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rocksdb/db/version_builder.cc
sdong 49628c9a83 Use std::numeric_limits<> (#9954) 
Summary:
Right now we still don't fully use std::numeric_limits but use a macro, mainly for supporting VS 2013. Right now we only support VS 2017 and up so it is not a problem. The code comment claims that MinGW still needs it. We don't have a CI running MinGW so it's hard to validate. since we now require C++17, it's hard to imagine MinGW would still build RocksDB but doesn't support std::numeric_limits<>.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9954

Test Plan: See CI Runs.

Reviewed By: riversand963

Differential Revision: D36173954

fbshipit-source-id: a35a73af17cdcae20e258cdef57fcf29a50b49e0
2022-05-05 13:08:21 -07:00

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/version_builder.h"
#include <algorithm>
#include <atomic>
#include <cinttypes>
#include <functional>
#include <map>
#include <memory>
#include <set>
#include <sstream>
#include <thread>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include "db/blob/blob_file_meta.h"
#include "db/dbformat.h"
#include "db/internal_stats.h"
#include "db/table_cache.h"
#include "db/version_set.h"
#include "port/port.h"
#include "table/table_reader.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
class VersionBuilder::Rep {
class NewestFirstBySeqNo {
public:
bool operator()(const FileMetaData* lhs, const FileMetaData* rhs) const {
assert(lhs);
assert(rhs);
if (lhs->fd.largest_seqno != rhs->fd.largest_seqno) {
return lhs->fd.largest_seqno > rhs->fd.largest_seqno;
}
if (lhs->fd.smallest_seqno != rhs->fd.smallest_seqno) {
return lhs->fd.smallest_seqno > rhs->fd.smallest_seqno;
}
// Break ties by file number
return lhs->fd.GetNumber() > rhs->fd.GetNumber();
}
};
class BySmallestKey {
public:
explicit BySmallestKey(const InternalKeyComparator* cmp) : cmp_(cmp) {}
bool operator()(const FileMetaData* lhs, const FileMetaData* rhs) const {
assert(lhs);
assert(rhs);
assert(cmp_);
const int r = cmp_->Compare(lhs->smallest, rhs->smallest);
if (r != 0) {
return (r < 0);
}
// Break ties by file number
return (lhs->fd.GetNumber() < rhs->fd.GetNumber());
}
private:
const InternalKeyComparator* cmp_;
};
struct LevelState {
std::unordered_set<uint64_t> deleted_files;
// Map from file number to file meta data.
std::unordered_map<uint64_t, FileMetaData*> added_files;
};
// A class that represents the accumulated changes (like additional garbage or
// newly linked/unlinked SST files) for a given blob file after applying a
// series of VersionEdits.
class BlobFileMetaDataDelta {
public:
bool IsEmpty() const {
return !additional_garbage_count_ && !additional_garbage_bytes_ &&
newly_linked_ssts_.empty() && newly_unlinked_ssts_.empty();
}
uint64_t GetAdditionalGarbageCount() const {
return additional_garbage_count_;
}
uint64_t GetAdditionalGarbageBytes() const {
return additional_garbage_bytes_;
}
const std::unordered_set<uint64_t>& GetNewlyLinkedSsts() const {
return newly_linked_ssts_;
}
const std::unordered_set<uint64_t>& GetNewlyUnlinkedSsts() const {
return newly_unlinked_ssts_;
}
void AddGarbage(uint64_t count, uint64_t bytes) {
additional_garbage_count_ += count;
additional_garbage_bytes_ += bytes;
}
void LinkSst(uint64_t sst_file_number) {
assert(newly_linked_ssts_.find(sst_file_number) ==
newly_linked_ssts_.end());
// Reconcile with newly unlinked SSTs on the fly. (Note: an SST can be
// linked to and unlinked from the same blob file in the case of a trivial
// move.)
auto it = newly_unlinked_ssts_.find(sst_file_number);
if (it != newly_unlinked_ssts_.end()) {
newly_unlinked_ssts_.erase(it);
} else {
newly_linked_ssts_.emplace(sst_file_number);
}
}
void UnlinkSst(uint64_t sst_file_number) {
assert(newly_unlinked_ssts_.find(sst_file_number) ==
newly_unlinked_ssts_.end());
// Reconcile with newly linked SSTs on the fly. (Note: an SST can be
// linked to and unlinked from the same blob file in the case of a trivial
// move.)
auto it = newly_linked_ssts_.find(sst_file_number);
if (it != newly_linked_ssts_.end()) {
newly_linked_ssts_.erase(it);
} else {
newly_unlinked_ssts_.emplace(sst_file_number);
}
}
private:
uint64_t additional_garbage_count_ = 0;
uint64_t additional_garbage_bytes_ = 0;
std::unordered_set<uint64_t> newly_linked_ssts_;
std::unordered_set<uint64_t> newly_unlinked_ssts_;
};
// A class that represents the state of a blob file after applying a series of
// VersionEdits. In addition to the resulting state, it also contains the
// delta (see BlobFileMetaDataDelta above). The resulting state can be used to
// identify obsolete blob files, while the delta makes it possible to
// efficiently detect trivial moves.
class MutableBlobFileMetaData {
public:
// To be used for brand new blob files
explicit MutableBlobFileMetaData(
std::shared_ptr<SharedBlobFileMetaData>&& shared_meta)
: shared_meta_(std::move(shared_meta)) {}
// To be used for pre-existing blob files
explicit MutableBlobFileMetaData(
const std::shared_ptr<BlobFileMetaData>& meta)
: shared_meta_(meta->GetSharedMeta()),
linked_ssts_(meta->GetLinkedSsts()),
garbage_blob_count_(meta->GetGarbageBlobCount()),
garbage_blob_bytes_(meta->GetGarbageBlobBytes()) {}
const std::shared_ptr<SharedBlobFileMetaData>& GetSharedMeta() const {
return shared_meta_;
}
uint64_t GetBlobFileNumber() const {
assert(shared_meta_);
return shared_meta_->GetBlobFileNumber();
}
bool HasDelta() const { return !delta_.IsEmpty(); }
const std::unordered_set<uint64_t>& GetLinkedSsts() const {
return linked_ssts_;
}
uint64_t GetGarbageBlobCount() const { return garbage_blob_count_; }
uint64_t GetGarbageBlobBytes() const { return garbage_blob_bytes_; }
bool AddGarbage(uint64_t count, uint64_t bytes) {
assert(shared_meta_);
if (garbage_blob_count_ + count > shared_meta_->GetTotalBlobCount() ||
garbage_blob_bytes_ + bytes > shared_meta_->GetTotalBlobBytes()) {
return false;
}
delta_.AddGarbage(count, bytes);
garbage_blob_count_ += count;
garbage_blob_bytes_ += bytes;
return true;
}
void LinkSst(uint64_t sst_file_number) {
delta_.LinkSst(sst_file_number);
assert(linked_ssts_.find(sst_file_number) == linked_ssts_.end());
linked_ssts_.emplace(sst_file_number);
}
void UnlinkSst(uint64_t sst_file_number) {
delta_.UnlinkSst(sst_file_number);
assert(linked_ssts_.find(sst_file_number) != linked_ssts_.end());
linked_ssts_.erase(sst_file_number);
}
private:
std::shared_ptr<SharedBlobFileMetaData> shared_meta_;
// Accumulated changes
BlobFileMetaDataDelta delta_;
// Resulting state after applying the changes
BlobFileMetaData::LinkedSsts linked_ssts_;
uint64_t garbage_blob_count_ = 0;
uint64_t garbage_blob_bytes_ = 0;
};
const FileOptions& file_options_;
const ImmutableCFOptions* const ioptions_;
TableCache* table_cache_;
VersionStorageInfo* base_vstorage_;
VersionSet* version_set_;
int num_levels_;
LevelState* levels_;
// Store sizes of levels larger than num_levels_. We do this instead of
// storing them in levels_ to avoid regression in case there are no files
// on invalid levels. The version is not consistent if in the end the files
// on invalid levels don't cancel out.
std::unordered_map<int, size_t> invalid_level_sizes_;
// Whether there are invalid new files or invalid deletion on levels larger
// than num_levels_.
bool has_invalid_levels_;
// Current levels of table files affected by additions/deletions.
std::unordered_map<uint64_t, int> table_file_levels_;
NewestFirstBySeqNo level_zero_cmp_;
BySmallestKey level_nonzero_cmp_;
// Mutable metadata objects for all blob files affected by the series of
// version edits.
std::map<uint64_t, MutableBlobFileMetaData> mutable_blob_file_metas_;
public:
Rep(const FileOptions& file_options, const ImmutableCFOptions* ioptions,
TableCache* table_cache, VersionStorageInfo* base_vstorage,
VersionSet* version_set)
: file_options_(file_options),
ioptions_(ioptions),
table_cache_(table_cache),
base_vstorage_(base_vstorage),
version_set_(version_set),
num_levels_(base_vstorage->num_levels()),
has_invalid_levels_(false),
level_nonzero_cmp_(base_vstorage_->InternalComparator()) {
assert(ioptions_);
levels_ = new LevelState[num_levels_];
}
~Rep() {
for (int level = 0; level < num_levels_; level++) {
const auto& added = levels_[level].added_files;
for (auto& pair : added) {
UnrefFile(pair.second);
}
}
delete[] levels_;
}
void UnrefFile(FileMetaData* f) {
f->refs--;
if (f->refs <= 0) {
if (f->table_reader_handle) {
assert(table_cache_ != nullptr);
table_cache_->ReleaseHandle(f->table_reader_handle);
f->table_reader_handle = nullptr;
}
delete f;
}
}
// Mapping used for checking the consistency of links between SST files and
// blob files. It is built using the forward links (table file -> blob file),
// and is subsequently compared with the inverse mapping stored in the
// BlobFileMetaData objects.
using ExpectedLinkedSsts =
std::unordered_map<uint64_t, BlobFileMetaData::LinkedSsts>;
static void UpdateExpectedLinkedSsts(
uint64_t table_file_number, uint64_t blob_file_number,
ExpectedLinkedSsts* expected_linked_ssts) {
assert(expected_linked_ssts);
if (blob_file_number == kInvalidBlobFileNumber) {
return;
}
(*expected_linked_ssts)[blob_file_number].emplace(table_file_number);
}
template <typename Checker>
Status CheckConsistencyDetailsForLevel(
const VersionStorageInfo* vstorage, int level, Checker checker,
const std::string& sync_point,
ExpectedLinkedSsts* expected_linked_ssts) const {
#ifdef NDEBUG
(void)sync_point;
#endif
assert(vstorage);
assert(level >= 0 && level < num_levels_);
assert(expected_linked_ssts);
const auto& level_files = vstorage->LevelFiles(level);
if (level_files.empty()) {
return Status::OK();
}
assert(level_files[0]);
UpdateExpectedLinkedSsts(level_files[0]->fd.GetNumber(),
level_files[0]->oldest_blob_file_number,
expected_linked_ssts);
for (size_t i = 1; i < level_files.size(); ++i) {
assert(level_files[i]);
UpdateExpectedLinkedSsts(level_files[i]->fd.GetNumber(),
level_files[i]->oldest_blob_file_number,
expected_linked_ssts);
auto lhs = level_files[i - 1];
auto rhs = level_files[i];
#ifndef NDEBUG
auto pair = std::make_pair(&lhs, &rhs);
TEST_SYNC_POINT_CALLBACK(sync_point, &pair);
#endif
const Status s = checker(lhs, rhs);
if (!s.ok()) {
return s;
}
}
return Status::OK();
}
// Make sure table files are sorted correctly and that the links between
// table files and blob files are consistent.
Status CheckConsistencyDetails(const VersionStorageInfo* vstorage) const {
assert(vstorage);
ExpectedLinkedSsts expected_linked_ssts;
if (num_levels_ > 0) {
// Check L0
{
auto l0_checker = [this](const FileMetaData* lhs,
const FileMetaData* rhs) {
assert(lhs);
assert(rhs);
if (!level_zero_cmp_(lhs, rhs)) {
std::ostringstream oss;
oss << "L0 files are not sorted properly: files #"
<< lhs->fd.GetNumber() << ", #" << rhs->fd.GetNumber();
return Status::Corruption("VersionBuilder", oss.str());
}
if (rhs->fd.smallest_seqno == rhs->fd.largest_seqno) {
// This is an external file that we ingested
const SequenceNumber external_file_seqno = rhs->fd.smallest_seqno;
if (!(external_file_seqno < lhs->fd.largest_seqno ||
external_file_seqno == 0)) {
std::ostringstream oss;
oss << "L0 file #" << lhs->fd.GetNumber() << " with seqno "
<< lhs->fd.smallest_seqno << ' ' << lhs->fd.largest_seqno
<< " vs. file #" << rhs->fd.GetNumber()
<< " with global_seqno " << external_file_seqno;
return Status::Corruption("VersionBuilder", oss.str());
}
} else if (lhs->fd.smallest_seqno <= rhs->fd.smallest_seqno) {
std::ostringstream oss;
oss << "L0 file #" << lhs->fd.GetNumber() << " with seqno "
<< lhs->fd.smallest_seqno << ' ' << lhs->fd.largest_seqno
<< " vs. file #" << rhs->fd.GetNumber() << " with seqno "
<< rhs->fd.smallest_seqno << ' ' << rhs->fd.largest_seqno;
return Status::Corruption("VersionBuilder", oss.str());
}
return Status::OK();
};
const Status s = CheckConsistencyDetailsForLevel(
vstorage, /* level */ 0, l0_checker,
"VersionBuilder::CheckConsistency0", &expected_linked_ssts);
if (!s.ok()) {
return s;
}
}
// Check L1 and up
const InternalKeyComparator* const icmp = vstorage->InternalComparator();
assert(icmp);
for (int level = 1; level < num_levels_; ++level) {
auto checker = [this, level, icmp](const FileMetaData* lhs,
const FileMetaData* rhs) {
assert(lhs);
assert(rhs);
if (!level_nonzero_cmp_(lhs, rhs)) {
std::ostringstream oss;
oss << 'L' << level << " files are not sorted properly: files #"
<< lhs->fd.GetNumber() << ", #" << rhs->fd.GetNumber();
return Status::Corruption("VersionBuilder", oss.str());
}
// Make sure there is no overlap in level
if (icmp->Compare(lhs->largest, rhs->smallest) >= 0) {
std::ostringstream oss;
oss << 'L' << level << " has overlapping ranges: file #"
<< lhs->fd.GetNumber()
<< " largest key: " << lhs->largest.DebugString(true)
<< " vs. file #" << rhs->fd.GetNumber()
<< " smallest key: " << rhs->smallest.DebugString(true);
return Status::Corruption("VersionBuilder", oss.str());
}
return Status::OK();
};
const Status s = CheckConsistencyDetailsForLevel(
vstorage, level, checker, "VersionBuilder::CheckConsistency1",
&expected_linked_ssts);
if (!s.ok()) {
return s;
}
}
}
// Make sure that all blob files in the version have non-garbage data and
// the links between them and the table files are consistent.
const auto& blob_files = vstorage->GetBlobFiles();
for (const auto& blob_file_meta : blob_files) {
assert(blob_file_meta);
const uint64_t blob_file_number = blob_file_meta->GetBlobFileNumber();
if (blob_file_meta->GetGarbageBlobCount() >=
blob_file_meta->GetTotalBlobCount()) {
std::ostringstream oss;
oss << "Blob file #" << blob_file_number
<< " consists entirely of garbage";
return Status::Corruption("VersionBuilder", oss.str());
}
if (blob_file_meta->GetLinkedSsts() !=
expected_linked_ssts[blob_file_number]) {
std::ostringstream oss;
oss << "Links are inconsistent between table files and blob file #"
<< blob_file_number;
return Status::Corruption("VersionBuilder", oss.str());
}
}
Status ret_s;
TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistencyBeforeReturn",
&ret_s);
return ret_s;
}
Status CheckConsistency(const VersionStorageInfo* vstorage) const {
assert(vstorage);
// Always run consistency checks in debug build
#ifdef NDEBUG
if (!vstorage->force_consistency_checks()) {
return Status::OK();
}
#endif
Status s = CheckConsistencyDetails(vstorage);
if (s.IsCorruption() && s.getState()) {
// Make it clear the error is due to force_consistency_checks = 1 or
// debug build
#ifdef NDEBUG
auto prefix = "force_consistency_checks";
#else
auto prefix = "force_consistency_checks(DEBUG)";
#endif
s = Status::Corruption(prefix, s.getState());
} else {
// was only expecting corruption with message, or OK
assert(s.ok());
}
return s;
}
bool CheckConsistencyForNumLevels() const {
// Make sure there are no files on or beyond num_levels().
if (has_invalid_levels_) {
return false;
}
for (const auto& pair : invalid_level_sizes_) {
const size_t level_size = pair.second;
if (level_size != 0) {
return false;
}
}
return true;
}
bool IsBlobFileInVersion(uint64_t blob_file_number) const {
auto mutable_it = mutable_blob_file_metas_.find(blob_file_number);
if (mutable_it != mutable_blob_file_metas_.end()) {
return true;
}
assert(base_vstorage_);
const auto meta = base_vstorage_->GetBlobFileMetaData(blob_file_number);
return !!meta;
}
MutableBlobFileMetaData* GetOrCreateMutableBlobFileMetaData(
uint64_t blob_file_number) {
auto mutable_it = mutable_blob_file_metas_.find(blob_file_number);
if (mutable_it != mutable_blob_file_metas_.end()) {
return &mutable_it->second;
}
assert(base_vstorage_);
const auto meta = base_vstorage_->GetBlobFileMetaData(blob_file_number);
if (meta) {
mutable_it = mutable_blob_file_metas_
.emplace(blob_file_number, MutableBlobFileMetaData(meta))
.first;
return &mutable_it->second;
}
return nullptr;
}
Status ApplyBlobFileAddition(const BlobFileAddition& blob_file_addition) {
const uint64_t blob_file_number = blob_file_addition.GetBlobFileNumber();
if (IsBlobFileInVersion(blob_file_number)) {
std::ostringstream oss;
oss << "Blob file #" << blob_file_number << " already added";
return Status::Corruption("VersionBuilder", oss.str());
}
// Note: we use C++11 for now but in C++14, this could be done in a more
// elegant way using generalized lambda capture.
VersionSet* const vs = version_set_;
const ImmutableCFOptions* const ioptions = ioptions_;
auto deleter = [vs, ioptions](SharedBlobFileMetaData* shared_meta) {
if (vs) {
assert(ioptions);
assert(!ioptions->cf_paths.empty());
assert(shared_meta);
vs->AddObsoleteBlobFile(shared_meta->GetBlobFileNumber(),
ioptions->cf_paths.front().path);
}
delete shared_meta;
};
auto shared_meta = SharedBlobFileMetaData::Create(
blob_file_number, blob_file_addition.GetTotalBlobCount(),
blob_file_addition.GetTotalBlobBytes(),
blob_file_addition.GetChecksumMethod(),
blob_file_addition.GetChecksumValue(), deleter);
mutable_blob_file_metas_.emplace(
blob_file_number, MutableBlobFileMetaData(std::move(shared_meta)));
return Status::OK();
}
Status ApplyBlobFileGarbage(const BlobFileGarbage& blob_file_garbage) {
const uint64_t blob_file_number = blob_file_garbage.GetBlobFileNumber();
MutableBlobFileMetaData* const mutable_meta =
GetOrCreateMutableBlobFileMetaData(blob_file_number);
if (!mutable_meta) {
std::ostringstream oss;
oss << "Blob file #" << blob_file_number << " not found";
return Status::Corruption("VersionBuilder", oss.str());
}
if (!mutable_meta->AddGarbage(blob_file_garbage.GetGarbageBlobCount(),
blob_file_garbage.GetGarbageBlobBytes())) {
std::ostringstream oss;
oss << "Garbage overflow for blob file #" << blob_file_number;
return Status::Corruption("VersionBuilder", oss.str());
}
return Status::OK();
}
int GetCurrentLevelForTableFile(uint64_t file_number) const {
auto it = table_file_levels_.find(file_number);
if (it != table_file_levels_.end()) {
return it->second;
}
assert(base_vstorage_);
return base_vstorage_->GetFileLocation(file_number).GetLevel();
}
uint64_t GetOldestBlobFileNumberForTableFile(int level,
uint64_t file_number) const {
assert(level < num_levels_);
const auto& added_files = levels_[level].added_files;
auto it = added_files.find(file_number);
if (it != added_files.end()) {
const FileMetaData* const meta = it->second;
assert(meta);
return meta->oldest_blob_file_number;
}
assert(base_vstorage_);
const FileMetaData* const meta =
base_vstorage_->GetFileMetaDataByNumber(file_number);
assert(meta);
return meta->oldest_blob_file_number;
}
Status ApplyFileDeletion(int level, uint64_t file_number) {
assert(level != VersionStorageInfo::FileLocation::Invalid().GetLevel());
const int current_level = GetCurrentLevelForTableFile(file_number);
if (level != current_level) {
if (level >= num_levels_) {
has_invalid_levels_ = true;
}
std::ostringstream oss;
oss << "Cannot delete table file #" << file_number << " from level "
<< level << " since it is ";
if (current_level ==
VersionStorageInfo::FileLocation::Invalid().GetLevel()) {
oss << "not in the LSM tree";
} else {
oss << "on level " << current_level;
}
return Status::Corruption("VersionBuilder", oss.str());
}
if (level >= num_levels_) {
assert(invalid_level_sizes_[level] > 0);
--invalid_level_sizes_[level];
table_file_levels_[file_number] =
VersionStorageInfo::FileLocation::Invalid().GetLevel();
return Status::OK();
}
const uint64_t blob_file_number =
GetOldestBlobFileNumberForTableFile(level, file_number);
if (blob_file_number != kInvalidBlobFileNumber) {
MutableBlobFileMetaData* const mutable_meta =
GetOrCreateMutableBlobFileMetaData(blob_file_number);
if (mutable_meta) {
mutable_meta->UnlinkSst(file_number);
}
}
auto& level_state = levels_[level];
auto& add_files = level_state.added_files;
auto add_it = add_files.find(file_number);
if (add_it != add_files.end()) {
UnrefFile(add_it->second);
add_files.erase(add_it);
}
auto& del_files = level_state.deleted_files;
assert(del_files.find(file_number) == del_files.end());
del_files.emplace(file_number);
table_file_levels_[file_number] =
VersionStorageInfo::FileLocation::Invalid().GetLevel();
return Status::OK();
}
Status ApplyFileAddition(int level, const FileMetaData& meta) {
assert(level != VersionStorageInfo::FileLocation::Invalid().GetLevel());
const uint64_t file_number = meta.fd.GetNumber();
const int current_level = GetCurrentLevelForTableFile(file_number);
if (current_level !=
VersionStorageInfo::FileLocation::Invalid().GetLevel()) {
if (level >= num_levels_) {
has_invalid_levels_ = true;
}
std::ostringstream oss;
oss << "Cannot add table file #" << file_number << " to level " << level
<< " since it is already in the LSM tree on level " << current_level;
return Status::Corruption("VersionBuilder", oss.str());
}
if (level >= num_levels_) {
++invalid_level_sizes_[level];
table_file_levels_[file_number] = level;
return Status::OK();
}
auto& level_state = levels_[level];
auto& del_files = level_state.deleted_files;
auto del_it = del_files.find(file_number);
if (del_it != del_files.end()) {
del_files.erase(del_it);
}
FileMetaData* const f = new FileMetaData(meta);
f->refs = 1;
auto& add_files = level_state.added_files;
assert(add_files.find(file_number) == add_files.end());
add_files.emplace(file_number, f);
const uint64_t blob_file_number = f->oldest_blob_file_number;
if (blob_file_number != kInvalidBlobFileNumber) {
MutableBlobFileMetaData* const mutable_meta =
GetOrCreateMutableBlobFileMetaData(blob_file_number);
if (mutable_meta) {
mutable_meta->LinkSst(file_number);
}
}
table_file_levels_[file_number] = level;
return Status::OK();
}
// Apply all of the edits in *edit to the current state.
Status Apply(const VersionEdit* edit) {
{
const Status s = CheckConsistency(base_vstorage_);
if (!s.ok()) {
return s;
}
}
// Note: we process the blob file related changes first because the
// table file addition/deletion logic depends on the blob files
// already being there.
// Add new blob files
for (const auto& blob_file_addition : edit->GetBlobFileAdditions()) {
const Status s = ApplyBlobFileAddition(blob_file_addition);
if (!s.ok()) {
return s;
}
}
// Increase the amount of garbage for blob files affected by GC
for (const auto& blob_file_garbage : edit->GetBlobFileGarbages()) {
const Status s = ApplyBlobFileGarbage(blob_file_garbage);
if (!s.ok()) {
return s;
}
}
// Delete table files
for (const auto& deleted_file : edit->GetDeletedFiles()) {
const int level = deleted_file.first;
const uint64_t file_number = deleted_file.second;
const Status s = ApplyFileDeletion(level, file_number);
if (!s.ok()) {
return s;
}
}
// Add new table files
for (const auto& new_file : edit->GetNewFiles()) {
const int level = new_file.first;
const FileMetaData& meta = new_file.second;
const Status s = ApplyFileAddition(level, meta);
if (!s.ok()) {
return s;
}
}
return Status::OK();
}
// Helper function template for merging the blob file metadata from the base
// version with the mutable metadata representing the state after applying the
// edits. The function objects process_base and process_mutable are
// respectively called to handle a base version object when there is no
// matching mutable object, and a mutable object when there is no matching
// base version object. process_both is called to perform the merge when a
// given blob file appears both in the base version and the mutable list. The
// helper stops processing objects if a function object returns false. Blob
// files with a file number below first_blob_file are not processed.
template <typename ProcessBase, typename ProcessMutable, typename ProcessBoth>
void MergeBlobFileMetas(uint64_t first_blob_file, ProcessBase process_base,
ProcessMutable process_mutable,
ProcessBoth process_both) const {
assert(base_vstorage_);
auto base_it = base_vstorage_->GetBlobFileMetaDataLB(first_blob_file);
const auto base_it_end = base_vstorage_->GetBlobFiles().end();
auto mutable_it = mutable_blob_file_metas_.lower_bound(first_blob_file);
const auto mutable_it_end = mutable_blob_file_metas_.end();
while (base_it != base_it_end && mutable_it != mutable_it_end) {
const auto& base_meta = *base_it;
assert(base_meta);
const uint64_t base_blob_file_number = base_meta->GetBlobFileNumber();
const uint64_t mutable_blob_file_number = mutable_it->first;
if (base_blob_file_number < mutable_blob_file_number) {
if (!process_base(base_meta)) {
return;
}
++base_it;
} else if (mutable_blob_file_number < base_blob_file_number) {
const auto& mutable_meta = mutable_it->second;
if (!process_mutable(mutable_meta)) {
return;
}
++mutable_it;
} else {
assert(base_blob_file_number == mutable_blob_file_number);
const auto& mutable_meta = mutable_it->second;
if (!process_both(base_meta, mutable_meta)) {
return;
}
++base_it;
++mutable_it;
}
}
while (base_it != base_it_end) {
const auto& base_meta = *base_it;
if (!process_base(base_meta)) {
return;
}
++base_it;
}
while (mutable_it != mutable_it_end) {
const auto& mutable_meta = mutable_it->second;
if (!process_mutable(mutable_meta)) {
return;
}
++mutable_it;
}
}
// Helper function template for finding the first blob file that has linked
// SSTs.
template <typename Meta>
static bool CheckLinkedSsts(const Meta& meta,
uint64_t* min_oldest_blob_file_num) {
assert(min_oldest_blob_file_num);
if (!meta.GetLinkedSsts().empty()) {
assert(*min_oldest_blob_file_num == kInvalidBlobFileNumber);
*min_oldest_blob_file_num = meta.GetBlobFileNumber();
return false;
}
return true;
}
// Find the oldest blob file that has linked SSTs.
uint64_t GetMinOldestBlobFileNumber() const {
uint64_t min_oldest_blob_file_num = kInvalidBlobFileNumber;
auto process_base =
[&min_oldest_blob_file_num](
const std::shared_ptr<BlobFileMetaData>& base_meta) {
assert(base_meta);
return CheckLinkedSsts(*base_meta, &min_oldest_blob_file_num);
};
auto process_mutable = [&min_oldest_blob_file_num](
const MutableBlobFileMetaData& mutable_meta) {
return CheckLinkedSsts(mutable_meta, &min_oldest_blob_file_num);
};
auto process_both = [&min_oldest_blob_file_num](
const std::shared_ptr<BlobFileMetaData>& base_meta,
const MutableBlobFileMetaData& mutable_meta) {
#ifndef NDEBUG
assert(base_meta);
assert(base_meta->GetSharedMeta() == mutable_meta.GetSharedMeta());
#else
(void)base_meta;
#endif
// Look at mutable_meta since it supersedes *base_meta
return CheckLinkedSsts(mutable_meta, &min_oldest_blob_file_num);
};
MergeBlobFileMetas(kInvalidBlobFileNumber, process_base, process_mutable,
process_both);
return min_oldest_blob_file_num;
}
static std::shared_ptr<BlobFileMetaData> CreateBlobFileMetaData(
const MutableBlobFileMetaData& mutable_meta) {
return BlobFileMetaData::Create(
mutable_meta.GetSharedMeta(), mutable_meta.GetLinkedSsts(),
mutable_meta.GetGarbageBlobCount(), mutable_meta.GetGarbageBlobBytes());
}
// Add the blob file specified by meta to *vstorage if it is determined to
// contain valid data (blobs).
template <typename Meta>
static void AddBlobFileIfNeeded(VersionStorageInfo* vstorage, Meta&& meta) {
assert(vstorage);
assert(meta);
if (meta->GetLinkedSsts().empty() &&
meta->GetGarbageBlobCount() >= meta->GetTotalBlobCount()) {
return;
}
vstorage->AddBlobFile(std::forward<Meta>(meta));
}
// Merge the blob file metadata from the base version with the changes (edits)
// applied, and save the result into *vstorage.
void SaveBlobFilesTo(VersionStorageInfo* vstorage) const {
assert(vstorage);
assert(base_vstorage_);
vstorage->ReserveBlob(base_vstorage_->GetBlobFiles().size() +
mutable_blob_file_metas_.size());
const uint64_t oldest_blob_file_with_linked_ssts =
GetMinOldestBlobFileNumber();
auto process_base =
[vstorage](const std::shared_ptr<BlobFileMetaData>& base_meta) {
assert(base_meta);
AddBlobFileIfNeeded(vstorage, base_meta);
return true;
};
auto process_mutable =
[vstorage](const MutableBlobFileMetaData& mutable_meta) {
AddBlobFileIfNeeded(vstorage, CreateBlobFileMetaData(mutable_meta));
return true;
};
auto process_both = [vstorage](
const std::shared_ptr<BlobFileMetaData>& base_meta,
const MutableBlobFileMetaData& mutable_meta) {
assert(base_meta);
assert(base_meta->GetSharedMeta() == mutable_meta.GetSharedMeta());
if (!mutable_meta.HasDelta()) {
assert(base_meta->GetGarbageBlobCount() ==
mutable_meta.GetGarbageBlobCount());
assert(base_meta->GetGarbageBlobBytes() ==
mutable_meta.GetGarbageBlobBytes());
assert(base_meta->GetLinkedSsts() == mutable_meta.GetLinkedSsts());
AddBlobFileIfNeeded(vstorage, base_meta);
return true;
}
AddBlobFileIfNeeded(vstorage, CreateBlobFileMetaData(mutable_meta));
return true;
};
MergeBlobFileMetas(oldest_blob_file_with_linked_ssts, process_base,
process_mutable, process_both);
}
void MaybeAddFile(VersionStorageInfo* vstorage, int level,
FileMetaData* f) const {
const uint64_t file_number = f->fd.GetNumber();
const auto& level_state = levels_[level];
const auto& del_files = level_state.deleted_files;
const auto del_it = del_files.find(file_number);
if (del_it != del_files.end()) {
// f is to-be-deleted table file
vstorage->RemoveCurrentStats(f);
} else {
const auto& add_files = level_state.added_files;
const auto add_it = add_files.find(file_number);
// Note: if the file appears both in the base version and in the added
// list, the added FileMetaData supersedes the one in the base version.
if (add_it != add_files.end() && add_it->second != f) {
vstorage->RemoveCurrentStats(f);
} else {
vstorage->AddFile(level, f);
}
}
}
template <typename Cmp>
void SaveSSTFilesTo(VersionStorageInfo* vstorage, int level, Cmp cmp) const {
// Merge the set of added files with the set of pre-existing files.
// Drop any deleted files. Store the result in *vstorage.
const auto& base_files = base_vstorage_->LevelFiles(level);
const auto& unordered_added_files = levels_[level].added_files;
vstorage->Reserve(level, base_files.size() + unordered_added_files.size());
// Sort added files for the level.
std::vector<FileMetaData*> added_files;
added_files.reserve(unordered_added_files.size());
for (const auto& pair : unordered_added_files) {
added_files.push_back(pair.second);
}
std::sort(added_files.begin(), added_files.end(), cmp);
auto base_iter = base_files.begin();
auto base_end = base_files.end();
auto added_iter = added_files.begin();
auto added_end = added_files.end();
while (added_iter != added_end || base_iter != base_end) {
if (base_iter == base_end ||
(added_iter != added_end && cmp(*added_iter, *base_iter))) {
MaybeAddFile(vstorage, level, *added_iter++);
} else {
MaybeAddFile(vstorage, level, *base_iter++);
}
}
}
void SaveSSTFilesTo(VersionStorageInfo* vstorage) const {
assert(vstorage);
if (!num_levels_) {
return;
}
SaveSSTFilesTo(vstorage, /* level */ 0, level_zero_cmp_);
for (int level = 1; level < num_levels_; ++level) {
SaveSSTFilesTo(vstorage, level, level_nonzero_cmp_);
}
}
// Save the current state in *vstorage.
Status SaveTo(VersionStorageInfo* vstorage) const {
Status s = CheckConsistency(base_vstorage_);
if (!s.ok()) {
return s;
}
s = CheckConsistency(vstorage);
if (!s.ok()) {
return s;
}
SaveSSTFilesTo(vstorage);
SaveBlobFilesTo(vstorage);
s = CheckConsistency(vstorage);
return s;
}
Status LoadTableHandlers(
InternalStats* internal_stats, int max_threads,
bool prefetch_index_and_filter_in_cache, bool is_initial_load,
const std::shared_ptr<const SliceTransform>& prefix_extractor,
size_t max_file_size_for_l0_meta_pin) {
assert(table_cache_ != nullptr);
size_t table_cache_capacity = table_cache_->get_cache()->GetCapacity();
bool always_load = (table_cache_capacity == TableCache::kInfiniteCapacity);
size_t max_load = std::numeric_limits<size_t>::max();
if (!always_load) {
// If it is initial loading and not set to always loading all the
// files, we only load up to kInitialLoadLimit files, to limit the
// time reopening the DB.
const size_t kInitialLoadLimit = 16;
size_t load_limit;
// If the table cache is not 1/4 full, we pin the table handle to
// file metadata to avoid the cache read costs when reading the file.
// The downside of pinning those files is that LRU won't be followed
// for those files. This doesn't matter much because if number of files
// of the DB excceeds table cache capacity, eventually no table reader
// will be pinned and LRU will be followed.
if (is_initial_load) {
load_limit = std::min(kInitialLoadLimit, table_cache_capacity / 4);
} else {
load_limit = table_cache_capacity / 4;
}
size_t table_cache_usage = table_cache_->get_cache()->GetUsage();
if (table_cache_usage >= load_limit) {
// TODO (yanqin) find a suitable status code.
return Status::OK();
} else {
max_load = load_limit - table_cache_usage;
}
}
// <file metadata, level>
std::vector<std::pair<FileMetaData*, int>> files_meta;
std::vector<Status> statuses;
for (int level = 0; level < num_levels_; level++) {
for (auto& file_meta_pair : levels_[level].added_files) {
auto* file_meta = file_meta_pair.second;
// If the file has been opened before, just skip it.
if (!file_meta->table_reader_handle) {
files_meta.emplace_back(file_meta, level);
statuses.emplace_back(Status::OK());
}
if (files_meta.size() >= max_load) {
break;
}
}
if (files_meta.size() >= max_load) {
break;
}
}
std::atomic<size_t> next_file_meta_idx(0);
std::function<void()> load_handlers_func([&]() {
while (true) {
size_t file_idx = next_file_meta_idx.fetch_add(1);
if (file_idx >= files_meta.size()) {
break;
}
auto* file_meta = files_meta[file_idx].first;
int level = files_meta[file_idx].second;
statuses[file_idx] = table_cache_->FindTable(
ReadOptions(), file_options_,
*(base_vstorage_->InternalComparator()), file_meta->fd,
&file_meta->table_reader_handle, prefix_extractor, false /*no_io */,
true /* record_read_stats */,
internal_stats->GetFileReadHist(level), false, level,
prefetch_index_and_filter_in_cache, max_file_size_for_l0_meta_pin,
file_meta->temperature);
if (file_meta->table_reader_handle != nullptr) {
// Load table_reader
file_meta->fd.table_reader = table_cache_->GetTableReaderFromHandle(
file_meta->table_reader_handle);
}
}
});
std::vector<port::Thread> threads;
for (int i = 1; i < max_threads; i++) {
threads.emplace_back(load_handlers_func);
}
load_handlers_func();
for (auto& t : threads) {
t.join();
}
Status ret;
for (const auto& s : statuses) {
if (!s.ok()) {
if (ret.ok()) {
ret = s;
}
}
}
return ret;
}
};
VersionBuilder::VersionBuilder(const FileOptions& file_options,
const ImmutableCFOptions* ioptions,
TableCache* table_cache,
VersionStorageInfo* base_vstorage,
VersionSet* version_set)
: rep_(new Rep(file_options, ioptions, table_cache, base_vstorage,
version_set)) {}
VersionBuilder::~VersionBuilder() = default;
bool VersionBuilder::CheckConsistencyForNumLevels() {
return rep_->CheckConsistencyForNumLevels();
}
Status VersionBuilder::Apply(const VersionEdit* edit) {
return rep_->Apply(edit);
}
Status VersionBuilder::SaveTo(VersionStorageInfo* vstorage) const {
return rep_->SaveTo(vstorage);
}
Status VersionBuilder::LoadTableHandlers(
InternalStats* internal_stats, int max_threads,
bool prefetch_index_and_filter_in_cache, bool is_initial_load,
const std::shared_ptr<const SliceTransform>& prefix_extractor,
size_t max_file_size_for_l0_meta_pin) {
return rep_->LoadTableHandlers(
internal_stats, max_threads, prefetch_index_and_filter_in_cache,
is_initial_load, prefix_extractor, max_file_size_for_l0_meta_pin);
}
uint64_t VersionBuilder::GetMinOldestBlobFileNumber() const {
return rep_->GetMinOldestBlobFileNumber();
}
BaseReferencedVersionBuilder::BaseReferencedVersionBuilder(
ColumnFamilyData* cfd)
: version_builder_(new VersionBuilder(
cfd->current()->version_set()->file_options(), cfd->ioptions(),
cfd->table_cache(), cfd->current()->storage_info(),
cfd->current()->version_set())),
version_(cfd->current()) {
version_->Ref();
}
BaseReferencedVersionBuilder::BaseReferencedVersionBuilder(
ColumnFamilyData* cfd, Version* v)
: version_builder_(new VersionBuilder(
cfd->current()->version_set()->file_options(), cfd->ioptions(),
cfd->table_cache(), v->storage_info(), v->version_set())),
version_(v) {
assert(version_ != cfd->current());
}
BaseReferencedVersionBuilder::~BaseReferencedVersionBuilder() {
version_->Unref();
}
} // namespace ROCKSDB_NAMESPACE
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