rocksdb/db/version_builder.cc
Levi Tamasi 78e291b17e Improve consistency checks in VersionBuilder (#6901)
Summary:
The patch cleans up the code and improves the consistency checks around
adding/deleting table files in `VersionBuilder`. Namely, it makes the checks
stricter and improves them in the following ways:
1) A table file can now only be deleted from the LSM tree using the level it
resides on. Earlier, there was some unnecessary wiggle room for
trivially moved files (they could be deleted using a lower level number than
the actual one).
2) A table file cannot be added to the tree if it is already present in the tree
on any level (not just the target level). The earlier code only had an assertion
(which is a no-op in release builds) that the newly added file is not already
present on the target level.
3) The above consistency checks around state transitions are now mandatory,
as opposed to the earlier `CheckConsistencyForDeletes`, which was a no-op
in release mode unless `force_consistency_checks` was set to `true`. The rationale
here is that assuming that the initial state is consistent, a valid transition leads to a
next state that is also consistent; however, an *invalid* transition offers no such
guarantee. Hence it makes sense to validate the transitions unconditionally,
and save `force_consistency_checks` for the paranoid checks that re-validate
the entire state.
4) The new checks build on the mechanism introduced in https://github.com/facebook/rocksdb/pull/6862,
which enables us to efficiently look up the location (level and position within level)
of files in a `Version` by file number. This makes the consistency checks much more
efficient than the earlier `CheckConsistencyForDeletes`, which essentially
performed a linear search.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6901

Test Plan:
Extended the unit tests and ran:

`make check`
`make whitebox_crash_test`

Reviewed By: ajkr

Differential Revision: D21822714

Pulled By: ltamasi

fbshipit-source-id: e2b29c8b6da1bf0f59004acc889e4870b2d18215
2020-06-03 11:24:55 -07:00

930 lines
30 KiB
C++

// 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 {
bool NewestFirstBySeqNo(FileMetaData* a, FileMetaData* b) {
if (a->fd.largest_seqno != b->fd.largest_seqno) {
return a->fd.largest_seqno > b->fd.largest_seqno;
}
if (a->fd.smallest_seqno != b->fd.smallest_seqno) {
return a->fd.smallest_seqno > b->fd.smallest_seqno;
}
// Break ties by file number
return a->fd.GetNumber() > b->fd.GetNumber();
}
namespace {
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());
}
} // namespace
class VersionBuilder::Rep {
private:
// Helper to sort files_ in v
// kLevel0 -- NewestFirstBySeqNo
// kLevelNon0 -- BySmallestKey
struct FileComparator {
enum SortMethod { kLevel0 = 0, kLevelNon0 = 1, } sort_method;
const InternalKeyComparator* internal_comparator;
FileComparator() : internal_comparator(nullptr) {}
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;
}
};
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;
};
class BlobFileMetaDataDelta {
public:
bool IsEmpty() const {
return !shared_meta_ && !additional_garbage_count_ &&
!additional_garbage_bytes_;
}
std::shared_ptr<SharedBlobFileMetaData> GetSharedMeta() const {
return shared_meta_;
}
uint64_t GetAdditionalGarbageCount() const {
return additional_garbage_count_;
}
uint64_t GetAdditionalGarbageBytes() const {
return additional_garbage_bytes_;
}
void SetSharedMeta(std::shared_ptr<SharedBlobFileMetaData> shared_meta) {
assert(!shared_meta_);
assert(shared_meta);
shared_meta_ = std::move(shared_meta);
}
void AddGarbage(uint64_t count, uint64_t bytes) {
additional_garbage_count_ += count;
additional_garbage_bytes_ += bytes;
}
private:
std::shared_ptr<SharedBlobFileMetaData> shared_meta_;
uint64_t additional_garbage_count_ = 0;
uint64_t additional_garbage_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_;
FileComparator level_zero_cmp_;
FileComparator level_nonzero_cmp_;
// Metadata delta for all blob files affected by the series of version edits.
std::map<uint64_t, BlobFileMetaDataDelta> blob_file_meta_deltas_;
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) {
assert(ioptions_);
levels_ = new LevelState[num_levels_];
level_zero_cmp_.sort_method = FileComparator::kLevel0;
level_nonzero_cmp_.sort_method = FileComparator::kLevelNon0;
level_nonzero_cmp_.internal_comparator =
base_vstorage_->InternalComparator();
}
~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;
}
}
bool IsBlobFileInVersion(uint64_t blob_file_number) const {
auto delta_it = blob_file_meta_deltas_.find(blob_file_number);
if (delta_it != blob_file_meta_deltas_.end()) {
if (delta_it->second.GetSharedMeta()) {
return true;
}
}
assert(base_vstorage_);
const auto& base_blob_files = base_vstorage_->GetBlobFiles();
auto base_it = base_blob_files.find(blob_file_number);
if (base_it != base_blob_files.end()) {
assert(base_it->second);
assert(base_it->second->GetSharedMeta());
return true;
}
return false;
}
Status CheckConsistencyOfOldestBlobFileReference(
const VersionStorageInfo* vstorage, uint64_t blob_file_number) const {
assert(vstorage);
// TODO: remove this check once we actually start recoding metadata for
// blob files in the MANIFEST.
if (vstorage->GetBlobFiles().empty()) {
return Status::OK();
}
if (blob_file_number == kInvalidBlobFileNumber) {
return Status::OK();
}
if (!IsBlobFileInVersion(blob_file_number)) {
std::ostringstream oss;
oss << "Blob file #" << blob_file_number
<< " is not part of this version";
return Status::Corruption("VersionBuilder", oss.str());
}
return Status::OK();
}
Status CheckConsistency(VersionStorageInfo* vstorage) {
#ifdef NDEBUG
if (!vstorage->force_consistency_checks()) {
// Dont run consistency checks in release mode except if
// explicitly asked to
return Status::OK();
}
#endif
// Make sure the files are sorted correctly and that the oldest blob file
// reference for each table file points to a valid blob file in this
// version.
for (int level = 0; level < num_levels_; level++) {
auto& level_files = vstorage->LevelFiles(level);
if (level_files.empty()) {
continue;
}
assert(level_files[0]);
Status s = CheckConsistencyOfOldestBlobFileReference(
vstorage, level_files[0]->oldest_blob_file_number);
if (!s.ok()) {
return s;
}
for (size_t i = 1; i < level_files.size(); i++) {
assert(level_files[i]);
s = CheckConsistencyOfOldestBlobFileReference(
vstorage, level_files[i]->oldest_blob_file_number);
if (!s.ok()) {
return s;
}
auto f1 = level_files[i - 1];
auto f2 = level_files[i];
if (level == 0) {
#ifndef NDEBUG
auto pair = std::make_pair(&f1, &f2);
TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistency0", &pair);
#endif
if (!level_zero_cmp_(f1, f2)) {
fprintf(stderr, "L0 files are not sorted properly");
return Status::Corruption("L0 files are not sorted properly");
}
if (f2->fd.smallest_seqno == f2->fd.largest_seqno) {
// This is an external file that we ingested
SequenceNumber external_file_seqno = f2->fd.smallest_seqno;
if (!(external_file_seqno < f1->fd.largest_seqno ||
external_file_seqno == 0)) {
fprintf(stderr,
"L0 file with seqno %" PRIu64 " %" PRIu64
" vs. file with global_seqno %" PRIu64 "\n",
f1->fd.smallest_seqno, f1->fd.largest_seqno,
external_file_seqno);
return Status::Corruption(
"L0 file with seqno " +
NumberToString(f1->fd.smallest_seqno) + " " +
NumberToString(f1->fd.largest_seqno) +
" vs. file with global_seqno" +
NumberToString(external_file_seqno) + " with fileNumber " +
NumberToString(f1->fd.GetNumber()));
}
} else if (f1->fd.smallest_seqno <= f2->fd.smallest_seqno) {
fprintf(stderr,
"L0 files seqno %" PRIu64 " %" PRIu64 " vs. %" PRIu64
" %" PRIu64 "\n",
f1->fd.smallest_seqno, f1->fd.largest_seqno,
f2->fd.smallest_seqno, f2->fd.largest_seqno);
return Status::Corruption(
"L0 files seqno " + NumberToString(f1->fd.smallest_seqno) +
" " + NumberToString(f1->fd.largest_seqno) + " " +
NumberToString(f1->fd.GetNumber()) + " vs. " +
NumberToString(f2->fd.smallest_seqno) + " " +
NumberToString(f2->fd.largest_seqno) + " " +
NumberToString(f2->fd.GetNumber()));
}
} else {
#ifndef NDEBUG
auto pair = std::make_pair(&f1, &f2);
TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistency1", &pair);
#endif
if (!level_nonzero_cmp_(f1, f2)) {
fprintf(stderr, "L%d files are not sorted properly", level);
return Status::Corruption("L" + NumberToString(level) +
" files are not sorted properly");
}
// Make sure there is no overlap in levels > 0
if (vstorage->InternalComparator()->Compare(f1->largest,
f2->smallest) >= 0) {
fprintf(stderr, "L%d have overlapping ranges %s vs. %s\n", level,
(f1->largest).DebugString(true).c_str(),
(f2->smallest).DebugString(true).c_str());
return Status::Corruption(
"L" + NumberToString(level) + " have overlapping ranges " +
(f1->largest).DebugString(true) + " vs. " +
(f2->smallest).DebugString(true));
}
}
}
}
// Make sure that all blob files in the version have non-garbage data.
const auto& blob_files = vstorage->GetBlobFiles();
for (const auto& pair : blob_files) {
const auto& blob_file_meta = pair.second;
assert(blob_file_meta);
if (blob_file_meta->GetGarbageBlobCount() >=
blob_file_meta->GetTotalBlobCount()) {
std::ostringstream oss;
oss << "Blob file #" << blob_file_meta->GetBlobFileNumber()
<< " consists entirely of garbage";
return Status::Corruption("VersionBuilder", oss.str());
}
}
Status ret_s;
TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistencyBeforeReturn",
&ret_s);
return ret_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;
}
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);
blob_file_meta_deltas_[blob_file_number].SetSharedMeta(
std::move(shared_meta));
return Status::OK();
}
Status ApplyBlobFileGarbage(const BlobFileGarbage& blob_file_garbage) {
const uint64_t blob_file_number = blob_file_garbage.GetBlobFileNumber();
if (!IsBlobFileInVersion(blob_file_number)) {
std::ostringstream oss;
oss << "Blob file #" << blob_file_number << " not found";
return Status::Corruption("VersionBuilder", oss.str());
}
blob_file_meta_deltas_[blob_file_number].AddGarbage(
blob_file_garbage.GetGarbageBlobCount(),
blob_file_garbage.GetGarbageBlobBytes());
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();
}
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();
}
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);
} else {
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);
} else {
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);
}
table_file_levels_[file_number] = level;
return Status::OK();
}
// Apply all of the edits in *edit to the current state.
Status Apply(VersionEdit* edit) {
{
const Status s = CheckConsistency(base_vstorage_);
if (!s.ok()) {
return s;
}
}
// Delete 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 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;
}
}
// 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;
}
}
return Status::OK();
}
static std::shared_ptr<BlobFileMetaData> CreateMetaDataForNewBlobFile(
const BlobFileMetaDataDelta& delta) {
auto shared_meta = delta.GetSharedMeta();
assert(shared_meta);
auto meta = BlobFileMetaData::Create(std::move(shared_meta),
delta.GetAdditionalGarbageCount(),
delta.GetAdditionalGarbageBytes());
return meta;
}
static std::shared_ptr<BlobFileMetaData>
GetOrCreateMetaDataForExistingBlobFile(
const std::shared_ptr<BlobFileMetaData>& base_meta,
const BlobFileMetaDataDelta& delta) {
assert(base_meta);
assert(!delta.GetSharedMeta());
if (delta.IsEmpty()) {
return base_meta;
}
auto shared_meta = base_meta->GetSharedMeta();
assert(shared_meta);
auto meta = BlobFileMetaData::Create(
std::move(shared_meta),
base_meta->GetGarbageBlobCount() + delta.GetAdditionalGarbageCount(),
base_meta->GetGarbageBlobBytes() + delta.GetAdditionalGarbageBytes());
return meta;
}
void AddBlobFileIfNeeded(
VersionStorageInfo* vstorage,
const std::shared_ptr<BlobFileMetaData>& meta) const {
assert(vstorage);
assert(meta);
if (meta->GetGarbageBlobCount() < meta->GetTotalBlobCount()) {
vstorage->AddBlobFile(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(base_vstorage_);
assert(vstorage);
const auto& base_blob_files = base_vstorage_->GetBlobFiles();
auto base_it = base_blob_files.begin();
const auto base_it_end = base_blob_files.end();
auto delta_it = blob_file_meta_deltas_.begin();
const auto delta_it_end = blob_file_meta_deltas_.end();
while (base_it != base_it_end && delta_it != delta_it_end) {
const uint64_t base_blob_file_number = base_it->first;
const uint64_t delta_blob_file_number = delta_it->first;
if (base_blob_file_number < delta_blob_file_number) {
const auto& base_meta = base_it->second;
assert(base_meta);
assert(base_meta->GetGarbageBlobCount() <
base_meta->GetTotalBlobCount());
vstorage->AddBlobFile(base_meta);
++base_it;
} else if (delta_blob_file_number < base_blob_file_number) {
// Note: blob file numbers are strictly increasing over time and
// once blob files get marked obsolete, they never reappear. Thus,
// this case is not possible.
assert(false);
++delta_it;
} else {
assert(base_blob_file_number == delta_blob_file_number);
const auto& base_meta = base_it->second;
const auto& delta = delta_it->second;
auto meta = GetOrCreateMetaDataForExistingBlobFile(base_meta, delta);
AddBlobFileIfNeeded(vstorage, meta);
++base_it;
++delta_it;
}
}
while (base_it != base_it_end) {
const auto& base_meta = base_it->second;
assert(base_meta);
assert(base_meta->GetGarbageBlobCount() < base_meta->GetTotalBlobCount());
vstorage->AddBlobFile(base_meta);
++base_it;
}
while (delta_it != delta_it_end) {
const auto& delta = delta_it->second;
auto meta = CreateMetaDataForNewBlobFile(delta);
AddBlobFileIfNeeded(vstorage, meta);
++delta_it;
}
}
// Save the current state in *v.
Status SaveTo(VersionStorageInfo* vstorage) {
Status s = CheckConsistency(base_vstorage_);
if (!s.ok()) {
return s;
}
s = CheckConsistency(vstorage);
if (!s.ok()) {
return s;
}
for (int level = 0; level < num_levels_; 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_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);
#ifndef NDEBUG
FileMetaData* prev_added_file = nullptr;
for (const auto& added : added_files) {
if (level > 0 && prev_added_file != nullptr) {
assert(base_vstorage_->InternalComparator()->Compare(
prev_added_file->smallest, added->smallest) <= 0);
}
prev_added_file = added;
}
#endif
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++);
}
}
}
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 SliceTransform* prefix_extractor) {
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 = port::kMaxSizet;
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(
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);
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();
}
for (const auto& s : statuses) {
if (!s.ok()) {
return s;
}
}
return Status::OK();
}
void MaybeAddFile(VersionStorageInfo* vstorage, int level, FileMetaData* f) {
if (levels_[level].deleted_files.count(f->fd.GetNumber()) > 0) {
// f is to-be-deleted table file
vstorage->RemoveCurrentStats(f);
} else {
assert(ioptions_);
vstorage->AddFile(level, f, ioptions_->info_log);
}
}
};
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(VersionEdit* edit) { return rep_->Apply(edit); }
Status VersionBuilder::SaveTo(VersionStorageInfo* vstorage) {
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 SliceTransform* prefix_extractor) {
return rep_->LoadTableHandlers(internal_stats, max_threads,
prefetch_index_and_filter_in_cache,
is_initial_load, prefix_extractor);
}
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