// 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). #include "db/db_impl/db_impl_secondary.h" #include #include "db/arena_wrapped_db_iter.h" #include "db/merge_context.h" #include "logging/auto_roll_logger.h" #include "monitoring/perf_context_imp.h" #include "util/cast_util.h" namespace ROCKSDB_NAMESPACE { #ifndef ROCKSDB_LITE DBImplSecondary::DBImplSecondary(const DBOptions& db_options, const std::string& dbname) : DBImpl(db_options, dbname) { ROCKS_LOG_INFO(immutable_db_options_.info_log, "Opening the db in secondary mode"); LogFlush(immutable_db_options_.info_log); } DBImplSecondary::~DBImplSecondary() {} Status DBImplSecondary::Recover( const std::vector& column_families, bool /*readonly*/, bool /*error_if_wal_file_exists*/, bool /*error_if_data_exists_in_wals*/, uint64_t*) { mutex_.AssertHeld(); JobContext job_context(0); Status s; s = static_cast(versions_.get()) ->Recover(column_families, &manifest_reader_, &manifest_reporter_, &manifest_reader_status_); if (!s.ok()) { return s; } if (immutable_db_options_.paranoid_checks && s.ok()) { s = CheckConsistency(); } // Initial max_total_in_memory_state_ before recovery logs. max_total_in_memory_state_ = 0; for (auto cfd : *versions_->GetColumnFamilySet()) { auto* mutable_cf_options = cfd->GetLatestMutableCFOptions(); max_total_in_memory_state_ += mutable_cf_options->write_buffer_size * mutable_cf_options->max_write_buffer_number; } if (s.ok()) { default_cf_handle_ = new ColumnFamilyHandleImpl( versions_->GetColumnFamilySet()->GetDefault(), this, &mutex_); default_cf_internal_stats_ = default_cf_handle_->cfd()->internal_stats(); single_column_family_mode_ = versions_->GetColumnFamilySet()->NumberOfColumnFamilies() == 1; std::unordered_set cfds_changed; s = FindAndRecoverLogFiles(&cfds_changed, &job_context); } if (s.IsPathNotFound()) { ROCKS_LOG_INFO(immutable_db_options_.info_log, "Secondary tries to read WAL, but WAL file(s) have already " "been purged by primary."); s = Status::OK(); } // TODO: update options_file_number_ needed? job_context.Clean(); return s; } // find new WAL and apply them in order to the secondary instance Status DBImplSecondary::FindAndRecoverLogFiles( std::unordered_set* cfds_changed, JobContext* job_context) { assert(nullptr != cfds_changed); assert(nullptr != job_context); Status s; std::vector logs; s = FindNewLogNumbers(&logs); if (s.ok() && !logs.empty()) { SequenceNumber next_sequence(kMaxSequenceNumber); s = RecoverLogFiles(logs, &next_sequence, cfds_changed, job_context); } return s; } // List wal_dir and find all new WALs, return these log numbers Status DBImplSecondary::FindNewLogNumbers(std::vector* logs) { assert(logs != nullptr); std::vector filenames; Status s; s = env_->GetChildren(immutable_db_options_.wal_dir, &filenames); if (s.IsNotFound()) { return Status::InvalidArgument("Failed to open wal_dir", immutable_db_options_.wal_dir); } else if (!s.ok()) { return s; } // if log_readers_ is non-empty, it means we have applied all logs with log // numbers smaller than the smallest log in log_readers_, so there is no // need to pass these logs to RecoverLogFiles uint64_t log_number_min = 0; if (!log_readers_.empty()) { log_number_min = log_readers_.begin()->first; } for (size_t i = 0; i < filenames.size(); i++) { uint64_t number; FileType type; if (ParseFileName(filenames[i], &number, &type) && type == kWalFile && number >= log_number_min) { logs->push_back(number); } } // Recover logs in the order that they were generated if (!logs->empty()) { std::sort(logs->begin(), logs->end()); } return s; } Status DBImplSecondary::MaybeInitLogReader( uint64_t log_number, log::FragmentBufferedReader** log_reader) { auto iter = log_readers_.find(log_number); // make sure the log file is still present if (iter == log_readers_.end() || iter->second->reader_->GetLogNumber() != log_number) { // delete the obsolete log reader if log number mismatch if (iter != log_readers_.end()) { log_readers_.erase(iter); } // initialize log reader from log_number // TODO: min_log_number_to_keep_2pc check needed? // Open the log file std::string fname = LogFileName(immutable_db_options_.wal_dir, log_number); ROCKS_LOG_INFO(immutable_db_options_.info_log, "Recovering log #%" PRIu64 " mode %d", log_number, static_cast(immutable_db_options_.wal_recovery_mode)); std::unique_ptr file_reader; { std::unique_ptr file; Status status = fs_->NewSequentialFile( fname, fs_->OptimizeForLogRead(file_options_), &file, nullptr); if (!status.ok()) { *log_reader = nullptr; return status; } file_reader.reset(new SequentialFileReader( std::move(file), fname, immutable_db_options_.log_readahead_size, io_tracer_)); } // Create the log reader. LogReaderContainer* log_reader_container = new LogReaderContainer( env_, immutable_db_options_.info_log, std::move(fname), std::move(file_reader), log_number); log_readers_.insert(std::make_pair( log_number, std::unique_ptr(log_reader_container))); } iter = log_readers_.find(log_number); assert(iter != log_readers_.end()); *log_reader = iter->second->reader_; return Status::OK(); } // After manifest recovery, replay WALs and refresh log_readers_ if necessary // REQUIRES: log_numbers are sorted in ascending order Status DBImplSecondary::RecoverLogFiles( const std::vector& log_numbers, SequenceNumber* next_sequence, std::unordered_set* cfds_changed, JobContext* job_context) { assert(nullptr != cfds_changed); assert(nullptr != job_context); mutex_.AssertHeld(); Status status; for (auto log_number : log_numbers) { log::FragmentBufferedReader* reader = nullptr; status = MaybeInitLogReader(log_number, &reader); if (!status.ok()) { return status; } assert(reader != nullptr); } for (auto log_number : log_numbers) { auto it = log_readers_.find(log_number); assert(it != log_readers_.end()); log::FragmentBufferedReader* reader = it->second->reader_; Status* wal_read_status = it->second->status_; assert(wal_read_status); // Manually update the file number allocation counter in VersionSet. versions_->MarkFileNumberUsed(log_number); // Determine if we should tolerate incomplete records at the tail end of the // Read all the records and add to a memtable std::string scratch; Slice record; WriteBatch batch; while (reader->ReadRecord(&record, &scratch, immutable_db_options_.wal_recovery_mode) && wal_read_status->ok() && status.ok()) { if (record.size() < WriteBatchInternal::kHeader) { reader->GetReporter()->Corruption( record.size(), Status::Corruption("log record too small")); continue; } status = WriteBatchInternal::SetContents(&batch, record); if (!status.ok()) { break; } SequenceNumber seq_of_batch = WriteBatchInternal::Sequence(&batch); std::vector column_family_ids; status = CollectColumnFamilyIdsFromWriteBatch(batch, &column_family_ids); if (status.ok()) { for (const auto id : column_family_ids) { ColumnFamilyData* cfd = versions_->GetColumnFamilySet()->GetColumnFamily(id); if (cfd == nullptr) { continue; } if (cfds_changed->count(cfd) == 0) { cfds_changed->insert(cfd); } const std::vector& l0_files = cfd->current()->storage_info()->LevelFiles(0); SequenceNumber seq = l0_files.empty() ? 0 : l0_files.back()->fd.largest_seqno; // If the write batch's sequence number is smaller than the last // sequence number of the largest sequence persisted for this column // family, then its data must reside in an SST that has already been // added in the prior MANIFEST replay. if (seq_of_batch <= seq) { continue; } auto curr_log_num = port::kMaxUint64; if (cfd_to_current_log_.count(cfd) > 0) { curr_log_num = cfd_to_current_log_[cfd]; } // If the active memtable contains records added by replaying an // earlier WAL, then we need to seal the memtable, add it to the // immutable memtable list and create a new active memtable. if (!cfd->mem()->IsEmpty() && (curr_log_num == port::kMaxUint64 || curr_log_num != log_number)) { const MutableCFOptions mutable_cf_options = *cfd->GetLatestMutableCFOptions(); MemTable* new_mem = cfd->ConstructNewMemtable(mutable_cf_options, seq_of_batch); cfd->mem()->SetNextLogNumber(log_number); cfd->imm()->Add(cfd->mem(), &job_context->memtables_to_free); new_mem->Ref(); cfd->SetMemtable(new_mem); } } bool has_valid_writes = false; status = WriteBatchInternal::InsertInto( &batch, column_family_memtables_.get(), nullptr /* flush_scheduler */, nullptr /* trim_history_scheduler*/, true, log_number, this, false /* concurrent_memtable_writes */, next_sequence, &has_valid_writes, seq_per_batch_, batch_per_txn_); } // If column family was not found, it might mean that the WAL write // batch references to the column family that was dropped after the // insert. We don't want to fail the whole write batch in that case -- // we just ignore the update. // That's why we set ignore missing column families to true // passing null flush_scheduler will disable memtable flushing which is // needed for secondary instances if (status.ok()) { for (const auto id : column_family_ids) { ColumnFamilyData* cfd = versions_->GetColumnFamilySet()->GetColumnFamily(id); if (cfd == nullptr) { continue; } std::unordered_map::iterator iter = cfd_to_current_log_.find(cfd); if (iter == cfd_to_current_log_.end()) { cfd_to_current_log_.insert({cfd, log_number}); } else if (log_number > iter->second) { iter->second = log_number; } } auto last_sequence = *next_sequence - 1; if ((*next_sequence != kMaxSequenceNumber) && (versions_->LastSequence() <= last_sequence)) { versions_->SetLastAllocatedSequence(last_sequence); versions_->SetLastPublishedSequence(last_sequence); versions_->SetLastSequence(last_sequence); } } else { // We are treating this as a failure while reading since we read valid // blocks that do not form coherent data reader->GetReporter()->Corruption(record.size(), status); } } if (status.ok() && !wal_read_status->ok()) { status = *wal_read_status; } if (!status.ok()) { return status; } } // remove logreaders from map after successfully recovering the WAL if (log_readers_.size() > 1) { auto erase_iter = log_readers_.begin(); std::advance(erase_iter, log_readers_.size() - 1); log_readers_.erase(log_readers_.begin(), erase_iter); } return status; } // Implementation of the DB interface Status DBImplSecondary::Get(const ReadOptions& read_options, ColumnFamilyHandle* column_family, const Slice& key, PinnableSlice* value) { return GetImpl(read_options, column_family, key, value); } Status DBImplSecondary::GetImpl(const ReadOptions& read_options, ColumnFamilyHandle* column_family, const Slice& key, PinnableSlice* pinnable_val) { assert(pinnable_val != nullptr); PERF_CPU_TIMER_GUARD(get_cpu_nanos, clock_); StopWatch sw(clock_, stats_, DB_GET); PERF_TIMER_GUARD(get_snapshot_time); auto cfh = static_cast(column_family); ColumnFamilyData* cfd = cfh->cfd(); if (tracer_) { InstrumentedMutexLock lock(&trace_mutex_); if (tracer_) { tracer_->Get(column_family, key); } } // Acquire SuperVersion SuperVersion* super_version = GetAndRefSuperVersion(cfd); SequenceNumber snapshot = versions_->LastSequence(); MergeContext merge_context; SequenceNumber max_covering_tombstone_seq = 0; Status s; LookupKey lkey(key, snapshot); PERF_TIMER_STOP(get_snapshot_time); bool done = false; if (super_version->mem->Get(lkey, pinnable_val->GetSelf(), /*timestamp=*/nullptr, &s, &merge_context, &max_covering_tombstone_seq, read_options)) { done = true; pinnable_val->PinSelf(); RecordTick(stats_, MEMTABLE_HIT); } else if ((s.ok() || s.IsMergeInProgress()) && super_version->imm->Get( lkey, pinnable_val->GetSelf(), /*timestamp=*/nullptr, &s, &merge_context, &max_covering_tombstone_seq, read_options)) { done = true; pinnable_val->PinSelf(); RecordTick(stats_, MEMTABLE_HIT); } if (!done && !s.ok() && !s.IsMergeInProgress()) { ReturnAndCleanupSuperVersion(cfd, super_version); return s; } if (!done) { PERF_TIMER_GUARD(get_from_output_files_time); super_version->current->Get(read_options, lkey, pinnable_val, /*timestamp=*/nullptr, &s, &merge_context, &max_covering_tombstone_seq); RecordTick(stats_, MEMTABLE_MISS); } { PERF_TIMER_GUARD(get_post_process_time); ReturnAndCleanupSuperVersion(cfd, super_version); RecordTick(stats_, NUMBER_KEYS_READ); size_t size = pinnable_val->size(); RecordTick(stats_, BYTES_READ, size); RecordTimeToHistogram(stats_, BYTES_PER_READ, size); PERF_COUNTER_ADD(get_read_bytes, size); } return s; } Iterator* DBImplSecondary::NewIterator(const ReadOptions& read_options, ColumnFamilyHandle* column_family) { if (read_options.managed) { return NewErrorIterator( Status::NotSupported("Managed iterator is not supported anymore.")); } if (read_options.read_tier == kPersistedTier) { return NewErrorIterator(Status::NotSupported( "ReadTier::kPersistedData is not yet supported in iterators.")); } Iterator* result = nullptr; auto cfh = static_cast_with_check(column_family); auto cfd = cfh->cfd(); ReadCallback* read_callback = nullptr; // No read callback provided. if (read_options.tailing) { return NewErrorIterator(Status::NotSupported( "tailing iterator not supported in secondary mode")); } else if (read_options.snapshot != nullptr) { // TODO (yanqin) support snapshot. return NewErrorIterator( Status::NotSupported("snapshot not supported in secondary mode")); } else { auto snapshot = versions_->LastSequence(); result = NewIteratorImpl(read_options, cfd, snapshot, read_callback); } return result; } ArenaWrappedDBIter* DBImplSecondary::NewIteratorImpl( const ReadOptions& read_options, ColumnFamilyData* cfd, SequenceNumber snapshot, ReadCallback* read_callback) { assert(nullptr != cfd); SuperVersion* super_version = cfd->GetReferencedSuperVersion(this); auto db_iter = NewArenaWrappedDbIterator( env_, read_options, *cfd->ioptions(), super_version->mutable_cf_options, super_version->current, snapshot, super_version->mutable_cf_options.max_sequential_skip_in_iterations, super_version->version_number, read_callback); auto internal_iter = NewInternalIterator( db_iter->GetReadOptions(), cfd, super_version, db_iter->GetArena(), db_iter->GetRangeDelAggregator(), snapshot, /* allow_unprepared_value */ true); db_iter->SetIterUnderDBIter(internal_iter); return db_iter; } Status DBImplSecondary::NewIterators( const ReadOptions& read_options, const std::vector& column_families, std::vector* iterators) { if (read_options.managed) { return Status::NotSupported("Managed iterator is not supported anymore."); } if (read_options.read_tier == kPersistedTier) { return Status::NotSupported( "ReadTier::kPersistedData is not yet supported in iterators."); } ReadCallback* read_callback = nullptr; // No read callback provided. if (iterators == nullptr) { return Status::InvalidArgument("iterators not allowed to be nullptr"); } iterators->clear(); iterators->reserve(column_families.size()); if (read_options.tailing) { return Status::NotSupported( "tailing iterator not supported in secondary mode"); } else if (read_options.snapshot != nullptr) { // TODO (yanqin) support snapshot. return Status::NotSupported("snapshot not supported in secondary mode"); } else { SequenceNumber read_seq = versions_->LastSequence(); for (auto cfh : column_families) { ColumnFamilyData* cfd = static_cast(cfh)->cfd(); iterators->push_back( NewIteratorImpl(read_options, cfd, read_seq, read_callback)); } } return Status::OK(); } Status DBImplSecondary::CheckConsistency() { mutex_.AssertHeld(); Status s = DBImpl::CheckConsistency(); // If DBImpl::CheckConsistency() which is stricter returns success, then we // do not need to give a second chance. if (s.ok()) { return s; } // It's possible that DBImpl::CheckConssitency() can fail because the primary // may have removed certain files, causing the GetFileSize(name) call to // fail and returning a PathNotFound. In this case, we take a best-effort // approach and just proceed. TEST_SYNC_POINT_CALLBACK( "DBImplSecondary::CheckConsistency:AfterFirstAttempt", &s); if (immutable_db_options_.skip_checking_sst_file_sizes_on_db_open) { return Status::OK(); } std::vector metadata; versions_->GetLiveFilesMetaData(&metadata); std::string corruption_messages; for (const auto& md : metadata) { // md.name has a leading "/". std::string file_path = md.db_path + md.name; uint64_t fsize = 0; s = env_->GetFileSize(file_path, &fsize); if (!s.ok() && (env_->GetFileSize(Rocks2LevelTableFileName(file_path), &fsize).ok() || s.IsPathNotFound())) { s = Status::OK(); } if (!s.ok()) { corruption_messages += "Can't access " + md.name + ": " + s.ToString() + "\n"; } } return corruption_messages.empty() ? Status::OK() : Status::Corruption(corruption_messages); } Status DBImplSecondary::TryCatchUpWithPrimary() { assert(versions_.get() != nullptr); assert(manifest_reader_.get() != nullptr); Status s; // read the manifest and apply new changes to the secondary instance std::unordered_set cfds_changed; JobContext job_context(0, true /*create_superversion*/); { InstrumentedMutexLock lock_guard(&mutex_); s = static_cast_with_check(versions_.get()) ->ReadAndApply(&mutex_, &manifest_reader_, manifest_reader_status_.get(), &cfds_changed); ROCKS_LOG_INFO(immutable_db_options_.info_log, "Last sequence is %" PRIu64, static_cast(versions_->LastSequence())); for (ColumnFamilyData* cfd : cfds_changed) { if (cfd->IsDropped()) { ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] is dropped\n", cfd->GetName().c_str()); continue; } VersionStorageInfo::LevelSummaryStorage tmp; ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] Level summary: %s\n", cfd->GetName().c_str(), cfd->current()->storage_info()->LevelSummary(&tmp)); } // list wal_dir to discover new WALs and apply new changes to the secondary // instance if (s.ok()) { s = FindAndRecoverLogFiles(&cfds_changed, &job_context); } if (s.IsPathNotFound()) { ROCKS_LOG_INFO( immutable_db_options_.info_log, "Secondary tries to read WAL, but WAL file(s) have already " "been purged by primary."); s = Status::OK(); } if (s.ok()) { for (auto cfd : cfds_changed) { cfd->imm()->RemoveOldMemTables(cfd->GetLogNumber(), &job_context.memtables_to_free); auto& sv_context = job_context.superversion_contexts.back(); cfd->InstallSuperVersion(&sv_context, &mutex_); sv_context.NewSuperVersion(); } } } job_context.Clean(); // Cleanup unused, obsolete files. JobContext purge_files_job_context(0); { InstrumentedMutexLock lock_guard(&mutex_); // Currently, secondary instance does not own the database files, thus it // is unnecessary for the secondary to force full scan. FindObsoleteFiles(&purge_files_job_context, /*force=*/false); } if (purge_files_job_context.HaveSomethingToDelete()) { PurgeObsoleteFiles(purge_files_job_context); } purge_files_job_context.Clean(); return s; } Status DB::OpenAsSecondary(const Options& options, const std::string& dbname, const std::string& secondary_path, DB** dbptr) { *dbptr = nullptr; DBOptions db_options(options); ColumnFamilyOptions cf_options(options); std::vector column_families; column_families.emplace_back(kDefaultColumnFamilyName, cf_options); std::vector handles; Status s = DB::OpenAsSecondary(db_options, dbname, secondary_path, column_families, &handles, dbptr); if (s.ok()) { assert(handles.size() == 1); delete handles[0]; } return s; } Status DB::OpenAsSecondary( const DBOptions& db_options, const std::string& dbname, const std::string& secondary_path, const std::vector& column_families, std::vector* handles, DB** dbptr) { *dbptr = nullptr; if (db_options.max_open_files != -1) { // TODO (yanqin) maybe support max_open_files != -1 by creating hard links // on SST files so that db secondary can still have access to old SSTs // while primary instance may delete original. return Status::InvalidArgument("require max_open_files to be -1"); } DBOptions tmp_opts(db_options); Status s; if (nullptr == tmp_opts.info_log) { s = CreateLoggerFromOptions(secondary_path, tmp_opts, &tmp_opts.info_log); if (!s.ok()) { tmp_opts.info_log = nullptr; } } handles->clear(); DBImplSecondary* impl = new DBImplSecondary(tmp_opts, dbname); impl->versions_.reset(new ReactiveVersionSet( dbname, &impl->immutable_db_options_, impl->file_options_, impl->table_cache_.get(), impl->write_buffer_manager_, &impl->write_controller_, impl->io_tracer_)); impl->column_family_memtables_.reset( new ColumnFamilyMemTablesImpl(impl->versions_->GetColumnFamilySet())); impl->wal_in_db_path_ = IsWalDirSameAsDBPath(&impl->immutable_db_options_); impl->mutex_.Lock(); s = impl->Recover(column_families, true, false, false); if (s.ok()) { for (auto cf : column_families) { auto cfd = impl->versions_->GetColumnFamilySet()->GetColumnFamily(cf.name); if (nullptr == cfd) { s = Status::InvalidArgument("Column family not found", cf.name); break; } handles->push_back(new ColumnFamilyHandleImpl(cfd, impl, &impl->mutex_)); } } SuperVersionContext sv_context(true /* create_superversion */); if (s.ok()) { for (auto cfd : *impl->versions_->GetColumnFamilySet()) { sv_context.NewSuperVersion(); cfd->InstallSuperVersion(&sv_context, &impl->mutex_); } } impl->mutex_.Unlock(); sv_context.Clean(); if (s.ok()) { *dbptr = impl; for (auto h : *handles) { impl->NewThreadStatusCfInfo( static_cast_with_check(h)->cfd()); } } else { for (auto h : *handles) { delete h; } handles->clear(); delete impl; } return s; } #else // !ROCKSDB_LITE Status DB::OpenAsSecondary(const Options& /*options*/, const std::string& /*name*/, const std::string& /*secondary_path*/, DB** /*dbptr*/) { return Status::NotSupported("Not supported in ROCKSDB_LITE."); } Status DB::OpenAsSecondary( const DBOptions& /*db_options*/, const std::string& /*dbname*/, const std::string& /*secondary_path*/, const std::vector& /*column_families*/, std::vector* /*handles*/, DB** /*dbptr*/) { return Status::NotSupported("Not supported in ROCKSDB_LITE."); } #endif // !ROCKSDB_LITE } // namespace ROCKSDB_NAMESPACE