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4bd3bc5c4f
rocksdb/utilities/blob_db/blob_db_impl.cc
Yi Wu 4bd3bc5c4f BlobDB: Fix VisibleToActiveSnapshot() (#4236) 
Summary:
There are two issues with `VisibleToActiveSnapshot`:
1. If there are no snapshots, `oldest_snapshot` will be 0 and `VisibleToActiveSnapshot` will always return true. Since the method is used to decide whether it is safe to delete obsolete files, obsolete file won't be able to delete in this case.
2. The `auto` keyword of `auto snapshots = db_impl_->snapshots()` translate to a copy of `const SnapshotList` instead of a reference. Since copy constructor of `SnapshotList` is not defined, using the copy may yield unexpected result.

Issue 2 actually hide issue 1 from being catch by tests. During test `snapshots.empty()` can return false while it should actually be empty, and `snapshots.oldest()` return an invalid address, making `oldest_snapshot` being some random large number.

The issue was originally reported by BlobDB early adopter at Kuaishou.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4236

Differential Revision: D9188706

Pulled By: yiwu-arbug

fbshipit-source-id: a0f2624b927cf9bf28c1bb534784fee5d106f5ea
2018-08-24 14:38:20 -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).
#ifndef ROCKSDB_LITE
#include "utilities/blob_db/blob_db_impl.h"
#include <algorithm>
#include <cinttypes>
#include <iomanip>
#include <memory>
#include "db/db_impl.h"
#include "db/write_batch_internal.h"
#include "monitoring/instrumented_mutex.h"
#include "monitoring/statistics.h"
#include "rocksdb/convenience.h"
#include "rocksdb/env.h"
#include "rocksdb/iterator.h"
#include "rocksdb/utilities/stackable_db.h"
#include "rocksdb/utilities/transaction.h"
#include "table/block.h"
#include "table/block_based_table_builder.h"
#include "table/block_builder.h"
#include "table/meta_blocks.h"
#include "util/cast_util.h"
#include "util/crc32c.h"
#include "util/file_reader_writer.h"
#include "util/filename.h"
#include "util/logging.h"
#include "util/mutexlock.h"
#include "util/random.h"
#include "util/stop_watch.h"
#include "util/sync_point.h"
#include "util/timer_queue.h"
#include "utilities/blob_db/blob_compaction_filter.h"
#include "utilities/blob_db/blob_db_iterator.h"
#include "utilities/blob_db/blob_db_listener.h"
#include "utilities/blob_db/blob_index.h"
namespace {
int kBlockBasedTableVersionFormat = 2;
} // end namespace
namespace rocksdb {
namespace blob_db {
WalFilter::WalProcessingOption BlobReconcileWalFilter::LogRecordFound(
unsigned long long /*log_number*/, const std::string& /*log_file_name*/,
const WriteBatch& /*batch*/, WriteBatch* /*new_batch*/,
bool* /*batch_changed*/) {
return WalFilter::WalProcessingOption::kContinueProcessing;
}
bool BlobFileComparator::operator()(
const std::shared_ptr<BlobFile>& lhs,
const std::shared_ptr<BlobFile>& rhs) const {
return lhs->BlobFileNumber() > rhs->BlobFileNumber();
}
bool BlobFileComparatorTTL::operator()(
const std::shared_ptr<BlobFile>& lhs,
const std::shared_ptr<BlobFile>& rhs) const {
assert(lhs->HasTTL() && rhs->HasTTL());
if (lhs->expiration_range_.first < rhs->expiration_range_.first) {
return true;
}
if (lhs->expiration_range_.first > rhs->expiration_range_.first) {
return false;
}
return lhs->BlobFileNumber() < rhs->BlobFileNumber();
}
BlobDBImpl::BlobDBImpl(const std::string& dbname,
const BlobDBOptions& blob_db_options,
const DBOptions& db_options,
const ColumnFamilyOptions& cf_options)
: BlobDB(),
dbname_(dbname),
db_impl_(nullptr),
env_(db_options.env),
bdb_options_(blob_db_options),
db_options_(db_options),
cf_options_(cf_options),
env_options_(db_options),
statistics_(db_options_.statistics.get()),
next_file_number_(1),
epoch_of_(0),
closed_(true),
open_file_count_(0),
total_blob_size_(0),
live_sst_size_(0),
fifo_eviction_seq_(0),
evict_expiration_up_to_(0),
debug_level_(0) {
blob_dir_ = (bdb_options_.path_relative)
? dbname + "/" + bdb_options_.blob_dir
: bdb_options_.blob_dir;
env_options_.bytes_per_sync = blob_db_options.bytes_per_sync;
}
BlobDBImpl::~BlobDBImpl() {
// CancelAllBackgroundWork(db_, true);
Status s __attribute__((__unused__)) = Close();
assert(s.ok());
}
Status BlobDBImpl::Close() {
if (closed_) {
return Status::OK();
}
closed_ = true;
// Close base DB before BlobDBImpl destructs to stop event listener and
// compaction filter call.
Status s = db_->Close();
// delete db_ anyway even if close failed.
delete db_;
// Reset pointers to avoid StackableDB delete the pointer again.
db_ = nullptr;
db_impl_ = nullptr;
if (!s.ok()) {
return s;
}
s = SyncBlobFiles();
return s;
}
BlobDBOptions BlobDBImpl::GetBlobDBOptions() const { return bdb_options_; }
Status BlobDBImpl::Open(std::vector<ColumnFamilyHandle*>* handles) {
assert(handles != nullptr);
assert(db_ == nullptr);
if (blob_dir_.empty()) {
return Status::NotSupported("No blob directory in options");
}
if (cf_options_.compaction_filter != nullptr ||
cf_options_.compaction_filter_factory != nullptr) {
return Status::NotSupported("Blob DB doesn't support compaction filter.");
}
Status s;
// Create info log.
if (db_options_.info_log == nullptr) {
s = CreateLoggerFromOptions(dbname_, db_options_, &db_options_.info_log);
if (!s.ok()) {
return s;
}
}
ROCKS_LOG_INFO(db_options_.info_log, "Opening BlobDB...");
// Open blob directory.
s = env_->CreateDirIfMissing(blob_dir_);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to create blob_dir %s, status: %s",
blob_dir_.c_str(), s.ToString().c_str());
}
s = env_->NewDirectory(blob_dir_, &dir_ent_);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to open blob_dir %s, status: %s", blob_dir_.c_str(),
s.ToString().c_str());
return s;
}
// Open blob files.
s = OpenAllBlobFiles();
if (!s.ok()) {
return s;
}
// Update options
db_options_.listeners.push_back(std::make_shared<BlobDBListener>(this));
cf_options_.compaction_filter_factory.reset(
new BlobIndexCompactionFilterFactory(this, env_, statistics_));
// Open base db.
ColumnFamilyDescriptor cf_descriptor(kDefaultColumnFamilyName, cf_options_);
s = DB::Open(db_options_, dbname_, {cf_descriptor}, handles, &db_);
if (!s.ok()) {
return s;
}
db_impl_ = static_cast_with_check<DBImpl, DB>(db_->GetRootDB());
UpdateLiveSSTSize();
// Start background jobs.
if (!bdb_options_.disable_background_tasks) {
StartBackgroundTasks();
}
ROCKS_LOG_INFO(db_options_.info_log, "BlobDB pointer %p", this);
bdb_options_.Dump(db_options_.info_log.get());
closed_ = false;
return s;
}
void BlobDBImpl::StartBackgroundTasks() {
// store a call to a member function and object
tqueue_.add(
kReclaimOpenFilesPeriodMillisecs,
std::bind(&BlobDBImpl::ReclaimOpenFiles, this, std::placeholders::_1));
tqueue_.add(static_cast<int64_t>(
bdb_options_.garbage_collection_interval_secs * 1000),
std::bind(&BlobDBImpl::RunGC, this, std::placeholders::_1));
tqueue_.add(
kDeleteObsoleteFilesPeriodMillisecs,
std::bind(&BlobDBImpl::DeleteObsoleteFiles, this, std::placeholders::_1));
tqueue_.add(kSanityCheckPeriodMillisecs,
std::bind(&BlobDBImpl::SanityCheck, this, std::placeholders::_1));
tqueue_.add(
kCheckSeqFilesPeriodMillisecs,
std::bind(&BlobDBImpl::CheckSeqFiles, this, std::placeholders::_1));
}
Status BlobDBImpl::GetAllBlobFiles(std::set<uint64_t>* file_numbers) {
assert(file_numbers != nullptr);
std::vector<std::string> all_files;
Status s = env_->GetChildren(blob_dir_, &all_files);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to get list of blob files, status: %s",
s.ToString().c_str());
return s;
}
for (const auto& file_name : all_files) {
uint64_t file_number;
FileType type;
bool success = ParseFileName(file_name, &file_number, &type);
if (success && type == kBlobFile) {
file_numbers->insert(file_number);
} else {
ROCKS_LOG_WARN(db_options_.info_log,
"Skipping file in blob directory: %s", file_name.c_str());
}
}
return s;
}
Status BlobDBImpl::OpenAllBlobFiles() {
std::set<uint64_t> file_numbers;
Status s = GetAllBlobFiles(&file_numbers);
if (!s.ok()) {
return s;
}
if (!file_numbers.empty()) {
next_file_number_.store(*file_numbers.rbegin() + 1);
}
std::string blob_file_list;
std::string obsolete_file_list;
for (auto& file_number : file_numbers) {
std::shared_ptr<BlobFile> blob_file = std::make_shared<BlobFile>(
this, blob_dir_, file_number, db_options_.info_log.get());
blob_file->MarkImmutable();
// Read file header and footer
Status read_metadata_status = blob_file->ReadMetadata(env_, env_options_);
if (read_metadata_status.IsCorruption()) {
// Remove incomplete file.
ObsoleteBlobFile(blob_file, 0 /*obsolete_seq*/, false /*update_size*/);
if (!obsolete_file_list.empty()) {
obsolete_file_list.append(", ");
}
obsolete_file_list.append(ToString(file_number));
continue;
} else if (!read_metadata_status.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Unable to read metadata of blob file % " PRIu64
", status: '%s'",
file_number, read_metadata_status.ToString().c_str());
return read_metadata_status;
}
total_blob_size_ += blob_file->GetFileSize();
blob_files_[file_number] = blob_file;
if (!blob_file_list.empty()) {
blob_file_list.append(", ");
}
blob_file_list.append(ToString(file_number));
}
ROCKS_LOG_INFO(db_options_.info_log,
"Found %" ROCKSDB_PRIszt " blob files: %s", blob_files_.size(),
blob_file_list.c_str());
ROCKS_LOG_INFO(db_options_.info_log,
"Found %" ROCKSDB_PRIszt
" incomplete or corrupted blob files: %s",
obsolete_files_.size(), obsolete_file_list.c_str());
return s;
}
void BlobDBImpl::CloseRandomAccessLocked(
const std::shared_ptr<BlobFile>& bfile) {
bfile->CloseRandomAccessLocked();
open_file_count_--;
}
std::shared_ptr<RandomAccessFileReader> BlobDBImpl::GetOrOpenRandomAccessReader(
const std::shared_ptr<BlobFile>& bfile, Env* env,
const EnvOptions& env_options) {
bool fresh_open = false;
auto rar = bfile->GetOrOpenRandomAccessReader(env, env_options, &fresh_open);
if (fresh_open) open_file_count_++;
return rar;
}
std::shared_ptr<BlobFile> BlobDBImpl::NewBlobFile(const std::string& reason) {
uint64_t file_num = next_file_number_++;
auto bfile = std::make_shared<BlobFile>(this, blob_dir_, file_num,
db_options_.info_log.get());
ROCKS_LOG_DEBUG(db_options_.info_log, "New blob file created: %s reason='%s'",
bfile->PathName().c_str(), reason.c_str());
LogFlush(db_options_.info_log);
return bfile;
}
Status BlobDBImpl::CreateWriterLocked(const std::shared_ptr<BlobFile>& bfile) {
std::string fpath(bfile->PathName());
std::unique_ptr<WritableFile> wfile;
Status s = env_->ReopenWritableFile(fpath, &wfile, env_options_);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to open blob file for write: %s status: '%s'"
" exists: '%s'",
fpath.c_str(), s.ToString().c_str(),
env_->FileExists(fpath).ToString().c_str());
return s;
}
std::unique_ptr<WritableFileWriter> fwriter;
fwriter.reset(new WritableFileWriter(std::move(wfile), env_options_));
uint64_t boffset = bfile->GetFileSize();
if (debug_level_ >= 2 && boffset) {
ROCKS_LOG_DEBUG(db_options_.info_log, "Open blob file: %s with offset: %d",
fpath.c_str(), boffset);
}
Writer::ElemType et = Writer::kEtNone;
if (bfile->file_size_ == BlobLogHeader::kSize) {
et = Writer::kEtFileHdr;
} else if (bfile->file_size_ > BlobLogHeader::kSize) {
et = Writer::kEtRecord;
} else if (bfile->file_size_) {
ROCKS_LOG_WARN(db_options_.info_log,
"Open blob file: %s with wrong size: %d", fpath.c_str(),
boffset);
return Status::Corruption("Invalid blob file size");
}
bfile->log_writer_ = std::make_shared<Writer>(
std::move(fwriter), env_, statistics_, bfile->file_number_,
bdb_options_.bytes_per_sync, db_options_.use_fsync, boffset);
bfile->log_writer_->last_elem_type_ = et;
return s;
}
std::shared_ptr<BlobFile> BlobDBImpl::FindBlobFileLocked(
uint64_t expiration) const {
if (open_ttl_files_.empty()) {
return nullptr;
}
std::shared_ptr<BlobFile> tmp = std::make_shared<BlobFile>();
tmp->SetHasTTL(true);
tmp->expiration_range_ = std::make_pair(expiration, 0);
tmp->file_number_ = std::numeric_limits<uint64_t>::max();
auto citr = open_ttl_files_.equal_range(tmp);
if (citr.first == open_ttl_files_.end()) {
assert(citr.second == open_ttl_files_.end());
std::shared_ptr<BlobFile> check = *(open_ttl_files_.rbegin());
return (check->expiration_range_.second <= expiration) ? nullptr : check;
}
if (citr.first != citr.second) {
return *(citr.first);
}
auto finditr = citr.second;
if (finditr != open_ttl_files_.begin()) {
--finditr;
}
bool b2 = (*finditr)->expiration_range_.second <= expiration;
bool b1 = (*finditr)->expiration_range_.first > expiration;
return (b1 || b2) ? nullptr : (*finditr);
}
std::shared_ptr<Writer> BlobDBImpl::CheckOrCreateWriterLocked(
const std::shared_ptr<BlobFile>& bfile) {
std::shared_ptr<Writer> writer = bfile->GetWriter();
if (writer) return writer;
Status s = CreateWriterLocked(bfile);
if (!s.ok()) return nullptr;
writer = bfile->GetWriter();
return writer;
}
std::shared_ptr<BlobFile> BlobDBImpl::SelectBlobFile() {
{
ReadLock rl(&mutex_);
if (open_non_ttl_file_ != nullptr) {
return open_non_ttl_file_;
}
}
// CHECK again
WriteLock wl(&mutex_);
if (open_non_ttl_file_ != nullptr) {
return open_non_ttl_file_;
}
std::shared_ptr<BlobFile> bfile = NewBlobFile("SelectBlobFile");
assert(bfile);
// file not visible, hence no lock
std::shared_ptr<Writer> writer = CheckOrCreateWriterLocked(bfile);
if (!writer) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to get writer from blob file: %s",
bfile->PathName().c_str());
return nullptr;
}
bfile->file_size_ = BlobLogHeader::kSize;
bfile->header_.compression = bdb_options_.compression;
bfile->header_.has_ttl = false;
bfile->header_.column_family_id =
reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily())->GetID();
bfile->header_valid_ = true;
bfile->SetColumnFamilyId(bfile->header_.column_family_id);
bfile->SetHasTTL(false);
bfile->SetCompression(bdb_options_.compression);
Status s = writer->WriteHeader(bfile->header_);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to write header to new blob file: %s"
" status: '%s'",
bfile->PathName().c_str(), s.ToString().c_str());
return nullptr;
}
blob_files_.insert(std::make_pair(bfile->BlobFileNumber(), bfile));
open_non_ttl_file_ = bfile;
total_blob_size_ += BlobLogHeader::kSize;
return bfile;
}
std::shared_ptr<BlobFile> BlobDBImpl::SelectBlobFileTTL(uint64_t expiration) {
assert(expiration != kNoExpiration);
uint64_t epoch_read = 0;
std::shared_ptr<BlobFile> bfile;
{
ReadLock rl(&mutex_);
bfile = FindBlobFileLocked(expiration);
epoch_read = epoch_of_.load();
}
if (bfile) {
assert(!bfile->Immutable());
return bfile;
}
uint64_t exp_low =
(expiration / bdb_options_.ttl_range_secs) * bdb_options_.ttl_range_secs;
uint64_t exp_high = exp_low + bdb_options_.ttl_range_secs;
ExpirationRange expiration_range = std::make_pair(exp_low, exp_high);
bfile = NewBlobFile("SelectBlobFileTTL");
assert(bfile);
ROCKS_LOG_INFO(db_options_.info_log, "New blob file TTL range: %s %d %d",
bfile->PathName().c_str(), exp_low, exp_high);
LogFlush(db_options_.info_log);
// we don't need to take lock as no other thread is seeing bfile yet
std::shared_ptr<Writer> writer = CheckOrCreateWriterLocked(bfile);
if (!writer) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to get writer from blob file with TTL: %s",
bfile->PathName().c_str());
return nullptr;
}
bfile->header_.expiration_range = expiration_range;
bfile->header_.compression = bdb_options_.compression;
bfile->header_.has_ttl = true;
bfile->header_.column_family_id =
reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily())->GetID();
;
bfile->header_valid_ = true;
bfile->SetColumnFamilyId(bfile->header_.column_family_id);
bfile->SetHasTTL(true);
bfile->SetCompression(bdb_options_.compression);
bfile->file_size_ = BlobLogHeader::kSize;
// set the first value of the range, since that is
// concrete at this time. also necessary to add to open_ttl_files_
bfile->expiration_range_ = expiration_range;
WriteLock wl(&mutex_);
// in case the epoch has shifted in the interim, then check
// check condition again - should be rare.
if (epoch_of_.load() != epoch_read) {
auto bfile2 = FindBlobFileLocked(expiration);
if (bfile2) return bfile2;
}
Status s = writer->WriteHeader(bfile->header_);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to write header to new blob file: %s"
" status: '%s'",
bfile->PathName().c_str(), s.ToString().c_str());
return nullptr;
}
blob_files_.insert(std::make_pair(bfile->BlobFileNumber(), bfile));
open_ttl_files_.insert(bfile);
total_blob_size_ += BlobLogHeader::kSize;
epoch_of_++;
return bfile;
}
class BlobDBImpl::BlobInserter : public WriteBatch::Handler {
private:
const WriteOptions& options_;
BlobDBImpl* blob_db_impl_;
uint32_t default_cf_id_;
WriteBatch batch_;
public:
BlobInserter(const WriteOptions& options, BlobDBImpl* blob_db_impl,
uint32_t default_cf_id)
: options_(options),
blob_db_impl_(blob_db_impl),
default_cf_id_(default_cf_id) {}
WriteBatch* batch() { return &batch_; }
virtual Status PutCF(uint32_t column_family_id, const Slice& key,
const Slice& value) override {
if (column_family_id != default_cf_id_) {
return Status::NotSupported(
"Blob DB doesn't support non-default column family.");
}
Status s = blob_db_impl_->PutBlobValue(options_, key, value,
kNoExpiration, &batch_);
return s;
}
virtual Status DeleteCF(uint32_t column_family_id,
const Slice& key) override {
if (column_family_id != default_cf_id_) {
return Status::NotSupported(
"Blob DB doesn't support non-default column family.");
}
Status s = WriteBatchInternal::Delete(&batch_, column_family_id, key);
return s;
}
virtual Status DeleteRange(uint32_t column_family_id, const Slice& begin_key,
const Slice& end_key) {
if (column_family_id != default_cf_id_) {
return Status::NotSupported(
"Blob DB doesn't support non-default column family.");
}
Status s = WriteBatchInternal::DeleteRange(&batch_, column_family_id,
begin_key, end_key);
return s;
}
virtual Status SingleDeleteCF(uint32_t /*column_family_id*/,
const Slice& /*key*/) override {
return Status::NotSupported("Not supported operation in blob db.");
}
virtual Status MergeCF(uint32_t /*column_family_id*/, const Slice& /*key*/,
const Slice& /*value*/) override {
return Status::NotSupported("Not supported operation in blob db.");
}
virtual void LogData(const Slice& blob) override { batch_.PutLogData(blob); }
};
Status BlobDBImpl::Write(const WriteOptions& options, WriteBatch* updates) {
StopWatch write_sw(env_, statistics_, BLOB_DB_WRITE_MICROS);
RecordTick(statistics_, BLOB_DB_NUM_WRITE);
uint32_t default_cf_id =
reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily())->GetID();
Status s;
BlobInserter blob_inserter(options, this, default_cf_id);
{
// Release write_mutex_ before DB write to avoid race condition with
// flush begin listener, which also require write_mutex_ to sync
// blob files.
MutexLock l(&write_mutex_);
s = updates->Iterate(&blob_inserter);
}
if (!s.ok()) {
return s;
}
return db_->Write(options, blob_inserter.batch());
}
Status BlobDBImpl::GetLiveFiles(std::vector<std::string>& ret,
uint64_t* manifest_file_size,
bool flush_memtable) {
// Hold a lock in the beginning to avoid updates to base DB during the call
ReadLock rl(&mutex_);
Status s = db_->GetLiveFiles(ret, manifest_file_size, flush_memtable);
if (!s.ok()) {
return s;
}
ret.reserve(ret.size() + blob_files_.size());
for (auto bfile_pair : blob_files_) {
auto blob_file = bfile_pair.second;
ret.emplace_back(blob_file->PathName());
}
return Status::OK();
}
void BlobDBImpl::GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) {
// Hold a lock in the beginning to avoid updates to base DB during the call
ReadLock rl(&mutex_);
db_->GetLiveFilesMetaData(metadata);
for (auto bfile_pair : blob_files_) {
auto blob_file = bfile_pair.second;
LiveFileMetaData filemetadata;
filemetadata.size = blob_file->GetFileSize();
filemetadata.name = blob_file->PathName();
auto cfh =
reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily());
filemetadata.column_family_name = cfh->GetName();
metadata->emplace_back(filemetadata);
}
}
Status BlobDBImpl::Put(const WriteOptions& options, const Slice& key,
const Slice& value) {
return PutUntil(options, key, value, kNoExpiration);
}
Status BlobDBImpl::PutWithTTL(const WriteOptions& options,
const Slice& key, const Slice& value,
uint64_t ttl) {
uint64_t now = EpochNow();
uint64_t expiration = kNoExpiration - now > ttl ? now + ttl : kNoExpiration;
return PutUntil(options, key, value, expiration);
}
Status BlobDBImpl::PutUntil(const WriteOptions& options, const Slice& key,
const Slice& value, uint64_t expiration) {
StopWatch write_sw(env_, statistics_, BLOB_DB_WRITE_MICROS);
RecordTick(statistics_, BLOB_DB_NUM_PUT);
TEST_SYNC_POINT("BlobDBImpl::PutUntil:Start");
Status s;
WriteBatch batch;
{
// Release write_mutex_ before DB write to avoid race condition with
// flush begin listener, which also require write_mutex_ to sync
// blob files.
MutexLock l(&write_mutex_);
s = PutBlobValue(options, key, value, expiration, &batch);
}
if (s.ok()) {
s = db_->Write(options, &batch);
}
TEST_SYNC_POINT("BlobDBImpl::PutUntil:Finish");
return s;
}
Status BlobDBImpl::PutBlobValue(const WriteOptions& /*options*/,
const Slice& key, const Slice& value,
uint64_t expiration, WriteBatch* batch) {
write_mutex_.AssertHeld();
Status s;
std::string index_entry;
uint32_t column_family_id =
reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily())->GetID();
if (value.size() < bdb_options_.min_blob_size) {
if (expiration == kNoExpiration) {
// Put as normal value
s = batch->Put(key, value);
RecordTick(statistics_, BLOB_DB_WRITE_INLINED);
} else {
// Inlined with TTL
BlobIndex::EncodeInlinedTTL(&index_entry, expiration, value);
s = WriteBatchInternal::PutBlobIndex(batch, column_family_id, key,
index_entry);
RecordTick(statistics_, BLOB_DB_WRITE_INLINED_TTL);
}
} else {
std::string compression_output;
Slice value_compressed = GetCompressedSlice(value, &compression_output);
std::string headerbuf;
Writer::ConstructBlobHeader(&headerbuf, key, value_compressed, expiration);
// Check DB size limit before selecting blob file to
// Since CheckSizeAndEvictBlobFiles() can close blob files, it needs to be
// done before calling SelectBlobFile().
s = CheckSizeAndEvictBlobFiles(headerbuf.size() + key.size() +
value_compressed.size());
if (!s.ok()) {
return s;
}
std::shared_ptr<BlobFile> bfile = (expiration != kNoExpiration)
? SelectBlobFileTTL(expiration)
: SelectBlobFile();
assert(bfile != nullptr);
assert(bfile->compression() == bdb_options_.compression);
s = AppendBlob(bfile, headerbuf, key, value_compressed, expiration,
&index_entry);
if (expiration == kNoExpiration) {
RecordTick(statistics_, BLOB_DB_WRITE_BLOB);
} else {
RecordTick(statistics_, BLOB_DB_WRITE_BLOB_TTL);
}
if (s.ok()) {
if (expiration != kNoExpiration) {
bfile->ExtendExpirationRange(expiration);
}
s = CloseBlobFileIfNeeded(bfile);
if (s.ok()) {
s = WriteBatchInternal::PutBlobIndex(batch, column_family_id, key,
index_entry);
}
} else {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to append blob to FILE: %s: KEY: %s VALSZ: %d"
" status: '%s' blob_file: '%s'",
bfile->PathName().c_str(), key.ToString().c_str(),
value.size(), s.ToString().c_str(),
bfile->DumpState().c_str());
}
}
RecordTick(statistics_, BLOB_DB_NUM_KEYS_WRITTEN);
RecordTick(statistics_, BLOB_DB_BYTES_WRITTEN, key.size() + value.size());
MeasureTime(statistics_, BLOB_DB_KEY_SIZE, key.size());
MeasureTime(statistics_, BLOB_DB_VALUE_SIZE, value.size());
return s;
}
Slice BlobDBImpl::GetCompressedSlice(const Slice& raw,
std::string* compression_output) const {
if (bdb_options_.compression == kNoCompression) {
return raw;
}
StopWatch compression_sw(env_, statistics_, BLOB_DB_COMPRESSION_MICROS);
CompressionType ct = bdb_options_.compression;
CompressionContext compression_ctx(ct);
CompressBlock(raw, compression_ctx, &ct, kBlockBasedTableVersionFormat,
compression_output);
return *compression_output;
}
void BlobDBImpl::GetCompactionContext(BlobCompactionContext* context) {
ReadLock l(&mutex_);
context->next_file_number = next_file_number_.load();
context->current_blob_files.clear();
for (auto& p : blob_files_) {
context->current_blob_files.insert(p.first);
}
context->fifo_eviction_seq = fifo_eviction_seq_;
context->evict_expiration_up_to = evict_expiration_up_to_;
}
void BlobDBImpl::UpdateLiveSSTSize() {
uint64_t live_sst_size = 0;
bool ok = GetIntProperty(DB::Properties::kLiveSstFilesSize, &live_sst_size);
if (ok) {
live_sst_size_.store(live_sst_size);
ROCKS_LOG_INFO(db_options_.info_log,
"Updated total SST file size: %" PRIu64 " bytes.",
live_sst_size);
} else {
ROCKS_LOG_ERROR(
db_options_.info_log,
"Failed to update total SST file size after flush or compaction.");
}
{
// Trigger FIFO eviction if needed.
MutexLock l(&write_mutex_);
Status s = CheckSizeAndEvictBlobFiles(0, true /*force*/);
if (s.IsNoSpace()) {
ROCKS_LOG_WARN(db_options_.info_log,
"DB grow out-of-space after SST size updated. Current live"
" SST size: %" PRIu64
" , current blob files size: %" PRIu64 ".",
live_sst_size_.load(), total_blob_size_.load());
}
}
}
Status BlobDBImpl::CheckSizeAndEvictBlobFiles(uint64_t blob_size,
bool force_evict) {
write_mutex_.AssertHeld();
uint64_t live_sst_size = live_sst_size_.load();
if (bdb_options_.max_db_size == 0 ||
live_sst_size + total_blob_size_.load() + blob_size <=
bdb_options_.max_db_size) {
return Status::OK();
}
if (bdb_options_.is_fifo == false ||
(!force_evict && live_sst_size + blob_size > bdb_options_.max_db_size)) {
// FIFO eviction is disabled, or no space to insert new blob even we evict
// all blob files.
return Status::NoSpace(
"Write failed, as writing it would exceed max_db_size limit.");
}
std::vector<std::shared_ptr<BlobFile>> candidate_files;
CopyBlobFiles(&candidate_files);
std::sort(candidate_files.begin(), candidate_files.end(),
BlobFileComparator());
fifo_eviction_seq_ = GetLatestSequenceNumber();
WriteLock l(&mutex_);
while (!candidate_files.empty() &&
live_sst_size + total_blob_size_.load() + blob_size >
bdb_options_.max_db_size) {
std::shared_ptr<BlobFile> blob_file = candidate_files.back();
candidate_files.pop_back();
WriteLock file_lock(&blob_file->mutex_);
if (blob_file->Obsolete()) {
// File already obsoleted by someone else.
continue;
}
// FIFO eviction can evict open blob files.
if (!blob_file->Immutable()) {
Status s = CloseBlobFile(blob_file, false /*need_lock*/);
if (!s.ok()) {
return s;
}
}
assert(blob_file->Immutable());
auto expiration_range = blob_file->GetExpirationRange();
ROCKS_LOG_INFO(db_options_.info_log,
"Evict oldest blob file since DB out of space. Current "
"live SST file size: %" PRIu64 ", total blob size: %" PRIu64
", max db size: %" PRIu64 ", evicted blob file #%" PRIu64
".",
live_sst_size, total_blob_size_.load(),
bdb_options_.max_db_size, blob_file->BlobFileNumber());
ObsoleteBlobFile(blob_file, fifo_eviction_seq_, true /*update_size*/);
evict_expiration_up_to_ = expiration_range.first;
RecordTick(statistics_, BLOB_DB_FIFO_NUM_FILES_EVICTED);
RecordTick(statistics_, BLOB_DB_FIFO_NUM_KEYS_EVICTED,
blob_file->BlobCount());
RecordTick(statistics_, BLOB_DB_FIFO_BYTES_EVICTED,
blob_file->GetFileSize());
TEST_SYNC_POINT("BlobDBImpl::EvictOldestBlobFile:Evicted");
}
if (live_sst_size + total_blob_size_.load() + blob_size >
bdb_options_.max_db_size) {
return Status::NoSpace(
"Write failed, as writing it would exceed max_db_size limit.");
}
return Status::OK();
}
Status BlobDBImpl::AppendBlob(const std::shared_ptr<BlobFile>& bfile,
const std::string& headerbuf, const Slice& key,
const Slice& value, uint64_t expiration,
std::string* index_entry) {
Status s;
uint64_t blob_offset = 0;
uint64_t key_offset = 0;
{
WriteLock lockbfile_w(&bfile->mutex_);
std::shared_ptr<Writer> writer = CheckOrCreateWriterLocked(bfile);
if (!writer) {
return Status::IOError("Failed to create blob writer");
}
// write the blob to the blob log.
s = writer->EmitPhysicalRecord(headerbuf, key, value, &key_offset,
&blob_offset);
}
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Invalid status in AppendBlob: %s status: '%s'",
bfile->PathName().c_str(), s.ToString().c_str());
return s;
}
// increment blob count
bfile->blob_count_++;
uint64_t size_put = headerbuf.size() + key.size() + value.size();
bfile->file_size_ += size_put;
total_blob_size_ += size_put;
if (expiration == kNoExpiration) {
BlobIndex::EncodeBlob(index_entry, bfile->BlobFileNumber(), blob_offset,
value.size(), bdb_options_.compression);
} else {
BlobIndex::EncodeBlobTTL(index_entry, expiration, bfile->BlobFileNumber(),
blob_offset, value.size(),
bdb_options_.compression);
}
return s;
}
std::vector<Status> BlobDBImpl::MultiGet(
const ReadOptions& read_options,
const std::vector<Slice>& keys, std::vector<std::string>* values) {
StopWatch multiget_sw(env_, statistics_, BLOB_DB_MULTIGET_MICROS);
RecordTick(statistics_, BLOB_DB_NUM_MULTIGET);
// Get a snapshot to avoid blob file get deleted between we
// fetch and index entry and reading from the file.
ReadOptions ro(read_options);
bool snapshot_created = SetSnapshotIfNeeded(&ro);
std::vector<Status> statuses;
statuses.reserve(keys.size());
values->clear();
values->reserve(keys.size());
PinnableSlice value;
for (size_t i = 0; i < keys.size(); i++) {
statuses.push_back(Get(ro, DefaultColumnFamily(), keys[i], &value));
values->push_back(value.ToString());
value.Reset();
}
if (snapshot_created) {
db_->ReleaseSnapshot(ro.snapshot);
}
return statuses;
}
bool BlobDBImpl::SetSnapshotIfNeeded(ReadOptions* read_options) {
assert(read_options != nullptr);
if (read_options->snapshot != nullptr) {
return false;
}
read_options->snapshot = db_->GetSnapshot();
return true;
}
Status BlobDBImpl::GetBlobValue(const Slice& key, const Slice& index_entry,
PinnableSlice* value) {
assert(value != nullptr);
BlobIndex blob_index;
Status s = blob_index.DecodeFrom(index_entry);
if (!s.ok()) {
return s;
}
if (blob_index.HasTTL() && blob_index.expiration() <= EpochNow()) {
return Status::NotFound("Key expired");
}
if (blob_index.IsInlined()) {
// TODO(yiwu): If index_entry is a PinnableSlice, we can also pin the same
// memory buffer to avoid extra copy.
value->PinSelf(blob_index.value());
return Status::OK();
}
if (blob_index.size() == 0) {
value->PinSelf("");
return Status::OK();
}
// offset has to have certain min, as we will read CRC
// later from the Blob Header, which needs to be also a
// valid offset.
if (blob_index.offset() <
(BlobLogHeader::kSize + BlobLogRecord::kHeaderSize + key.size())) {
if (debug_level_ >= 2) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Invalid blob index file_number: %" PRIu64
" blob_offset: %" PRIu64 " blob_size: %" PRIu64
" key: %s",
blob_index.file_number(), blob_index.offset(),
blob_index.size(), key.data());
}
return Status::NotFound("Invalid blob offset");
}
std::shared_ptr<BlobFile> bfile;
{
ReadLock rl(&mutex_);
auto hitr = blob_files_.find(blob_index.file_number());
// file was deleted
if (hitr == blob_files_.end()) {
return Status::NotFound("Blob Not Found as blob file missing");
}
bfile = hitr->second;
}
if (blob_index.size() == 0 && value != nullptr) {
value->PinSelf("");
return Status::OK();
}
// takes locks when called
std::shared_ptr<RandomAccessFileReader> reader =
GetOrOpenRandomAccessReader(bfile, env_, env_options_);
assert(blob_index.offset() > key.size() + sizeof(uint32_t));
uint64_t record_offset = blob_index.offset() - key.size() - sizeof(uint32_t);
uint64_t record_size = sizeof(uint32_t) + key.size() + blob_index.size();
// Allocate the buffer. This is safe in C++11
std::string buffer_str(record_size, static_cast<char>(0));
char* buffer = &buffer_str[0];
// A partial blob record contain checksum, key and value.
Slice blob_record;
{
StopWatch read_sw(env_, statistics_, BLOB_DB_BLOB_FILE_READ_MICROS);
s = reader->Read(record_offset, record_size, &blob_record, buffer);
RecordTick(statistics_, BLOB_DB_BLOB_FILE_BYTES_READ, blob_record.size());
}
if (!s.ok()) {
ROCKS_LOG_DEBUG(db_options_.info_log,
"Failed to read blob from blob file %" PRIu64
", blob_offset: %" PRIu64 ", blob_size: %" PRIu64
", key_size: " PRIu64 ", read " PRIu64
" bytes, status: '%s'",
bfile->BlobFileNumber(), blob_index.offset(),
blob_index.size(), key.size(), s.ToString().c_str());
return s;
}
if (blob_record.size() != record_size) {
ROCKS_LOG_DEBUG(db_options_.info_log,
"Failed to read blob from blob file %" PRIu64
", blob_offset: %" PRIu64 ", blob_size: %" PRIu64
", key_size: " PRIu64 ", read " PRIu64
" bytes, status: '%s'",
bfile->BlobFileNumber(), blob_index.offset(),
blob_index.size(), key.size(), s.ToString().c_str());
return Status::Corruption("Failed to retrieve blob from blob index.");
}
Slice crc_slice(blob_record.data(), sizeof(uint32_t));
Slice blob_value(blob_record.data() + sizeof(uint32_t) + key.size(),
blob_index.size());
uint32_t crc_exp;
if (!GetFixed32(&crc_slice, &crc_exp)) {
ROCKS_LOG_DEBUG(db_options_.info_log,
"Unable to decode CRC from blob file %" PRIu64
", blob_offset: %" PRIu64 ", blob_size: %" PRIu64
", key size: %" PRIu64 ", status: '%s'",
bfile->BlobFileNumber(), blob_index.offset(),
blob_index.size(), key.size(), s.ToString().c_str());
return Status::Corruption("Unable to decode checksum.");
}
uint32_t crc = crc32c::Value(blob_record.data() + sizeof(uint32_t),
blob_record.size() - sizeof(uint32_t));
crc = crc32c::Mask(crc); // Adjust for storage
if (crc != crc_exp) {
if (debug_level_ >= 2) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Blob crc mismatch file: %s blob_offset: %" PRIu64
" blob_size: %" PRIu64 " key: %s status: '%s'",
bfile->PathName().c_str(), blob_index.offset(),
blob_index.size(), key.data(), s.ToString().c_str());
}
return Status::Corruption("Corruption. Blob CRC mismatch");
}
if (bfile->compression() == kNoCompression) {
value->PinSelf(blob_value);
} else {
BlockContents contents;
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily());
{
StopWatch decompression_sw(env_, statistics_,
BLOB_DB_DECOMPRESSION_MICROS);
UncompressionContext uncompression_ctx(bfile->compression());
s = UncompressBlockContentsForCompressionType(
uncompression_ctx, blob_value.data(), blob_value.size(), &contents,
kBlockBasedTableVersionFormat, *(cfh->cfd()->ioptions()));
}
value->PinSelf(contents.data);
}
return s;
}
Status BlobDBImpl::Get(const ReadOptions& read_options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value) {
StopWatch get_sw(env_, statistics_, BLOB_DB_GET_MICROS);
RecordTick(statistics_, BLOB_DB_NUM_GET);
return GetImpl(read_options, column_family, key, value);
}
Status BlobDBImpl::GetImpl(const ReadOptions& read_options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value) {
if (column_family != DefaultColumnFamily()) {
return Status::NotSupported(
"Blob DB doesn't support non-default column family.");
}
// Get a snapshot to avoid blob file get deleted between we
// fetch and index entry and reading from the file.
// TODO(yiwu): For Get() retry if file not found would be a simpler strategy.
ReadOptions ro(read_options);
bool snapshot_created = SetSnapshotIfNeeded(&ro);
Status s;
bool is_blob_index = false;
s = db_impl_->GetImpl(ro, column_family, key, value,
nullptr /*value_found*/, nullptr /*read_callback*/,
&is_blob_index);
TEST_SYNC_POINT("BlobDBImpl::Get:AfterIndexEntryGet:1");
TEST_SYNC_POINT("BlobDBImpl::Get:AfterIndexEntryGet:2");
if (s.ok() && is_blob_index) {
std::string index_entry = value->ToString();
value->Reset();
s = GetBlobValue(key, index_entry, value);
}
if (snapshot_created) {
db_->ReleaseSnapshot(ro.snapshot);
}
RecordTick(statistics_, BLOB_DB_NUM_KEYS_READ);
RecordTick(statistics_, BLOB_DB_BYTES_READ, value->size());
return s;
}
std::pair<bool, int64_t> BlobDBImpl::SanityCheck(bool aborted) {
if (aborted) return std::make_pair(false, -1);
ROCKS_LOG_INFO(db_options_.info_log, "Starting Sanity Check");
ROCKS_LOG_INFO(db_options_.info_log, "Number of files %" PRIu64,
blob_files_.size());
ROCKS_LOG_INFO(db_options_.info_log, "Number of open files %" PRIu64,
open_ttl_files_.size());
for (auto bfile : open_ttl_files_) {
assert(!bfile->Immutable());
}
uint64_t epoch_now = EpochNow();
for (auto bfile_pair : blob_files_) {
auto bfile = bfile_pair.second;
ROCKS_LOG_INFO(
db_options_.info_log, "Blob File %s %" PRIu64 " %" PRIu64 " %" PRIu64,
bfile->PathName().c_str(), bfile->GetFileSize(), bfile->BlobCount(),
(bfile->expiration_range_.second - epoch_now));
}
// reschedule
return std::make_pair(true, -1);
}
Status BlobDBImpl::CloseBlobFile(std::shared_ptr<BlobFile> bfile,
bool need_lock) {
assert(bfile != nullptr);
write_mutex_.AssertHeld();
Status s;
ROCKS_LOG_INFO(db_options_.info_log,
"Closing blob file %" PRIu64 ". Path: %s",
bfile->BlobFileNumber(), bfile->PathName().c_str());
{
std::unique_ptr<WriteLock> lock;
if (need_lock) {
lock.reset(new WriteLock(&mutex_));
}
if (bfile->HasTTL()) {
size_t erased __attribute__((__unused__));
erased = open_ttl_files_.erase(bfile);
} else if (bfile == open_non_ttl_file_) {
open_non_ttl_file_ = nullptr;
}
}
if (!bfile->closed_.load()) {
std::unique_ptr<WriteLock> file_lock;
if (need_lock) {
file_lock.reset(new WriteLock(&bfile->mutex_));
}
s = bfile->WriteFooterAndCloseLocked();
}
if (s.ok()) {
total_blob_size_ += BlobLogFooter::kSize;
} else {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to close blob file %" PRIu64 "with error: %s",
bfile->BlobFileNumber(), s.ToString().c_str());
}
return s;
}
Status BlobDBImpl::CloseBlobFileIfNeeded(std::shared_ptr<BlobFile>& bfile) {
// atomic read
if (bfile->GetFileSize() < bdb_options_.blob_file_size) {
return Status::OK();
}
return CloseBlobFile(bfile);
}
void BlobDBImpl::ObsoleteBlobFile(std::shared_ptr<BlobFile> blob_file,
SequenceNumber obsolete_seq,
bool update_size) {
// Should hold write lock of mutex_ or during DB open.
blob_file->MarkObsolete(obsolete_seq);
obsolete_files_.push_back(blob_file);
assert(total_blob_size_.load() >= blob_file->GetFileSize());
if (update_size) {
total_blob_size_ -= blob_file->GetFileSize();
}
}
bool BlobDBImpl::VisibleToActiveSnapshot(
const std::shared_ptr<BlobFile>& bfile) {
assert(bfile->Obsolete());
// We check whether the oldest snapshot is no less than the last sequence
// by the time the blob file become obsolete. If so, the blob file is not
// visible to all existing snapshots.
//
// If we keep track of the earliest sequence of the keys in the blob file,
// we could instead check if there's a snapshot falls in range
// [earliest_sequence, obsolete_sequence). But doing so will make the
// implementation more complicated.
SequenceNumber obsolete_sequence = bfile->GetObsoleteSequence();
SequenceNumber oldest_snapshot = kMaxSequenceNumber;
{
// Need to lock DBImpl mutex before access snapshot list.
InstrumentedMutexLock l(db_impl_->mutex());
auto& snapshots = db_impl_->snapshots();
if (!snapshots.empty()) {
oldest_snapshot = snapshots.oldest()->GetSequenceNumber();
}
}
return oldest_snapshot < obsolete_sequence;
}
std::pair<bool, int64_t> BlobDBImpl::CheckSeqFiles(bool aborted) {
if (aborted) return std::make_pair(false, -1);
std::vector<std::shared_ptr<BlobFile>> process_files;
{
uint64_t epoch_now = EpochNow();
ReadLock rl(&mutex_);
for (auto bfile : open_ttl_files_) {
{
ReadLock lockbfile_r(&bfile->mutex_);
if (bfile->expiration_range_.second > epoch_now) {
continue;
}
process_files.push_back(bfile);
}
}
}
MutexLock l(&write_mutex_);
for (auto bfile : process_files) {
CloseBlobFile(bfile);
}
return std::make_pair(true, -1);
}
Status BlobDBImpl::SyncBlobFiles() {
MutexLock l(&write_mutex_);
std::vector<std::shared_ptr<BlobFile>> process_files;
{
ReadLock rl(&mutex_);
for (auto fitr : open_ttl_files_) {
process_files.push_back(fitr);
}
if (open_non_ttl_file_ != nullptr) {
process_files.push_back(open_non_ttl_file_);
}
}
Status s;
for (auto& blob_file : process_files) {
s = blob_file->Fsync();
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to sync blob file %" PRIu64 ", status: %s",
blob_file->BlobFileNumber(), s.ToString().c_str());
return s;
}
}
s = dir_ent_->Fsync();
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failed to sync blob directory, status: %s",
s.ToString().c_str());
}
return s;
}
std::pair<bool, int64_t> BlobDBImpl::ReclaimOpenFiles(bool aborted) {
if (aborted) return std::make_pair(false, -1);
if (open_file_count_.load() < kOpenFilesTrigger) {
return std::make_pair(true, -1);
}
// in the future, we should sort by last_access_
// instead of closing every file
ReadLock rl(&mutex_);
for (auto const& ent : blob_files_) {
auto bfile = ent.second;
if (bfile->last_access_.load() == -1) continue;
WriteLock lockbfile_w(&bfile->mutex_);
CloseRandomAccessLocked(bfile);
}
return std::make_pair(true, -1);
}
// Write callback for garbage collection to check if key has been updated
// since last read. Similar to how OptimisticTransaction works. See inline
// comment in GCFileAndUpdateLSM().
class BlobDBImpl::GarbageCollectionWriteCallback : public WriteCallback {
public:
GarbageCollectionWriteCallback(ColumnFamilyData* cfd, const Slice& key,
SequenceNumber upper_bound)
: cfd_(cfd), key_(key), upper_bound_(upper_bound) {}
virtual Status Callback(DB* db) override {
auto* db_impl = reinterpret_cast<DBImpl*>(db);
auto* sv = db_impl->GetAndRefSuperVersion(cfd_);
SequenceNumber latest_seq = 0;
bool found_record_for_key = false;
bool is_blob_index = false;
Status s = db_impl->GetLatestSequenceForKey(
sv, key_, false /*cache_only*/, &latest_seq, &found_record_for_key,
&is_blob_index);
db_impl->ReturnAndCleanupSuperVersion(cfd_, sv);
if (!s.ok() && !s.IsNotFound()) {
// Error.
assert(!s.IsBusy());
return s;
}
if (s.IsNotFound()) {
assert(!found_record_for_key);
return Status::Busy("Key deleted");
}
assert(found_record_for_key);
assert(is_blob_index);
if (latest_seq > upper_bound_) {
return Status::Busy("Key overwritten");
}
return s;
}
virtual bool AllowWriteBatching() override { return false; }
private:
ColumnFamilyData* cfd_;
// Key to check
Slice key_;
// Upper bound of sequence number to proceed.
SequenceNumber upper_bound_;
};
// iterate over the blobs sequentially and check if the blob sequence number
// is the latest. If it is the latest, preserve it, otherwise delete it
// if it is TTL based, and the TTL has expired, then
// we can blow the entity if the key is still the latest or the Key is not
// found
// WHAT HAPPENS IF THE KEY HAS BEEN OVERRIDEN. Then we can drop the blob
// without doing anything if the earliest snapshot is not
// referring to that sequence number, i.e. it is later than the sequence number
// of the new key
//
// if it is not TTL based, then we can blow the key if the key has been
// DELETED in the LSM
Status BlobDBImpl::GCFileAndUpdateLSM(const std::shared_ptr<BlobFile>& bfptr,
GCStats* gc_stats) {
StopWatch gc_sw(env_, statistics_, BLOB_DB_GC_MICROS);
uint64_t now = EpochNow();
std::shared_ptr<Reader> reader =
bfptr->OpenRandomAccessReader(env_, db_options_, env_options_);
if (!reader) {
ROCKS_LOG_ERROR(db_options_.info_log,
"File sequential reader could not be opened",
bfptr->PathName().c_str());
return Status::IOError("failed to create sequential reader");
}
BlobLogHeader header;
Status s = reader->ReadHeader(&header);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Failure to read header for blob-file %s",
bfptr->PathName().c_str());
return s;
}
auto* cfh =
db_impl_->GetColumnFamilyHandleUnlocked(bfptr->column_family_id());
auto* cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(cfh)->cfd();
auto column_family_id = cfd->GetID();
bool has_ttl = header.has_ttl;
// this reads the key but skips the blob
Reader::ReadLevel shallow = Reader::kReadHeaderKey;
bool file_expired = has_ttl && now >= bfptr->GetExpirationRange().second;
if (!file_expired) {
// read the blob because you have to write it back to new file
shallow = Reader::kReadHeaderKeyBlob;
}
BlobLogRecord record;
std::shared_ptr<BlobFile> newfile;
std::shared_ptr<Writer> new_writer;
uint64_t blob_offset = 0;
while (true) {
assert(s.ok());
// Read the next blob record.
Status read_record_status =
reader->ReadRecord(&record, shallow, &blob_offset);
// Exit if we reach the end of blob file.
// TODO(yiwu): properly handle ReadRecord error.
if (!read_record_status.ok()) {
break;
}
gc_stats->blob_count++;
// Similar to OptimisticTransaction, we obtain latest_seq from
// base DB, which is guaranteed to be no smaller than the sequence of
// current key. We use a WriteCallback on write to check the key sequence
// on write. If the key sequence is larger than latest_seq, we know
// a new versions is inserted and the old blob can be disgard.
//
// We cannot use OptimisticTransaction because we need to pass
// is_blob_index flag to GetImpl.
SequenceNumber latest_seq = GetLatestSequenceNumber();
bool is_blob_index = false;
PinnableSlice index_entry;
Status get_status = db_impl_->GetImpl(
ReadOptions(), cfh, record.key, &index_entry, nullptr /*value_found*/,
nullptr /*read_callback*/, &is_blob_index);
TEST_SYNC_POINT("BlobDBImpl::GCFileAndUpdateLSM:AfterGetFromBaseDB");
if (!get_status.ok() && !get_status.IsNotFound()) {
// error
s = get_status;
ROCKS_LOG_ERROR(db_options_.info_log,
"Error while getting index entry: %s",
s.ToString().c_str());
break;
}
if (get_status.IsNotFound() || !is_blob_index) {
// Either the key is deleted or updated with a newer version whish is
// inlined in LSM.
gc_stats->num_keys_overwritten++;
gc_stats->bytes_overwritten += record.record_size();
continue;
}
BlobIndex blob_index;
s = blob_index.DecodeFrom(index_entry);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Error while decoding index entry: %s",
s.ToString().c_str());
break;
}
if (blob_index.IsInlined() ||
blob_index.file_number() != bfptr->BlobFileNumber() ||
blob_index.offset() != blob_offset) {
// Key has been overwritten. Drop the blob record.
gc_stats->num_keys_overwritten++;
gc_stats->bytes_overwritten += record.record_size();
continue;
}
GarbageCollectionWriteCallback callback(cfd, record.key, latest_seq);
// If key has expired, remove it from base DB.
// TODO(yiwu): Blob indexes will be remove by BlobIndexCompactionFilter.
// We can just drop the blob record.
if (file_expired || (has_ttl && now >= record.expiration)) {
gc_stats->num_keys_expired++;
gc_stats->bytes_expired += record.record_size();
TEST_SYNC_POINT("BlobDBImpl::GCFileAndUpdateLSM:BeforeDelete");
WriteBatch delete_batch;
Status delete_status = delete_batch.Delete(record.key);
if (delete_status.ok()) {
delete_status = db_impl_->WriteWithCallback(WriteOptions(),
&delete_batch, &callback);
}
if (!delete_status.ok() && !delete_status.IsBusy()) {
// We hit an error.
s = delete_status;
ROCKS_LOG_ERROR(db_options_.info_log,
"Error while deleting expired key: %s",
s.ToString().c_str());
break;
}
// Continue to next blob record or retry.
continue;
}
// Relocate the blob record to new file.
if (!newfile) {
// new file
std::string reason("GC of ");
reason += bfptr->PathName();
newfile = NewBlobFile(reason);
new_writer = CheckOrCreateWriterLocked(newfile);
// Can't use header beyond this point
newfile->header_ = std::move(header);
newfile->header_valid_ = true;
newfile->file_size_ = BlobLogHeader::kSize;
newfile->SetColumnFamilyId(bfptr->column_family_id());
newfile->SetHasTTL(bfptr->HasTTL());
newfile->SetCompression(bfptr->compression());
newfile->expiration_range_ = bfptr->expiration_range_;
s = new_writer->WriteHeader(newfile->header_);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"File: %s - header writing failed",
newfile->PathName().c_str());
break;
}
// We don't add the file to open_ttl_files_ or open_non_ttl_files_, to
// avoid user writes writing to the file, and avoid CheckSeqFiles close
// the file by mistake.
WriteLock wl(&mutex_);
blob_files_.insert(std::make_pair(newfile->BlobFileNumber(), newfile));
}
std::string new_index_entry;
uint64_t new_blob_offset = 0;
uint64_t new_key_offset = 0;
// write the blob to the blob log.
s = new_writer->AddRecord(record.key, record.value, record.expiration,
&new_key_offset, &new_blob_offset);
BlobIndex::EncodeBlob(&new_index_entry, newfile->BlobFileNumber(),
new_blob_offset, record.value.size(),
bdb_options_.compression);
newfile->blob_count_++;
newfile->file_size_ +=
BlobLogRecord::kHeaderSize + record.key.size() + record.value.size();
TEST_SYNC_POINT("BlobDBImpl::GCFileAndUpdateLSM:BeforeRelocate");
WriteBatch rewrite_batch;
Status rewrite_status = WriteBatchInternal::PutBlobIndex(
&rewrite_batch, column_family_id, record.key, new_index_entry);
if (rewrite_status.ok()) {
rewrite_status = db_impl_->WriteWithCallback(WriteOptions(),
&rewrite_batch, &callback);
}
if (rewrite_status.ok()) {
gc_stats->num_keys_relocated++;
gc_stats->bytes_relocated += record.record_size();
} else if (rewrite_status.IsBusy()) {
// The key is overwritten in the meanwhile. Drop the blob record.
gc_stats->num_keys_overwritten++;
gc_stats->bytes_overwritten += record.record_size();
} else {
// We hit an error.
s = rewrite_status;
ROCKS_LOG_ERROR(db_options_.info_log, "Error while relocating key: %s",
s.ToString().c_str());
break;
}
} // end of ReadRecord loop
{
WriteLock wl(&mutex_);
ObsoleteBlobFile(bfptr, GetLatestSequenceNumber(), true /*update_size*/);
}
ROCKS_LOG_INFO(
db_options_.info_log,
"%s blob file %" PRIu64 ". Total blob records: %" PRIu64
", expired: %" PRIu64 " keys/%" PRIu64
" bytes, updated or deleted by user: %" PRIu64 " keys/%" PRIu64
" bytes, rewrite to new file: %" PRIu64 " keys/%" PRIu64 " bytes.",
s.ok() ? "Successfully garbage collected" : "Failed to garbage collect",
bfptr->BlobFileNumber(), gc_stats->blob_count, gc_stats->num_keys_expired,
gc_stats->bytes_expired, gc_stats->num_keys_overwritten,
gc_stats->bytes_overwritten, gc_stats->num_keys_relocated,
gc_stats->bytes_relocated);
RecordTick(statistics_, BLOB_DB_GC_NUM_FILES);
RecordTick(statistics_, BLOB_DB_GC_NUM_KEYS_OVERWRITTEN,
gc_stats->num_keys_overwritten);
RecordTick(statistics_, BLOB_DB_GC_NUM_KEYS_EXPIRED,
gc_stats->num_keys_expired);
RecordTick(statistics_, BLOB_DB_GC_BYTES_OVERWRITTEN,
gc_stats->bytes_overwritten);
RecordTick(statistics_, BLOB_DB_GC_BYTES_EXPIRED, gc_stats->bytes_expired);
if (newfile != nullptr) {
{
MutexLock l(&write_mutex_);
CloseBlobFile(newfile);
}
total_blob_size_ += newfile->file_size_;
ROCKS_LOG_INFO(db_options_.info_log, "New blob file %" PRIu64 ".",
newfile->BlobFileNumber());
RecordTick(statistics_, BLOB_DB_GC_NUM_NEW_FILES);
RecordTick(statistics_, BLOB_DB_GC_NUM_KEYS_RELOCATED,
gc_stats->num_keys_relocated);
RecordTick(statistics_, BLOB_DB_GC_BYTES_RELOCATED,
gc_stats->bytes_relocated);
}
if (!s.ok()) {
RecordTick(statistics_, BLOB_DB_GC_FAILURES);
}
return s;
}
std::pair<bool, int64_t> BlobDBImpl::DeleteObsoleteFiles(bool aborted) {
if (aborted) return std::make_pair(false, -1);
{
ReadLock rl(&mutex_);
if (obsolete_files_.empty()) return std::make_pair(true, -1);
}
std::list<std::shared_ptr<BlobFile>> tobsolete;
{
WriteLock wl(&mutex_);
tobsolete.swap(obsolete_files_);
}
bool file_deleted = false;
for (auto iter = tobsolete.begin(); iter != tobsolete.end();) {
auto bfile = *iter;
{
ReadLock lockbfile_r(&bfile->mutex_);
if (VisibleToActiveSnapshot(bfile)) {
ROCKS_LOG_INFO(db_options_.info_log,
"Could not delete file due to snapshot failure %s",
bfile->PathName().c_str());
++iter;
continue;
}
}
ROCKS_LOG_INFO(db_options_.info_log,
"Will delete file due to snapshot success %s",
bfile->PathName().c_str());
blob_files_.erase(bfile->BlobFileNumber());
Status s = env_->DeleteFile(bfile->PathName());
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"File failed to be deleted as obsolete %s",
bfile->PathName().c_str());
++iter;
continue;
}
file_deleted = true;
ROCKS_LOG_INFO(db_options_.info_log,
"File deleted as obsolete from blob dir %s",
bfile->PathName().c_str());
iter = tobsolete.erase(iter);
}
// directory change. Fsync
if (file_deleted) {
dir_ent_->Fsync();
}
// put files back into obsolete if for some reason, delete failed
if (!tobsolete.empty()) {
WriteLock wl(&mutex_);
for (auto bfile : tobsolete) {
obsolete_files_.push_front(bfile);
}
}
return std::make_pair(!aborted, -1);
}
void BlobDBImpl::CopyBlobFiles(
std::vector<std::shared_ptr<BlobFile>>* bfiles_copy) {
ReadLock rl(&mutex_);
for (auto const& p : blob_files_) {
bfiles_copy->push_back(p.second);
}
}
std::pair<bool, int64_t> BlobDBImpl::RunGC(bool aborted) {
if (aborted) {
return std::make_pair(false, -1);
}
// TODO(yiwu): Garbage collection implementation.
// reschedule
return std::make_pair(true, -1);
}
Iterator* BlobDBImpl::NewIterator(const ReadOptions& read_options) {
auto* cfd =
reinterpret_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily())->cfd();
// Get a snapshot to avoid blob file get deleted between we
// fetch and index entry and reading from the file.
ManagedSnapshot* own_snapshot = nullptr;
const Snapshot* snapshot = read_options.snapshot;
if (snapshot == nullptr) {
own_snapshot = new ManagedSnapshot(db_);
snapshot = own_snapshot->snapshot();
}
auto* iter = db_impl_->NewIteratorImpl(
read_options, cfd, snapshot->GetSequenceNumber(),
nullptr /*read_callback*/, true /*allow_blob*/);
return new BlobDBIterator(own_snapshot, iter, this, env_, statistics_);
}
Status DestroyBlobDB(const std::string& dbname, const Options& options,
const BlobDBOptions& bdb_options) {
const ImmutableDBOptions soptions(SanitizeOptions(dbname, options));
Env* env = soptions.env;
Status status;
std::string blobdir;
blobdir = (bdb_options.path_relative) ? dbname + "/" + bdb_options.blob_dir
: bdb_options.blob_dir;
std::vector<std::string> filenames;
env->GetChildren(blobdir, &filenames);
for (const auto& f : filenames) {
uint64_t number;
FileType type;
if (ParseFileName(f, &number, &type) && type == kBlobFile) {
Status del = env->DeleteFile(blobdir + "/" + f);
if (status.ok() && !del.ok()) {
status = del;
}
}
}
env->DeleteDir(blobdir);
Status destroy = DestroyDB(dbname, options);
if (status.ok() && !destroy.ok()) {
status = destroy;
}
return status;
}
#ifndef NDEBUG
Status BlobDBImpl::TEST_GetBlobValue(const Slice& key, const Slice& index_entry,
PinnableSlice* value) {
return GetBlobValue(key, index_entry, value);
}
std::vector<std::shared_ptr<BlobFile>> BlobDBImpl::TEST_GetBlobFiles() const {
ReadLock l(&mutex_);
std::vector<std::shared_ptr<BlobFile>> blob_files;
for (auto& p : blob_files_) {
blob_files.emplace_back(p.second);
}
return blob_files;
}
std::vector<std::shared_ptr<BlobFile>> BlobDBImpl::TEST_GetObsoleteFiles()
const {
ReadLock l(&mutex_);
std::vector<std::shared_ptr<BlobFile>> obsolete_files;
for (auto& bfile : obsolete_files_) {
obsolete_files.emplace_back(bfile);
}
return obsolete_files;
}
void BlobDBImpl::TEST_DeleteObsoleteFiles() {
DeleteObsoleteFiles(false /*abort*/);
}
Status BlobDBImpl::TEST_CloseBlobFile(std::shared_ptr<BlobFile>& bfile) {
MutexLock l(&write_mutex_);
return CloseBlobFile(bfile);
}
void BlobDBImpl::TEST_ObsoleteBlobFile(std::shared_ptr<BlobFile>& blob_file,
SequenceNumber obsolete_seq,
bool update_size) {
return ObsoleteBlobFile(blob_file, obsolete_seq, update_size);
}
Status BlobDBImpl::TEST_GCFileAndUpdateLSM(std::shared_ptr<BlobFile>& bfile,
GCStats* gc_stats) {
return GCFileAndUpdateLSM(bfile, gc_stats);
}
void BlobDBImpl::TEST_RunGC() { RunGC(false /*abort*/); }
uint64_t BlobDBImpl::TEST_live_sst_size() { return live_sst_size_.load(); }
#endif // !NDEBUG
} // namespace blob_db
} // namespace rocksdb
#endif // ROCKSDB_LITE
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