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rocksdb/db/version_set.cc

2994 lines
101 KiB

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/version_set.h"
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <algorithm>
#include <map>
#include <set>
#include <climits>
#include <unordered_map>
#include <vector>
#include <stdio.h>
#include "db/filename.h"
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/memtable.h"
#include "db/merge_context.h"
#include "db/table_cache.h"
#include "db/compaction.h"
#include "rocksdb/env.h"
#include "rocksdb/merge_operator.h"
#include "table/table_reader.h"
#include "table/merger.h"
#include "table/two_level_iterator.h"
#include "table/format.h"
#include "table/plain_table_factory.h"
#include "table/meta_blocks.h"
#include "util/coding.h"
#include "util/logging.h"
#include "util/stop_watch.h"
namespace rocksdb {
namespace {
// Find File in FileLevel data structure
// Within an index range defined by left and right
int FindFileInRange(const InternalKeyComparator& icmp,
const FileLevel& 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;
}
bool NewestFirstBySeqNo(FileMetaData* a, FileMetaData* b) {
if (a->smallest_seqno != b->smallest_seqno) {
return a->smallest_seqno > b->smallest_seqno;
}
if (a->largest_seqno != b->largest_seqno) {
return a->largest_seqno > b->largest_seqno;
}
// Break ties by file number
return a->fd.GetNumber() > b->fd.GetNumber();
}
bool BySmallestKey(FileMetaData* a, FileMetaData* b,
const InternalKeyComparator* cmp) {
int r = cmp->Compare(a->smallest, b->smallest);
if (r != 0) {
return (r < 0);
}
// Break ties by file number
return (a->fd.GetNumber() < b->fd.GetNumber());
}
// 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<FileLevel>* file_levels,
unsigned int num_levels,
FileIndexer* file_indexer,
const Comparator* user_comparator,
const InternalKeyComparator* internal_comparator)
: num_levels_(num_levels),
curr_level_(-1),
search_left_bound_(0),
search_right_bound_(FileIndexer::kLevelMaxIndex),
#ifndef NDEBUG
files_(files),
#endif
file_levels_(file_levels),
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 < (*file_levels_)[0].num_files; ++i) {
auto* r = (*file_levels_)[0].files[i].fd.table_reader;
if (r) {
r->Prepare(ikey);
}
}
}
}
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_];
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 Level 0 files
// If there are only 3 or less level 0 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
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;
}
private:
unsigned int num_levels_;
unsigned int curr_level_;
int search_left_bound_;
int search_right_bound_;
#ifndef NDEBUG
std::vector<FileMetaData*>* files_;
#endif
autovector<FileLevel>* file_levels_;
bool search_ended_;
FileLevel* 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_ = &(*file_levels_)[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_ = curr_file_level_->num_files - 1;
}
start_index = FindFileInRange(*internal_comparator_,
*curr_file_level_, ikey_,
search_left_bound_, search_right_bound_);
} else {
// search_left_bound > search_right_bound, key does not exist in
// this level. Since no comparision 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
Version::~Version() {
assert(refs_ == 0);
// Remove from linked list
prev_->next_ = next_;
next_->prev_ = prev_;
// Drop references to files
for (int level = 0; level < num_levels_; level++) {
for (size_t i = 0; i < files_[level].size(); i++) {
FileMetaData* f = files_[level][i];
assert(f->refs > 0);
f->refs--;
if (f->refs <= 0) {
if (f->table_reader_handle) {
cfd_->table_cache()->ReleaseHandle(f->table_reader_handle);
f->table_reader_handle = nullptr;
}
vset_->obsolete_files_.push_back(f);
}
}
}
delete[] files_;
}
int FindFile(const InternalKeyComparator& icmp,
const FileLevel& file_level,
const Slice& key) {
return FindFileInRange(icmp, file_level, key, 0, file_level.num_files);
}
void DoGenerateFileLevel(FileLevel* file_level,
const std::vector<FileMetaData*>& files,
Arena* arena) {
assert(file_level);
assert(files.size() >= 0);
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.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 FileLevel& 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(*smallest_user_key, kMaxSequenceNumber,kValueTypeForSeek);
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]);
}
// 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 Version::LevelFileNumIterator : public Iterator {
public:
LevelFileNumIterator(const InternalKeyComparator& icmp,
const FileLevel* flevel)
: icmp_(icmp),
flevel_(flevel),
index_(flevel->num_files),
current_value_(0, 0, 0) { // Marks as invalid
}
virtual bool Valid() const {
return index_ < flevel_->num_files;
}
virtual void Seek(const Slice& target) {
index_ = FindFile(icmp_, *flevel_, target);
}
virtual void SeekToFirst() { index_ = 0; }
virtual void SeekToLast() {
index_ = (flevel_->num_files == 0) ? 0 : flevel_->num_files - 1;
}
virtual void Next() {
assert(Valid());
index_++;
}
virtual void Prev() {
assert(Valid());
if (index_ == 0) {
index_ = flevel_->num_files; // Marks as invalid
} else {
index_--;
}
}
Slice key() const {
assert(Valid());
return flevel_->files[index_].largest_key;
}
Slice value() const {
assert(Valid());
auto file_meta = flevel_->files[index_];
current_value_ = file_meta.fd;
return Slice(reinterpret_cast<const char*>(&current_value_),
sizeof(FileDescriptor));
}
virtual Status status() const { return Status::OK(); }
private:
const InternalKeyComparator icmp_;
const FileLevel* flevel_;
uint32_t index_;
mutable FileDescriptor current_value_;
};
class Version::LevelFileIteratorState : public TwoLevelIteratorState {
public:
LevelFileIteratorState(TableCache* table_cache,
const ReadOptions& read_options, const EnvOptions& env_options,
const InternalKeyComparator& icomparator, bool for_compaction,
bool prefix_enabled)
: TwoLevelIteratorState(prefix_enabled),
table_cache_(table_cache), read_options_(read_options),
env_options_(env_options), icomparator_(icomparator),
for_compaction_(for_compaction) {}
Iterator* NewSecondaryIterator(const Slice& meta_handle) override {
if (meta_handle.size() != sizeof(FileDescriptor)) {
return NewErrorIterator(
Status::Corruption("FileReader invoked with unexpected value"));
} else {
const FileDescriptor* fd =
reinterpret_cast<const FileDescriptor*>(meta_handle.data());
return table_cache_->NewIterator(
read_options_, env_options_, icomparator_, *fd,
nullptr /* don't need reference to table*/, for_compaction_);
}
}
bool PrefixMayMatch(const Slice& internal_key) override {
return true;
}
private:
TableCache* table_cache_;
const ReadOptions read_options_;
const EnvOptions& env_options_;
const InternalKeyComparator& icomparator_;
bool for_compaction_;
};
Status Version::GetTableProperties(std::shared_ptr<const TableProperties>* tp,
const FileMetaData* file_meta,
const std::string* fname) {
auto table_cache = cfd_->table_cache();
auto options = cfd_->options();
Status s = table_cache->GetTableProperties(
vset_->storage_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;
if (fname != nullptr) {
s = options->env->NewRandomAccessFile(
*fname, &file, vset_->storage_options_);
} else {
s = options->env->NewRandomAccessFile(
TableFileName(vset_->options_->db_paths, file_meta->fd.GetNumber(),
file_meta->fd.GetPathId()),
&file, vset_->storage_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.
s = ReadTableProperties(
file.get(), file_meta->fd.GetFileSize(),
Footer::kInvalidTableMagicNumber /* table's magic number */,
vset_->env_, options->info_log.get(), &raw_table_properties);
if (!s.ok()) {
return s;
}
RecordTick(options->statistics.get(), NUMBER_DIRECT_LOAD_TABLE_PROPERTIES);
*tp = std::shared_ptr<const TableProperties>(raw_table_properties);
return s;
}
Status Version::GetPropertiesOfAllTables(TablePropertiesCollection* props) {
for (int level = 0; level < num_levels_; level++) {
for (const auto& file_meta : files_[level]) {
auto fname =
TableFileName(vset_->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();
}
size_t Version::GetMemoryUsageByTableReaders() {
size_t total_usage = 0;
for (auto& file_level : file_levels_) {
for (size_t i = 0; i < file_level.num_files; i++) {
total_usage += cfd_->table_cache()->GetMemoryUsageByTableReader(
vset_->storage_options_, cfd_->internal_comparator(),
file_level.files[i].fd);
}
}
return total_usage;
}
uint64_t Version::GetEstimatedActiveKeys() {
// Estimation will be not accurate when:
// (1) there is merge keys
// (2) keys are directly overwritten
// (3) deletion on non-existing keys
return num_non_deletions_ - num_deletions_;
}
void Version::AddIterators(const ReadOptions& read_options,
const EnvOptions& soptions,
std::vector<Iterator*>* iters) {
// Merge all level zero files together since they may overlap
for (size_t i = 0; i < file_levels_[0].num_files; i++) {
const auto& file = file_levels_[0].files[i];
iters->push_back(cfd_->table_cache()->NewIterator(
read_options, soptions, cfd_->internal_comparator(), file.fd));
}
// For levels > 0, we can use a concatenating iterator that sequentially
// walks through the non-overlapping files in the level, opening them
// lazily.
for (int level = 1; level < num_levels_; level++) {
if (file_levels_[level].num_files != 0) {
iters->push_back(NewTwoLevelIterator(new LevelFileIteratorState(
cfd_->table_cache(), read_options, soptions,
cfd_->internal_comparator(), false /* for_compaction */,
cfd_->options()->prefix_extractor != nullptr),
new LevelFileNumIterator(cfd_->internal_comparator(),
&file_levels_[level])));
}
}
}
void Version::AddIterators(const ReadOptions& read_options,
const EnvOptions& soptions,
MergeIteratorBuilder* merge_iter_builder) {
// Merge all level zero files together since they may overlap
for (size_t i = 0; i < file_levels_[0].num_files; i++) {
const auto& file = file_levels_[0].files[i];
merge_iter_builder->AddIterator(cfd_->table_cache()->NewIterator(
read_options, soptions, cfd_->internal_comparator(), file.fd, nullptr,
false, merge_iter_builder->GetArena()));
}
// For levels > 0, we can use a concatenating iterator that sequentially
// walks through the non-overlapping files in the level, opening them
// lazily.
for (int level = 1; level < num_levels_; level++) {
if (file_levels_[level].num_files != 0) {
merge_iter_builder->AddIterator(NewTwoLevelIterator(
new LevelFileIteratorState(
cfd_->table_cache(), read_options, soptions,
cfd_->internal_comparator(), false /* for_compaction */,
cfd_->options()->prefix_extractor != nullptr),
new LevelFileNumIterator(cfd_->internal_comparator(),
&file_levels_[level]), merge_iter_builder->GetArena()));
}
}
}
// Callback from TableCache::Get()
enum SaverState {
kNotFound,
kFound,
kDeleted,
kCorrupt,
kMerge // saver contains the current merge result (the operands)
};
namespace version_set {
struct Saver {
SaverState state;
const Comparator* ucmp;
Slice user_key;
bool* value_found; // Is value set correctly? Used by KeyMayExist
std::string* value;
const MergeOperator* merge_operator;
// the merge operations encountered;
MergeContext* merge_context;
Logger* logger;
Statistics* statistics;
};
} // namespace version_set
// Called from TableCache::Get and Table::Get when file/block in which
// key may exist are not there in TableCache/BlockCache respectively. In this
// case we can't guarantee that key does not exist and are not permitted to do
// IO to be certain.Set the status=kFound and value_found=false to let the
// caller know that key may exist but is not there in memory
static void MarkKeyMayExist(void* arg) {
version_set::Saver* s = reinterpret_cast<version_set::Saver*>(arg);
s->state = kFound;
if (s->value_found != nullptr) {
*(s->value_found) = false;
}
}
static bool SaveValue(void* arg, const ParsedInternalKey& parsed_key,
const Slice& v) {
version_set::Saver* s = reinterpret_cast<version_set::Saver*>(arg);
MergeContext* merge_contex = s->merge_context;
std::string merge_result; // temporary area for merge results later
assert(s != nullptr && merge_contex != nullptr);
// TODO: Merge?
if (s->ucmp->Compare(parsed_key.user_key, s->user_key) == 0) {
// Key matches. Process it
switch (parsed_key.type) {
case kTypeValue:
if (kNotFound == s->state) {
s->state = kFound;
s->value->assign(v.data(), v.size());
} else if (kMerge == s->state) {
assert(s->merge_operator != nullptr);
s->state = kFound;
if (!s->merge_operator->FullMerge(s->user_key, &v,
merge_contex->GetOperands(),
s->value, s->logger)) {
RecordTick(s->statistics, NUMBER_MERGE_FAILURES);
s->state = kCorrupt;
}
} else {
assert(false);
}
return false;
case kTypeDeletion:
if (kNotFound == s->state) {
s->state = kDeleted;
} else if (kMerge == s->state) {
s->state = kFound;
if (!s->merge_operator->FullMerge(s->user_key, nullptr,
merge_contex->GetOperands(),
s->value, s->logger)) {
RecordTick(s->statistics, NUMBER_MERGE_FAILURES);
s->state = kCorrupt;
}
} else {
assert(false);
}
return false;
case kTypeMerge:
assert(s->state == kNotFound || s->state == kMerge);
s->state = kMerge;
merge_contex->PushOperand(v);
return true;
default:
assert(false);
break;
}
}
// s->state could be Corrupt, merge or notfound
return false;
}
Version::Version(ColumnFamilyData* cfd, VersionSet* vset,
uint64_t version_number)
: cfd_(cfd),
internal_comparator_((cfd == nullptr) ? nullptr
: &cfd->internal_comparator()),
user_comparator_(
(cfd == nullptr) ? nullptr : internal_comparator_->user_comparator()),
table_cache_((cfd == nullptr) ? nullptr : cfd->table_cache()),
merge_operator_((cfd == nullptr) ? nullptr
: cfd->options()->merge_operator.get()),
info_log_((cfd == nullptr) ? nullptr : cfd->options()->info_log.get()),
db_statistics_((cfd == nullptr) ? nullptr
: cfd->options()->statistics.get()),
// cfd is nullptr if Version is dummy
num_levels_(cfd == nullptr ? 0 : cfd->NumberLevels()),
num_non_empty_levels_(num_levels_),
file_indexer_(cfd == nullptr
? nullptr
: cfd->internal_comparator().user_comparator()),
vset_(vset),
next_(this),
prev_(this),
refs_(0),
files_(new std::vector<FileMetaData*>[num_levels_]),
files_by_size_(num_levels_),
next_file_to_compact_by_size_(num_levels_),
compaction_score_(num_levels_),
compaction_level_(num_levels_),
version_number_(version_number),
total_file_size_(0),
total_raw_key_size_(0),
total_raw_value_size_(0),
num_non_deletions_(0),
num_deletions_(0) {
if (cfd != nullptr && cfd->current() != nullptr) {
total_file_size_ = cfd->current()->total_file_size_;
total_raw_key_size_ = cfd->current()->total_raw_key_size_;
total_raw_value_size_ = cfd->current()->total_raw_value_size_;
num_non_deletions_ = cfd->current()->num_non_deletions_;
num_deletions_ = cfd->current()->num_deletions_;
}
}
void Version::Get(const ReadOptions& options,
const LookupKey& k,
std::string* value,
Status* status,
MergeContext* merge_context,
bool* value_found) {
Slice ikey = k.internal_key();
Slice user_key = k.user_key();
assert(status->ok() || status->IsMergeInProgress());
version_set::Saver saver;
saver.state = status->ok()? kNotFound : kMerge;
saver.ucmp = user_comparator_;
saver.user_key = user_key;
saver.value_found = value_found;
saver.value = value;
saver.merge_operator = merge_operator_;
saver.merge_context = merge_context;
saver.logger = info_log_;
saver.statistics = db_statistics_;
FilePicker fp(files_, user_key, ikey, &file_levels_, num_non_empty_levels_,
&file_indexer_, user_comparator_, internal_comparator_);
FdWithKeyRange* f = fp.GetNextFile();
while (f != nullptr) {
*status = table_cache_->Get(options, *internal_comparator_, f->fd, ikey,
&saver, SaveValue, MarkKeyMayExist);
// TODO: examine the behavior for corrupted key
if (!status->ok()) {
return;
}
switch (saver.state) {
case kNotFound:
break; // Keep searching in other files
case kFound:
return;
case kDeleted:
*status = Status::NotFound(); // Use empty error message for speed
return;
case kCorrupt:
*status = Status::Corruption("corrupted key for ", user_key);
return;
case kMerge:
break;
}
f = fp.GetNextFile();
}
if (kMerge == saver.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;
if (merge_operator_->FullMerge(user_key, nullptr,
saver.merge_context->GetOperands(), value,
info_log_)) {
*status = Status::OK();
} else {
RecordTick(db_statistics_, NUMBER_MERGE_FAILURES);
*status = Status::Corruption("could not perform end-of-key merge for ",
user_key);
}
} else {
*status = Status::NotFound(); // Use an empty error message for speed
}
}
void Version::GenerateFileLevels() {
file_levels_.resize(num_non_empty_levels_);
for (int level = 0; level < num_non_empty_levels_; level++) {
DoGenerateFileLevel(&file_levels_[level], files_[level], &arena_);
}
}
void Version::PrepareApply(std::vector<uint64_t>& size_being_compacted) {
UpdateTemporaryStats();
ComputeCompactionScore(size_being_compacted);
UpdateFilesBySize();
UpdateNumNonEmptyLevels();
file_indexer_.UpdateIndex(&arena_, num_non_empty_levels_, files_);
GenerateFileLevels();
}
bool Version::MaybeInitializeFileMetaData(FileMetaData* file_meta) {
if (file_meta->num_entries > 0) {
return false;
}
std::shared_ptr<const TableProperties> tp;
Status s = GetTableProperties(&tp, file_meta);
if (!s.ok()) {
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 Version::UpdateTemporaryStats() {
static const int kDeletionWeightOnCompaction = 2;
// incrementally update the average value size by
// including newly added files into the global stats
int init_count = 0;
int total_count = 0;
for (int level = 0; level < num_levels_; level++) {
for (auto* file_meta : files_[level]) {
if (MaybeInitializeFileMetaData(file_meta)) {
// each FileMeta will be initialized only once.
total_file_size_ += file_meta->fd.GetFileSize();
total_raw_key_size_ += file_meta->raw_key_size;
total_raw_value_size_ += file_meta->raw_value_size;
num_non_deletions_ +=
file_meta->num_entries - file_meta->num_deletions;
num_deletions_ += file_meta->num_deletions;
init_count++;
}
total_count++;
}
}
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).
if (file_meta->compensated_file_size == 0) {
file_meta->compensated_file_size = file_meta->fd.GetFileSize() +
file_meta->num_deletions * average_value_size *
kDeletionWeightOnCompaction;
}
}
}
}
void Version::ComputeCompactionScore(
std::vector<uint64_t>& size_being_compacted) {
double max_score = 0;
int max_score_level = 0;
int max_input_level =
cfd_->compaction_picker()->MaxInputLevel(NumberLevels());
for (int level = 0; level <= max_input_level; 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 numfiles = 0;
uint64_t total_size = 0;
for (unsigned int i = 0; i < files_[level].size(); i++) {
if (!files_[level][i]->being_compacted) {
total_size += files_[level][i]->compensated_file_size;
numfiles++;
}
}
if (cfd_->options()->compaction_style == kCompactionStyleFIFO) {
score = static_cast<double>(total_size) /
cfd_->options()->compaction_options_fifo.max_table_files_size;
} else if (numfiles >= cfd_->options()->level0_stop_writes_trigger) {
// If we are slowing down writes, then we better compact that first
score = 1000000;
} else if (numfiles >= cfd_->options()->level0_slowdown_writes_trigger) {
score = 10000;
} else {
score = static_cast<double>(numfiles) /
cfd_->options()->level0_file_num_compaction_trigger;
}
} else {
// Compute the ratio of current size to size limit.
const uint64_t level_bytes =
TotalCompensatedFileSize(files_[level]) - size_being_compacted[level];
score = static_cast<double>(level_bytes) /
cfd_->compaction_picker()->MaxBytesForLevel(level);
if (max_score < score) {
max_score = score;
max_score_level = level;
}
}
compaction_level_[level] = level;
compaction_score_[level] = score;
}
// update the max compaction score in levels 1 to n-1
max_compaction_score_ = max_score;
max_compaction_score_level_ = max_score_level;
// 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 < NumberLevels() - 2; i++) {
for (int j = i + 1; j < NumberLevels() - 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;
}
}
}
}
namespace {
// Compator that is used to sort files based on their size
// In normal mode: descending size
bool CompareCompensatedSizeDescending(const Version::Fsize& first,
const Version::Fsize& second) {
return (first.file->compensated_file_size >
second.file->compensated_file_size);
}
} // anonymous namespace
void Version::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;
}
}
}
void Version::UpdateFilesBySize() {
if (cfd_->options()->compaction_style == kCompactionStyleFIFO ||
cfd_->options()->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 < NumberLevels() - 1; level++) {
const std::vector<FileMetaData*>& files = files_[level];
auto& files_by_size = files_by_size_[level];
assert(files_by_size.size() == 0);
// populate a temp vector for sorting based on size
std::vector<Fsize> temp(files.size());
for (unsigned int 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 = Version::number_of_files_to_sort_;
if (num > temp.size()) {
num = temp.size();
}
std::partial_sort(temp.begin(), temp.begin() + num, temp.end(),
CompareCompensatedSizeDescending);
assert(temp.size() == files.size());
// initialize files_by_size_
for (unsigned int i = 0; i < temp.size(); i++) {
files_by_size.push_back(temp[i].index);
}
next_file_to_compact_by_size_[level] = 0;
assert(files_[level].size() == files_by_size_[level].size());
}
}
void Version::Ref() {
++refs_;
}
bool Version::Unref() {
assert(refs_ >= 1);
--refs_;
if (refs_ == 0) {
delete this;
return true;
}
return false;
}
bool Version::NeedsCompaction() const {
// In universal compaction case, this check doesn't really
// check the compaction condition, but checks num of files threshold
// only. We are not going to miss any compaction opportunity
// but it's likely that more compactions are scheduled but
// ending up with nothing to do. We can improve it later.
// TODO(sdong): improve this function to be accurate for universal
// compactions.
int max_input_level =
cfd_->compaction_picker()->MaxInputLevel(NumberLevels());
for (int i = 0; i <= max_input_level; i++) {
if (compaction_score_[i] >= 1) {
return true;
}
}
return false;
}
bool Version::OverlapInLevel(int level,
const Slice* smallest_user_key,
const Slice* largest_user_key) {
return SomeFileOverlapsRange(cfd_->internal_comparator(), (level > 0),
file_levels_[level], smallest_user_key,
largest_user_key);
}
int Version::PickLevelForMemTableOutput(
const Slice& smallest_user_key,
const Slice& largest_user_key) {
int level = 0;
if (!OverlapInLevel(0, &smallest_user_key, &largest_user_key)) {
// Push to next level if there is no overlap in next level,
// and the #bytes overlapping in the level after that are limited.
InternalKey start(smallest_user_key, kMaxSequenceNumber, kValueTypeForSeek);
InternalKey limit(largest_user_key, 0, static_cast<ValueType>(0));
std::vector<FileMetaData*> overlaps;
int max_mem_compact_level = cfd_->options()->max_mem_compaction_level;
while (max_mem_compact_level > 0 && level < max_mem_compact_level) {
if (OverlapInLevel(level + 1, &smallest_user_key, &largest_user_key)) {
break;
}
if (level + 2 >= num_levels_) {
level++;
break;
}
GetOverlappingInputs(level + 2, &start, &limit, &overlaps);
const uint64_t sum = TotalFileSize(overlaps);
if (sum > cfd_->compaction_picker()->MaxGrandParentOverlapBytes(level)) {
break;
}
level++;
}
}
return level;
}
// 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 Version::GetOverlappingInputs(int level,
const InternalKey* begin,
const InternalKey* end,
std::vector<FileMetaData*>* inputs,
int hint_index,
int* file_index) {
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 = cfd_->internal_comparator().user_comparator();
if (begin != nullptr && end != nullptr && level > 0) {
GetOverlappingInputsBinarySearch(level, user_begin, user_end, inputs,
hint_index, file_index);
return;
}
for (size_t i = 0; i < file_levels_[level].num_files; ) {
FdWithKeyRange* f = &(file_levels_[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) {
// 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 = i-1;
}
}
}
}
// 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.
void Version::GetOverlappingInputsBinarySearch(
int level,
const Slice& user_begin,
const Slice& user_end,
std::vector<FileMetaData*>* inputs,
int hint_index,
int* file_index) {
assert(level > 0);
int min = 0;
int mid = 0;
int max = files_[level].size() -1;
bool foundOverlap = false;
const Comparator* user_cmp = cfd_->internal_comparator().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 = &(file_levels_[level].files[mid]);
const Slice file_start = ExtractUserKey(f->smallest_key);
const Slice file_limit = ExtractUserKey(f->largest_key);
if (user_cmp->Compare(file_limit, user_begin) < 0) {
min = mid + 1;
} else if (user_cmp->Compare(user_end, file_start) < 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;
}
ExtendOverlappingInputs(level, user_begin, user_end, inputs, mid);
}
// Store in "*inputs" all files in "level" that overlap [begin,end]
// The midIndex 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 Version::ExtendOverlappingInputs(
int level,
const Slice& user_begin,
const Slice& user_end,
std::vector<FileMetaData*>* inputs,
unsigned int midIndex) {
const Comparator* user_cmp = cfd_->internal_comparator().user_comparator();
const FdWithKeyRange* files = file_levels_[level].files;
#ifndef NDEBUG
{
// assert that the file at midIndex overlaps with the range
assert(midIndex < file_levels_[level].num_files);
const FdWithKeyRange* f = &files[midIndex];
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
int startIndex = midIndex + 1;
int endIndex = midIndex;
int count __attribute__((unused)) = 0;
// check backwards from 'mid' to lower indices
for (int i = midIndex; 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) {
startIndex = i;
assert((count++, true));
} else {
break;
}
}
// check forward from 'mid+1' to higher indices
for (unsigned int i = midIndex+1; i < file_levels_[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));
endIndex = i;
} else {
break;
}
}
assert(count == endIndex - startIndex + 1);
// insert overlapping files into vector
for (int i = startIndex; i <= endIndex; i++) {
FileMetaData* f = files_[level][i];
inputs->push_back(f);
}
}
// 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 Version::HasOverlappingUserKey(
const std::vector<FileMetaData*>* inputs,
int level) {
// If inputs empty, there is no overlap.
// If level == 0, it is assumed that all needed files were already included.
if (inputs->empty() || level == 0){
return false;
}
const Comparator* user_cmp = cfd_->internal_comparator().user_comparator();
const FileLevel& file_level = file_levels_[level];
const FdWithKeyRange* files = file_levels_[level].files;
const size_t kNumFiles = file_level.num_files;
// Check the last file in inputs against the file after it
size_t last_file = FindFile(cfd_->internal_comparator(), file_level,
inputs->back()->largest.Encode());
assert(0 <= last_file && last_file < kNumFiles); // File should exist!
if (last_file < kNumFiles-1) { // If not the last file
const Slice last_key_in_input = ExtractUserKey(
files[last_file].largest_key);
const Slice first_key_after = ExtractUserKey(
files[last_file+1].smallest_key);
if (user_cmp->Compare(last_key_in_input, first_key_after) == 0) {
// The last user key in input overlaps with the next file's first key
return true;
}
}
// Check the first file in inputs against the file just before it
size_t first_file = FindFile(cfd_->internal_comparator(), file_level,
inputs->front()->smallest.Encode());
assert(0 <= first_file && first_file <= last_file); // File should exist!
if (first_file > 0) { // If not first file
const Slice& first_key_in_input = ExtractUserKey(
files[first_file].smallest_key);
const Slice& last_key_before = ExtractUserKey(
files[first_file-1].largest_key);
if (user_cmp->Compare(first_key_in_input, last_key_before) == 0) {
// The first user key in input overlaps with the previous file's last key
return true;
}
}
return false;
}
int64_t Version::NumLevelBytes(int level) const {
assert(level >= 0);
assert(level < NumberLevels());
return TotalFileSize(files_[level]);
}
const char* Version::LevelSummary(LevelSummaryStorage* scratch) const {
int len = snprintf(scratch->buffer, sizeof(scratch->buffer), "files[");
for (int i = 0; i < NumberLevels(); 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;
}
snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len, "]");
return scratch->buffer;
}
const char* Version::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, 16);
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 Version::MaxNextLevelOverlappingBytes() {
uint64_t result = 0;
std::vector<FileMetaData*> overlaps;
for (int level = 1; level < NumberLevels() - 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;
}
void Version::AddLiveFiles(std::vector<FileDescriptor>* live) {
for (int level = 0; level < NumberLevels(); level++) {
const std::vector<FileMetaData*>& files = files_[level];
for (const auto& file : files) {
live->push_back(file->fd);
}
}
}
std::string Version::DebugString(bool hex) const {
std::string r;
for (int level = 0; level < num_levels_; level++) {
// E.g.,
// --- level 1 ---
// 17:123['a' .. 'd']
// 20:43['e' .. 'g']
r.append("--- level ");
AppendNumberTo(&r, level);
r.append(" --- version# ");
AppendNumberTo(&r, version_number_);
r.append(" ---\n");
const std::vector<FileMetaData*>& files = 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("]\n");
}
}
return r;
}
// this is used to batch writes to the manifest file
struct VersionSet::ManifestWriter {
Status status;
bool done;
port::CondVar cv;
ColumnFamilyData* cfd;
VersionEdit* edit;
explicit ManifestWriter(port::Mutex* mu, ColumnFamilyData* cfd,
VersionEdit* e)
: done(false), cv(mu), cfd(cfd), edit(e) {}
};
// A helper class so we can efficiently apply a whole sequence
// of edits to a particular state without creating intermediate
// Versions that contain full copies of the intermediate state.
class VersionSet::Builder {
private:
// Helper to sort v->files_
// kLevel0 -- NewestFirstBySeqNo
// kLevelNon0 -- BySmallestKey
struct FileComparator {
enum SortMethod {
kLevel0 = 0,
kLevelNon0 = 1,
} sort_method;
const InternalKeyComparator* internal_comparator;
bool operator()(FileMetaData* f1, FileMetaData* f2) const {
switch (sort_method) {
case kLevel0:
return NewestFirstBySeqNo(f1, f2);
case kLevelNon0:
return BySmallestKey(f1, f2, internal_comparator);
}
assert(false);
return false;
}
};
typedef std::set<FileMetaData*, FileComparator> FileSet;
struct LevelState {
std::set<uint64_t> deleted_files;
FileSet* added_files;
};
ColumnFamilyData* cfd_;
Version* base_;
LevelState* levels_;
FileComparator level_zero_cmp_;
FileComparator level_nonzero_cmp_;
public:
Builder(ColumnFamilyData* cfd) : cfd_(cfd), base_(cfd->current()) {
base_->Ref();
levels_ = new LevelState[base_->NumberLevels()];
level_zero_cmp_.sort_method = FileComparator::kLevel0;
level_nonzero_cmp_.sort_method = FileComparator::kLevelNon0;
level_nonzero_cmp_.internal_comparator = &cfd->internal_comparator();
levels_[0].added_files = new FileSet(level_zero_cmp_);
for (int level = 1; level < base_->NumberLevels(); level++) {
levels_[level].added_files = new FileSet(level_nonzero_cmp_);
}
}
~Builder() {
for (int level = 0; level < base_->NumberLevels(); level++) {
const FileSet* added = levels_[level].added_files;
std::vector<FileMetaData*> to_unref;
to_unref.reserve(added->size());
for (FileSet::const_iterator it = added->begin();
it != added->end(); ++it) {
to_unref.push_back(*it);
}
delete added;
for (uint32_t i = 0; i < to_unref.size(); i++) {
FileMetaData* f = to_unref[i];
f->refs--;
if (f->refs <= 0) {
if (f->table_reader_handle) {
cfd_->table_cache()->ReleaseHandle(f->table_reader_handle);
f->table_reader_handle = nullptr;
}
delete f;
}
}
}
delete[] levels_;
base_->Unref();
}
void CheckConsistency(Version* v) {
#ifndef NDEBUG
// make sure the files are sorted correctly
for (int level = 0; level < v->NumberLevels(); level++) {
for (size_t i = 1; i < v->files_[level].size(); i++) {
auto f1 = v->files_[level][i - 1];
auto f2 = v->files_[level][i];
if (level == 0) {
assert(level_zero_cmp_(f1, f2));
assert(f1->largest_seqno > f2->largest_seqno);
} else {
assert(level_nonzero_cmp_(f1, f2));
// Make sure there is no overlap in levels > 0
if (cfd_->internal_comparator().Compare(f1->largest, f2->smallest) >=
0) {
fprintf(stderr, "overlapping ranges in same level %s vs. %s\n",
(f1->largest).DebugString().c_str(),
(f2->smallest).DebugString().c_str());
abort();
}
}
}
}
#endif
}
void CheckConsistencyForDeletes(VersionEdit* edit, uint64_t number,
int level) {
#ifndef NDEBUG
// a file to be deleted better exist in the previous version
bool found = false;
for (int l = 0; !found && l < base_->NumberLevels(); l++) {
const std::vector<FileMetaData*>& base_files = base_->files_[l];
for (unsigned int i = 0; i < base_files.size(); i++) {
FileMetaData* f = base_files[i];
if (f->fd.GetNumber() == number) {
found = true;
break;
}
}
}
// if the file did not exist in the previous version, then it
// is possibly moved from lower level to higher level in current
// version
for (int l = level+1; !found && l < base_->NumberLevels(); l++) {
const FileSet* added = levels_[l].added_files;
for (FileSet::const_iterator added_iter = added->begin();
added_iter != added->end(); ++added_iter) {
FileMetaData* f = *added_iter;
if (f->fd.GetNumber() == number) {
found = true;
break;
}
}
}
// maybe this file was added in a previous edit that was Applied
if (!found) {
const FileSet* added = levels_[level].added_files;
for (FileSet::const_iterator added_iter = added->begin();
added_iter != added->end(); ++added_iter) {
FileMetaData* f = *added_iter;
if (f->fd.GetNumber() == number) {
found = true;
break;
}
}
}
if (!found) {
fprintf(stderr, "not found %" PRIu64 "\n", number);
}
assert(found);
#endif
}
// Apply all of the edits in *edit to the current state.
void Apply(VersionEdit* edit) {
CheckConsistency(base_);
// Delete files
const VersionEdit::DeletedFileSet& del = edit->deleted_files_;
for (const auto& del_file : del) {
const auto level = del_file.first;
const auto number = del_file.second;
levels_[level].deleted_files.insert(number);
CheckConsistencyForDeletes(edit, number, level);
}
// Add new files
for (const auto& new_file : edit->new_files_) {
const int level = new_file.first;
FileMetaData* f = new FileMetaData(new_file.second);
f->refs = 1;
levels_[level].deleted_files.erase(f->fd.GetNumber());
levels_[level].added_files->insert(f);
}
}
// Save the current state in *v.
void SaveTo(Version* v) {
CheckConsistency(base_);
CheckConsistency(v);
for (int level = 0; level < base_->NumberLevels(); level++) {
const auto& cmp = (level == 0) ? level_zero_cmp_ : level_nonzero_cmp_;
// Merge the set of added files with the set of pre-existing files.
// Drop any deleted files. Store the result in *v.
const auto& base_files = base_->files_[level];
auto base_iter = base_files.begin();
auto base_end = base_files.end();
const auto& added_files = *levels_[level].added_files;
v->files_[level].reserve(base_files.size() + added_files.size());
for (const auto& added : added_files) {
// Add all smaller files listed in base_
for (auto bpos = std::upper_bound(base_iter, base_end, added, cmp);
base_iter != bpos;
++base_iter) {
MaybeAddFile(v, level, *base_iter);
}
MaybeAddFile(v, level, added);
}
// Add remaining base files
for (; base_iter != base_end; ++base_iter) {
MaybeAddFile(v, level, *base_iter);
}
}
CheckConsistency(v);
}
void LoadTableHandlers() {
for (int level = 0; level < cfd_->NumberLevels(); level++) {
for (auto& file_meta : *(levels_[level].added_files)) {
assert (!file_meta->table_reader_handle);
cfd_->table_cache()->FindTable(
base_->vset_->storage_options_, cfd_->internal_comparator(),
file_meta->fd, &file_meta->table_reader_handle, false);
if (file_meta->table_reader_handle != nullptr) {
// Load table_reader
file_meta->fd.table_reader =
cfd_->table_cache()->GetTableReaderFromHandle(
file_meta->table_reader_handle);
}
}
}
}
void MaybeAddFile(Version* v, int level, FileMetaData* f) {
if (levels_[level].deleted_files.count(f->fd.GetNumber()) > 0) {
// File is deleted: do nothing
} else {
auto* files = &v->files_[level];
if (level > 0 && !files->empty()) {
// Must not overlap
assert(cfd_->internal_comparator().Compare(
(*files)[files->size() - 1]->largest, f->smallest) < 0);
}
f->refs++;
files->push_back(f);
}
}
};
VersionSet::VersionSet(const std::string& dbname, const DBOptions* options,
const EnvOptions& storage_options, Cache* table_cache)
: column_family_set_(new ColumnFamilySet(dbname, options, storage_options,
table_cache)),
env_(options->env),
dbname_(dbname),
options_(options),
next_file_number_(2),
manifest_file_number_(0), // Filled by Recover()
pending_manifest_file_number_(0),
last_sequence_(0),
prev_log_number_(0),
current_version_number_(0),
manifest_file_size_(0),
storage_options_(storage_options),
storage_options_compactions_(storage_options_) {}
VersionSet::~VersionSet() {
// we need to delete column_family_set_ because its destructor depends on
// VersionSet
column_family_set_.reset();
for (auto file : obsolete_files_) {
delete file;
}
obsolete_files_.clear();
}
void VersionSet::AppendVersion(ColumnFamilyData* column_family_data,
Version* v) {
// 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,
VersionEdit* edit, port::Mutex* mu,
Directory* db_directory, bool new_descriptor_log,
const ColumnFamilyOptions* options) {
mu->AssertHeld();
// 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(edit->is_column_family_add_);
assert(options != nullptr);
}
// queue our request
ManifestWriter w(mu, column_family_data, edit);
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();
}
return Status::OK();
}
std::vector<VersionEdit*> batch_edits;
Version* v = nullptr;
std::unique_ptr<Builder> builder(nullptr);
// process all requests in the queue
ManifestWriter* last_writer = &w;
assert(!manifest_writers_.empty());
assert(manifest_writers_.front() == &w);
if (edit->IsColumnFamilyManipulation()) {
// no group commits for column family add or drop
LogAndApplyCFHelper(edit);
batch_edits.push_back(edit);
} else {
v = new Version(column_family_data, this, current_version_number_++);
builder.reset(new Builder(column_family_data));
for (const auto& writer : manifest_writers_) {
if (writer->edit->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;
LogAndApplyHelper(column_family_data, builder.get(), v, last_writer->edit,
mu);
batch_edits.push_back(last_writer->edit);
}
builder->SaveTo(v);
}
// 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_ > options_->max_manifest_file_size) {
pending_manifest_file_number_ = NewFileNumber();
batch_edits.back()->SetNextFile(next_file_number_);
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) {
edit->SetMaxColumnFamily(column_family_set_->GetMaxColumnFamily());
}
}
// Unlock during expensive operations. New writes cannot get here
// because &w is ensuring that all new writes get queued.
{
std::vector<uint64_t> size_being_compacted;
if (!edit->IsColumnFamilyManipulation()) {
size_being_compacted.resize(v->NumberLevels() - 1);
// calculate the amount of data being compacted at every level
column_family_data->compaction_picker()->SizeBeingCompacted(
size_being_compacted);
}
mu->Unlock();
if (!edit->IsColumnFamilyManipulation() && options_->max_open_files == -1) {
// unlimited table cache. Pre-load table handle now.
// Need to do it out of the mutex.
builder->LoadTableHandlers();
}
// This is fine because everything inside of this block is serialized --
// only one thread can be here at the same time
if (new_descriptor_log) {
// create manifest file
Log(options_->info_log,
"Creating manifest %" PRIu64 "\n", pending_manifest_file_number_);
unique_ptr<WritableFile> descriptor_file;
s = env_->NewWritableFile(
DescriptorFileName(dbname_, pending_manifest_file_number_),
&descriptor_file, env_->OptimizeForManifestWrite(storage_options_));
if (s.ok()) {
descriptor_file->SetPreallocationBlockSize(
options_->manifest_preallocation_size);
descriptor_log_.reset(new log::Writer(std::move(descriptor_file)));
s = WriteSnapshot(descriptor_log_.get());
}
}
if (!edit->IsColumnFamilyManipulation()) {
// This is cpu-heavy operations, which should be called outside mutex.
v->PrepareApply(size_being_compacted);
}
// Write new record to MANIFEST log
if (s.ok()) {
for (auto& e : batch_edits) {
std::string record;
e->EncodeTo(&record);
s = descriptor_log_->AddRecord(record);
if (!s.ok()) {
break;
}
}
if (s.ok()) {
if (options_->use_fsync) {
StopWatch sw(env_, options_->statistics.get(),
MANIFEST_FILE_SYNC_MICROS);
s = descriptor_log_->file()->Fsync();
} else {
StopWatch sw(env_, options_->statistics.get(),
MANIFEST_FILE_SYNC_MICROS);
s = descriptor_log_->file()->Sync();
}
}
if (!s.ok()) {
Log(options_->info_log, "MANIFEST write: %s\n", s.ToString().c_str());
bool all_records_in = true;
for (auto& e : batch_edits) {
std::string record;
e->EncodeTo(&record);
if (!ManifestContains(pending_manifest_file_number_, record)) {
all_records_in = false;
break;
}
}
if (all_records_in) {
Log(options_->info_log,
"MANIFEST contains log record despite error; advancing to new "
"version to prevent mismatch between in-memory and logged state"
" If paranoid is set, then the db is now in readonly mode.");
s = Status::OK();
}
}
}
// If we just created a new descriptor file, install it by writing a
// new CURRENT file that points to it.
if (s.ok() && new_descriptor_log) {
s = SetCurrentFile(env_, dbname_, pending_manifest_file_number_,
db_directory);
if (s.ok() && pending_manifest_file_number_ > manifest_file_number_) {
// delete old manifest file
Log(options_->info_log,
"Deleting manifest %" PRIu64 " current manifest %" PRIu64 "\n",
manifest_file_number_, pending_manifest_file_number_);
// we don't care about an error here, PurgeObsoleteFiles will take care
// of it later
env_->DeleteFile(DescriptorFileName(dbname_, manifest_file_number_));
}
}
if (s.ok()) {
// find offset in manifest file where this version is stored.
new_manifest_file_size = descriptor_log_->file()->GetFileSize();
}
LogFlush(options_->info_log);
mu->Lock();
}
// Install the new version
if (s.ok()) {
if (edit->is_column_family_add_) {
// no group commit on column family add
assert(batch_edits.size() == 1);
assert(options != nullptr);
CreateColumnFamily(*options, edit);
} else if (edit->is_column_family_drop_) {
assert(batch_edits.size() == 1);
column_family_data->SetDropped();
if (column_family_data->Unref()) {
delete column_family_data;
}
} else {
uint64_t max_log_number_in_batch = 0;
for (auto& e : batch_edits) {
if (e->has_log_number_) {
max_log_number_in_batch =
std::max(max_log_number_in_batch, e->log_number_);
}
}
if (max_log_number_in_batch != 0) {
assert(column_family_data->GetLogNumber() <= max_log_number_in_batch);
column_family_data->SetLogNumber(max_log_number_in_batch);
}
AppendVersion(column_family_data, v);
}
manifest_file_number_ = pending_manifest_file_number_;
manifest_file_size_ = new_manifest_file_size;
prev_log_number_ = edit->prev_log_number_;
} else {
Log(options_->info_log, "Error in committing version %lu to [%s]",
(unsigned long)v->GetVersionNumber(),
column_family_data->GetName().c_str());
delete v;
if (new_descriptor_log) {
Log(options_->info_log,
"Deleting manifest %" PRIu64 " current manifest %" PRIu64 "\n",
manifest_file_number_, pending_manifest_file_number_);
descriptor_log_.reset();
env_->DeleteFile(
DescriptorFileName(dbname_, pending_manifest_file_number_));
}
}
pending_manifest_file_number_ = 0;
// wake up all the waiting writers
while (true) {
ManifestWriter* ready = manifest_writers_.front();
manifest_writers_.pop_front();
if (ready != &w) {
ready->status = s;
ready->done = true;
ready->cv.Signal();
}
if (ready == last_writer) break;
}
// Notify new head of write queue
if (!manifest_writers_.empty()) {
manifest_writers_.front()->cv.Signal();
}
return s;
}
void VersionSet::LogAndApplyCFHelper(VersionEdit* edit) {
assert(edit->IsColumnFamilyManipulation());
edit->SetNextFile(next_file_number_);
edit->SetLastSequence(last_sequence_);
if (edit->is_column_family_drop_) {
// if we drop column family, we have to make sure to save max column family,
// so that we don't reuse existing ID
edit->SetMaxColumnFamily(column_family_set_->GetMaxColumnFamily());
}
}
void VersionSet::LogAndApplyHelper(ColumnFamilyData* cfd, Builder* builder,
Version* v, VersionEdit* edit,
port::Mutex* mu) {
mu->AssertHeld();
assert(!edit->IsColumnFamilyManipulation());
if (edit->has_log_number_) {
assert(edit->log_number_ >= cfd->GetLogNumber());
assert(edit->log_number_ < next_file_number_);
}
if (!edit->has_prev_log_number_) {
edit->SetPrevLogNumber(prev_log_number_);
}
edit->SetNextFile(next_file_number_);
edit->SetLastSequence(last_sequence_);
builder->Apply(edit);
}
Status VersionSet::Recover(
const std::vector<ColumnFamilyDescriptor>& column_families,
bool read_only) {
std::unordered_map<std::string, ColumnFamilyOptions> cf_name_to_options;
for (auto cf : column_families) {
cf_name_to_options.insert({cf.name, cf.options});
}
// keeps track of column families in manifest that were not found in
// column families parameters. if those column families are not dropped
// by subsequent manifest records, Recover() will return failure status
std::unordered_map<int, std::string> column_families_not_found;
// Read "CURRENT" file, which contains a pointer to the current manifest file
std::string manifest_filename;
Status s = ReadFileToString(
env_, CurrentFileName(dbname_), &manifest_filename
);
if (!s.ok()) {
return s;
}
if (manifest_filename.empty() ||
manifest_filename.back() != '\n') {
return Status::Corruption("CURRENT file does not end with newline");
}
// remove the trailing '\n'
manifest_filename.resize(manifest_filename.size() - 1);
FileType type;
bool parse_ok =
ParseFileName(manifest_filename, &manifest_file_number_, &type);
if (!parse_ok || type != kDescriptorFile) {
return Status::Corruption("CURRENT file corrupted");
}
Log(options_->info_log, "Recovering from manifest file: %s\n",
manifest_filename.c_str());
manifest_filename = dbname_ + "/" + manifest_filename;
unique_ptr<SequentialFile> manifest_file;
s = env_->NewSequentialFile(manifest_filename, &manifest_file,
storage_options_);
if (!s.ok()) {
return s;
}
uint64_t manifest_file_size;
s = env_->GetFileSize(manifest_filename, &manifest_file_size);
if (!s.ok()) {
return s;
}
bool have_log_number = false;
bool have_prev_log_number = false;
bool have_next_file = false;
bool have_last_sequence = false;
uint64_t next_file = 0;
uint64_t last_sequence = 0;
uint64_t log_number = 0;
uint64_t prev_log_number = 0;
uint32_t max_column_family = 0;
std::unordered_map<uint32_t, Builder*> builders;
// add default column family
auto default_cf_iter = cf_name_to_options.find(kDefaultColumnFamilyName);
if (default_cf_iter == cf_name_to_options.end()) {
return Status::InvalidArgument("Default column family not specified");
}
VersionEdit default_cf_edit;
default_cf_edit.AddColumnFamily(kDefaultColumnFamilyName);
default_cf_edit.SetColumnFamily(0);
ColumnFamilyData* default_cfd =
CreateColumnFamily(default_cf_iter->second, &default_cf_edit);
builders.insert({0, new Builder(default_cfd)});
{
VersionSet::LogReporter reporter;
reporter.status = &s;
log::Reader reader(std::move(manifest_file), &reporter, true /*checksum*/,
0 /*initial_offset*/);
Slice record;
std::string scratch;
while (reader.ReadRecord(&record, &scratch) && s.ok()) {
VersionEdit edit;
s = edit.DecodeFrom(record);
if (!s.ok()) {
break;
}
// Not found means that user didn't supply that column
// family option AND we encountered column family add
// record. Once we encounter column family drop record,
// we will delete the column family from
// column_families_not_found.
bool cf_in_not_found =
column_families_not_found.find(edit.column_family_) !=
column_families_not_found.end();
// in builders means that user supplied that column family
// option AND that we encountered column family add record
bool cf_in_builders =
builders.find(edit.column_family_) != builders.end();
// they can't both be true
assert(!(cf_in_not_found && cf_in_builders));
ColumnFamilyData* cfd = nullptr;
if (edit.is_column_family_add_) {
if (cf_in_builders || cf_in_not_found) {
s = Status::Corruption(
"Manifest adding the same column family twice");
break;
}
auto cf_options = cf_name_to_options.find(edit.column_family_name_);
if (cf_options == cf_name_to_options.end()) {
column_families_not_found.insert(
{edit.column_family_, edit.column_family_name_});
} else {
cfd = CreateColumnFamily(cf_options->second, &edit);
builders.insert({edit.column_family_, new Builder(cfd)});
}
} else if (edit.is_column_family_drop_) {
if (cf_in_builders) {
auto builder = builders.find(edit.column_family_);
assert(builder != builders.end());
delete builder->second;
builders.erase(builder);
cfd = column_family_set_->GetColumnFamily(edit.column_family_);
if (cfd->Unref()) {
delete cfd;
cfd = nullptr;
} else {
// who else can have reference to cfd!?
assert(false);
}
} else if (cf_in_not_found) {
column_families_not_found.erase(edit.column_family_);
} else {
s = Status::Corruption(
"Manifest - dropping non-existing column family");
break;
}
} else if (!cf_in_not_found) {
if (!cf_in_builders) {
s = Status::Corruption(
"Manifest record referencing unknown column family");
break;
}
cfd = column_family_set_->GetColumnFamily(edit.column_family_);
// this should never happen since cf_in_builders is true
assert(cfd != nullptr);
if (edit.max_level_ >= cfd->current()->NumberLevels()) {
s = Status::InvalidArgument(
"db has more levels than options.num_levels");
break;
}
// if it is not column family add or column family drop,
// then it's a file add/delete, which should be forwarded
// to builder
auto builder = builders.find(edit.column_family_);
assert(builder != builders.end());
builder->second->Apply(&edit);
}
if (cfd != nullptr) {
if (edit.has_log_number_) {
if (cfd->GetLogNumber() > edit.log_number_) {
Log(options_->info_log,
"MANIFEST corruption detected, but ignored - Log numbers in "
"records NOT monotonically increasing");
} else {
cfd->SetLogNumber(edit.log_number_);
have_log_number = true;
}
}
if (edit.has_comparator_ &&
edit.comparator_ != cfd->user_comparator()->Name()) {
s = Status::InvalidArgument(
cfd->user_comparator()->Name(),
"does not match existing comparator " + edit.comparator_);
break;
}
}
if (edit.has_prev_log_number_) {
prev_log_number = edit.prev_log_number_;
have_prev_log_number = true;
}
if (edit.has_next_file_number_) {
next_file = edit.next_file_number_;
have_next_file = true;
}
if (edit.has_max_column_family_) {
max_column_family = edit.max_column_family_;
}
if (edit.has_last_sequence_) {
last_sequence = edit.last_sequence_;
have_last_sequence = true;
}
}
}
if (s.ok()) {
if (!have_next_file) {
s = Status::Corruption("no meta-nextfile entry in descriptor");
} else if (!have_log_number) {
s = Status::Corruption("no meta-lognumber entry in descriptor");
} else if (!have_last_sequence) {
s = Status::Corruption("no last-sequence-number entry in descriptor");
}
if (!have_prev_log_number) {
prev_log_number = 0;
}
column_family_set_->UpdateMaxColumnFamily(max_column_family);
MarkFileNumberUsed(prev_log_number);
MarkFileNumberUsed(log_number);
}
// there were some column families in the MANIFEST that weren't specified
// in the argument. This is OK in read_only mode
if (read_only == false && column_families_not_found.size() > 0) {
std::string list_of_not_found;
for (const auto& cf : column_families_not_found) {
list_of_not_found += ", " + cf.second;
}
list_of_not_found = list_of_not_found.substr(2);
s = Status::InvalidArgument(
"You have to open all column families. Column families not opened: " +
list_of_not_found);
}
if (s.ok()) {
for (auto cfd : *column_family_set_) {
auto builders_iter = builders.find(cfd->GetID());
assert(builders_iter != builders.end());
auto builder = builders_iter->second;
if (options_->max_open_files == -1) {
// unlimited table cache. Pre-load table handle now.
// Need to do it out of the mutex.
builder->LoadTableHandlers();
}
Version* v = new Version(cfd, this, current_version_number_++);
builder->SaveTo(v);
// Install recovered version
std::vector<uint64_t> size_being_compacted(v->NumberLevels() - 1);
cfd->compaction_picker()->SizeBeingCompacted(size_being_compacted);
v->PrepareApply(size_being_compacted);
AppendVersion(cfd, v);
}
manifest_file_size_ = manifest_file_size;
next_file_number_ = next_file + 1;
last_sequence_ = last_sequence;
prev_log_number_ = prev_log_number;
Log(options_->info_log,
"Recovered from manifest file:%s succeeded,"
"manifest_file_number is %lu, next_file_number is %lu, "
"last_sequence is %lu, log_number is %lu,"
"prev_log_number is %lu,"
"max_column_family is %u\n",
manifest_filename.c_str(), (unsigned long)manifest_file_number_,
(unsigned long)next_file_number_, (unsigned long)last_sequence_,
(unsigned long)log_number, (unsigned long)prev_log_number_,
column_family_set_->GetMaxColumnFamily());
for (auto cfd : *column_family_set_) {
Log(options_->info_log,
"Column family [%s] (ID %u), log number is %" PRIu64 "\n",
cfd->GetName().c_str(), cfd->GetID(), cfd->GetLogNumber());
}
}
for (auto builder : builders) {
delete builder.second;
}
return s;
}
Status VersionSet::ListColumnFamilies(std::vector<std::string>* column_families,
const std::string& dbname, Env* env) {
// these are just for performance reasons, not correcntes,
// so we're fine using the defaults
EnvOptions soptions;
// Read "CURRENT" file, which contains a pointer to the current manifest file
std::string current;
Status s = ReadFileToString(env, CurrentFileName(dbname), &current);
if (!s.ok()) {
return s;
}
if (current.empty() || current[current.size()-1] != '\n') {
return Status::Corruption("CURRENT file does not end with newline");
}
current.resize(current.size() - 1);
std::string dscname = dbname + "/" + current;
unique_ptr<SequentialFile> file;
s = env->NewSequentialFile(dscname, &file, soptions);
if (!s.ok()) {
return s;
}
std::map<uint32_t, std::string> column_family_names;
// default column family is always implicitly there
column_family_names.insert({0, kDefaultColumnFamilyName});
VersionSet::LogReporter reporter;
reporter.status = &s;
log::Reader reader(std::move(file), &reporter, true /*checksum*/,
0 /*initial_offset*/);
Slice record;
std::string scratch;
while (reader.ReadRecord(&record, &scratch) && s.ok()) {
VersionEdit edit;
s = edit.DecodeFrom(record);
if (!s.ok()) {
break;
}
if (edit.is_column_family_add_) {
if (column_family_names.find(edit.column_family_) !=
column_family_names.end()) {
s = Status::Corruption("Manifest adding the same column family twice");
break;
}
column_family_names.insert(
{edit.column_family_, edit.column_family_name_});
} else if (edit.is_column_family_drop_) {
if (column_family_names.find(edit.column_family_) ==
column_family_names.end()) {
s = Status::Corruption(
"Manifest - dropping non-existing column family");
break;
}
column_family_names.erase(edit.column_family_);
}
}
column_families->clear();
if (s.ok()) {
for (const auto& iter : column_family_names) {
column_families->push_back(iter.second);
}
}
return s;
}
#ifndef ROCKSDB_LITE
Status VersionSet::ReduceNumberOfLevels(const std::string& dbname,
const Options* options,
const EnvOptions& storage_options,
int new_levels) {
if (new_levels <= 1) {
return Status::InvalidArgument(
"Number of levels needs to be bigger than 1");
}
ColumnFamilyOptions cf_options(*options);
std::shared_ptr<Cache> tc(NewLRUCache(
options->max_open_files - 10, options->table_cache_numshardbits,
options->table_cache_remove_scan_count_limit));
VersionSet versions(dbname, options, storage_options, tc.get());
Status status;
std::vector<ColumnFamilyDescriptor> dummy;
ColumnFamilyDescriptor dummy_descriptor(kDefaultColumnFamilyName,
ColumnFamilyOptions(*options));
dummy.push_back(dummy_descriptor);
status = versions.Recover(dummy);
if (!status.ok()) {
return status;
}
Version* current_version =
versions.GetColumnFamilySet()->GetDefault()->current();
int current_levels = current_version->NumberLevels();
if (current_levels <= new_levels) {
return Status::OK();
}
// Make sure there are file only on one level from
// (new_levels-1) to (current_levels-1)
int first_nonempty_level = -1;
int first_nonempty_level_filenum = 0;
for (int i = new_levels - 1; i < current_levels; i++) {
int file_num = current_version->NumLevelFiles(i);
if (file_num != 0) {
if (first_nonempty_level < 0) {
first_nonempty_level = i;
first_nonempty_level_filenum = file_num;
} else {
char msg[255];
snprintf(msg, sizeof(msg),
"Found at least two levels containing files: "
"[%d:%d],[%d:%d].\n",
first_nonempty_level, first_nonempty_level_filenum, i,
file_num);
return Status::InvalidArgument(msg);
}
}
}
std::vector<FileMetaData*>* old_files_list = current_version->files_;
// we need to allocate an array with the old number of levels size to
// avoid SIGSEGV in WriteSnapshot()
// however, all levels bigger or equal to new_levels will be empty
std::vector<FileMetaData*>* new_files_list =
new std::vector<FileMetaData*>[current_levels];
for (int i = 0; i < new_levels - 1; i++) {
new_files_list[i] = old_files_list[i];
}
if (first_nonempty_level > 0) {
new_files_list[new_levels - 1] = old_files_list[first_nonempty_level];
}
delete[] current_version->files_;
current_version->files_ = new_files_list;
current_version->num_levels_ = new_levels;
VersionEdit ve;
port::Mutex dummy_mutex;
MutexLock l(&dummy_mutex);
return versions.LogAndApply(versions.GetColumnFamilySet()->GetDefault(), &ve,
&dummy_mutex, nullptr, true);
}
Status VersionSet::DumpManifest(Options& options, std::string& dscname,
bool verbose, bool hex) {
// Open the specified manifest file.
unique_ptr<SequentialFile> file;
Status s = options.env->NewSequentialFile(dscname, &file, storage_options_);
if (!s.ok()) {
return s;
}
bool have_prev_log_number = false;
bool have_next_file = false;
bool have_last_sequence = false;
uint64_t next_file = 0;
uint64_t last_sequence = 0;
uint64_t prev_log_number = 0;
int count = 0;
std::unordered_map<uint32_t, std::string> comparators;
std::unordered_map<uint32_t, Builder*> builders;
// add default column family
VersionEdit default_cf_edit;
default_cf_edit.AddColumnFamily(kDefaultColumnFamilyName);
default_cf_edit.SetColumnFamily(0);
ColumnFamilyData* default_cfd =
CreateColumnFamily(ColumnFamilyOptions(options), &default_cf_edit);
builders.insert({0, new Builder(default_cfd)});
{
VersionSet::LogReporter reporter;
reporter.status = &s;
log::Reader reader(std::move(file), &reporter, true/*checksum*/,
0/*initial_offset*/);
Slice record;
std::string scratch;
while (reader.ReadRecord(&record, &scratch) && s.ok()) {
VersionEdit edit;
s = edit.DecodeFrom(record);
if (!s.ok()) {
break;
}
// Write out each individual edit
if (verbose) {
printf("*************************Edit[%d] = %s\n",
count, edit.DebugString(hex).c_str());
}
count++;
bool cf_in_builders =
builders.find(edit.column_family_) != builders.end();
if (edit.has_comparator_) {
comparators.insert({edit.column_family_, edit.comparator_});
}
ColumnFamilyData* cfd = nullptr;
if (edit.is_column_family_add_) {
if (cf_in_builders) {
s = Status::Corruption(
"Manifest adding the same column family twice");
break;
}
cfd = CreateColumnFamily(ColumnFamilyOptions(options), &edit);
builders.insert({edit.column_family_, new Builder(cfd)});
} else if (edit.is_column_family_drop_) {
if (!cf_in_builders) {
s = Status::Corruption(
"Manifest - dropping non-existing column family");
break;
}
auto builder_iter = builders.find(edit.column_family_);
delete builder_iter->second;
builders.erase(builder_iter);
comparators.erase(edit.column_family_);
cfd = column_family_set_->GetColumnFamily(edit.column_family_);
assert(cfd != nullptr);
cfd->Unref();
delete cfd;
cfd = nullptr;
} else {
if (!cf_in_builders) {
s = Status::Corruption(
"Manifest record referencing unknown column family");
break;
}
cfd = column_family_set_->GetColumnFamily(edit.column_family_);
// this should never happen since cf_in_builders is true
assert(cfd != nullptr);
// if it is not column family add or column family drop,
// then it's a file add/delete, which should be forwarded
// to builder
auto builder = builders.find(edit.column_family_);
assert(builder != builders.end());
builder->second->Apply(&edit);
}
if (cfd != nullptr && edit.has_log_number_) {
cfd->SetLogNumber(edit.log_number_);
}
if (edit.has_prev_log_number_) {
prev_log_number = edit.prev_log_number_;
have_prev_log_number = true;
}
if (edit.has_next_file_number_) {
next_file = edit.next_file_number_;
have_next_file = true;
}
if (edit.has_last_sequence_) {
last_sequence = edit.last_sequence_;
have_last_sequence = true;
}
if (edit.has_max_column_family_) {
column_family_set_->UpdateMaxColumnFamily(edit.max_column_family_);
}
}
}
file.reset();
if (s.ok()) {
if (!have_next_file) {
s = Status::Corruption("no meta-nextfile entry in descriptor");
printf("no meta-nextfile entry in descriptor");
} else if (!have_last_sequence) {
printf("no last-sequence-number entry in descriptor");
s = Status::Corruption("no last-sequence-number entry in descriptor");
}
if (!have_prev_log_number) {
prev_log_number = 0;
}
}
if (s.ok()) {
for (auto cfd : *column_family_set_) {
auto builders_iter = builders.find(cfd->GetID());
assert(builders_iter != builders.end());
auto builder = builders_iter->second;
Version* v = new Version(cfd, this, current_version_number_++);
builder->SaveTo(v);
std::vector<uint64_t> size_being_compacted(v->NumberLevels() - 1);
cfd->compaction_picker()->SizeBeingCompacted(size_being_compacted);
v->PrepareApply(size_being_compacted);
delete builder;
printf("--------------- Column family \"%s\" (ID %u) --------------\n",
cfd->GetName().c_str(), (unsigned int)cfd->GetID());
printf("log number: %lu\n", (unsigned long)cfd->GetLogNumber());
auto comparator = comparators.find(cfd->GetID());
if (comparator != comparators.end()) {
printf("comparator: %s\n", comparator->second.c_str());
} else {
printf("comparator: <NO COMPARATOR>\n");
}
printf("%s \n", v->DebugString(hex).c_str());
delete v;
}
next_file_number_ = next_file + 1;
last_sequence_ = last_sequence;
prev_log_number_ = prev_log_number;
printf(
"next_file_number %lu last_sequence "
"%lu prev_log_number %lu max_column_family %u\n",
(unsigned long)next_file_number_, (unsigned long)last_sequence,
(unsigned long)prev_log_number,
column_family_set_->GetMaxColumnFamily());
}
return s;
}
#endif // ROCKSDB_LITE
void VersionSet::MarkFileNumberUsed(uint64_t number) {
if (next_file_number_ <= number) {
next_file_number_ = number + 1;
}
}
Status VersionSet::WriteSnapshot(log::Writer* log) {
// TODO: Break up into multiple records to reduce memory usage on recovery?
// WARNING: This method doesn't hold a mutex!!
// This is done without DB mutex lock held, but only within single-threaded
// LogAndApply. Column family manipulations can only happen within LogAndApply
// (the same single thread), so we're safe to iterate.
for (auto cfd : *column_family_set_) {
{
// Store column family info
VersionEdit edit;
if (cfd->GetID() != 0) {
// default column family is always there,
// no need to explicitly write it
edit.AddColumnFamily(cfd->GetName());
edit.SetColumnFamily(cfd->GetID());
}
edit.SetComparatorName(
cfd->internal_comparator().user_comparator()->Name());
std::string record;
edit.EncodeTo(&record);
Status s = log->AddRecord(record);
if (!s.ok()) {
return s;
}
}
{
// Save files
VersionEdit edit;
edit.SetColumnFamily(cfd->GetID());
for (int level = 0; level < cfd->NumberLevels(); level++) {
for (const auto& f : cfd->current()->files_[level]) {
edit.AddFile(level, f->fd.GetNumber(), f->fd.GetPathId(),
f->fd.GetFileSize(), f->smallest, f->largest,
f->smallest_seqno, f->largest_seqno);
}
}
edit.SetLogNumber(cfd->GetLogNumber());
std::string record;
edit.EncodeTo(&record);
Status s = log->AddRecord(record);
if (!s.ok()) {
return s;
}
}
}
return Status::OK();
}
// Opens the mainfest file and reads all records
// till it finds the record we are looking for.
bool VersionSet::ManifestContains(uint64_t manifest_file_number,
const std::string& record) const {
std::string fname =
DescriptorFileName(dbname_, manifest_file_number);
Log(options_->info_log, "ManifestContains: checking %s\n", fname.c_str());
unique_ptr<SequentialFile> file;
Status s = env_->NewSequentialFile(fname, &file, storage_options_);
if (!s.ok()) {
Log(options_->info_log, "ManifestContains: %s\n", s.ToString().c_str());
Log(options_->info_log,
"ManifestContains: is unable to reopen the manifest file %s",
fname.c_str());
return false;
}
log::Reader reader(std::move(file), nullptr, true/*checksum*/, 0);
Slice r;
std::string scratch;
bool result = false;
while (reader.ReadRecord(&r, &scratch)) {
if (r == Slice(record)) {
result = true;
break;
}
}
Log(options_->info_log, "ManifestContains: result = %d\n", result ? 1 : 0);
return result;
}
uint64_t VersionSet::ApproximateOffsetOf(Version* v, const InternalKey& ikey) {
uint64_t result = 0;
for (int level = 0; level < v->NumberLevels(); level++) {
const std::vector<FileMetaData*>& files = v->files_[level];
for (size_t i = 0; i < files.size(); i++) {
if (v->cfd_->internal_comparator().Compare(files[i]->largest, ikey) <=
0) {
// Entire file is before "ikey", so just add the file size
result += files[i]->fd.GetFileSize();
} else if (v->cfd_->internal_comparator().Compare(files[i]->smallest,
ikey) > 0) {
// Entire file is after "ikey", so ignore
if (level > 0) {
// Files other than level 0 are sorted by meta->smallest, so
// no further files in this level will contain data for
// "ikey".
break;
}
} else {
// "ikey" falls in the range for this table. Add the
// approximate offset of "ikey" within the table.
TableReader* table_reader_ptr;
Iterator* iter = v->cfd_->table_cache()->NewIterator(
ReadOptions(), storage_options_, v->cfd_->internal_comparator(),
files[i]->fd, &table_reader_ptr);
if (table_reader_ptr != nullptr) {
result += table_reader_ptr->ApproximateOffsetOf(ikey.Encode());
}
delete iter;
}
}
}
return result;
}
void VersionSet::AddLiveFiles(std::vector<FileDescriptor>* live_list) {
// pre-calculate space requirement
int64_t total_files = 0;
for (auto cfd : *column_family_set_) {
Version* dummy_versions = cfd->dummy_versions();
for (Version* v = dummy_versions->next_; v != dummy_versions;
v = v->next_) {
for (int level = 0; level < v->NumberLevels(); level++) {
total_files += v->files_[level].size();
}
}
}
// just one time extension to the right size
live_list->reserve(live_list->size() + total_files);
for (auto cfd : *column_family_set_) {
Version* dummy_versions = cfd->dummy_versions();
for (Version* v = dummy_versions->next_; v != dummy_versions;
v = v->next_) {
for (int level = 0; level < v->NumberLevels(); level++) {
for (const auto& f : v->files_[level]) {
live_list->push_back(f->fd);
}
}
}
}
}
Iterator* VersionSet::MakeInputIterator(Compaction* c) {
auto cfd = c->column_family_data();
ReadOptions read_options;
read_options.verify_checksums =
cfd->options()->verify_checksums_in_compaction;
read_options.fill_cache = false;
// Level-0 files have to be merged together. For other levels,
// we will make a concatenating iterator per level.
// TODO(opt): use concatenating iterator for level-0 if there is no overlap
const int space = (c->level() == 0 ?
c->input_levels(0)->num_files + c->num_input_levels() - 1:
c->num_input_levels());
Iterator** list = new Iterator*[space];
int num = 0;
for (int which = 0; which < c->num_input_levels(); which++) {
if (c->input_levels(which)->num_files != 0) {
if (c->level(which) == 0) {
const FileLevel* flevel = c->input_levels(which);
for (size_t i = 0; i < flevel->num_files; i++) {
list[num++] = cfd->table_cache()->NewIterator(
read_options, storage_options_compactions_,
cfd->internal_comparator(), flevel->files[i].fd, nullptr,
true /* for compaction */);
}
} else {
// Create concatenating iterator for the files from this level
list[num++] = NewTwoLevelIterator(new Version::LevelFileIteratorState(
cfd->table_cache(), read_options, storage_options_,
cfd->internal_comparator(), true /* for_compaction */,
false /* prefix enabled */),
new Version::LevelFileNumIterator(cfd->internal_comparator(),
c->input_levels(which)));
}
}
}
assert(num <= space);
Iterator* result = NewMergingIterator(
&c->column_family_data()->internal_comparator(), list, num);
delete[] list;
return result;
}
// verify that the files listed in this compaction are present
// in the current version
bool VersionSet::VerifyCompactionFileConsistency(Compaction* c) {
#ifndef NDEBUG
Version* version = c->column_family_data()->current();
if (c->input_version() != version) {
Log(options_->info_log,
"[%s] VerifyCompactionFileConsistency version mismatch",
c->column_family_data()->GetName().c_str());
}
// verify files in level
int level = c->level();
for (int i = 0; i < c->num_input_files(0); i++) {
uint64_t number = c->input(0, i)->fd.GetNumber();
// look for this file in the current version
bool found = false;
for (unsigned int j = 0; j < version->files_[level].size(); j++) {
FileMetaData* f = version->files_[level][j];
if (f->fd.GetNumber() == number) {
found = true;
break;
}
}
if (!found) {
return false; // input files non existant in current version
}
}
// verify level+1 files
level++;
for (int i = 0; i < c->num_input_files(1); i++) {
uint64_t number = c->input(1, i)->fd.GetNumber();
// look for this file in the current version
bool found = false;
for (unsigned int j = 0; j < version->files_[level].size(); j++) {
FileMetaData* f = version->files_[level][j];
if (f->fd.GetNumber() == number) {
found = true;
break;
}
}
if (!found) {
return false; // input files non existant in current version
}
}
#endif
return true; // everything good
}
Status VersionSet::GetMetadataForFile(uint64_t number, int* filelevel,
FileMetaData** meta,
ColumnFamilyData** cfd) {
for (auto cfd_iter : *column_family_set_) {
Version* version = cfd_iter->current();
for (int level = 0; level < version->NumberLevels(); level++) {
for (const auto& file : version->files_[level]) {
if (file->fd.GetNumber() == number) {
*meta = file;
*filelevel = level;
*cfd = cfd_iter;
return Status::OK();
}
}
}
}
return Status::NotFound("File not present in any level");
}
void VersionSet::GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) {
for (auto cfd : *column_family_set_) {
for (int level = 0; level < cfd->NumberLevels(); level++) {
for (const auto& file : cfd->current()->files_[level]) {
LiveFileMetaData filemetadata;
filemetadata.column_family_name = cfd->GetName();
uint32_t path_id = file->fd.GetPathId();
if (path_id < options_->db_paths.size()) {
filemetadata.db_path = options_->db_paths[path_id].path;
} else {
assert(!options_->db_paths.empty());
filemetadata.db_path = options_->db_paths.back().path;
}
filemetadata.name = MakeTableFileName("", file->fd.GetNumber());
filemetadata.level = level;
filemetadata.size = file->fd.GetFileSize();
filemetadata.smallestkey = file->smallest.user_key().ToString();
filemetadata.largestkey = file->largest.user_key().ToString();
filemetadata.smallest_seqno = file->smallest_seqno;
filemetadata.largest_seqno = file->largest_seqno;
metadata->push_back(filemetadata);
}
}
}
}
void VersionSet::GetObsoleteFiles(std::vector<FileMetaData*>* files) {
files->insert(files->end(), obsolete_files_.begin(), obsolete_files_.end());
obsolete_files_.clear();
}
ColumnFamilyData* VersionSet::CreateColumnFamily(
const ColumnFamilyOptions& options, VersionEdit* edit) {
assert(edit->is_column_family_add_);
Version* dummy_versions = new Version(nullptr, this);
auto new_cfd = column_family_set_->CreateColumnFamily(
edit->column_family_name_, edit->column_family_, dummy_versions, options);
Version* v = new Version(new_cfd, this, current_version_number_++);
AppendVersion(new_cfd, v);
new_cfd->CreateNewMemtable();
new_cfd->SetLogNumber(edit->log_number_);
return new_cfd;
}
} // namespace rocksdb