blob: 782ebc263eb2ae0266c6fa664f68dfb3b273ab97 [file] [log] [blame]
// 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.
#include "db/version_set.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <stdio.h>
#include <algorithm>
#include <climits>
#include <map>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>
#include "db/compaction.h"
#include "db/internal_stats.h"
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/memtable.h"
#include "db/merge_context.h"
#include "db/merge_helper.h"
#include "db/pinned_iterators_manager.h"
#include "db/table_cache.h"
#include "db/version_builder.h"
#include "monitoring/file_read_sample.h"
#include "monitoring/perf_context_imp.h"
#include "rocksdb/env.h"
#include "rocksdb/merge_operator.h"
#include "rocksdb/write_buffer_manager.h"
#include "table/format.h"
#include "table/get_context.h"
#include "table/internal_iterator.h"
#include "table/merging_iterator.h"
#include "table/meta_blocks.h"
#include "table/plain_table_factory.h"
#include "table/table_reader.h"
#include "table/two_level_iterator.h"
#include "util/coding.h"
#include "util/file_reader_writer.h"
#include "util/filename.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
#include "util/sync_point.h"
namespace rocksdb {
namespace {
// Find File in LevelFilesBrief data structure
// Within an index range defined by left and right
int FindFileInRange(const InternalKeyComparator& icmp,
const LevelFilesBrief& file_level,
const Slice& key,
uint32_t left,
uint32_t right) {
while (left < right) {
uint32_t mid = (left + right) / 2;
const FdWithKeyRange& f = file_level.files[mid];
if (icmp.InternalKeyComparator::Compare(f.largest_key, key) < 0) {
// Key at "mid.largest" is < "target". Therefore all
// files at or before "mid" are uninteresting.
left = mid + 1;
} else {
// Key at "mid.largest" is >= "target". Therefore all files
// after "mid" are uninteresting.
right = mid;
}
}
return right;
}
// Class to help choose the next file to search for the particular key.
// Searches and returns files level by level.
// We can search level-by-level since entries never hop across
// levels. Therefore we are guaranteed that if we find data
// in a smaller level, later levels are irrelevant (unless we
// are MergeInProgress).
class FilePicker {
public:
FilePicker(std::vector<FileMetaData*>* files, const Slice& user_key,
const Slice& ikey, autovector<LevelFilesBrief>* file_levels,
unsigned int num_levels, FileIndexer* file_indexer,
const Comparator* user_comparator,
const InternalKeyComparator* internal_comparator)
: num_levels_(num_levels),
curr_level_(static_cast<unsigned int>(-1)),
returned_file_level_(static_cast<unsigned int>(-1)),
hit_file_level_(static_cast<unsigned int>(-1)),
search_left_bound_(0),
search_right_bound_(FileIndexer::kLevelMaxIndex),
#ifndef NDEBUG
files_(files),
#endif
level_files_brief_(file_levels),
is_hit_file_last_in_level_(false),
user_key_(user_key),
ikey_(ikey),
file_indexer_(file_indexer),
user_comparator_(user_comparator),
internal_comparator_(internal_comparator) {
// Setup member variables to search first level.
search_ended_ = !PrepareNextLevel();
if (!search_ended_) {
// Prefetch Level 0 table data to avoid cache miss if possible.
for (unsigned int i = 0; i < (*level_files_brief_)[0].num_files; ++i) {
auto* r = (*level_files_brief_)[0].files[i].fd.table_reader;
if (r) {
r->Prepare(ikey);
}
}
}
}
int GetCurrentLevel() const { return curr_level_; }
FdWithKeyRange* GetNextFile() {
while (!search_ended_) { // Loops over different levels.
while (curr_index_in_curr_level_ < curr_file_level_->num_files) {
// Loops over all files in current level.
FdWithKeyRange* f = &curr_file_level_->files[curr_index_in_curr_level_];
hit_file_level_ = curr_level_;
is_hit_file_last_in_level_ =
curr_index_in_curr_level_ == curr_file_level_->num_files - 1;
int cmp_largest = -1;
// Do key range filtering of files or/and fractional cascading if:
// (1) not all the files are in level 0, or
// (2) there are more than 3 current level files
// If there are only 3 or less current level files in the system, we skip
// the key range filtering. In this case, more likely, the system is
// highly tuned to minimize number of tables queried by each query,
// so it is unlikely that key range filtering is more efficient than
// querying the files.
if (num_levels_ > 1 || curr_file_level_->num_files > 3) {
// Check if key is within a file's range. If search left bound and
// right bound point to the same find, we are sure key falls in
// range.
assert(
curr_level_ == 0 ||
curr_index_in_curr_level_ == start_index_in_curr_level_ ||
user_comparator_->Compare(user_key_,
ExtractUserKey(f->smallest_key)) <= 0);
int cmp_smallest = user_comparator_->Compare(user_key_,
ExtractUserKey(f->smallest_key));
if (cmp_smallest >= 0) {
cmp_largest = user_comparator_->Compare(user_key_,
ExtractUserKey(f->largest_key));
}
// Setup file search bound for the next level based on the
// comparison results
if (curr_level_ > 0) {
file_indexer_->GetNextLevelIndex(curr_level_,
curr_index_in_curr_level_,
cmp_smallest, cmp_largest,
&search_left_bound_,
&search_right_bound_);
}
// Key falls out of current file's range
if (cmp_smallest < 0 || cmp_largest > 0) {
if (curr_level_ == 0) {
++curr_index_in_curr_level_;
continue;
} else {
// Search next level.
break;
}
}
}
#ifndef NDEBUG
// Sanity check to make sure that the files are correctly sorted
if (prev_file_) {
if (curr_level_ != 0) {
int comp_sign = internal_comparator_->Compare(
prev_file_->largest_key, f->smallest_key);
assert(comp_sign < 0);
} else {
// level == 0, the current file cannot be newer than the previous
// one. Use compressed data structure, has no attribute seqNo
assert(curr_index_in_curr_level_ > 0);
assert(!NewestFirstBySeqNo(files_[0][curr_index_in_curr_level_],
files_[0][curr_index_in_curr_level_-1]));
}
}
prev_file_ = f;
#endif
returned_file_level_ = curr_level_;
if (curr_level_ > 0 && cmp_largest < 0) {
// No more files to search in this level.
search_ended_ = !PrepareNextLevel();
} else {
++curr_index_in_curr_level_;
}
return f;
}
// Start searching next level.
search_ended_ = !PrepareNextLevel();
}
// Search ended.
return nullptr;
}
// getter for current file level
// for GET_HIT_L0, GET_HIT_L1 & GET_HIT_L2_AND_UP counts
unsigned int GetHitFileLevel() { return hit_file_level_; }
// Returns true if the most recent "hit file" (i.e., one returned by
// GetNextFile()) is at the last index in its level.
bool IsHitFileLastInLevel() { return is_hit_file_last_in_level_; }
private:
unsigned int num_levels_;
unsigned int curr_level_;
unsigned int returned_file_level_;
unsigned int hit_file_level_;
int32_t search_left_bound_;
int32_t search_right_bound_;
#ifndef NDEBUG
std::vector<FileMetaData*>* files_;
#endif
autovector<LevelFilesBrief>* level_files_brief_;
bool search_ended_;
bool is_hit_file_last_in_level_;
LevelFilesBrief* curr_file_level_;
unsigned int curr_index_in_curr_level_;
unsigned int start_index_in_curr_level_;
Slice user_key_;
Slice ikey_;
FileIndexer* file_indexer_;
const Comparator* user_comparator_;
const InternalKeyComparator* internal_comparator_;
#ifndef NDEBUG
FdWithKeyRange* prev_file_;
#endif
// Setup local variables to search next level.
// Returns false if there are no more levels to search.
bool PrepareNextLevel() {
curr_level_++;
while (curr_level_ < num_levels_) {
curr_file_level_ = &(*level_files_brief_)[curr_level_];
if (curr_file_level_->num_files == 0) {
// When current level is empty, the search bound generated from upper
// level must be [0, -1] or [0, FileIndexer::kLevelMaxIndex] if it is
// also empty.
assert(search_left_bound_ == 0);
assert(search_right_bound_ == -1 ||
search_right_bound_ == FileIndexer::kLevelMaxIndex);
// Since current level is empty, it will need to search all files in
// the next level
search_left_bound_ = 0;
search_right_bound_ = FileIndexer::kLevelMaxIndex;
curr_level_++;
continue;
}
// Some files may overlap each other. We find
// all files that overlap user_key and process them in order from
// newest to oldest. In the context of merge-operator, this can occur at
// any level. Otherwise, it only occurs at Level-0 (since Put/Deletes
// are always compacted into a single entry).
int32_t start_index;
if (curr_level_ == 0) {
// On Level-0, we read through all files to check for overlap.
start_index = 0;
} else {
// On Level-n (n>=1), files are sorted. Binary search to find the
// earliest file whose largest key >= ikey. Search left bound and
// right bound are used to narrow the range.
if (search_left_bound_ == search_right_bound_) {
start_index = search_left_bound_;
} else if (search_left_bound_ < search_right_bound_) {
if (search_right_bound_ == FileIndexer::kLevelMaxIndex) {
search_right_bound_ =
static_cast<int32_t>(curr_file_level_->num_files) - 1;
}
start_index =
FindFileInRange(*internal_comparator_, *curr_file_level_, ikey_,
static_cast<uint32_t>(search_left_bound_),
static_cast<uint32_t>(search_right_bound_));
} else {
// search_left_bound > search_right_bound, key does not exist in
// this level. Since no comparison is done in this level, it will
// need to search all files in the next level.
search_left_bound_ = 0;
search_right_bound_ = FileIndexer::kLevelMaxIndex;
curr_level_++;
continue;
}
}
start_index_in_curr_level_ = start_index;
curr_index_in_curr_level_ = start_index;
#ifndef NDEBUG
prev_file_ = nullptr;
#endif
return true;
}
// curr_level_ = num_levels_. So, no more levels to search.
return false;
}
};
} // anonymous namespace
VersionStorageInfo::~VersionStorageInfo() { delete[] files_; }
Version::~Version() {
assert(refs_ == 0);
// Remove from linked list
prev_->next_ = next_;
next_->prev_ = prev_;
// Drop references to files
for (int level = 0; level < storage_info_.num_levels_; level++) {
for (size_t i = 0; i < storage_info_.files_[level].size(); i++) {
FileMetaData* f = storage_info_.files_[level][i];
assert(f->refs > 0);
f->refs--;
if (f->refs <= 0) {
vset_->obsolete_files_.push_back(f);
}
}
}
}
int FindFile(const InternalKeyComparator& icmp,
const LevelFilesBrief& file_level,
const Slice& key) {
return FindFileInRange(icmp, file_level, key, 0,
static_cast<uint32_t>(file_level.num_files));
}
void DoGenerateLevelFilesBrief(LevelFilesBrief* file_level,
const std::vector<FileMetaData*>& files,
Arena* arena) {
assert(file_level);
assert(arena);
size_t num = files.size();
file_level->num_files = num;
char* mem = arena->AllocateAligned(num * sizeof(FdWithKeyRange));
file_level->files = new (mem)FdWithKeyRange[num];
for (size_t i = 0; i < num; i++) {
Slice smallest_key = files[i]->smallest.Encode();
Slice largest_key = files[i]->largest.Encode();
// Copy key slice to sequential memory
size_t smallest_size = smallest_key.size();
size_t largest_size = largest_key.size();
mem = arena->AllocateAligned(smallest_size + largest_size);
memcpy(mem, smallest_key.data(), smallest_size);
memcpy(mem + smallest_size, largest_key.data(), largest_size);
FdWithKeyRange& f = file_level->files[i];
f.fd = files[i]->fd;
f.file_metadata = files[i];
f.smallest_key = Slice(mem, smallest_size);
f.largest_key = Slice(mem + smallest_size, largest_size);
}
}
static bool AfterFile(const Comparator* ucmp,
const Slice* user_key, const FdWithKeyRange* f) {
// nullptr user_key occurs before all keys and is therefore never after *f
return (user_key != nullptr &&
ucmp->Compare(*user_key, ExtractUserKey(f->largest_key)) > 0);
}
static bool BeforeFile(const Comparator* ucmp,
const Slice* user_key, const FdWithKeyRange* f) {
// nullptr user_key occurs after all keys and is therefore never before *f
return (user_key != nullptr &&
ucmp->Compare(*user_key, ExtractUserKey(f->smallest_key)) < 0);
}
bool SomeFileOverlapsRange(
const InternalKeyComparator& icmp,
bool disjoint_sorted_files,
const LevelFilesBrief& file_level,
const Slice* smallest_user_key,
const Slice* largest_user_key) {
const Comparator* ucmp = icmp.user_comparator();
if (!disjoint_sorted_files) {
// Need to check against all files
for (size_t i = 0; i < file_level.num_files; i++) {
const FdWithKeyRange* f = &(file_level.files[i]);
if (AfterFile(ucmp, smallest_user_key, f) ||
BeforeFile(ucmp, largest_user_key, f)) {
// No overlap
} else {
return true; // Overlap
}
}
return false;
}
// Binary search over file list
uint32_t index = 0;
if (smallest_user_key != nullptr) {
// Find the earliest possible internal key for smallest_user_key
InternalKey small;
small.SetMaxPossibleForUserKey(*smallest_user_key);
index = FindFile(icmp, file_level, small.Encode());
}
if (index >= file_level.num_files) {
// beginning of range is after all files, so no overlap.
return false;
}
return !BeforeFile(ucmp, largest_user_key, &file_level.files[index]);
}
namespace {
// An internal iterator. For a given version/level pair, yields
// information about the files in the level. For a given entry, key()
// is the largest key that occurs in the file, and value() is an
// 16-byte value containing the file number and file size, both
// encoded using EncodeFixed64.
class LevelFileNumIterator : public InternalIterator {
public:
LevelFileNumIterator(const InternalKeyComparator& icmp,
const LevelFilesBrief* flevel, bool should_sample)
: icmp_(icmp),
flevel_(flevel),
index_(static_cast<uint32_t>(flevel->num_files)),
current_value_(0, 0, 0), // Marks as invalid
should_sample_(should_sample) {}
virtual bool Valid() const override { return index_ < flevel_->num_files; }
virtual void Seek(const Slice& target) override {
index_ = FindFile(icmp_, *flevel_, target);
}
virtual void SeekForPrev(const Slice& target) override {
SeekForPrevImpl(target, &icmp_);
}
virtual void SeekToFirst() override { index_ = 0; }
virtual void SeekToLast() override {
index_ = (flevel_->num_files == 0)
? 0
: static_cast<uint32_t>(flevel_->num_files) - 1;
}
virtual void Next() override {
assert(Valid());
index_++;
}
virtual void Prev() override {
assert(Valid());
if (index_ == 0) {
index_ = static_cast<uint32_t>(flevel_->num_files); // Marks as invalid
} else {
index_--;
}
}
Slice key() const override {
assert(Valid());
return flevel_->files[index_].largest_key;
}
Slice value() const override {
assert(Valid());
auto file_meta = flevel_->files[index_];
if (should_sample_) {
sample_file_read_inc(file_meta.file_metadata);
}
current_value_ = file_meta.fd;
return Slice(reinterpret_cast<const char*>(&current_value_),
sizeof(FileDescriptor));
}
virtual Status status() const override { return Status::OK(); }
private:
const InternalKeyComparator icmp_;
const LevelFilesBrief* flevel_;
uint32_t index_;
mutable FileDescriptor current_value_;
bool should_sample_;
};
class LevelFileIteratorState : public TwoLevelIteratorState {
public:
// @param skip_filters Disables loading/accessing the filter block
LevelFileIteratorState(TableCache* table_cache,
const ReadOptions& read_options,
const EnvOptions& env_options,
const InternalKeyComparator& icomparator,
HistogramImpl* file_read_hist, bool for_compaction,
bool prefix_enabled, bool skip_filters, int level,
RangeDelAggregator* range_del_agg)
: TwoLevelIteratorState(prefix_enabled),
table_cache_(table_cache),
read_options_(read_options),
env_options_(env_options),
icomparator_(icomparator),
file_read_hist_(file_read_hist),
for_compaction_(for_compaction),
skip_filters_(skip_filters),
level_(level),
range_del_agg_(range_del_agg) {}
InternalIterator* NewSecondaryIterator(const Slice& meta_handle) override {
if (meta_handle.size() != sizeof(FileDescriptor)) {
return NewErrorInternalIterator(
Status::Corruption("FileReader invoked with unexpected value"));
}
const FileDescriptor* fd =
reinterpret_cast<const FileDescriptor*>(meta_handle.data());
return table_cache_->NewIterator(
read_options_, env_options_, icomparator_, *fd, range_del_agg_,
nullptr /* don't need reference to table */, file_read_hist_,
for_compaction_, nullptr /* arena */, skip_filters_, level_);
}
bool PrefixMayMatch(const Slice& internal_key) override {
return true;
}
bool KeyReachedUpperBound(const Slice& internal_key) override {
return read_options_.iterate_upper_bound != nullptr &&
icomparator_.user_comparator()->Compare(
ExtractUserKey(internal_key),
*read_options_.iterate_upper_bound) >= 0;
}
private:
TableCache* table_cache_;
const ReadOptions read_options_;
const EnvOptions& env_options_;
const InternalKeyComparator& icomparator_;
HistogramImpl* file_read_hist_;
bool for_compaction_;
bool skip_filters_;
int level_;
RangeDelAggregator* range_del_agg_;
};
// A wrapper of version builder which references the current version in
// constructor and unref it in the destructor.
// Both of the constructor and destructor need to be called inside DB Mutex.
class BaseReferencedVersionBuilder {
public:
explicit BaseReferencedVersionBuilder(ColumnFamilyData* cfd)
: version_builder_(new VersionBuilder(
cfd->current()->version_set()->env_options(), cfd->table_cache(),
cfd->current()->storage_info(), cfd->ioptions()->info_log)),
version_(cfd->current()) {
version_->Ref();
}
~BaseReferencedVersionBuilder() {
delete version_builder_;
version_->Unref();
}
VersionBuilder* version_builder() { return version_builder_; }
private:
VersionBuilder* version_builder_;
Version* version_;
};
} // anonymous namespace
Status Version::GetTableProperties(std::shared_ptr<const TableProperties>* tp,
const FileMetaData* file_meta,
const std::string* fname) const {
auto table_cache = cfd_->table_cache();
auto ioptions = cfd_->ioptions();
Status s = table_cache->GetTableProperties(
vset_->env_options_, cfd_->internal_comparator(), file_meta->fd,
tp, true /* no io */);
if (s.ok()) {
return s;
}
// We only ignore error type `Incomplete` since it's by design that we
// disallow table when it's not in table cache.
if (!s.IsIncomplete()) {
return s;
}
// 2. Table is not present in table cache, we'll read the table properties
// directly from the properties block in the file.
std::unique_ptr<RandomAccessFile> file;
std::string file_name;
if (fname != nullptr) {
file_name = *fname;
} else {
file_name =
TableFileName(vset_->db_options_->db_paths, file_meta->fd.GetNumber(),
file_meta->fd.GetPathId());
}
s = ioptions->env->NewRandomAccessFile(file_name, &file, vset_->env_options_);
if (!s.ok()) {
return s;
}
TableProperties* raw_table_properties;
// By setting the magic number to kInvalidTableMagicNumber, we can by
// pass the magic number check in the footer.
std::unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(file), file_name));
s = ReadTableProperties(
file_reader.get(), file_meta->fd.GetFileSize(),
Footer::kInvalidTableMagicNumber /* table's magic number */, *ioptions, &raw_table_properties);
if (!s.ok()) {
return s;
}
RecordTick(ioptions->statistics, NUMBER_DIRECT_LOAD_TABLE_PROPERTIES);
*tp = std::shared_ptr<const TableProperties>(raw_table_properties);
return s;
}
Status Version::GetPropertiesOfAllTables(TablePropertiesCollection* props) {
Status s;
for (int level = 0; level < storage_info_.num_levels_; level++) {
s = GetPropertiesOfAllTables(props, level);
if (!s.ok()) {
return s;
}
}
return Status::OK();
}
Status Version::GetPropertiesOfAllTables(TablePropertiesCollection* props,
int level) {
for (const auto& file_meta : storage_info_.files_[level]) {
auto fname =
TableFileName(vset_->db_options_->db_paths, file_meta->fd.GetNumber(),
file_meta->fd.GetPathId());
// 1. If the table is already present in table cache, load table
// properties from there.
std::shared_ptr<const TableProperties> table_properties;
Status s = GetTableProperties(&table_properties, file_meta, &fname);
if (s.ok()) {
props->insert({fname, table_properties});
} else {
return s;
}
}
return Status::OK();
}
Status Version::GetPropertiesOfTablesInRange(
const Range* range, std::size_t n, TablePropertiesCollection* props) const {
for (int level = 0; level < storage_info_.num_non_empty_levels(); level++) {
for (decltype(n) i = 0; i < n; i++) {
// Convert user_key into a corresponding internal key.
InternalKey k1(range[i].start, kMaxSequenceNumber, kValueTypeForSeek);
InternalKey k2(range[i].limit, kMaxSequenceNumber, kValueTypeForSeek);
std::vector<FileMetaData*> files;
storage_info_.GetOverlappingInputs(level, &k1, &k2, &files, -1, nullptr,
false);
for (const auto& file_meta : files) {
auto fname =
TableFileName(vset_->db_options_->db_paths,
file_meta->fd.GetNumber(), file_meta->fd.GetPathId());
if (props->count(fname) == 0) {
// 1. If the table is already present in table cache, load table
// properties from there.
std::shared_ptr<const TableProperties> table_properties;
Status s = GetTableProperties(&table_properties, file_meta, &fname);
if (s.ok()) {
props->insert({fname, table_properties});
} else {
return s;
}
}
}
}
}
return Status::OK();
}
Status Version::GetAggregatedTableProperties(
std::shared_ptr<const TableProperties>* tp, int level) {
TablePropertiesCollection props;
Status s;
if (level < 0) {
s = GetPropertiesOfAllTables(&props);
} else {
s = GetPropertiesOfAllTables(&props, level);
}
if (!s.ok()) {
return s;
}
auto* new_tp = new TableProperties();
for (const auto& item : props) {
new_tp->Add(*item.second);
}
tp->reset(new_tp);
return Status::OK();
}
size_t Version::GetMemoryUsageByTableReaders() {
size_t total_usage = 0;
for (auto& file_level : storage_info_.level_files_brief_) {
for (size_t i = 0; i < file_level.num_files; i++) {
total_usage += cfd_->table_cache()->GetMemoryUsageByTableReader(
vset_->env_options_, cfd_->internal_comparator(),
file_level.files[i].fd);
}
}
return total_usage;
}
void Version::GetColumnFamilyMetaData(ColumnFamilyMetaData* cf_meta) {
assert(cf_meta);
assert(cfd_);
cf_meta->name = cfd_->GetName();
cf_meta->size = 0;
cf_meta->file_count = 0;
cf_meta->levels.clear();
auto* ioptions = cfd_->ioptions();
auto* vstorage = storage_info();
for (int level = 0; level < cfd_->NumberLevels(); level++) {
uint64_t level_size = 0;
cf_meta->file_count += vstorage->LevelFiles(level).size();
std::vector<SstFileMetaData> files;
for (const auto& file : vstorage->LevelFiles(level)) {
uint32_t path_id = file->fd.GetPathId();
std::string file_path;
if (path_id < ioptions->db_paths.size()) {
file_path = ioptions->db_paths[path_id].path;
} else {
assert(!ioptions->db_paths.empty());
file_path = ioptions->db_paths.back().path;
}
files.emplace_back(
MakeTableFileName("", file->fd.GetNumber()), file_path,
file->fd.GetFileSize(), file->smallest_seqno, file->largest_seqno,
file->smallest.user_key().ToString(),
file->largest.user_key().ToString(),
file->stats.num_reads_sampled.load(std::memory_order_relaxed),
file->being_compacted);
level_size += file->fd.GetFileSize();
}
cf_meta->levels.emplace_back(
level, level_size, std::move(files));
cf_meta->size += level_size;
}
}
uint64_t VersionStorageInfo::GetEstimatedActiveKeys() const {
// Estimation will be inaccurate when:
// (1) there exist merge keys
// (2) keys are directly overwritten
// (3) deletion on non-existing keys
// (4) low number of samples
if (current_num_samples_ == 0) {
return 0;
}
if (current_num_non_deletions_ <= current_num_deletions_) {
return 0;
}
uint64_t est = current_num_non_deletions_ - current_num_deletions_;
uint64_t file_count = 0;
for (int level = 0; level < num_levels_; ++level) {
file_count += files_[level].size();
}
if (current_num_samples_ < file_count) {
// casting to avoid overflowing
return
static_cast<uint64_t>(
(est * static_cast<double>(file_count) / current_num_samples_)
);
} else {
return est;
}
}
double VersionStorageInfo::GetEstimatedCompressionRatioAtLevel(
int level) const {
assert(level < num_levels_);
uint64_t sum_file_size_bytes = 0;
uint64_t sum_data_size_bytes = 0;
for (auto* file_meta : files_[level]) {
sum_file_size_bytes += file_meta->fd.GetFileSize();
sum_data_size_bytes += file_meta->raw_key_size + file_meta->raw_value_size;
}
if (sum_file_size_bytes == 0) {
return -1.0;
}
return static_cast<double>(sum_data_size_bytes) / sum_file_size_bytes;
}
void Version::AddIterators(const ReadOptions& read_options,
const EnvOptions& soptions,
MergeIteratorBuilder* merge_iter_builder,
RangeDelAggregator* range_del_agg) {
assert(storage_info_.finalized_);
for (int level = 0; level < storage_info_.num_non_empty_levels(); level++) {
AddIteratorsForLevel(read_options, soptions, merge_iter_builder, level,
range_del_agg);
}
}
void Version::AddIteratorsForLevel(const ReadOptions& read_options,
const EnvOptions& soptions,
MergeIteratorBuilder* merge_iter_builder,
int level,
RangeDelAggregator* range_del_agg) {
assert(storage_info_.finalized_);
if (level >= storage_info_.num_non_empty_levels()) {
// This is an empty level
return;
} else if (storage_info_.LevelFilesBrief(level).num_files == 0) {
// No files in this level
return;
}
bool should_sample = should_sample_file_read();
auto* arena = merge_iter_builder->GetArena();
if (level == 0) {
// Merge all level zero files together since they may overlap
for (size_t i = 0; i < storage_info_.LevelFilesBrief(0).num_files; i++) {
const auto& file = storage_info_.LevelFilesBrief(0).files[i];
merge_iter_builder->AddIterator(cfd_->table_cache()->NewIterator(
read_options, soptions, cfd_->internal_comparator(), file.fd,
range_del_agg, nullptr, cfd_->internal_stats()->GetFileReadHist(0),
false, arena, false /* skip_filters */, 0 /* level */));
}
if (should_sample) {
// Count ones for every L0 files. This is done per iterator creation
// rather than Seek(), while files in other levels are recored per seek.
// If users execute one range query per iterator, there may be some
// discrepancy here.
for (FileMetaData* meta : storage_info_.LevelFiles(0)) {
sample_file_read_inc(meta);
}
}
} else {
// For levels > 0, we can use a concatenating iterator that sequentially
// walks through the non-overlapping files in the level, opening them
// lazily.
auto* mem = arena->AllocateAligned(sizeof(LevelFileIteratorState));
auto* state = new (mem)
LevelFileIteratorState(cfd_->table_cache(), read_options, soptions,
cfd_->internal_comparator(),
cfd_->internal_stats()->GetFileReadHist(level),
false /* for_compaction */,
cfd_->ioptions()->prefix_extractor != nullptr,
IsFilterSkipped(level), level, range_del_agg);
mem = arena->AllocateAligned(sizeof(LevelFileNumIterator));
auto* first_level_iter = new (mem) LevelFileNumIterator(
cfd_->internal_comparator(), &storage_info_.LevelFilesBrief(level),
should_sample_file_read());
merge_iter_builder->AddIterator(
NewTwoLevelIterator(state, first_level_iter, arena, false));
}
}
void Version::AddRangeDelIteratorsForLevel(
const ReadOptions& read_options, const EnvOptions& soptions, int level,
std::vector<InternalIterator*>* range_del_iters) {
range_del_iters->clear();
for (size_t i = 0; i < storage_info_.LevelFilesBrief(level).num_files; i++) {
const auto& file = storage_info_.LevelFilesBrief(level).files[i];
auto* range_del_iter = cfd_->table_cache()->NewRangeTombstoneIterator(
read_options, soptions, cfd_->internal_comparator(), file.fd,
cfd_->internal_stats()->GetFileReadHist(level),
false /* skip_filters */, level);
if (range_del_iter != nullptr) {
range_del_iters->push_back(range_del_iter);
}
}
}
VersionStorageInfo::VersionStorageInfo(
const InternalKeyComparator* internal_comparator,
const Comparator* user_comparator, int levels,
CompactionStyle compaction_style, VersionStorageInfo* ref_vstorage,
bool _force_consistency_checks)
: internal_comparator_(internal_comparator),
user_comparator_(user_comparator),
// cfd is nullptr if Version is dummy
num_levels_(levels),
num_non_empty_levels_(0),
file_indexer_(user_comparator),
compaction_style_(compaction_style),
files_(new std::vector<FileMetaData*>[num_levels_]),
base_level_(num_levels_ == 1 ? -1 : 1),
files_by_compaction_pri_(num_levels_),
level0_non_overlapping_(false),
next_file_to_compact_by_size_(num_levels_),
compaction_score_(num_levels_),
compaction_level_(num_levels_),
l0_delay_trigger_count_(0),
accumulated_file_size_(0),
accumulated_raw_key_size_(0),
accumulated_raw_value_size_(0),
accumulated_num_non_deletions_(0),
accumulated_num_deletions_(0),
current_num_non_deletions_(0),
current_num_deletions_(0),
current_num_samples_(0),
estimated_compaction_needed_bytes_(0),
finalized_(false),
force_consistency_checks_(_force_consistency_checks) {
if (ref_vstorage != nullptr) {
accumulated_file_size_ = ref_vstorage->accumulated_file_size_;
accumulated_raw_key_size_ = ref_vstorage->accumulated_raw_key_size_;
accumulated_raw_value_size_ = ref_vstorage->accumulated_raw_value_size_;
accumulated_num_non_deletions_ =
ref_vstorage->accumulated_num_non_deletions_;
accumulated_num_deletions_ = ref_vstorage->accumulated_num_deletions_;
current_num_non_deletions_ = ref_vstorage->current_num_non_deletions_;
current_num_deletions_ = ref_vstorage->current_num_deletions_;
current_num_samples_ = ref_vstorage->current_num_samples_;
}
}
Version::Version(ColumnFamilyData* column_family_data, VersionSet* vset,
uint64_t version_number)
: env_(vset->env_),
cfd_(column_family_data),
info_log_((cfd_ == nullptr) ? nullptr : cfd_->ioptions()->info_log),
db_statistics_((cfd_ == nullptr) ? nullptr
: cfd_->ioptions()->statistics),
table_cache_((cfd_ == nullptr) ? nullptr : cfd_->table_cache()),
merge_operator_((cfd_ == nullptr) ? nullptr
: cfd_->ioptions()->merge_operator),
storage_info_(
(cfd_ == nullptr) ? nullptr : &cfd_->internal_comparator(),
(cfd_ == nullptr) ? nullptr : cfd_->user_comparator(),
cfd_ == nullptr ? 0 : cfd_->NumberLevels(),
cfd_ == nullptr ? kCompactionStyleLevel
: cfd_->ioptions()->compaction_style,
(cfd_ == nullptr || cfd_->current() == nullptr)
? nullptr
: cfd_->current()->storage_info(),
cfd_ == nullptr ? false : cfd_->ioptions()->force_consistency_checks),
vset_(vset),
next_(this),
prev_(this),
refs_(0),
version_number_(version_number) {}
void Version::Get(const ReadOptions& read_options, const LookupKey& k,
PinnableSlice* value, Status* status,
MergeContext* merge_context,
RangeDelAggregator* range_del_agg, bool* value_found,
bool* key_exists, SequenceNumber* seq, bool* is_blob) {
Slice ikey = k.internal_key();
Slice user_key = k.user_key();
assert(status->ok() || status->IsMergeInProgress());
if (key_exists != nullptr) {
// will falsify below if not found
*key_exists = true;
}
PinnedIteratorsManager pinned_iters_mgr;
GetContext get_context(
user_comparator(), merge_operator_, info_log_, db_statistics_,
status->ok() ? GetContext::kNotFound : GetContext::kMerge, user_key,
value, value_found, merge_context, range_del_agg, this->env_, seq,
merge_operator_ ? &pinned_iters_mgr : nullptr, is_blob);
// Pin blocks that we read to hold merge operands
if (merge_operator_) {
pinned_iters_mgr.StartPinning();
}
FilePicker fp(
storage_info_.files_, user_key, ikey, &storage_info_.level_files_brief_,
storage_info_.num_non_empty_levels_, &storage_info_.file_indexer_,
user_comparator(), internal_comparator());
FdWithKeyRange* f = fp.GetNextFile();
while (f != nullptr) {
if (get_context.sample()) {
sample_file_read_inc(f->file_metadata);
}
*status = table_cache_->Get(
read_options, *internal_comparator(), f->fd, ikey, &get_context,
cfd_->internal_stats()->GetFileReadHist(fp.GetHitFileLevel()),
IsFilterSkipped(static_cast<int>(fp.GetHitFileLevel()),
fp.IsHitFileLastInLevel()),
fp.GetCurrentLevel());
// TODO: examine the behavior for corrupted key
if (!status->ok()) {
return;
}
switch (get_context.State()) {
case GetContext::kNotFound:
// Keep searching in other files
break;
case GetContext::kFound:
if (fp.GetHitFileLevel() == 0) {
RecordTick(db_statistics_, GET_HIT_L0);
} else if (fp.GetHitFileLevel() == 1) {
RecordTick(db_statistics_, GET_HIT_L1);
} else if (fp.GetHitFileLevel() >= 2) {
RecordTick(db_statistics_, GET_HIT_L2_AND_UP);
}
return;
case GetContext::kDeleted:
// Use empty error message for speed
*status = Status::NotFound();
return;
case GetContext::kCorrupt:
*status = Status::Corruption("corrupted key for ", user_key);
return;
case GetContext::kMerge:
break;
case GetContext::kBlobIndex:
ROCKS_LOG_ERROR(info_log_, "Encounter unexpected blob index.");
*status = Status::NotSupported(
"Encounter unexpected blob index. Please open DB with "
"rocksdb::blob_db::BlobDB instead.");
return;
}
f = fp.GetNextFile();
}
if (GetContext::kMerge == get_context.State()) {
if (!merge_operator_) {
*status = Status::InvalidArgument(
"merge_operator is not properly initialized.");
return;
}
// merge_operands are in saver and we hit the beginning of the key history
// do a final merge of nullptr and operands;
std::string* str_value = value != nullptr ? value->GetSelf() : nullptr;
*status = MergeHelper::TimedFullMerge(
merge_operator_, user_key, nullptr, merge_context->GetOperands(),
str_value, info_log_, db_statistics_, env_,
nullptr /* result_operand */, true);
if (LIKELY(value != nullptr)) {
value->PinSelf();
}
} else {
if (key_exists != nullptr) {
*key_exists = false;
}
*status = Status::NotFound(); // Use an empty error message for speed
}
}
bool Version::IsFilterSkipped(int level, bool is_file_last_in_level) {
// Reaching the bottom level implies misses at all upper levels, so we'll
// skip checking the filters when we predict a hit.
return cfd_->ioptions()->optimize_filters_for_hits &&
(level > 0 || is_file_last_in_level) &&
level == storage_info_.num_non_empty_levels() - 1;
}
void VersionStorageInfo::GenerateLevelFilesBrief() {
level_files_brief_.resize(num_non_empty_levels_);
for (int level = 0; level < num_non_empty_levels_; level++) {
DoGenerateLevelFilesBrief(
&level_files_brief_[level], files_[level], &arena_);
}
}
void Version::PrepareApply(
const MutableCFOptions& mutable_cf_options,
bool update_stats) {
UpdateAccumulatedStats(update_stats);
storage_info_.UpdateNumNonEmptyLevels();
storage_info_.CalculateBaseBytes(*cfd_->ioptions(), mutable_cf_options);
storage_info_.UpdateFilesByCompactionPri(cfd_->ioptions()->compaction_pri);
storage_info_.GenerateFileIndexer();
storage_info_.GenerateLevelFilesBrief();
storage_info_.GenerateLevel0NonOverlapping();
}
bool Version::MaybeInitializeFileMetaData(FileMetaData* file_meta) {
if (file_meta->init_stats_from_file ||
file_meta->compensated_file_size > 0) {
return false;
}
std::shared_ptr<const TableProperties> tp;
Status s = GetTableProperties(&tp, file_meta);
file_meta->init_stats_from_file = true;
if (!s.ok()) {
ROCKS_LOG_ERROR(vset_->db_options_->info_log,
"Unable to load table properties for file %" PRIu64
" --- %s\n",
file_meta->fd.GetNumber(), s.ToString().c_str());
return false;
}
if (tp.get() == nullptr) return false;
file_meta->num_entries = tp->num_entries;
file_meta->num_deletions = GetDeletedKeys(tp->user_collected_properties);
file_meta->raw_value_size = tp->raw_value_size;
file_meta->raw_key_size = tp->raw_key_size;
return true;
}
void VersionStorageInfo::UpdateAccumulatedStats(FileMetaData* file_meta) {
assert(file_meta->init_stats_from_file);
accumulated_file_size_ += file_meta->fd.GetFileSize();
accumulated_raw_key_size_ += file_meta->raw_key_size;
accumulated_raw_value_size_ += file_meta->raw_value_size;
accumulated_num_non_deletions_ +=
file_meta->num_entries - file_meta->num_deletions;
accumulated_num_deletions_ += file_meta->num_deletions;
current_num_non_deletions_ +=
file_meta->num_entries - file_meta->num_deletions;
current_num_deletions_ += file_meta->num_deletions;
current_num_samples_++;
}
void VersionStorageInfo::RemoveCurrentStats(FileMetaData* file_meta) {
if (file_meta->init_stats_from_file) {
current_num_non_deletions_ -=
file_meta->num_entries - file_meta->num_deletions;
current_num_deletions_ -= file_meta->num_deletions;
current_num_samples_--;
}
}
void Version::UpdateAccumulatedStats(bool update_stats) {
if (update_stats) {
// maximum number of table properties loaded from files.
const int kMaxInitCount = 20;
int init_count = 0;
// here only the first kMaxInitCount files which haven't been
// initialized from file will be updated with num_deletions.
// The motivation here is to cap the maximum I/O per Version creation.
// The reason for choosing files from lower-level instead of higher-level
// is that such design is able to propagate the initialization from
// lower-level to higher-level: When the num_deletions of lower-level
// files are updated, it will make the lower-level files have accurate
// compensated_file_size, making lower-level to higher-level compaction
// will be triggered, which creates higher-level files whose num_deletions
// will be updated here.
for (int level = 0;
level < storage_info_.num_levels_ && init_count < kMaxInitCount;
++level) {
for (auto* file_meta : storage_info_.files_[level]) {
if (MaybeInitializeFileMetaData(file_meta)) {
// each FileMeta will be initialized only once.
storage_info_.UpdateAccumulatedStats(file_meta);
// when option "max_open_files" is -1, all the file metadata has
// already been read, so MaybeInitializeFileMetaData() won't incur
// any I/O cost. "max_open_files=-1" means that the table cache passed
// to the VersionSet and then to the ColumnFamilySet has a size of
// TableCache::kInfiniteCapacity
if (vset_->GetColumnFamilySet()->get_table_cache()->GetCapacity() ==
TableCache::kInfiniteCapacity) {
continue;
}
if (++init_count >= kMaxInitCount) {
break;
}
}
}
}
// In case all sampled-files contain only deletion entries, then we
// load the table-property of a file in higher-level to initialize
// that value.
for (int level = storage_info_.num_levels_ - 1;
storage_info_.accumulated_raw_value_size_ == 0 && level >= 0;
--level) {
for (int i = static_cast<int>(storage_info_.files_[level].size()) - 1;
storage_info_.accumulated_raw_value_size_ == 0 && i >= 0; --i) {
if (MaybeInitializeFileMetaData(storage_info_.files_[level][i])) {
storage_info_.UpdateAccumulatedStats(storage_info_.files_[level][i]);
}
}
}
}
storage_info_.ComputeCompensatedSizes();
}
void VersionStorageInfo::ComputeCompensatedSizes() {
static const int kDeletionWeightOnCompaction = 2;
uint64_t average_value_size = GetAverageValueSize();
// compute the compensated size
for (int level = 0; level < num_levels_; level++) {
for (auto* file_meta : files_[level]) {
// Here we only compute compensated_file_size for those file_meta
// which compensated_file_size is uninitialized (== 0). This is true only
// for files that have been created right now and no other thread has
// access to them. That's why we can safely mutate compensated_file_size.
if (file_meta->compensated_file_size == 0) {
file_meta->compensated_file_size = file_meta->fd.GetFileSize();
// Here we only boost the size of deletion entries of a file only
// when the number of deletion entries is greater than the number of
// non-deletion entries in the file. The motivation here is that in
// a stable workload, the number of deletion entries should be roughly
// equal to the number of non-deletion entries. If we compensate the
// size of deletion entries in a stable workload, the deletion
// compensation logic might introduce unwanted effet which changes the
// shape of LSM tree.
if (file_meta->num_deletions * 2 >= file_meta->num_entries) {
file_meta->compensated_file_size +=
(file_meta->num_deletions * 2 - file_meta->num_entries) *
average_value_size * kDeletionWeightOnCompaction;
}
}
}
}
}
int VersionStorageInfo::MaxInputLevel() const {
if (compaction_style_ == kCompactionStyleLevel) {
return num_levels() - 2;
}
return 0;
}
int VersionStorageInfo::MaxOutputLevel(bool allow_ingest_behind) const {
if (allow_ingest_behind) {
assert(num_levels() > 1);
return num_levels() - 2;
}
return num_levels() - 1;
}
void VersionStorageInfo::EstimateCompactionBytesNeeded(
const MutableCFOptions& mutable_cf_options) {
// Only implemented for level-based compaction
if (compaction_style_ != kCompactionStyleLevel) {
estimated_compaction_needed_bytes_ = 0;
return;
}
// Start from Level 0, if level 0 qualifies compaction to level 1,
// we estimate the size of compaction.
// Then we move on to the next level and see whether it qualifies compaction
// to the next level. The size of the level is estimated as the actual size
// on the level plus the input bytes from the previous level if there is any.
// If it exceeds, take the exceeded bytes as compaction input and add the size
// of the compaction size to tatal size.
// We keep doing it to Level 2, 3, etc, until the last level and return the
// accumulated bytes.
uint64_t bytes_compact_to_next_level = 0;
uint64_t level_size = 0;
for (auto* f : files_[0]) {
level_size += f->fd.GetFileSize();
}
// Level 0
bool level0_compact_triggered = false;
if (static_cast<int>(files_[0].size()) >=
mutable_cf_options.level0_file_num_compaction_trigger ||
level_size >= mutable_cf_options.max_bytes_for_level_base) {
level0_compact_triggered = true;
estimated_compaction_needed_bytes_ = level_size;
bytes_compact_to_next_level = level_size;
} else {
estimated_compaction_needed_bytes_ = 0;
}
// Level 1 and up.
uint64_t bytes_next_level = 0;
for (int level = base_level(); level <= MaxInputLevel(); level++) {
level_size = 0;
if (bytes_next_level > 0) {
#ifndef NDEBUG
uint64_t level_size2 = 0;
for (auto* f : files_[level]) {
level_size2 += f->fd.GetFileSize();
}
assert(level_size2 == bytes_next_level);
#endif
level_size = bytes_next_level;
bytes_next_level = 0;
} else {
for (auto* f : files_[level]) {
level_size += f->fd.GetFileSize();
}
}
if (level == base_level() && level0_compact_triggered) {
// Add base level size to compaction if level0 compaction triggered.
estimated_compaction_needed_bytes_ += level_size;
}
// Add size added by previous compaction
level_size += bytes_compact_to_next_level;
bytes_compact_to_next_level = 0;
uint64_t level_target = MaxBytesForLevel(level);
if (level_size > level_target) {
bytes_compact_to_next_level = level_size - level_target;
// Estimate the actual compaction fan-out ratio as size ratio between
// the two levels.
assert(bytes_next_level == 0);
if (level + 1 < num_levels_) {
for (auto* f : files_[level + 1]) {
bytes_next_level += f->fd.GetFileSize();
}
}
if (bytes_next_level > 0) {
assert(level_size > 0);
estimated_compaction_needed_bytes_ += static_cast<uint64_t>(
static_cast<double>(bytes_compact_to_next_level) *
(static_cast<double>(bytes_next_level) /
static_cast<double>(level_size) +
1));
}
}
}
}
namespace {
uint32_t GetExpiredTtlFilesCount(const ImmutableCFOptions& ioptions,
const std::vector<FileMetaData*>& files) {
uint32_t ttl_expired_files_count = 0;
int64_t _current_time;
auto status = ioptions.env->GetCurrentTime(&_current_time);
if (status.ok()) {
const uint64_t current_time = static_cast<uint64_t>(_current_time);
for (auto f : files) {
if (!f->being_compacted && f->fd.table_reader != nullptr &&
f->fd.table_reader->GetTableProperties() != nullptr) {
auto creation_time =
f->fd.table_reader->GetTableProperties()->creation_time;
if (creation_time > 0 &&
creation_time <
(current_time - ioptions.compaction_options_fifo.ttl)) {
ttl_expired_files_count++;
}
}
}
}
return ttl_expired_files_count;
}
} // anonymous namespace
void VersionStorageInfo::ComputeCompactionScore(
const ImmutableCFOptions& immutable_cf_options,
const MutableCFOptions& mutable_cf_options) {
for (int level = 0; level <= MaxInputLevel(); level++) {
double score;
if (level == 0) {
// We treat level-0 specially by bounding the number of files
// instead of number of bytes for two reasons:
//
// (1) With larger write-buffer sizes, it is nice not to do too
// many level-0 compactions.
//
// (2) The files in level-0 are merged on every read and
// therefore we wish to avoid too many files when the individual
// file size is small (perhaps because of a small write-buffer
// setting, or very high compression ratios, or lots of
// overwrites/deletions).
int num_sorted_runs = 0;
uint64_t total_size = 0;
for (auto* f : files_[level]) {
if (!f->being_compacted) {
total_size += f->compensated_file_size;
num_sorted_runs++;
}
}
if (compaction_style_ == kCompactionStyleUniversal) {
// For universal compaction, we use level0 score to indicate
// compaction score for the whole DB. Adding other levels as if
// they are L0 files.
for (int i = 1; i < num_levels(); i++) {
if (!files_[i].empty() && !files_[i][0]->being_compacted) {
num_sorted_runs++;
}
}
}
if (compaction_style_ == kCompactionStyleFIFO) {
score =
static_cast<double>(total_size) /
immutable_cf_options.compaction_options_fifo.max_table_files_size;
if (immutable_cf_options.compaction_options_fifo.allow_compaction) {
score = std::max(
static_cast<double>(num_sorted_runs) /
mutable_cf_options.level0_file_num_compaction_trigger,
score);
}
if (immutable_cf_options.compaction_options_fifo.ttl > 0) {
score = std::max(static_cast<double>(GetExpiredTtlFilesCount(
immutable_cf_options, files_[level])),
score);
}
} else {
score = static_cast<double>(num_sorted_runs) /
mutable_cf_options.level0_file_num_compaction_trigger;
if (compaction_style_ == kCompactionStyleLevel && num_levels() > 1) {
// Level-based involves L0->L0 compactions that can lead to oversized
// L0 files. Take into account size as well to avoid later giant
// compactions to the base level.
score = std::max(
score, static_cast<double>(total_size) /
mutable_cf_options.max_bytes_for_level_base);
}
}
} else {
// Compute the ratio of current size to size limit.
uint64_t level_bytes_no_compacting = 0;
for (auto f : files_[level]) {
if (!f->being_compacted) {
level_bytes_no_compacting += f->compensated_file_size;
}
}
score = static_cast<double>(level_bytes_no_compacting) /
MaxBytesForLevel(level);
}
compaction_level_[level] = level;
compaction_score_[level] = score;
}
// sort all the levels based on their score. Higher scores get listed
// first. Use bubble sort because the number of entries are small.
for (int i = 0; i < num_levels() - 2; i++) {
for (int j = i + 1; j < num_levels() - 1; j++) {
if (compaction_score_[i] < compaction_score_[j]) {
double score = compaction_score_[i];
int level = compaction_level_[i];
compaction_score_[i] = compaction_score_[j];
compaction_level_[i] = compaction_level_[j];
compaction_score_[j] = score;
compaction_level_[j] = level;
}
}
}
ComputeFilesMarkedForCompaction();
EstimateCompactionBytesNeeded(mutable_cf_options);
}
void VersionStorageInfo::ComputeFilesMarkedForCompaction() {
files_marked_for_compaction_.clear();
int last_qualify_level = 0;
// Do not include files from the last level with data
// If table properties collector suggests a file on the last level,
// we should not move it to a new level.
for (int level = num_levels() - 1; level >= 1; level--) {
if (!files_[level].empty()) {
last_qualify_level = level - 1;
break;
}
}
for (int level = 0; level <= last_qualify_level; level++) {
for (auto* f : files_[level]) {
if (!f->being_compacted && f->marked_for_compaction) {
files_marked_for_compaction_.emplace_back(level, f);
}
}
}
}
namespace {
// used to sort files by size
struct Fsize {
size_t index;
FileMetaData* file;
};
// Compator that is used to sort files based on their size
// In normal mode: descending size
bool CompareCompensatedSizeDescending(const Fsize& first, const Fsize& second) {
return (first.file->compensated_file_size >
second.file->compensated_file_size);
}
} // anonymous namespace
void VersionStorageInfo::AddFile(int level, FileMetaData* f, Logger* info_log) {
auto* level_files = &files_[level];
// Must not overlap
#ifndef NDEBUG
if (level > 0 && !level_files->empty() &&
internal_comparator_->Compare(
(*level_files)[level_files->size() - 1]->largest, f->smallest) >= 0) {
auto* f2 = (*level_files)[level_files->size() - 1];
if (info_log != nullptr) {
Error(info_log, "Adding new file %" PRIu64
" range (%s, %s) to level %d but overlapping "
"with existing file %" PRIu64 " %s %s",
f->fd.GetNumber(), f->smallest.DebugString(true).c_str(),
f->largest.DebugString(true).c_str(), level, f2->fd.GetNumber(),
f2->smallest.DebugString(true).c_str(),
f2->largest.DebugString(true).c_str());
LogFlush(info_log);
}
assert(false);
}
#endif
f->refs++;
level_files->push_back(f);
}
// Version::PrepareApply() need to be called before calling the function, or
// following functions called:
// 1. UpdateNumNonEmptyLevels();
// 2. CalculateBaseBytes();
// 3. UpdateFilesByCompactionPri();
// 4. GenerateFileIndexer();
// 5. GenerateLevelFilesBrief();
// 6. GenerateLevel0NonOverlapping();
void VersionStorageInfo::SetFinalized() {
finalized_ = true;
#ifndef NDEBUG
if (compaction_style_ != kCompactionStyleLevel) {
// Not level based compaction.
return;
}
assert(base_level_ < 0 || num_levels() == 1 ||
(base_level_ >= 1 && base_level_ < num_levels()));
// Verify all levels newer than base_level are empty except L0
for (int level = 1; level < base_level(); level++) {
assert(NumLevelBytes(level) == 0);
}
uint64_t max_bytes_prev_level = 0;
for (int level = base_level(); level < num_levels() - 1; level++) {
if (LevelFiles(level).size() == 0) {
continue;
}
assert(MaxBytesForLevel(level) >= max_bytes_prev_level);
max_bytes_prev_level = MaxBytesForLevel(level);
}
int num_empty_non_l0_level = 0;
for (int level = 0; level < num_levels(); level++) {
assert(LevelFiles(level).size() == 0 ||
LevelFiles(level).size() == LevelFilesBrief(level).num_files);
if (level > 0 && NumLevelBytes(level) > 0) {
num_empty_non_l0_level++;
}
if (LevelFiles(level).size() > 0) {
assert(level < num_non_empty_levels());
}
}
assert(compaction_level_.size() > 0);
assert(compaction_level_.size() == compaction_score_.size());
#endif
}
void VersionStorageInfo::UpdateNumNonEmptyLevels() {
num_non_empty_levels_ = num_levels_;
for (int i = num_levels_ - 1; i >= 0; i--) {
if (files_[i].size() != 0) {
return;
} else {
num_non_empty_levels_ = i;
}
}
}
namespace {
// Sort `temp` based on ratio of overlapping size over file size
void SortFileByOverlappingRatio(
const InternalKeyComparator& icmp, const std::vector<FileMetaData*>& files,
const std::vector<FileMetaData*>& next_level_files,
std::vector<Fsize>* temp) {
std::unordered_map<uint64_t, uint64_t> file_to_order;
auto next_level_it = next_level_files.begin();
for (auto& file : files) {
uint64_t overlapping_bytes = 0;
// Skip files in next level that is smaller than current file
while (next_level_it != next_level_files.end() &&
icmp.Compare((*next_level_it)->largest, file->smallest) < 0) {
next_level_it++;
}
while (next_level_it != next_level_files.end() &&
icmp.Compare((*next_level_it)->smallest, file->largest) < 0) {
overlapping_bytes += (*next_level_it)->fd.file_size;
if (icmp.Compare((*next_level_it)->largest, file->largest) > 0) {
// next level file cross large boundary of current file.
break;
}
next_level_it++;
}
assert(file->fd.file_size != 0);
file_to_order[file->fd.GetNumber()] =
overlapping_bytes * 1024u / file->fd.file_size;
}
std::sort(temp->begin(), temp->end(),
[&](const Fsize& f1, const Fsize& f2) -> bool {
return file_to_order[f1.file->fd.GetNumber()] <
file_to_order[f2.file->fd.GetNumber()];
});
}
} // namespace
void VersionStorageInfo::UpdateFilesByCompactionPri(
CompactionPri compaction_pri) {
if (compaction_style_ == kCompactionStyleFIFO ||
compaction_style_ == kCompactionStyleUniversal) {
// don't need this
return;
}
// No need to sort the highest level because it is never compacted.
for (int level = 0; level < num_levels() - 1; level++) {
const std::vector<FileMetaData*>& files = files_[level];
auto& files_by_compaction_pri = files_by_compaction_pri_[level];
assert(files_by_compaction_pri.size() == 0);
// populate a temp vector for sorting based on size
std::vector<Fsize> temp(files.size());
for (size_t i = 0; i < files.size(); i++) {
temp[i].index = i;
temp[i].file = files[i];
}
// sort the top number_of_files_to_sort_ based on file size
size_t num = VersionStorageInfo::kNumberFilesToSort;
if (num > temp.size()) {
num = temp.size();
}
switch (compaction_pri) {
case kByCompensatedSize:
std::partial_sort(temp.begin(), temp.begin() + num, temp.end(),
CompareCompensatedSizeDescending);
break;
case kOldestLargestSeqFirst:
std::sort(temp.begin(), temp.end(),
[](const Fsize& f1, const Fsize& f2) -> bool {
return f1.file->largest_seqno < f2.file->largest_seqno;
});
break;
case kOldestSmallestSeqFirst:
std::sort(temp.begin(), temp.end(),
[](const Fsize& f1, const Fsize& f2) -> bool {
return f1.file->smallest_seqno < f2.file->smallest_seqno;
});
break;
case kMinOverlappingRatio:
SortFileByOverlappingRatio(*internal_comparator_, files_[level],
files_[level + 1], &temp);
break;
default:
assert(false);
}
assert(temp.size() == files.size());
// initialize files_by_compaction_pri_
for (size_t i = 0; i < temp.size(); i++) {
files_by_compaction_pri.push_back(static_cast<int>(temp[i].index));
}
next_file_to_compact_by_size_[level] = 0;
assert(files_[level].size() == files_by_compaction_pri_[level].size());
}
}
void VersionStorageInfo::GenerateLevel0NonOverlapping() {
assert(!finalized_);
level0_non_overlapping_ = true;
if (level_files_brief_.size() == 0) {
return;
}
// A copy of L0 files sorted by smallest key
std::vector<FdWithKeyRange> level0_sorted_file(
level_files_brief_[0].files,
level_files_brief_[0].files + level_files_brief_[0].num_files);
std::sort(level0_sorted_file.begin(), level0_sorted_file.end(),
[this](const FdWithKeyRange& f1, const FdWithKeyRange& f2) -> bool {
return (internal_comparator_->Compare(f1.smallest_key,
f2.smallest_key) < 0);
});
for (size_t i = 1; i < level0_sorted_file.size(); ++i) {
FdWithKeyRange& f = level0_sorted_file[i];
FdWithKeyRange& prev = level0_sorted_file[i - 1];
if (internal_comparator_->Compare(prev.largest_key, f.smallest_key) >= 0) {
level0_non_overlapping_ = false;
break;
}
}
}
void Version::Ref() {
++refs_;
}
bool Version::Unref() {
assert(refs_ >= 1);
--refs_;
if (refs_ == 0) {
delete this;
return true;
}
return false;
}
bool VersionStorageInfo::OverlapInLevel(int level,
const Slice* smallest_user_key,
const Slice* largest_user_key) {
if (level >= num_non_empty_levels_) {
// empty level, no overlap
return false;
}
return SomeFileOverlapsRange(*internal_comparator_, (level > 0),
level_files_brief_[level], smallest_user_key,
largest_user_key);
}
// Store in "*inputs" all files in "level" that overlap [begin,end]
// If hint_index is specified, then it points to a file in the
// overlapping range.
// The file_index returns a pointer to any file in an overlapping range.
void VersionStorageInfo::GetOverlappingInputs(
int level, const InternalKey* begin, const InternalKey* end,
std::vector<FileMetaData*>* inputs, int hint_index, int* file_index,
bool expand_range) const {
if (level >= num_non_empty_levels_) {
// this level is empty, no overlapping inputs
return;
}
inputs->clear();
Slice user_begin, user_end;
if (begin != nullptr) {
user_begin = begin->user_key();
}
if (end != nullptr) {
user_end = end->user_key();
}
if (file_index) {
*file_index = -1;
}
const Comparator* user_cmp = user_comparator_;
if (begin != nullptr && end != nullptr && level > 0) {
GetOverlappingInputsRangeBinarySearch(level, user_begin, user_end, inputs,
hint_index, file_index);
return;
}
for (size_t i = 0; i < level_files_brief_[level].num_files; ) {
FdWithKeyRange* f = &(level_files_brief_[level].files[i++]);
const Slice file_start = ExtractUserKey(f->smallest_key);
const Slice file_limit = ExtractUserKey(f->largest_key);
if (begin != nullptr && user_cmp->Compare(file_limit, user_begin) < 0) {
// "f" is completely before specified range; skip it
} else if (end != nullptr && user_cmp->Compare(file_start, user_end) > 0) {
// "f" is completely after specified range; skip it
} else {
inputs->push_back(files_[level][i-1]);
if (level == 0 && expand_range) {
// Level-0 files may overlap each other. So check if the newly
// added file has expanded the range. If so, restart search.
if (begin != nullptr && user_cmp->Compare(file_start, user_begin) < 0) {
user_begin = file_start;
inputs->clear();
i = 0;
} else if (end != nullptr
&& user_cmp->Compare(file_limit, user_end) > 0) {
user_end = file_limit;
inputs->clear();
i = 0;
}
} else if (file_index) {
*file_index = static_cast<int>(i) - 1;
}
}
}
}
// Store in "*inputs" files in "level" that within range [begin,end]
// Guarantee a "clean cut" boundary between the files in inputs
// and the surrounding files and the maxinum number of files.
// This will ensure that no parts of a key are lost during compaction.
// If hint_index is specified, then it points to a file in the range.
// The file_index returns a pointer to any file in an overlapping range.
void VersionStorageInfo::GetCleanInputsWithinInterval(
int level, const InternalKey* begin, const InternalKey* end,
std::vector<FileMetaData*>* inputs, int hint_index, int* file_index) const {
if (level >= num_non_empty_levels_) {
// this level is empty, no inputs within range
return;
}
inputs->clear();
Slice user_begin, user_end;
if (begin != nullptr) {
user_begin = begin->user_key();
}
if (end != nullptr) {
user_end = end->user_key();
}
if (file_index) {
*file_index = -1;
}
if (begin != nullptr && end != nullptr && level > 0) {
GetOverlappingInputsRangeBinarySearch(level, user_begin, user_end, inputs,
hint_index, file_index,
true /* within_interval */);
}
}
// Store in "*inputs" all files in "level" that overlap [begin,end]
// Employ binary search to find at least one file that overlaps the
// specified range. From that file, iterate backwards and
// forwards to find all overlapping files.
// if within_range is set, then only store the maximum clean inputs
// within range [begin, end]. "clean" means there is a boudnary
// between the files in "*inputs" and the surrounding files
void VersionStorageInfo::GetOverlappingInputsRangeBinarySearch(
int level, const Slice& user_begin, const Slice& user_end,
std::vector<FileMetaData*>* inputs, int hint_index, int* file_index,
bool within_interval) const {
assert(level > 0);
int min = 0;
int mid = 0;
int max = static_cast<int>(files_[level].size()) - 1;
bool foundOverlap = false;
const Comparator* user_cmp = user_comparator_;
// if the caller already knows the index of a file that has overlap,
// then we can skip the binary search.
if (hint_index != -1) {
mid = hint_index;
foundOverlap = true;
}
while (!foundOverlap && min <= max) {
mid = (min + max)/2;
FdWithKeyRange* f = &(level_files_brief_[level].files[mid]);
const Slice file_start = ExtractUserKey(f->smallest_key);
const Slice file_limit = ExtractUserKey(f->largest_key);
if ((!within_interval && user_cmp->Compare(file_limit, user_begin) < 0) ||
(within_interval && user_cmp->Compare(file_start, user_begin) < 0)) {
min = mid + 1;
} else if ((!within_interval &&
user_cmp->Compare(user_end, file_start) < 0) ||
(within_interval &&
user_cmp->Compare(user_end, file_limit) < 0)) {
max = mid - 1;
} else {
foundOverlap = true;
break;
}
}
// If there were no overlapping files, return immediately.
if (!foundOverlap) {
return;
}
// returns the index where an overlap is found
if (file_index) {
*file_index = mid;
}
int start_index, end_index;
if (within_interval) {
ExtendFileRangeWithinInterval(level, user_begin, user_end, mid, &start_index,
&end_index);
} else {
ExtendFileRangeOverlappingInterval(level, user_begin, user_end, mid,
&start_index, &end_index);
}
assert(end_index >= start_index);
// insert overlapping files into vector
for (int i = start_index; i <= end_index; i++) {
inputs->push_back(files_[level][i]);
}
}
// Store in *start_index and *end_index the range of all files in
// "level" that overlap [begin,end]
// The mid_index specifies the index of at least one file that
// overlaps the specified range. From that file, iterate backward
// and forward to find all overlapping files.
// Use FileLevel in searching, make it faster
void VersionStorageInfo::ExtendFileRangeOverlappingInterval(
int level, const Slice& user_begin, const Slice& user_end,
unsigned int mid_index, int* start_index, int* end_index) const {
const Comparator* user_cmp = user_comparator_;
const FdWithKeyRange* files = level_files_brief_[level].files;
#ifndef NDEBUG
{
// assert that the file at mid_index overlaps with the range
assert(mid_index < level_files_brief_[level].num_files);
const FdWithKeyRange* f = &files[mid_index];
const Slice fstart = ExtractUserKey(f->smallest_key);
const Slice flimit = ExtractUserKey(f->largest_key);
if (user_cmp->Compare(fstart, user_begin) >= 0) {
assert(user_cmp->Compare(fstart, user_end) <= 0);
} else {
assert(user_cmp->Compare(flimit, user_begin) >= 0);
}
}
#endif
*start_index = mid_index + 1;
*end_index = mid_index;
int count __attribute__((unused)) = 0;
// check backwards from 'mid' to lower indices
for (int i = mid_index; i >= 0 ; i--) {
const FdWithKeyRange* f = &files[i];
const Slice file_limit = ExtractUserKey(f->largest_key);
if (user_cmp->Compare(file_limit, user_begin) >= 0) {
*start_index = i;
assert((count++, true));
} else {
break;
}
}
// check forward from 'mid+1' to higher indices
for (unsigned int i = mid_index+1;
i < level_files_brief_[level].num_files; i++) {
const FdWithKeyRange* f = &files[i];
const Slice file_start = ExtractUserKey(f->smallest_key);
if (user_cmp->Compare(file_start, user_end) <= 0) {
assert((count++, true));
*end_index = i;
} else {
break;
}
}
assert(count == *end_index - *start_index + 1);
}
// Store in *start_index and *end_index the clean range of all files in
// "level" within [begin,end]
// The mid_index specifies the index of at least one file within
// the specified range. From that file, iterate backward
// and forward to find all overlapping files and then "shrink" to
// the clean range required.
// Use FileLevel in searching, make it faster
void VersionStorageInfo::ExtendFileRangeWithinInterval(
int level, const Slice& user_begin, const Slice& user_end,
unsigned int mid_index, int* start_index, int* end_index) const {
assert(level != 0);
const Comparator* user_cmp = user_comparator_;
const FdWithKeyRange* files = level_files_brief_[level].files;
#ifndef NDEBUG
{
// assert that the file at mid_index is within the range
assert(mid_index < level_files_brief_[level].num_files);
const FdWithKeyRange* f = &files[mid_index];
const Slice fstart = ExtractUserKey(f->smallest_key);
const Slice flimit = ExtractUserKey(f->largest_key);
assert(user_cmp->Compare(fstart, user_begin) >= 0 &&
user_cmp->Compare(flimit, user_end) <= 0);
}
#endif
ExtendFileRangeOverlappingInterval(level, user_begin, user_end, mid_index,
start_index, end_index);
int left = *start_index;
int right = *end_index;
// shrink from left to right
while (left <= right) {
const Slice& first_key_in_range = ExtractUserKey(files[left].smallest_key);
if (user_cmp->Compare(first_key_in_range, user_begin) < 0) {
left++;
continue;
}
if (left > 0) { // If not first file
const Slice& last_key_before =
ExtractUserKey(files[left - 1].largest_key);
if (user_cmp->Equal(first_key_in_range, last_key_before)) {
// The first user key in range overlaps with the previous file's last
// key
left++;
continue;
}
}
break;
}
// shrink from right to left
while (left <= right) {
const Slice last_key_in_range = ExtractUserKey(files[right].largest_key);
if (user_cmp->Compare(last_key_in_range, user_end) > 0) {
right--;
continue;
}
if (right < static_cast<int>(level_files_brief_[level].num_files) -
1) { // If not the last file
const Slice first_key_after =
ExtractUserKey(files[right + 1].smallest_key);
if (user_cmp->Equal(last_key_in_range, first_key_after)) {
// The last user key in range overlaps with the next file's first key
right--;
continue;
}
}
break;
}
*start_index = left;
*end_index = right;
}
uint64_t VersionStorageInfo::NumLevelBytes(int level) const {
assert(level >= 0);
assert(level < num_levels());
return TotalFileSize(files_[level]);
}
const char* VersionStorageInfo::LevelSummary(
LevelSummaryStorage* scratch) const {
int len = 0;
if (compaction_style_ == kCompactionStyleLevel && num_levels() > 1) {
assert(base_level_ < static_cast<int>(level_max_bytes_.size()));
len = snprintf(scratch->buffer, sizeof(scratch->buffer),
"base level %d max bytes base %" PRIu64 " ", base_level_,
level_max_bytes_[base_level_]);
}
len +=
snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len, "files[");
for (int i = 0; i < num_levels(); i++) {
int sz = sizeof(scratch->buffer) - len;
int ret = snprintf(scratch->buffer + len, sz, "%d ", int(files_[i].size()));
if (ret < 0 || ret >= sz) break;
len += ret;
}
if (len > 0) {
// overwrite the last space
--len;
}
len += snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len,
"] max score %.2f", compaction_score_[0]);
if (!files_marked_for_compaction_.empty()) {
snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len,
" (%" ROCKSDB_PRIszt " files need compaction)",
files_marked_for_compaction_.size());
}
return scratch->buffer;
}
const char* VersionStorageInfo::LevelFileSummary(FileSummaryStorage* scratch,
int level) const {
int len = snprintf(scratch->buffer, sizeof(scratch->buffer), "files_size[");
for (const auto& f : files_[level]) {
int sz = sizeof(scratch->buffer) - len;
char sztxt[16];
AppendHumanBytes(f->fd.GetFileSize(), sztxt, sizeof(sztxt));
int ret = snprintf(scratch->buffer + len, sz,
"#%" PRIu64 "(seq=%" PRIu64 ",sz=%s,%d) ",
f->fd.GetNumber(), f->smallest_seqno, sztxt,
static_cast<int>(f->being_compacted));
if (ret < 0 || ret >= sz)
break;
len += ret;
}
// overwrite the last space (only if files_[level].size() is non-zero)
if (files_[level].size() && len > 0) {
--len;
}
snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len, "]");
return scratch->buffer;
}
int64_t VersionStorageInfo::MaxNextLevelOverlappingBytes() {
uint64_t result = 0;
std::vector<FileMetaData*> overlaps;
for (int level = 1; level < num_levels() - 1; level++) {
for (const auto& f : files_[level]) {
GetOverlappingInputs(level + 1, &f->smallest, &f->largest, &overlaps);
const uint64_t sum = TotalFileSize(overlaps);
if (sum > result) {
result = sum;
}
}
}
return result;
}
uint64_t VersionStorageInfo::MaxBytesForLevel(int level) const {
// Note: the result for level zero is not really used since we set
// the level-0 compaction threshold based on number of files.
assert(level >= 0);
assert(level < static_cast<int>(level_max_bytes_.size()));
return level_max_bytes_[level];
}
void VersionStorageInfo::CalculateBaseBytes(const ImmutableCFOptions& ioptions,
const MutableCFOptions& options) {
// Special logic to set number of sorted runs.
// It is to match the previous behavior when all files are in L0.
int num_l0_count = static_cast<int>(files_[0].size());
if (compaction_style_ == kCompactionStyleUniversal) {
// For universal compaction, we use level0 score to indicate
// compaction score for the whole DB. Adding other levels as if
// they are L0 files.
for (int i = 1; i < num_levels(); i++) {
if (!files_[i].empty()) {
num_l0_count++;
}
}
}
set_l0_delay_trigger_count(num_l0_count);
level_max_bytes_.resize(ioptions.num_levels);
if (!ioptions.level_compaction_dynamic_level_bytes) {
base_level_ = (ioptions.compaction_style == kCompactionStyleLevel) ? 1 : -1;
// Calculate for static bytes base case
for (int i = 0; i < ioptions.num_levels; ++i) {
if (i == 0 && ioptions.compaction_style == kCompactionStyleUniversal) {
level_max_bytes_[i] = options.max_bytes_for_level_base;
} else if (i > 1) {
level_max_bytes_[i] = MultiplyCheckOverflow(
MultiplyCheckOverflow(level_max_bytes_[i - 1],
options.max_bytes_for_level_multiplier),
options.MaxBytesMultiplerAdditional(i - 1));
} else {
level_max_bytes_[i] = options.max_bytes_for_level_base;
}
}
} else {
uint64_t max_level_size = 0;
int first_non_empty_level = -1;
// Find size of non-L0 level of most data.
// Cannot use the size of the last level because it can be empty or less
// than previous levels after compaction.
for (int i = 1; i < num_levels_; i++) {
uint64_t total_size = 0;
for (const auto& f : files_[i]) {
total_size += f->fd.GetFileSize();
}
if (total_size > 0 && first_non_empty_level == -1) {
first_non_empty_level = i;
}
if (total_size > max_level_size) {
max_level_size = total_size;
}
}
// Prefill every level's max bytes to disallow compaction from there.
for (int i = 0; i < num_levels_; i++) {
level_max_bytes_[i] = std::numeric_limits<uint64_t>::max();
}
if (max_level_size == 0) {
// No data for L1 and up. L0 compacts to last level directly.
// No compaction from L1+ needs to be scheduled.
base_level_ = num_levels_ - 1;
} else {
uint64_t base_bytes_max = options.max_bytes_for_level_base;
uint64_t base_bytes_min = static_cast<uint64_t>(
base_bytes_max / options.max_bytes_for_level_multiplier);
// Try whether we can make last level's target size to be max_level_size
uint64_t cur_level_size = max_level_size;
for (int i = num_levels_ - 2; i >= first_non_empty_level; i--) {
// Round up after dividing
cur_level_size = static_cast<uint64_t>(
cur_level_size / options.max_bytes_for_level_multiplier);
}
// Calculate base level and its size.
uint64_t base_level_size;
if (cur_level_size <= base_bytes_min) {
// Case 1. If we make target size of last level to be max_level_size,
// target size of the first non-empty level would be smaller than
// base_bytes_min. We set it be base_bytes_min.
base_level_size = base_bytes_min + 1U;
base_level_ = first_non_empty_level;
ROCKS_LOG_WARN(ioptions.info_log,
"More existing levels in DB than needed. "
"max_bytes_for_level_multiplier may not be guaranteed.");
} else {
// Find base level (where L0 data is compacted to).
base_level_ = first_non_empty_level;
while (base_level_ > 1 && cur_level_size > base_bytes_max) {
--base_level_;
cur_level_size = static_cast<uint64_t>(
cur_level_size / options.max_bytes_for_level_multiplier);
}
if (cur_level_size > base_bytes_max) {
// Even L1 will be too large
assert(base_level_ == 1);
base_level_size = base_bytes_max;
} else {
base_level_size = cur_level_size;
}
}
uint64_t level_size = base_level_size;
for (int i = base_level_; i < num_levels_; i++) {
if (i > base_level_) {
level_size = MultiplyCheckOverflow(
level_size, options.max_bytes_for_level_multiplier);
}
// Don't set any level below base_bytes_max. Otherwise, the LSM can
// assume an hourglass shape where L1+ sizes are smaller than L0. This
// causes compaction scoring, which depends on level sizes, to favor L1+
// at the expense of L0, which may fill up and stall.
level_max_bytes_[i] = std::max(level_size, base_bytes_max);
}
}
}
}
uint64_t VersionStorageInfo::EstimateLiveDataSize() const {
// Estimate the live data size by adding up the size of the last level for all
// key ranges. Note: Estimate depends on the ordering of files in level 0
// because files in level 0 can be overlapping.
uint64_t size = 0;
auto ikey_lt = [this](InternalKey* x, InternalKey* y) {
return internal_comparator_->Compare(*x, *y) < 0;
};
// (Ordered) map of largest keys in non-overlapping files
std::map<InternalKey*, FileMetaData*, decltype(ikey_lt)> ranges(ikey_lt);
for (int l = num_levels_ - 1; l >= 0; l--) {
bool found_end = false;
for (auto file : files_[l]) {
// Find the first file where the largest key is larger than the smallest
// key of the current file. If this file does not overlap with the
// current file, none of the files in the map does. If there is
// no potential overlap, we can safely insert the rest of this level
// (if the level is not 0) into the map without checking again because
// the elements in the level are sorted and non-overlapping.
auto lb = (found_end && l != 0) ?
ranges.end() : ranges.lower_bound(&file->smallest);
found_end = (lb == ranges.end());
if (found_end || internal_comparator_->Compare(
file->largest, (*lb).second->smallest) < 0) {
ranges.emplace_hint(lb, &file->largest, file);
size += file->fd.file_size;
}
}
}
return size;
}
void Version::AddLiveFiles(std::vector<FileDescriptor>* live) {
for (int level = 0; level < storage_info_.num_levels(); level++) {
const std::vector<FileMetaData*>& files = storage_info_.files_[level];
for (const auto& file : files) {
live->push_back(file->fd);
}
}
}
std::string Version::DebugString(bool hex, bool print_stats) const {
std::string r;
for (int level = 0; level < storage_info_.num_levels_; level++) {
// E.g.,
// --- level 1 ---
// 17:123['a' .. 'd']
// 20:43['e' .. 'g']
//
// if print_stats=true:
// 17:123['a' .. 'd'](4096)
r.append("--- level ");
AppendNumberTo(&r, level);
r.append(" --- version# ");
AppendNumberTo(&r, version_number_);
r.append(" ---\n");
const std::vector<FileMetaData*>& files = storage_info_.files_[level];
for (size_t i = 0; i < files.size(); i++) {
r.push_back(' ');
AppendNumberTo(&r, files[i]->fd.GetNumber());
r.push_back(':');
AppendNumberTo(&r, files[i]->fd.GetFileSize());
r.append("[");
r.append(files[i]->smallest.DebugString(hex));
r.append(" .. ");
r.append(files[i]->largest.DebugString(hex));
r.append("]");
if (print_stats) {
r.append("(");
r.append(ToString(
files[i]->stats.num_reads_sampled.load(std::memory_order_relaxed)));
r.append(")");
}
r.append("\n");
}
}
return r;
}
// this is used to batch writes to the manifest file
struct VersionSet::ManifestWriter {
Status status;
bool done;
InstrumentedCondVar cv;
ColumnFamilyData* cfd;
const autovector<VersionEdit*>& edit_list;
explicit ManifestWriter(InstrumentedMutex* mu, ColumnFamilyData* _cfd,
const autovector<VersionEdit*>& e)
: done(false), cv(mu), cfd(_cfd), edit_list(e) {}
};
VersionSet::VersionSet(const std::string& dbname,
const ImmutableDBOptions* db_options,
const EnvOptions& storage_options, Cache* table_cache,
WriteBufferManager* write_buffer_manager,
WriteController* write_controller)
: column_family_set_(
new ColumnFamilySet(dbname, db_options, storage_options, table_cache,
write_buffer_manager, write_controller)),
env_(db_options->env),
dbname_(dbname),
db_options_(db_options),
next_file_number_(2),
manifest_file_number_(0), // Filled by Recover()
pending_manifest_file_number_(0),
last_sequence_(0),
last_to_be_written_sequence_(0),
prev_log_number_(0),
current_version_number_(0),
manifest_file_size_(0),
env_options_(storage_options),
env_options_compactions_(
env_->OptimizeForCompactionTableRead(env_options_, *db_options_)) {}
void CloseTables(void* ptr, size_t) {
TableReader* table_reader = reinterpret_cast<TableReader*>(ptr);
table_reader->Close();
}
VersionSet::~VersionSet() {
// we need to delete column_family_set_ because its destructor depends on
// VersionSet
Cache* table_cache = column_family_set_->get_table_cache();
table_cache->ApplyToAllCacheEntries(&CloseTables, false /* thread_safe */);
column_family_set_.reset();
for (auto file : obsolete_files_) {
if (file->table_reader_handle) {
table_cache->Release(file->table_reader_handle);
TableCache::Evict(table_cache, file->fd.GetNumber());
}
delete file;
}
obsolete_files_.clear();
}
void VersionSet::AppendVersion(ColumnFamilyData* column_family_data,
Version* v) {
// compute new compaction score
v->storage_info()->ComputeCompactionScore(
*column_family_data->ioptions(),
*column_family_data->GetLatestMutableCFOptions());
// Mark v finalized
v->storage_info_.SetFinalized();
// Make "v" current
assert(v->refs_ == 0);
Version* current = column_family_data->current();
assert(v != current);
if (current != nullptr) {
assert(current->refs_ > 0);
current->Unref();
}
column_family_data->SetCurrent(v);
v->Ref();
// Append to linked list
v->prev_ = column_family_data->dummy_versions()->prev_;
v->next_ = column_family_data->dummy_versions();
v->prev_->next_ = v;
v->next_->prev_ = v;
}
Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
const MutableCFOptions& mutable_cf_options,
const autovector<VersionEdit*>& edit_list,
InstrumentedMutex* mu, Directory* db_directory,
bool new_descriptor_log,
const ColumnFamilyOptions* new_cf_options) {
mu->AssertHeld();
// num of edits
auto num_edits = edit_list.size();
if (num_edits == 0) {
return Status::OK();
} else if (num_edits > 1) {
#ifndef NDEBUG
// no group commits for column family add or drop
for (auto& edit : edit_list) {
assert(!edit->IsColumnFamilyManipulation());
}
#endif
}
// column_family_data can be nullptr only if this is column_family_add.
// in that case, we also need to specify ColumnFamilyOptions
if (column_family_data == nullptr) {
assert(num_edits == 1);
assert(edit_list[0]->is_column_family_add_);
assert(new_cf_options != nullptr);
}
// queue our request
ManifestWriter w(mu, column_family_data, edit_list);
manifest_writers_.push_back(&w);
while (!w.done && &w != manifest_writers_.front()) {
w.cv.Wait();
}
if (w.done) {
return w.status;
}
if (column_family_data != nullptr && column_family_data->IsDropped()) {
// if column family is dropped by the time we get here, no need to write
// anything to the manifest
manifest_writers_.pop_front();
// Notify new head of write queue
if (!manifest_writers_.empty()) {
manifest_writers_.front()->cv.Signal();
}
// we steal this code to also inform about cf-drop
return Status::ShutdownInProgress();
}
autovector<VersionEdit*> batch_edits;
Version* v = nullptr;
std::unique_ptr<BaseReferencedVersionBuilder> builder_guard(nullptr);
// process all requests in the queue
ManifestWriter* last_writer = &w;
assert(!manifest_writers_.empty());
assert(manifest_writers_.front() == &w);
if (w.edit_list.front()->IsColumnFamilyManipulation()) {
// no group commits for column family add or drop
LogAndApplyCFHelper(w.edit_list.front());
batch_edits.push_back(w.edit_list.front());
} else {
v = new Version(column_family_data, this, current_version_number_++);
builder_guard.reset(new BaseReferencedVersionBuilder(column_family_data));
auto* builder = builder_guard->version_builder();
for (const auto& writer : manifest_writers_) {
if (writer->edit_list.front()->IsColumnFamilyManipulation() ||
writer->cfd->GetID() != column_family_data->GetID()) {
// no group commits for column family add or drop
// also, group commits across column families are not supported
break;
}
last_writer = writer;
for (const auto& edit : writer->edit_list) {
LogAndApplyHelper(column_family_data, builder, v, edit, mu);
batch_edits.push_back(edit);
}
}
builder->SaveTo(v->storage_info());
}
// Initialize new descriptor log file if necessary by creating
// a temporary file that contains a snapshot of the current version.
uint64_t new_manifest_file_size = 0;
Status s;
assert(pending_manifest_file_number_ == 0);
if (!descriptor_log_ ||
manifest_file_size_ > db_options_->max_manifest_file_size) {
pending_manifest_file_number_ = NewFileNumber();
batch_edits.back()->SetNextFile(next_file_number_.load());
new_descriptor_log = true;
} else {
pending_manifest_file_number_ = manifest_file_number_;
}
if (new_descriptor_log) {
// if we're writing out new snapshot make sure to persist max column family
if (column_family_set_->GetMaxColumnFamily() > 0) {
w.edit_list.front()->SetMaxColumnFamily(
column_family_set_->GetMaxColumnFamily());
}
}
// Unlock during expensive operations. New writes cannot get here
// because &w is ensuring that all new writes get queued.
{
mu->Unlock();
TEST_SYNC_POINT("VersionSet::LogAndApply:WriteManifest");
if (!w.edit_list.front()->IsColumnFamilyManipulation() &&
this->GetColumnFamilySet()->get_table_cache()->GetCapacity() ==
TableCache::kInfiniteCapacity) {
// unlimited table cache. Pre-load table handle now.
// Need to do it out of the mutex.
builder_guard->version_builder()->LoadTableHandlers(
column_family_data