB mutex held during access
const autovector<std::pair<int, FileMetaData*>>&
BottommostFilesMarkedForCompaction() const {
assert(finalized_);
return bottommost_files_marked_for_compaction_;
}
// REQUIRES: ComputeCompactionScore has been called
// REQUIRES: DB mutex held during access
const autovector<std::pair<int, FileMetaData*>>& FilesMarkedForForcedBlobGC()
const {
assert(finalized_);
return files_marked_for_forced_blob_gc_;
}
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: PrepareForVersionAppend has been called
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.
uint64_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() const {
return internal_comparator_;
}
// Returns maximum total bytes of data on a given level.
uint64_t MaxBytesForLevel(int level) const;
// 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,
InstrumentedMutex* mu) {
InstrumentedMutexLock l(mu);
estimated_compaction_needed_bytes_ = v;
}
bool force_consistency_checks() const { return force_consistency_checks_; }
SequenceNumber bottommost_files_mark_threshold() const {
return bottommost_files_mark_threshold_;
}
// 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);
Env::WriteLifeTimeHint CalculateSSTWriteHint(int level) const;
private:
void ComputeCompensatedSizes();
void UpdateNumNonEmptyLevels();
void CalculateBaseBytes(const ImmutableOptions& ioptions,
const MutableCFOptions& options);
void UpdateFilesByCompactionPri(const ImmutableOptions& immutable_options,
const MutableCFOptions& mutable_cf_options);
void GenerateFileIndexer() {
file_indexer_.UpdateIndex(&arena_, num_non_empty_levels_, files_);
}
void GenerateLevelFilesBrief();
void GenerateLevel0NonOverlapping();
void GenerateBottommostFiles();
void GenerateFileLocationIndex();
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_NAMESPACE::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_;
// Map of all table files in version. Maps file number to (level, position on
// level).
using FileLocations = UnorderedMap<uint64_t, FileLocation>;
FileLocations file_locations_;
// Vector of blob files in version sorted by blob file number.
BlobFiles blob_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_;
// Applies to level compaction when
// `level_compaction_dynamic_level_bytes=true`. All non-empty levels <=
// lowest_unnecessary_level_ are not needed and will be drained automatically.
// -1 if there is no unnecessary level,
int lowest_unnecessary_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(). Used by Leveled and Universal Compaction.
autovector<std::pair<int, FileMetaData*>> files_marked_for_compaction_;
autovector<std::pair<int, FileMetaData*>> expired_ttl_files_;
autovector<std::pair<int, FileMetaData*>>
files_marked_for_periodic_compaction_;
// 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_;
autovector<std::pair<int, FileMetaData*>> files_marked_for_forced_blob_gc_;
// 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 ComputeCompactionScore.
// 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.
// Compact cursors for round-robin compactions in each level
std::vector<InternalKey> compact_cursor_;
// 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_;
// Used for computing bottommost files marked for compaction and checking for
// offpeak time.
SystemClock* clock_;
uint32_t bottommost_file_compaction_delay_;
bool finalized_;
// If set to true, we will run consistency checks even if RocksDB
// is compiled in release mode
bool force_consistency_checks_;
EpochNumberRequirement epoch_number_requirement_;
OffpeakTimeOption offpeak_time_option_;
friend class Version;
friend class VersionSet;
};
struct ObsoleteFileInfo {
FileMetaData* metadata;
std::string path;
// If true, the FileMataData should be destroyed but the file should
// not be deleted. This is because another FileMetaData still references
// the file, usually because the file is trivial moved so two FileMetadata
// is managing the file.
bool only_delete_metadata = false;
// To apply to this file
uint32_t uncache_aggressiveness = 0;
ObsoleteFileInfo() noexcept
: metadata(nullptr), only_delete_metadata(false) {}
ObsoleteFileInfo(FileMetaData* f, const std::string& file_path,
uint32_t _uncache_aggressiveness,
std::shared_ptr<CacheReservationManager>
file_metadata_cache_res_mgr_arg = nullptr)
: metadata(f),
path(file_path),
uncache_aggressiveness(_uncache_aggressiveness),
file_metadata_cache_res_mgr(
std::move(file_metadata_cache_res_mgr_arg)) {}
ObsoleteFileInfo(const ObsoleteFileInfo&) = delete;
ObsoleteFileInfo& operator=(const ObsoleteFileInfo&) = delete;
ObsoleteFileInfo(ObsoleteFileInfo&& rhs) noexcept : ObsoleteFileInfo() {
*this = std::move(rhs);
}
ObsoleteFileInfo& operator=(ObsoleteFileInfo&& rhs) noexcept {
metadata = rhs.metadata;
rhs.metadata = nullptr;
path = std::move(rhs.path);
only_delete_metadata = rhs.only_delete_metadata;
rhs.only_delete_metadata = false;
uncache_aggressiveness = rhs.uncache_aggressiveness;
rhs.uncache_aggressiveness = 0;
file_metadata_cache_res_mgr = rhs.file_metadata_cache_res_mgr;
rhs.file_metadata_cache_res_mgr = nullptr;
return *this;
}
void DeleteMetadata() {
if (file_metadata_cache_res_mgr) {
Status s = file_metadata_cache_res_mgr->UpdateCacheReservation(
metadata->ApproximateMemoryUsage(), false /* increase */);
s.PermitUncheckedError();
}
delete metadata;
metadata = nullptr;
}
private:
std::shared_ptr<CacheReservationManager> file_metadata_cache_res_mgr;
};
class ObsoleteBlobFileInfo {
public:
ObsoleteBlobFileInfo(uint64_t blob_file_number, std::string path)
: blob_file_number_(blob_file_number), path_(std::move(path)) {}
uint64_t GetBlobFileNumber() const { return blob_file_number_; }
const std::string& GetPath() const { return path_; }
private:
uint64_t blob_file_number_;
std::string path_;
};
using MultiGetRange = MultiGetContext::Range;
// A column family's version consists of the table and blob files owned by
// the column family at a certain point in time.
class Version {
public:
// Append to *iters a sequence of iterators that will
// yield the contents of this Version when merged together.
// @param read_options Must outlive any iterator built by
// `merger_iter_builder`.
void AddIterators(const ReadOptions& read_options,
const FileOptions& soptions,
MergeIteratorBuilder* merger_iter_builder,
bool allow_unprepared_value);
// @param read_options Must outlive any iterator built by
// `merger_iter_builder`.
void AddIteratorsForLevel(const ReadOptions& read_options,
const FileOptions& soptions,
MergeIteratorBuilder* merger_iter_builder,
int level, bool allow_unprepared_value);
Status OverlapWithLevelIterator(const ReadOptions&, const FileOptions&,
const Slice& smallest_user_key,
const Slice& largest_user_key, int level,
bool* overlap);
// Lookup the value for key or get all merge operands for key.
// If do_merge = true (default) then lookup value for key.
// Behavior if do_merge = true:
// If found, store it in *value 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.
// Behavior if do_merge = false
// If the key has any merge operands then store them in
// merge_context.operands_list and don't merge the operands
// REQUIRES: lock is not held
// REQUIRES: pinned_iters_mgr != nullptr
void Get(const ReadOptions&, const LookupKey& key, PinnableSlice* value,
PinnableWideColumns* columns, std::string* timestamp, Status* status,
MergeContext* merge_context,
SequenceNumber* max_covering_tombstone_seq,
PinnedIteratorsManager* pinned_iters_mgr,
bool* value_found = nullptr, bool* key_exists = nullptr,
SequenceNumber* seq = nullptr, ReadCallback* callback = nullptr,
bool* is_blob = nullptr, bool do_merge = true);
void MultiGet(const ReadOptions&, MultiGetRange* range,
ReadCallback* callback = nullptr);
// Interprets blob_index_slice as a blob reference, and (assuming the
// corresponding blob file is part of this Version) retrieves the blob and
// saves it in *value.
// REQUIRES: blob_index_slice stores an encoded blob reference
Status GetBlob(const ReadOptions& read_options, const Slice& user_key,
const Slice& blob_index_slice,
FilePrefetchBuffer* prefetch_buffer, PinnableSlice* value,
uint64_t* bytes_read) const;
// Retrieves a blob using a blob reference and saves it in *value,
// assuming the corresponding blob file is part of this Version.
Status GetBlob(const ReadOptions& read_options, const Slice& user_key,
const BlobIndex& blob_index,
FilePrefetchBuffer* prefetch_buffer, PinnableSlice* value,
uint64_t* bytes_read) const;
struct BlobReadContext {
BlobReadContext(const BlobIndex& blob_idx, const KeyContext* key_ctx)
: blob_index(blob_idx), key_context(key_ctx) {}
BlobIndex blob_index;
const KeyContext* key_context;
PinnableSlice result;
};
using BlobReadContexts = std::vector<BlobReadContext>;
void MultiGetBlob(const ReadOptions& read_options, MultiGetRange& range,
std::unordered_map<uint64_t, BlobReadContexts>& blob_ctxs);
// Loads some stats information from files (if update_stats is set) and
// populates derived data structures. Call without mutex held. It needs to be
// called before appending the version to the version set.
void PrepareAppend(const MutableCFOptions& mutable_cf_options,
const ReadOptions& read_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_table_files and
// *live_blob_files.
void AddLiveFiles(std::vector<uint64_t>* live_table_files,
std::vector<uint64_t>* live_blob_files) const;
// Remove live files that are in the delete candidate lists.
void RemoveLiveFiles(
std::vector<ObsoleteFileInfo>& sst_delete_candidates,
std::vector<ObsoleteBlobFileInfo>& blob_delete_candidates) const;
// 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(const ReadOptions& read_options,
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 std::shared_ptr.
Status GetPropertiesOfAllTables(const ReadOptions& read_options,
TablePropertiesCollection* props);
Status GetPropertiesOfAllTables(const ReadOptions& read_options,
TablePropertiesCollection* props, int level);
Status GetPropertiesOfTablesInRange(const ReadOptions& read_options,
const autovector<UserKeyRange>& ranges,
TablePropertiesCollection* props) const;
// Print summary of range delete tombstones in SST files into out_str,
// with maximum max_entries_to_print entries printed out.
Status TablesRangeTombstoneSummary(int max_entries_to_print,
std::string* out_str);
// 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(
const ReadOptions& read_options,
std::shared_ptr<const TableProperties>* tp, int level = -1);
uint64_t GetEstimatedActiveKeys() {
return storage_info_.GetEstimatedActiveKeys();
}
size_t GetMemoryUsageByTableReaders(const ReadOptions& read_options);
ColumnFamilyData* cfd() const { return cfd_; }
// Return the next Version in the linked list.
Version* Next() const { return next_; }
int TEST_refs() const { return refs_; }
VersionStorageInfo* storage_info() { return &storage_info_; }
const VersionStorageInfo* storage_info() const { return &storage_info_; }
VersionSet* version_set() { return vset_; }
void GetColumnFamilyMetaData(ColumnFamilyMetaData* cf_meta);
void GetSstFilesBoundaryKeys(Slice* smallest_user_key,
Slice* largest_user_key);
uint64_t GetSstFilesSize();
// Retrieves the file_creation_time of the oldest file in the DB.
// Prerequisite for this API is max_open_files = -1
void GetCreationTimeOfOldestFile(uint64_t* creation_time);
const MutableCFOptions& GetMutableCFOptions() { return mutable_cf_options_; }
InternalIterator* TEST_GetLevelIterator(
const ReadOptions& read_options, MergeIteratorBuilder* merge_iter_builder,
int level, bool allow_unprepared_value);
private:
Env* env_;
SystemClock* clock_;
friend class ReactiveVersionSet;
friend class VersionSet;
friend class VersionEditHandler;
friend class VersionEditHandlerPointInTime;
const InternalKeyComparator* internal_comparator() const {
return storage_info_.internal_comparator_;
}
const Comparator* user_comparator() const {
return storage_info_.user_comparator_;
}
// 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(const ReadOptions& read_options,
FileMetaData* file_meta);
// Update the accumulated stats associated with the current version.
// This accumulated stats will be used in compaction.
void UpdateAccumulatedStats(const ReadOptions& read_options);
DECLARE_SYNC_AND_ASYNC(
/* ret_type */ Status, /* func_name */ MultiGetFromSST,
const ReadOptions& read_options, MultiGetRange file_range,
int hit_file_level, bool skip_filters, bool skip_range_deletions,
FdWithKeyRange* f,
std::unordered_map<uint64_t, BlobReadContexts>& blob_ctxs,
TableCache::TypedHandle* table_handle, uint64_t& num_filter_read,
uint64_t& num_index_read, uint64_t& num_sst_read);
#ifdef USE_COROUTINES
// MultiGet using async IO to read data blocks from SST files in parallel
// within and across levels
Status MultiGetAsync(
const ReadOptions& options, MultiGetRange* range,
std::unordered_map<uint64_t, BlobReadContexts>* blob_ctxs);
// A helper function to lookup a batch of keys in a single level. It will
// queue coroutine tasks to mget_tasks. It may also split the input batch
// by creating a new batch with keys definitely not in this level and
// enqueuing it to to_process.
Status ProcessBatch(
const ReadOptions& read_options, FilePickerMultiGet* batch,
std::vector<folly::coro::Task<Status>>& mget_tasks,
std::unordered_map<uint64_t, BlobReadContexts>* blob_ctxs,
autovector<FilePickerMultiGet, 4>& batches, std::deque<size_t>& waiting,
std::deque<size_t>& to_process, unsigned int& num_tasks_queued,
std::unordered_map<int, std::tuple<uint64_t, uint64_t, uint64_t>>&
mget_stats);
#endif
ColumnFamilyData* cfd_; // ColumnFamilyData to which this Version belongs
Logger* info_log_;
Statistics* db_statistics_;
TableCache* table_cache_;
BlobSource* blob_source_;
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 FileOptions file_options_;
const MutableCFOptions mutable_cf_options_;
// Cached value to avoid recomputing it on every read.
const size_t max_file_size_for_l0_meta_pin_;
// A version number that uniquely represents this version. This is
// used for debugging and logging purposes only.
uint64_t version_number_;
std::shared_ptr<IOTracer> io_tracer_;
bool use_async_io_;
Version(ColumnFamilyData* cfd, VersionSet* vset, const FileOptions& file_opt,
MutableCFOptions mutable_cf_options,
const std::shared_ptr<IOTracer>& io_tracer,
uint64_t version_number = 0,
EpochNumberRequirement epoch_number_requirement =
EpochNumberRequirement::kMustPresent);
~Version();
// No copying allowed
Version(const Version&) = delete;
void operator=(const Version&) = delete;
};
class BaseReferencedVersionBuilder;
class AtomicGroupReadBuffer {
public:
AtomicGroupReadBuffer() = default;
Status AddEdit(VersionEdit* edit);
void Clear();
bool IsFull() const;
bool IsEmpty() const;
uint64_t TEST_read_edits_in_atomic_group() const {
return read_edits_in_atomic_group_;
}
std::vector<VersionEdit>& replay_buffer() { return replay_buffer_; }
private:
uint64_t read_edits_in_atomic_group_ = 0;
std::vector<VersionEdit> replay_buffer_;
};
// VersionSet is the collection of versions of all the column families of the
// database. Each database owns one VersionSet. A VersionSet has access to all
// column families via ColumnFamilySet, i.e. set of the column families.
class VersionSet {
public:
VersionSet(const std::string& dbname, const ImmutableDBOptions* db_options,
const FileOptions& file_options, Cache* table_cache,
WriteBufferManager* write_buffer_manager,
WriteController* write_controller,
BlockCacheTracer* const block_cache_tracer,
const std::shared_ptr<IOTracer>& io_tracer,
const std::string& db_id, const std::string& db_session_id,
const std::string& daily_offpeak_time_utc,
ErrorHandler* const error_handler, const bool read_only);
// No copying allowed
VersionSet(const VersionSet&) = delete;
void operator=(const VersionSet&) = delete;
virtual ~VersionSet();
virtual Status Close(FSDirectory* db_dir, InstrumentedMutex* mu);
Status LogAndApplyToDefaultColumnFamily(
const ReadOptions& read_options, const WriteOptions& write_options,
VersionEdit* edit, InstrumentedMutex* mu,
FSDirectory* dir_contains_current_file, bool new_descriptor_log = false,
const ColumnFamilyOptions* column_family_options = nullptr) {
ColumnFamilyData* default_cf = GetColumnFamilySet()->GetDefault();
const MutableCFOptions* cf_options =
default_cf->GetLatestMutableCFOptions();
return LogAndApply(default_cf, *cf_options, read_options, write_options,
edit, mu, dir_contains_current_file, new_descriptor_log,
column_family_options);
}
// 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,
const ReadOptions& read_options, const WriteOptions& write_options,
VersionEdit* edit, InstrumentedMutex* mu,
FSDirectory* dir_contains_current_file, bool new_descriptor_log = false,
const ColumnFamilyOptions* column_family_options = nullptr,
const std::function<void(const Status&)>& manifest_wcb = {}) {
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, read_options,
write_options, edit_lists, mu, dir_contains_current_file,
new_descriptor_log, column_family_options,
{manifest_wcb});
}
// 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 ReadOptions& read_options, const WriteOptions& write_options,
const autovector<VersionEdit*>& edit_list, InstrumentedMutex* mu,
FSDirectory* dir_contains_current_file, bool new_descriptor_log = false,
const ColumnFamilyOptions* column_family_options = nullptr,
const std::function<void(const Status&)>& manifest_wcb = {}) {
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, read_options,
write_options, edit_lists, mu, dir_contains_current_file,
new_descriptor_log, column_family_options,
{manifest_wcb});
}
// 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.
virtual Status LogAndApply(
const autovector<ColumnFamilyData*>& cfds,
const autovector<const MutableCFOptions*>& mutable_cf_options_list,
const ReadOptions& read_options, const WriteOptions& write_options,
const autovector<autovector<VersionEdit*>>& edit_lists,
InstrumentedMutex* mu, FSDirectory* dir_contains_current_file,
bool new_descriptor_log = false,
const ColumnFamilyOptions* new_cf_options = nullptr,
const std::vector<std::function<void(const Status&)>>& manifest_wcbs =
{});
static Status GetCurrentManifestPath(const std::string& dbname,
FileSystem* fs,
std::string* manifest_filename,
uint64_t* manifest_file_number);
void WakeUpWaitingManifestWriters();
// Recover the last saved descriptor (MANIFEST) 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, std::string* db_id = nullptr,
bool no_error_if_files_missing = false, bool is_retry = false,
Status* log_status = nullptr);
// Do a best-efforts recovery (Options.best_efforts_recovery=true) from all
// available MANIFEST files. Similar to `Recover` with these differences:
// 1) not only the latest MANIFEST can be used, if it's not available or
// no successful recovery can be achieved with it, this function also tries
// to recover from previous MANIFEST files, in reverse chronological order
// until a successful recovery can be achieved.
// 2) this function doesn't just aim to recover to the latest version, if that
// is not available, the most recent point in time version will be saved in
// memory. Check doc for `VersionEditHandlerPointInTime` for more details.
Status TryRecover(const std::vector<ColumnFamilyDescriptor>& column_families,
bool read_only,
const std::vector<std::string>& files_in_dbname,
std::string* db_id, bool* has_missing_table_file);
// Try to recover the version set to the most recent consistent state
// recorded in the specified manifest.
Status TryRecoverFromOneManifest(
const std::string& manifest_path,
const std::vector<ColumnFamilyDescriptor>& column_families,
bool read_only, std::string* db_id, bool* has_missing_table_file);
// Recover the next epoch number of each CFs and epoch number
// of their files (if missing)
void RecoverEpochNumbers();
// 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, FileSystem* fs);
static Status ListColumnFamiliesFromManifest(
const std::string& manifest_path, FileSystem* fs,
std::vector<std::string>* column_families);
// 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 FileOptions& file_options,
int new_levels);
// Get the checksum information of all live files
Status GetLiveFilesChecksumInfo(FileChecksumList* checksum_list);
// printf contents (for debugging)
Status DumpManifest(Options& options, std::string& manifestFileName,
bool verbose, bool hex = false, bool json = false,
const std::vector<ColumnFamilyDescriptor>& cf_descs = {});
const std::string& DbSessionId() const { return db_session_id_; }
// 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() const {
return min_log_number_to_keep_.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 MarkMinLogNumberToKeep(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, although we still use `min_log_number_to_keep_` to determine when
// to delete a WAL file.
uint64_t MinLogNumberWithUnflushedData() const {
return PreComputeMinLogNumberWithUnflushedData(nullptr);
}
// Returns the minimum log number which still has data not flushed to any SST
// file.
// Empty column families' log number is considered to be
// new_log_number_for_empty_cf.
uint64_t PreComputeMinLogNumberWithUnflushedData(
uint64_t new_log_number_for_empty_cf) const {
uint64_t min_log_num = std::numeric_limits<uint64_t>::max();
for (auto cfd : *column_family_set_) {
// It's safe to ignore dropped column families here:
// cfd->IsDropped() becomes true after the drop is persisted in MANIFEST.
uint64_t num =
cfd->IsEmpty() ? new_log_number_for_empty_cf : cfd->GetLogNumber();
if (min_log_num > num && !cfd->IsDropped()) {
min_log_num = num;
}
}
return min_log_num;
}
// 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;
}
// Returns the minimum log number which still has data not flushed to any SST
// file, except data from `cfds_to_skip`.
uint64_t PreComputeMinLogNumberWithUnflushedData(
const std::unordered_set<const ColumnFamilyData*>& cfds_to_skip) const {
uint64_t min_log_num = std::numeric_limits<uint64_t>::max();
for (auto cfd : *column_family_set_) {
if (cfds_to_skip.count(cfd)) {
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.
// @param read_options Must outlive the returned iterator.
// @param start, end indicates compaction range
InternalIterator* MakeInputIterator(
const ReadOptions& read_options, const Compaction* c,
RangeDelAggregator* range_del_agg,
const FileOptions& file_options_compactions,
const std::optional<const Slice>& start,
const std::optional<const Slice>& end);
// Add all files listed in any live version to *live_table_files and
// *live_blob_files. Note that these lists may contain duplicates.
void AddLiveFiles(std::vector<uint64_t>* live_table_files,
std::vector<uint64_t>* live_blob_files) const;
// Remove live files that are in the delete candidate lists.
void RemoveLiveFiles(
std::vector<ObsoleteFileInfo>& sst_delete_candidates,
std::vector<ObsoleteBlobFileInfo>& blob_delete_candidates) const;
// Return the approximate size of data to be scanned for range [start, end)
// in levels [start_level, end_level). If end_level == -1 it will search
// through all non-empty levels
uint64_t ApproximateSize(const SizeApproximationOptions& options,
const ReadOptions& read_options, Version* v,
const Slice& start, const Slice& end,
int start_level, int end_level,
TableReaderCaller caller);
// Return the size of the current manifest file
uint64_t manifest_file_size() const { return manifest_file_size_; }
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 AddObsoleteBlobFile(uint64_t blob_file_number, std::string path) {
// TODO: Erase file from BlobFileCache?
obsolete_blob_files_.emplace_back(blob_file_number, std::move(path));
}
void GetObsoleteFiles(std::vector<ObsoleteFileInfo>* files,
std::vector<ObsoleteBlobFileInfo>* blob_files,
std::vector<std::string>* manifest_filenames,
uint64_t min_pending_output);
// REQUIRES: DB mutex held
uint64_t GetObsoleteSstFilesSize() const;
ColumnFamilySet* GetColumnFamilySet() { return column_family_set_.get(); }
const UnorderedMap<uint32_t, size_t>& GetRunningColumnFamiliesTimestampSize()
const {
return column_family_set_->GetRunningColumnFamiliesTimestampSize();
}
const UnorderedMap<uint32_t, size_t>&
GetColumnFamiliesTimestampSizeForRecord() const {
return column_family_set_->GetColumnFamiliesTimestampSizeForRecord();
}
RefedColumnFamilySet GetRefedColumnFamilySet() {
return RefedColumnFamilySet(GetColumnFamilySet());
}
const FileOptions& file_options() { return file_options_; }
void ChangeFileOptions(const MutableDBOptions& new_options) {
file_options_.writable_file_max_buffer_size =
new_options.writable_file_max_buffer_size;
}
// TODO - Consider updating together when file options change in SetDBOptions
const OffpeakTimeOption& offpeak_time_option() {
return offpeak_time_option_;
}
void ChangeOffpeakTimeOption(const std::string& daily_offpeak_time_utc) {
offpeak_time_option_.SetFromOffpeakTimeString(daily_offpeak_time_utc);
}
const ImmutableDBOptions* db_options() const { return db_options_; }
static uint64_t GetNumLiveVersions(Version* dummy_versions);
static uint64_t GetTotalSstFilesSize(Version* dummy_versions);
static uint64_t GetTotalBlobFileSize(Version* dummy_versions);
// Get the IO Status returned by written Manifest.
const IOStatus& io_status() const { return io_status_; }
// The returned WalSet needs to be accessed with DB mutex held.
const WalSet& GetWalSet() const { return wals_; }
void TEST_CreateAndAppendVersion(ColumnFamilyData* cfd) {
assert(cfd);
const auto& mutable_cf_options = *cfd->GetLatestMutableCFOptions();
Version* const version =
new Version(cfd, this, file_options_, mutable_cf_options, io_tracer_);
constexpr bool update_stats = false;
// TODO: plumb Env::IOActivity, Env::IOPriority
const ReadOptions read_options;
version->PrepareAppend(mutable_cf_options, read_options, update_stats);
AppendVersion(cfd, version);
}
protected:
struct ManifestWriter;
friend class Version;
friend class VersionEditHandler;
friend class VersionEditHandlerPointInTime;
friend class DumpManifestHandler;
friend class DBImpl;
friend class DBImplReadOnly;
struct LogReporter : public log::Reader::Reporter {
Status* status;
void Corruption(size_t /*bytes*/, const Status& s) override {
if (status->ok()) {
*status = s;
}
}
};
void Reset();
// Returns approximated offset of a key in a file for a given version.
uint64_t ApproximateOffsetOf(const ReadOptions& read_options, Version* v,
const FdWithKeyRange& f, const Slice& key,
TableReaderCaller caller);
// Returns approximated data size between start and end keys in a file
// for a given version.
uint64_t ApproximateSize(const ReadOptions& read_options, Version* v,
const FdWithKeyRange& f, const Slice& start,
const Slice& end, TableReaderCaller caller);
struct MutableCFState {
uint64_t log_number;
std::string full_history_ts_low;
explicit MutableCFState() = default;
explicit MutableCFState(uint64_t _log_number, std::string ts_low)
: log_number(_log_number), full_history_ts_low(std::move(ts_low)) {}
};
// Save current contents to *log
Status WriteCurrentStateToManifest(
const WriteOptions& write_options,
const std::unordered_map<uint32_t, MutableCFState>& curr_state,
const VersionEdit& wal_additions, log::Writer* log, IOStatus& io_s);
void AppendVersion(ColumnFamilyData* column_family_data, Version* v);
ColumnFamilyData* CreateColumnFamily(const ColumnFamilyOptions& cf_options,
const ReadOptions& read_options,
const VersionEdit* edit);
Status VerifyFileMetadata(const ReadOptions& read_options,
ColumnFamilyData* cfd, const std::string& fpath,
int level, const FileMetaData& meta);
// Protected by DB mutex.
WalSet wals_;
std::unique_ptr<ColumnFamilySet> column_family_set_;
Cache* table_cache_;
Env* const env_;
FileSystemPtr const fs_;
SystemClock* const clock_;
const std::string dbname_;
std::string db_id_;
const ImmutableDBOptions* const db_options_;
std::atomic<uint64_t> next_file_number_;
// Any WAL number smaller than this should be ignored during recovery,
// and is qualified for being deleted.
std::atomic<uint64_t> min_log_number_to_keep_ = {0};
uint64_t manifest_file_number_;
uint64_t options_file_number_;
uint64_t options_file_size_;
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 sequence number of data committed to the descriptor (manifest
// file).
SequenceNumber descriptor_last_sequence_ = 0;
// 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
std::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_;
// Obsolete files, or during DB shutdown any files not referenced by what's
// left of the in-memory LSM state.
std::vector<ObsoleteFileInfo> obsolete_files_;
std::vector<ObsoleteBlobFileInfo> obsolete_blob_files_;
std::vector<std::string> obsolete_manifests_;
// env options for all reads and writes except compactions
FileOptions file_options_;
BlockCacheTracer* const block_cache_tracer_;
// Store the IO status when Manifest is written
IOStatus io_status_;
std::shared_ptr<IOTracer> io_tracer_;
std::string db_session_id_;
// Off-peak time option used for compaction scoring
OffpeakTimeOption offpeak_time_option_;
// Pointer to the DB's ErrorHandler.
ErrorHandler* const error_handler_;
private:
// REQUIRES db mutex at beginning. may release and re-acquire db mutex
Status ProcessManifestWrites(std::deque<ManifestWriter>& writers,
InstrumentedMutex* mu,
FSDirectory* dir_contains_current_file,
bool new_descriptor_log,
const ColumnFamilyOptions* new_cf_options,
const ReadOptions& read_options,
const WriteOptions& write_options);
void LogAndApplyCFHelper(VersionEdit* edit,
SequenceNumber* max_last_sequence);
Status LogAndApplyHelper(ColumnFamilyData* cfd, VersionBuilder* b,
VersionEdit* edit, SequenceNumber* max_last_sequence,
InstrumentedMutex* mu);
const bool read_only_;
bool closed_;
};
// ReactiveVersionSet represents a collection of versions of the column
// families of the database. Users of ReactiveVersionSet, e.g. DBImplSecondary,
// need to replay the MANIFEST (description log in older terms) in order to
// reconstruct and install versions.
class ReactiveVersionSet : public VersionSet {
public:
ReactiveVersionSet(const std::string& dbname,
const ImmutableDBOptions* _db_options,
const FileOptions& _file_options, Cache* table_cache,
WriteBufferManager* write_buffer_manager,
WriteController* write_controller,
const std::shared_ptr<IOTracer>& io_tracer);
~ReactiveVersionSet() override;
Status Close(FSDirectory* /*db_dir*/, InstrumentedMutex* /*mu*/) override {
return Status::OK();
}
Status ReadAndApply(
InstrumentedMutex* mu,
std::unique_ptr<log::FragmentBufferedReader>* manifest_reader,
Status* manifest_read_status,
std::unordered_set<ColumnFamilyData*>* cfds_changed,
std::vector<std::string>* files_to_delete);
Status Recover(const std::vector<ColumnFamilyDescriptor>& column_families,
std::unique_ptr<log::FragmentBufferedReader>* manifest_reader,
std::unique_ptr<log::Reader::Reporter>* manifest_reporter,
std::unique_ptr<Status>* manifest_reader_status);
#ifndef NDEBUG
uint64_t TEST_read_edits_in_atomic_group() const;
#endif //! NDEBUG
std::vector<VersionEdit>& replay_buffer();
protected:
// REQUIRES db mutex
Status ApplyOneVersionEditToBuilder(
VersionEdit& edit, std::unordered_set<ColumnFamilyData*>* cfds_changed,
VersionEdit* version_edit);
Status MaybeSwitchManifest(
log::Reader::Reporter* reporter,
std::unique_ptr<log::FragmentBufferedReader>* manifest_reader);
private:
std::unique_ptr<ManifestTailer> manifest_tailer_;
// TODO: plumb Env::IOActivity, Env::IOPriority
const ReadOptions read_options_;
using VersionSet::LogAndApply;
using VersionSet::Recover;
Status LogAndApply(
const autovector<ColumnFamilyData*>& /*cfds*/,
const autovector<const MutableCFOptions*>& /*mutable_cf_options_list*/,
const ReadOptions& /* read_options */,
const WriteOptions& /* write_options */,
const autovector<autovector<VersionEdit*>>& /*edit_lists*/,
InstrumentedMutex* /*mu*/, FSDirectory* /*dir_contains_current_file*/,
bool /*new_descriptor_log*/, const ColumnFamilyOptions* /*new_cf_option*/,
const std::vector<std::function<void(const Status&)>>& /*manifest_wcbs*/)
override {
return Status::NotSupported("not supported in reactive mode");
}
// No copy allowed
ReactiveVersionSet(const ReactiveVersionSet&);
ReactiveVersionSet& operator=(const ReactiveVersionSet&);
};
} // namespace ROCKSDB_NAMESPACE
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