// 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/db_impl.h" #ifndef __STDC_FORMAT_MACROS #define __STDC_FORMAT_MACROS #endif #include #include "db/builder.h" #include "db/error_handler.h" #include "db/event_helpers.h" #include "monitoring/iostats_context_imp.h" #include "monitoring/perf_context_imp.h" #include "monitoring/thread_status_updater.h" #include "monitoring/thread_status_util.h" #include "util/concurrent_task_limiter_impl.h" #include "util/sst_file_manager_impl.h" #include "util/sync_point.h" namespace rocksdb { bool DBImpl::EnoughRoomForCompaction( ColumnFamilyData* cfd, const std::vector& inputs, bool* sfm_reserved_compact_space, LogBuffer* log_buffer) { // Check if we have enough room to do the compaction bool enough_room = true; #ifndef ROCKSDB_LITE auto sfm = static_cast( immutable_db_options_.sst_file_manager.get()); if (sfm) { // Pass the current bg_error_ to SFM so it can decide what checks to // perform. If this DB instance hasn't seen any error yet, the SFM can be // optimistic and not do disk space checks enough_room = sfm->EnoughRoomForCompaction(cfd, inputs, error_handler_.GetBGError()); if (enough_room) { *sfm_reserved_compact_space = true; } } #else (void)cfd; (void)inputs; (void)sfm_reserved_compact_space; #endif // ROCKSDB_LITE if (!enough_room) { // Just in case tests want to change the value of enough_room TEST_SYNC_POINT_CALLBACK( "DBImpl::BackgroundCompaction():CancelledCompaction", &enough_room); ROCKS_LOG_BUFFER(log_buffer, "Cancelled compaction because not enough room"); RecordTick(stats_, COMPACTION_CANCELLED, 1); } return enough_room; } bool DBImpl::RequestCompactionToken(ColumnFamilyData* cfd, bool force, std::unique_ptr* token, LogBuffer* log_buffer) { assert(*token == nullptr); auto limiter = static_cast( cfd->ioptions()->compaction_thread_limiter.get()); if (limiter == nullptr) { return true; } *token = limiter->GetToken(force); if (*token != nullptr) { ROCKS_LOG_BUFFER(log_buffer, "Thread limiter [%s] increase [%s] compaction task, " "force: %s, tasks after: %d", limiter->GetName().c_str(), cfd->GetName().c_str(), force ? "true" : "false", limiter->GetOutstandingTask()); return true; } return false; } Status DBImpl::SyncClosedLogs(JobContext* job_context) { TEST_SYNC_POINT("DBImpl::SyncClosedLogs:Start"); mutex_.AssertHeld(); autovector logs_to_sync; uint64_t current_log_number = logfile_number_; while (logs_.front().number < current_log_number && logs_.front().getting_synced) { log_sync_cv_.Wait(); } for (auto it = logs_.begin(); it != logs_.end() && it->number < current_log_number; ++it) { auto& log = *it; assert(!log.getting_synced); log.getting_synced = true; logs_to_sync.push_back(log.writer); } Status s; if (!logs_to_sync.empty()) { mutex_.Unlock(); for (log::Writer* log : logs_to_sync) { ROCKS_LOG_INFO(immutable_db_options_.info_log, "[JOB %d] Syncing log #%" PRIu64, job_context->job_id, log->get_log_number()); s = log->file()->Sync(immutable_db_options_.use_fsync); if (!s.ok()) { break; } } if (s.ok()) { s = directories_.GetWalDir()->Fsync(); } mutex_.Lock(); // "number <= current_log_number - 1" is equivalent to // "number < current_log_number". MarkLogsSynced(current_log_number - 1, true, s); if (!s.ok()) { error_handler_.SetBGError(s, BackgroundErrorReason::kFlush); TEST_SYNC_POINT("DBImpl::SyncClosedLogs:Failed"); return s; } } return s; } Status DBImpl::FlushMemTableToOutputFile( ColumnFamilyData* cfd, const MutableCFOptions& mutable_cf_options, bool* made_progress, JobContext* job_context, SuperVersionContext* superversion_context, std::vector& snapshot_seqs, SequenceNumber earliest_write_conflict_snapshot, SnapshotChecker* snapshot_checker, LogBuffer* log_buffer) { mutex_.AssertHeld(); assert(cfd->imm()->NumNotFlushed() != 0); assert(cfd->imm()->IsFlushPending()); FlushJob flush_job( dbname_, cfd, immutable_db_options_, mutable_cf_options, nullptr /* memtable_id */, env_options_for_compaction_, versions_.get(), &mutex_, &shutting_down_, snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker, job_context, log_buffer, directories_.GetDbDir(), GetDataDir(cfd, 0U), GetCompressionFlush(*cfd->ioptions(), mutable_cf_options), stats_, &event_logger_, mutable_cf_options.report_bg_io_stats, true /* sync_output_directory */, true /* write_manifest */); FileMetaData file_meta; TEST_SYNC_POINT("DBImpl::FlushMemTableToOutputFile:BeforePickMemtables"); flush_job.PickMemTable(); TEST_SYNC_POINT("DBImpl::FlushMemTableToOutputFile:AfterPickMemtables"); #ifndef ROCKSDB_LITE // may temporarily unlock and lock the mutex. NotifyOnFlushBegin(cfd, &file_meta, mutable_cf_options, job_context->job_id, flush_job.GetTableProperties()); #endif // ROCKSDB_LITE Status s; if (logfile_number_ > 0 && versions_->GetColumnFamilySet()->NumberOfColumnFamilies() > 1) { // If there are more than one column families, we need to make sure that // all the log files except the most recent one are synced. Otherwise if // the host crashes after flushing and before WAL is persistent, the // flushed SST may contain data from write batches whose updates to // other column families are missing. // SyncClosedLogs() may unlock and re-lock the db_mutex. s = SyncClosedLogs(job_context); } else { TEST_SYNC_POINT("DBImpl::SyncClosedLogs:Skip"); } // Within flush_job.Run, rocksdb may call event listener to notify // file creation and deletion. // // Note that flush_job.Run will unlock and lock the db_mutex, // and EventListener callback will be called when the db_mutex // is unlocked by the current thread. if (s.ok()) { s = flush_job.Run(&logs_with_prep_tracker_, &file_meta); } else { flush_job.Cancel(); } if (s.ok()) { InstallSuperVersionAndScheduleWork(cfd, superversion_context, mutable_cf_options); if (made_progress) { *made_progress = true; } VersionStorageInfo::LevelSummaryStorage tmp; ROCKS_LOG_BUFFER(log_buffer, "[%s] Level summary: %s\n", cfd->GetName().c_str(), cfd->current()->storage_info()->LevelSummary(&tmp)); } if (!s.ok() && !s.IsShutdownInProgress()) { Status new_bg_error = s; error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush); } if (s.ok()) { #ifndef ROCKSDB_LITE // may temporarily unlock and lock the mutex. NotifyOnFlushCompleted(cfd, &file_meta, mutable_cf_options, job_context->job_id, flush_job.GetTableProperties()); auto sfm = static_cast( immutable_db_options_.sst_file_manager.get()); if (sfm) { // Notify sst_file_manager that a new file was added std::string file_path = MakeTableFileName( cfd->ioptions()->cf_paths[0].path, file_meta.fd.GetNumber()); sfm->OnAddFile(file_path); if (sfm->IsMaxAllowedSpaceReached()) { Status new_bg_error = Status::SpaceLimit("Max allowed space was reached"); TEST_SYNC_POINT_CALLBACK( "DBImpl::FlushMemTableToOutputFile:MaxAllowedSpaceReached", &new_bg_error); error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush); } } #endif // ROCKSDB_LITE } return s; } Status DBImpl::FlushMemTablesToOutputFiles( const autovector& bg_flush_args, bool* made_progress, JobContext* job_context, LogBuffer* log_buffer) { if (immutable_db_options_.atomic_flush) { return AtomicFlushMemTablesToOutputFiles(bg_flush_args, made_progress, job_context, log_buffer); } std::vector snapshot_seqs; SequenceNumber earliest_write_conflict_snapshot; SnapshotChecker* snapshot_checker; GetSnapshotContext(job_context, &snapshot_seqs, &earliest_write_conflict_snapshot, &snapshot_checker); Status status; for (auto& arg : bg_flush_args) { ColumnFamilyData* cfd = arg.cfd_; MutableCFOptions mutable_cf_options = *cfd->GetLatestMutableCFOptions(); SuperVersionContext* superversion_context = arg.superversion_context_; Status s = FlushMemTableToOutputFile( cfd, mutable_cf_options, made_progress, job_context, superversion_context, snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker, log_buffer); if (!s.ok()) { status = s; if (!s.IsShutdownInProgress()) { // At this point, DB is not shutting down, nor is cfd dropped. // Something is wrong, thus we break out of the loop. break; } } } return status; } /* * Atomically flushes multiple column families. * * For each column family, all memtables with ID smaller than or equal to the * ID specified in bg_flush_args will be flushed. Only after all column * families finish flush will this function commit to MANIFEST. If any of the * column families are not flushed successfully, this function does not have * any side-effect on the state of the database. */ Status DBImpl::AtomicFlushMemTablesToOutputFiles( const autovector& bg_flush_args, bool* made_progress, JobContext* job_context, LogBuffer* log_buffer) { mutex_.AssertHeld(); autovector cfds; for (const auto& arg : bg_flush_args) { cfds.emplace_back(arg.cfd_); } #ifndef NDEBUG for (const auto cfd : cfds) { assert(cfd->imm()->NumNotFlushed() != 0); assert(cfd->imm()->IsFlushPending()); } #endif /* !NDEBUG */ std::vector snapshot_seqs; SequenceNumber earliest_write_conflict_snapshot; SnapshotChecker* snapshot_checker; GetSnapshotContext(job_context, &snapshot_seqs, &earliest_write_conflict_snapshot, &snapshot_checker); autovector distinct_output_dirs; std::vector jobs; std::vector all_mutable_cf_options; int num_cfs = static_cast(cfds.size()); all_mutable_cf_options.reserve(num_cfs); for (int i = 0; i < num_cfs; ++i) { auto cfd = cfds[i]; Directory* data_dir = GetDataDir(cfd, 0U); // Add to distinct output directories if eligible. Use linear search. Since // the number of elements in the vector is not large, performance should be // tolerable. bool found = false; for (const auto dir : distinct_output_dirs) { if (dir == data_dir) { found = true; break; } } if (!found) { distinct_output_dirs.emplace_back(data_dir); } all_mutable_cf_options.emplace_back(*cfd->GetLatestMutableCFOptions()); const MutableCFOptions& mutable_cf_options = all_mutable_cf_options.back(); const uint64_t* max_memtable_id = &(bg_flush_args[i].max_memtable_id_); jobs.emplace_back( dbname_, cfds[i], immutable_db_options_, mutable_cf_options, max_memtable_id, env_options_for_compaction_, versions_.get(), &mutex_, &shutting_down_, snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker, job_context, log_buffer, directories_.GetDbDir(), data_dir, GetCompressionFlush(*cfd->ioptions(), mutable_cf_options), stats_, &event_logger_, mutable_cf_options.report_bg_io_stats, false /* sync_output_directory */, false /* write_manifest */); jobs.back().PickMemTable(); } autovector file_meta; Status s; assert(num_cfs == static_cast(jobs.size())); for (int i = 0; i != num_cfs; ++i) { file_meta.emplace_back(); #ifndef ROCKSDB_LITE const MutableCFOptions& mutable_cf_options = *cfds[i]->GetLatestMutableCFOptions(); // may temporarily unlock and lock the mutex. NotifyOnFlushBegin(cfds[i], &file_meta[i], mutable_cf_options, job_context->job_id, jobs[i].GetTableProperties()); #endif /* !ROCKSDB_LITE */ } if (logfile_number_ > 0) { // TODO (yanqin) investigate whether we should sync the closed logs for // single column family case. s = SyncClosedLogs(job_context); } // exec_status stores the execution status of flush_jobs as // autovector> exec_status; for (int i = 0; i != num_cfs; ++i) { // Initially all jobs are not executed, with status OK. exec_status.emplace_back(false, Status::OK()); } if (s.ok()) { // TODO (yanqin): parallelize jobs with threads. for (int i = 1; i != num_cfs; ++i) { exec_status[i].second = jobs[i].Run(&logs_with_prep_tracker_, &file_meta[i]); exec_status[i].first = true; } if (num_cfs > 1) { TEST_SYNC_POINT( "DBImpl::AtomicFlushMemTablesToOutputFiles:SomeFlushJobsComplete:1"); TEST_SYNC_POINT( "DBImpl::AtomicFlushMemTablesToOutputFiles:SomeFlushJobsComplete:2"); } exec_status[0].second = jobs[0].Run(&logs_with_prep_tracker_, &file_meta[0]); exec_status[0].first = true; Status error_status; for (const auto& e : exec_status) { if (!e.second.ok()) { s = e.second; if (!e.second.IsShutdownInProgress()) { // If a flush job did not return OK, and the CF is not dropped, and // the DB is not shutting down, then we have to return this result to // caller later. error_status = e.second; } } } s = error_status.ok() ? s : error_status; } if (s.ok() || s.IsShutdownInProgress()) { // Sync on all distinct output directories. for (auto dir : distinct_output_dirs) { if (dir != nullptr) { s = dir->Fsync(); if (!s.ok()) { break; } } } } if (s.ok()) { auto wait_to_install_func = [&]() { bool ready = true; for (size_t i = 0; i != cfds.size(); ++i) { const auto& mems = jobs[i].GetMemTables(); if (cfds[i]->IsDropped()) { // If the column family is dropped, then do not wait. continue; } else if (!mems.empty() && cfds[i]->imm()->GetEarliestMemTableID() < mems[0]->GetID()) { // If a flush job needs to install the flush result for mems and // mems[0] is not the earliest memtable, it means another thread must // be installing flush results for the same column family, then the // current thread needs to wait. ready = false; break; } else if (mems.empty() && cfds[i]->imm()->GetEarliestMemTableID() <= bg_flush_args[i].max_memtable_id_) { // If a flush job does not need to install flush results, then it has // to wait until all memtables up to max_memtable_id_ (inclusive) are // installed. ready = false; break; } } return ready; }; bool resuming_from_bg_err = error_handler_.IsDBStopped(); while ((!error_handler_.IsDBStopped() || error_handler_.GetRecoveryError().ok()) && !wait_to_install_func()) { atomic_flush_install_cv_.Wait(); } s = resuming_from_bg_err ? error_handler_.GetRecoveryError() : error_handler_.GetBGError(); } if (s.ok()) { autovector tmp_cfds; autovector*> mems_list; autovector mutable_cf_options_list; for (int i = 0; i != num_cfs; ++i) { const auto& mems = jobs[i].GetMemTables(); if (!cfds[i]->IsDropped() && !mems.empty()) { tmp_cfds.emplace_back(cfds[i]); mems_list.emplace_back(&mems); mutable_cf_options_list.emplace_back(&all_mutable_cf_options[i]); } } s = InstallMemtableAtomicFlushResults( nullptr /* imm_lists */, tmp_cfds, mutable_cf_options_list, mems_list, versions_.get(), &mutex_, file_meta, &job_context->memtables_to_free, directories_.GetDbDir(), log_buffer); } if (s.ok() || s.IsShutdownInProgress()) { assert(num_cfs == static_cast(job_context->superversion_contexts.size())); for (int i = 0; i != num_cfs; ++i) { if (cfds[i]->IsDropped()) { continue; } InstallSuperVersionAndScheduleWork(cfds[i], &job_context->superversion_contexts[i], *cfds[i]->GetLatestMutableCFOptions()); VersionStorageInfo::LevelSummaryStorage tmp; ROCKS_LOG_BUFFER(log_buffer, "[%s] Level summary: %s\n", cfds[i]->GetName().c_str(), cfds[i]->current()->storage_info()->LevelSummary(&tmp)); } if (made_progress) { *made_progress = true; } #ifndef ROCKSDB_LITE auto sfm = static_cast( immutable_db_options_.sst_file_manager.get()); for (int i = 0; i != num_cfs; ++i) { if (cfds[i]->IsDropped()) { continue; } NotifyOnFlushCompleted(cfds[i], &file_meta[i], *cfds[i]->GetLatestMutableCFOptions(), job_context->job_id, jobs[i].GetTableProperties()); if (sfm) { std::string file_path = MakeTableFileName( cfds[i]->ioptions()->cf_paths[0].path, file_meta[i].fd.GetNumber()); sfm->OnAddFile(file_path); if (sfm->IsMaxAllowedSpaceReached() && error_handler_.GetBGError().ok()) { Status new_bg_error = Status::SpaceLimit("Max allowed space was reached"); error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush); } } } #endif // ROCKSDB_LITE } // Need to undo atomic flush if something went wrong, i.e. s is not OK and // it is not because of CF drop. if (!s.ok() && !s.IsShutdownInProgress()) { // Have to cancel the flush jobs that have NOT executed because we need to // unref the versions. for (int i = 0; i != num_cfs; ++i) { if (!exec_status[i].first) { jobs[i].Cancel(); } } for (int i = 0; i != num_cfs; ++i) { if (exec_status[i].first && exec_status[i].second.ok()) { auto& mems = jobs[i].GetMemTables(); cfds[i]->imm()->RollbackMemtableFlush(mems, file_meta[i].fd.GetNumber()); } } Status new_bg_error = s; error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush); } return s; } void DBImpl::NotifyOnFlushBegin(ColumnFamilyData* cfd, FileMetaData* file_meta, const MutableCFOptions& mutable_cf_options, int job_id, TableProperties prop) { #ifndef ROCKSDB_LITE if (immutable_db_options_.listeners.size() == 0U) { return; } mutex_.AssertHeld(); if (shutting_down_.load(std::memory_order_acquire)) { return; } bool triggered_writes_slowdown = (cfd->current()->storage_info()->NumLevelFiles(0) >= mutable_cf_options.level0_slowdown_writes_trigger); bool triggered_writes_stop = (cfd->current()->storage_info()->NumLevelFiles(0) >= mutable_cf_options.level0_stop_writes_trigger); // release lock while notifying events mutex_.Unlock(); { FlushJobInfo info; info.cf_id = cfd->GetID(); info.cf_name = cfd->GetName(); // TODO(yhchiang): make db_paths dynamic in case flush does not // go to L0 in the future. info.file_path = MakeTableFileName(cfd->ioptions()->cf_paths[0].path, file_meta->fd.GetNumber()); info.thread_id = env_->GetThreadID(); info.job_id = job_id; info.triggered_writes_slowdown = triggered_writes_slowdown; info.triggered_writes_stop = triggered_writes_stop; info.smallest_seqno = file_meta->fd.smallest_seqno; info.largest_seqno = file_meta->fd.largest_seqno; info.table_properties = prop; info.flush_reason = cfd->GetFlushReason(); for (auto listener : immutable_db_options_.listeners) { listener->OnFlushBegin(this, info); } } mutex_.Lock(); // no need to signal bg_cv_ as it will be signaled at the end of the // flush process. #else (void)cfd; (void)file_meta; (void)mutable_cf_options; (void)job_id; (void)prop; #endif // ROCKSDB_LITE } void DBImpl::NotifyOnFlushCompleted(ColumnFamilyData* cfd, FileMetaData* file_meta, const MutableCFOptions& mutable_cf_options, int job_id, TableProperties prop) { #ifndef ROCKSDB_LITE if (immutable_db_options_.listeners.size() == 0U) { return; } mutex_.AssertHeld(); if (shutting_down_.load(std::memory_order_acquire)) { return; } bool triggered_writes_slowdown = (cfd->current()->storage_info()->NumLevelFiles(0) >= mutable_cf_options.level0_slowdown_writes_trigger); bool triggered_writes_stop = (cfd->current()->storage_info()->NumLevelFiles(0) >= mutable_cf_options.level0_stop_writes_trigger); // release lock while notifying events mutex_.Unlock(); { FlushJobInfo info; info.cf_id = cfd->GetID(); info.cf_name = cfd->GetName(); // TODO(yhchiang): make db_paths dynamic in case flush does not // go to L0 in the future. info.file_path = MakeTableFileName(cfd->ioptions()->cf_paths[0].path, file_meta->fd.GetNumber()); info.thread_id = env_->GetThreadID(); info.job_id = job_id; info.triggered_writes_slowdown = triggered_writes_slowdown; info.triggered_writes_stop = triggered_writes_stop; info.smallest_seqno = file_meta->fd.smallest_seqno; info.largest_seqno = file_meta->fd.largest_seqno; info.table_properties = prop; info.flush_reason = cfd->GetFlushReason(); for (auto listener : immutable_db_options_.listeners) { listener->OnFlushCompleted(this, info); } } mutex_.Lock(); // no need to signal bg_cv_ as it will be signaled at the end of the // flush process. #else (void)cfd; (void)file_meta; (void)mutable_cf_options; (void)job_id; (void)prop; #endif // ROCKSDB_LITE } Status DBImpl::CompactRange(const CompactRangeOptions& options, ColumnFamilyHandle* column_family, const Slice* begin, const Slice* end) { auto cfh = reinterpret_cast(column_family); auto cfd = cfh->cfd(); if (options.target_path_id >= cfd->ioptions()->cf_paths.size()) { return Status::InvalidArgument("Invalid target path ID"); } bool exclusive = options.exclusive_manual_compaction; bool flush_needed = true; if (begin != nullptr && end != nullptr) { // TODO(ajkr): We could also optimize away the flush in certain cases where // one/both sides of the interval are unbounded. But it requires more // changes to RangesOverlapWithMemtables. Range range(*begin, *end); SuperVersion* super_version = cfd->GetReferencedSuperVersion(&mutex_); cfd->RangesOverlapWithMemtables({range}, super_version, &flush_needed); CleanupSuperVersion(super_version); } Status s; if (flush_needed) { FlushOptions fo; fo.allow_write_stall = options.allow_write_stall; if (immutable_db_options_.atomic_flush) { autovector cfds; mutex_.Lock(); SelectColumnFamiliesForAtomicFlush(&cfds); mutex_.Unlock(); s = AtomicFlushMemTables(cfds, fo, FlushReason::kManualCompaction, false /* writes_stopped */); } else { s = FlushMemTable(cfd, fo, FlushReason::kManualCompaction, false /* writes_stopped*/); } if (!s.ok()) { LogFlush(immutable_db_options_.info_log); return s; } } int max_level_with_files = 0; { InstrumentedMutexLock l(&mutex_); Version* base = cfd->current(); for (int level = 1; level < base->storage_info()->num_non_empty_levels(); level++) { if (base->storage_info()->OverlapInLevel(level, begin, end)) { max_level_with_files = level; } } } int final_output_level = 0; if (cfd->ioptions()->compaction_style == kCompactionStyleUniversal && cfd->NumberLevels() > 1) { // Always compact all files together. final_output_level = cfd->NumberLevels() - 1; // if bottom most level is reserved if (immutable_db_options_.allow_ingest_behind) { final_output_level--; } s = RunManualCompaction(cfd, ColumnFamilyData::kCompactAllLevels, final_output_level, options.target_path_id, options.max_subcompactions, begin, end, exclusive); } else { for (int level = 0; level <= max_level_with_files; level++) { int output_level; // in case the compaction is universal or if we're compacting the // bottom-most level, the output level will be the same as input one. // level 0 can never be the bottommost level (i.e. if all files are in // level 0, we will compact to level 1) if (cfd->ioptions()->compaction_style == kCompactionStyleUniversal || cfd->ioptions()->compaction_style == kCompactionStyleFIFO) { output_level = level; } else if (level == max_level_with_files && level > 0) { if (options.bottommost_level_compaction == BottommostLevelCompaction::kSkip) { // Skip bottommost level compaction continue; } else if (options.bottommost_level_compaction == BottommostLevelCompaction::kIfHaveCompactionFilter && cfd->ioptions()->compaction_filter == nullptr && cfd->ioptions()->compaction_filter_factory == nullptr) { // Skip bottommost level compaction since we don't have a compaction // filter continue; } output_level = level; } else { output_level = level + 1; if (cfd->ioptions()->compaction_style == kCompactionStyleLevel && cfd->ioptions()->level_compaction_dynamic_level_bytes && level == 0) { output_level = ColumnFamilyData::kCompactToBaseLevel; } } s = RunManualCompaction(cfd, level, output_level, options.target_path_id, options.max_subcompactions, begin, end, exclusive); if (!s.ok()) { break; } if (output_level == ColumnFamilyData::kCompactToBaseLevel) { final_output_level = cfd->NumberLevels() - 1; } else if (output_level > final_output_level) { final_output_level = output_level; } TEST_SYNC_POINT("DBImpl::RunManualCompaction()::1"); TEST_SYNC_POINT("DBImpl::RunManualCompaction()::2"); } } if (!s.ok()) { LogFlush(immutable_db_options_.info_log); return s; } if (options.change_level) { ROCKS_LOG_INFO(immutable_db_options_.info_log, "[RefitLevel] waiting for background threads to stop"); s = PauseBackgroundWork(); if (s.ok()) { s = ReFitLevel(cfd, final_output_level, options.target_level); } ContinueBackgroundWork(); } LogFlush(immutable_db_options_.info_log); { InstrumentedMutexLock l(&mutex_); // an automatic compaction that has been scheduled might have been // preempted by the manual compactions. Need to schedule it back. MaybeScheduleFlushOrCompaction(); } return s; } Status DBImpl::CompactFiles(const CompactionOptions& compact_options, ColumnFamilyHandle* column_family, const std::vector& input_file_names, const int output_level, const int output_path_id, std::vector* const output_file_names, CompactionJobInfo* compaction_job_info) { #ifdef ROCKSDB_LITE (void)compact_options; (void)column_family; (void)input_file_names; (void)output_level; (void)output_path_id; (void)output_file_names; (void)compaction_job_info; // not supported in lite version return Status::NotSupported("Not supported in ROCKSDB LITE"); #else if (column_family == nullptr) { return Status::InvalidArgument("ColumnFamilyHandle must be non-null."); } auto cfd = reinterpret_cast(column_family)->cfd(); assert(cfd); Status s; JobContext job_context(0, true); LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, immutable_db_options_.info_log.get()); // Perform CompactFiles TEST_SYNC_POINT("TestCompactFiles::IngestExternalFile2"); { InstrumentedMutexLock l(&mutex_); // This call will unlock/lock the mutex to wait for current running // IngestExternalFile() calls to finish. WaitForIngestFile(); // We need to get current after `WaitForIngestFile`, because // `IngestExternalFile` may add files that overlap with `input_file_names` auto* current = cfd->current(); current->Ref(); s = CompactFilesImpl(compact_options, cfd, current, input_file_names, output_file_names, output_level, output_path_id, &job_context, &log_buffer, compaction_job_info); current->Unref(); } // Find and delete obsolete files { InstrumentedMutexLock l(&mutex_); // If !s.ok(), this means that Compaction failed. In that case, we want // to delete all obsolete files we might have created and we force // FindObsoleteFiles(). This is because job_context does not // catch all created files if compaction failed. FindObsoleteFiles(&job_context, !s.ok()); } // release the mutex // delete unnecessary files if any, this is done outside the mutex if (job_context.HaveSomethingToClean() || job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) { // Have to flush the info logs before bg_compaction_scheduled_-- // because if bg_flush_scheduled_ becomes 0 and the lock is // released, the deconstructor of DB can kick in and destroy all the // states of DB so info_log might not be available after that point. // It also applies to access other states that DB owns. log_buffer.FlushBufferToLog(); if (job_context.HaveSomethingToDelete()) { // no mutex is locked here. No need to Unlock() and Lock() here. PurgeObsoleteFiles(job_context); } job_context.Clean(); } return s; #endif // ROCKSDB_LITE } #ifndef ROCKSDB_LITE Status DBImpl::CompactFilesImpl( const CompactionOptions& compact_options, ColumnFamilyData* cfd, Version* version, const std::vector& input_file_names, std::vector* const output_file_names, const int output_level, int output_path_id, JobContext* job_context, LogBuffer* log_buffer, CompactionJobInfo* compaction_job_info) { mutex_.AssertHeld(); if (shutting_down_.load(std::memory_order_acquire)) { return Status::ShutdownInProgress(); } std::unordered_set input_set; for (const auto& file_name : input_file_names) { input_set.insert(TableFileNameToNumber(file_name)); } ColumnFamilyMetaData cf_meta; // TODO(yhchiang): can directly use version here if none of the // following functions call is pluggable to external developers. version->GetColumnFamilyMetaData(&cf_meta); if (output_path_id < 0) { if (cfd->ioptions()->cf_paths.size() == 1U) { output_path_id = 0; } else { return Status::NotSupported( "Automatic output path selection is not " "yet supported in CompactFiles()"); } } Status s = cfd->compaction_picker()->SanitizeCompactionInputFiles( &input_set, cf_meta, output_level); if (!s.ok()) { return s; } std::vector input_files; s = cfd->compaction_picker()->GetCompactionInputsFromFileNumbers( &input_files, &input_set, version->storage_info(), compact_options); if (!s.ok()) { return s; } for (const auto& inputs : input_files) { if (cfd->compaction_picker()->AreFilesInCompaction(inputs.files)) { return Status::Aborted( "Some of the necessary compaction input " "files are already being compacted"); } } bool sfm_reserved_compact_space = false; // First check if we have enough room to do the compaction bool enough_room = EnoughRoomForCompaction( cfd, input_files, &sfm_reserved_compact_space, log_buffer); if (!enough_room) { // m's vars will get set properly at the end of this function, // as long as status == CompactionTooLarge return Status::CompactionTooLarge(); } // At this point, CompactFiles will be run. bg_compaction_scheduled_++; std::unique_ptr c; assert(cfd->compaction_picker()); c.reset(cfd->compaction_picker()->CompactFiles( compact_options, input_files, output_level, version->storage_info(), *cfd->GetLatestMutableCFOptions(), output_path_id)); // we already sanitized the set of input files and checked for conflicts // without releasing the lock, so we're guaranteed a compaction can be formed. assert(c != nullptr); c->SetInputVersion(version); // deletion compaction currently not allowed in CompactFiles. assert(!c->deletion_compaction()); std::vector snapshot_seqs; SequenceNumber earliest_write_conflict_snapshot; SnapshotChecker* snapshot_checker; GetSnapshotContext(job_context, &snapshot_seqs, &earliest_write_conflict_snapshot, &snapshot_checker); auto pending_outputs_inserted_elem = CaptureCurrentFileNumberInPendingOutputs(); assert(is_snapshot_supported_ || snapshots_.empty()); CompactionJobStats compaction_job_stats; CompactionJob compaction_job( job_context->job_id, c.get(), immutable_db_options_, env_options_for_compaction_, versions_.get(), &shutting_down_, preserve_deletes_seqnum_.load(), log_buffer, directories_.GetDbDir(), GetDataDir(c->column_family_data(), c->output_path_id()), stats_, &mutex_, &error_handler_, snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker, table_cache_, &event_logger_, c->mutable_cf_options()->paranoid_file_checks, c->mutable_cf_options()->report_bg_io_stats, dbname_, &compaction_job_stats); // Creating a compaction influences the compaction score because the score // takes running compactions into account (by skipping files that are already // being compacted). Since we just changed compaction score, we recalculate it // here. version->storage_info()->ComputeCompactionScore(*cfd->ioptions(), *c->mutable_cf_options()); compaction_job.Prepare(); mutex_.Unlock(); TEST_SYNC_POINT("CompactFilesImpl:0"); TEST_SYNC_POINT("CompactFilesImpl:1"); compaction_job.Run(); TEST_SYNC_POINT("CompactFilesImpl:2"); TEST_SYNC_POINT("CompactFilesImpl:3"); mutex_.Lock(); Status status = compaction_job.Install(*c->mutable_cf_options()); if (status.ok()) { InstallSuperVersionAndScheduleWork(c->column_family_data(), &job_context->superversion_contexts[0], *c->mutable_cf_options()); } c->ReleaseCompactionFiles(s); #ifndef ROCKSDB_LITE // Need to make sure SstFileManager does its bookkeeping auto sfm = static_cast( immutable_db_options_.sst_file_manager.get()); if (sfm && sfm_reserved_compact_space) { sfm->OnCompactionCompletion(c.get()); } #endif // ROCKSDB_LITE ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem); if (compaction_job_info != nullptr) { BuildCompactionJobInfo(cfd, c.get(), s, compaction_job_stats, job_context->job_id, version, compaction_job_info); } if (status.ok()) { // Done } else if (status.IsShutdownInProgress()) { // Ignore compaction errors found during shutting down } else { ROCKS_LOG_WARN(immutable_db_options_.info_log, "[%s] [JOB %d] Compaction error: %s", c->column_family_data()->GetName().c_str(), job_context->job_id, status.ToString().c_str()); error_handler_.SetBGError(status, BackgroundErrorReason::kCompaction); } if (output_file_names != nullptr) { for (const auto newf : c->edit()->GetNewFiles()) { (*output_file_names) .push_back(TableFileName(c->immutable_cf_options()->cf_paths, newf.second.fd.GetNumber(), newf.second.fd.GetPathId())); } } c.reset(); bg_compaction_scheduled_--; if (bg_compaction_scheduled_ == 0) { bg_cv_.SignalAll(); } TEST_SYNC_POINT("CompactFilesImpl:End"); return status; } #endif // ROCKSDB_LITE Status DBImpl::PauseBackgroundWork() { InstrumentedMutexLock guard_lock(&mutex_); bg_compaction_paused_++; while (bg_bottom_compaction_scheduled_ > 0 || bg_compaction_scheduled_ > 0 || bg_flush_scheduled_ > 0) { bg_cv_.Wait(); } bg_work_paused_++; return Status::OK(); } Status DBImpl::ContinueBackgroundWork() { InstrumentedMutexLock guard_lock(&mutex_); if (bg_work_paused_ == 0) { return Status::InvalidArgument(); } assert(bg_work_paused_ > 0); assert(bg_compaction_paused_ > 0); bg_compaction_paused_--; bg_work_paused_--; // It's sufficient to check just bg_work_paused_ here since // bg_work_paused_ is always no greater than bg_compaction_paused_ if (bg_work_paused_ == 0) { MaybeScheduleFlushOrCompaction(); } return Status::OK(); } void DBImpl::NotifyOnCompactionBegin(ColumnFamilyData* cfd, Compaction *c, const Status &st, const CompactionJobStats& job_stats, int job_id) { #ifndef ROCKSDB_LITE if (immutable_db_options_.listeners.empty()) { return; } mutex_.AssertHeld(); if (shutting_down_.load(std::memory_order_acquire)) { return; } Version* current = cfd->current(); current->Ref(); // release lock while notifying events mutex_.Unlock(); TEST_SYNC_POINT("DBImpl::NotifyOnCompactionBegin::UnlockMutex"); { CompactionJobInfo info; info.cf_name = cfd->GetName(); info.status = st; info.thread_id = env_->GetThreadID(); info.job_id = job_id; info.base_input_level = c->start_level(); info.output_level = c->output_level(); info.stats = job_stats; info.table_properties = c->GetOutputTableProperties(); info.compaction_reason = c->compaction_reason(); info.compression = c->output_compression(); for (size_t i = 0; i < c->num_input_levels(); ++i) { for (const auto fmd : *c->inputs(i)) { auto fn = TableFileName(c->immutable_cf_options()->cf_paths, fmd->fd.GetNumber(), fmd->fd.GetPathId()); info.input_files.push_back(fn); if (info.table_properties.count(fn) == 0) { std::shared_ptr tp; auto s = current->GetTableProperties(&tp, fmd, &fn); if (s.ok()) { info.table_properties[fn] = tp; } } } } for (const auto newf : c->edit()->GetNewFiles()) { info.output_files.push_back(TableFileName( c->immutable_cf_options()->cf_paths, newf.second.fd.GetNumber(), newf.second.fd.GetPathId())); } for (auto listener : immutable_db_options_.listeners) { listener->OnCompactionBegin(this, info); } } mutex_.Lock(); current->Unref(); #else (void)cfd; (void)c; (void)st; (void)job_stats; (void)job_id; #endif // ROCKSDB_LITE } void DBImpl::NotifyOnCompactionCompleted( ColumnFamilyData* cfd, Compaction* c, const Status& st, const CompactionJobStats& compaction_job_stats, const int job_id) { #ifndef ROCKSDB_LITE if (immutable_db_options_.listeners.size() == 0U) { return; } mutex_.AssertHeld(); if (shutting_down_.load(std::memory_order_acquire)) { return; } Version* current = cfd->current(); current->Ref(); // release lock while notifying events mutex_.Unlock(); TEST_SYNC_POINT("DBImpl::NotifyOnCompactionCompleted::UnlockMutex"); { CompactionJobInfo info; BuildCompactionJobInfo(cfd, c, st, compaction_job_stats, job_id, current, &info); for (auto listener : immutable_db_options_.listeners) { listener->OnCompactionCompleted(this, info); } } mutex_.Lock(); current->Unref(); // no need to signal bg_cv_ as it will be signaled at the end of the // flush process. #else (void)cfd; (void)c; (void)st; (void)compaction_job_stats; (void)job_id; #endif // ROCKSDB_LITE } // REQUIREMENT: block all background work by calling PauseBackgroundWork() // before calling this function Status DBImpl::ReFitLevel(ColumnFamilyData* cfd, int level, int target_level) { assert(level < cfd->NumberLevels()); if (target_level >= cfd->NumberLevels()) { return Status::InvalidArgument("Target level exceeds number of levels"); } SuperVersionContext sv_context(/* create_superversion */ true); Status status; InstrumentedMutexLock guard_lock(&mutex_); // only allow one thread refitting if (refitting_level_) { ROCKS_LOG_INFO(immutable_db_options_.info_log, "[ReFitLevel] another thread is refitting"); return Status::NotSupported("another thread is refitting"); } refitting_level_ = true; const MutableCFOptions mutable_cf_options = *cfd->GetLatestMutableCFOptions(); // move to a smaller level int to_level = target_level; if (target_level < 0) { to_level = FindMinimumEmptyLevelFitting(cfd, mutable_cf_options, level); } auto* vstorage = cfd->current()->storage_info(); if (to_level > level) { if (level == 0) { return Status::NotSupported( "Cannot change from level 0 to other levels."); } // Check levels are empty for a trivial move for (int l = level + 1; l <= to_level; l++) { if (vstorage->NumLevelFiles(l) > 0) { return Status::NotSupported( "Levels between source and target are not empty for a move."); } } } if (to_level != level) { ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] Before refitting:\n%s", cfd->GetName().c_str(), cfd->current()->DebugString().data()); VersionEdit edit; edit.SetColumnFamily(cfd->GetID()); for (const auto& f : vstorage->LevelFiles(level)) { edit.DeleteFile(level, f->fd.GetNumber()); edit.AddFile(to_level, f->fd.GetNumber(), f->fd.GetPathId(), f->fd.GetFileSize(), f->smallest, f->largest, f->fd.smallest_seqno, f->fd.largest_seqno, f->marked_for_compaction); } ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] Apply version edit:\n%s", cfd->GetName().c_str(), edit.DebugString().data()); status = versions_->LogAndApply(cfd, mutable_cf_options, &edit, &mutex_, directories_.GetDbDir()); InstallSuperVersionAndScheduleWork(cfd, &sv_context, mutable_cf_options); ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] LogAndApply: %s\n", cfd->GetName().c_str(), status.ToString().data()); if (status.ok()) { ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] After refitting:\n%s", cfd->GetName().c_str(), cfd->current()->DebugString().data()); } } sv_context.Clean(); refitting_level_ = false; return status; } int DBImpl::NumberLevels(ColumnFamilyHandle* column_family) { auto cfh = reinterpret_cast(column_family); return cfh->cfd()->NumberLevels(); } int DBImpl::MaxMemCompactionLevel(ColumnFamilyHandle* /*column_family*/) { return 0; } int DBImpl::Level0StopWriteTrigger(ColumnFamilyHandle* column_family) { auto cfh = reinterpret_cast(column_family); InstrumentedMutexLock l(&mutex_); return cfh->cfd() ->GetSuperVersion() ->mutable_cf_options.level0_stop_writes_trigger; } Status DBImpl::Flush(const FlushOptions& flush_options, ColumnFamilyHandle* column_family) { auto cfh = reinterpret_cast(column_family); ROCKS_LOG_INFO(immutable_db_options_.info_log, "[%s] Manual flush start.", cfh->GetName().c_str()); Status s; if (immutable_db_options_.atomic_flush) { s = AtomicFlushMemTables({cfh->cfd()}, flush_options, FlushReason::kManualFlush); } else { s = FlushMemTable(cfh->cfd(), flush_options, FlushReason::kManualFlush); } ROCKS_LOG_INFO(immutable_db_options_.info_log, "[%s] Manual flush finished, status: %s\n", cfh->GetName().c_str(), s.ToString().c_str()); return s; } Status DBImpl::Flush(const FlushOptions& flush_options, const std::vector& column_families) { Status s; if (!immutable_db_options_.atomic_flush) { for (auto cfh : column_families) { s = Flush(flush_options, cfh); if (!s.ok()) { break; } } } else { ROCKS_LOG_INFO(immutable_db_options_.info_log, "Manual atomic flush start.\n" "=====Column families:====="); for (auto cfh : column_families) { auto cfhi = static_cast(cfh); ROCKS_LOG_INFO(immutable_db_options_.info_log, "%s", cfhi->GetName().c_str()); } ROCKS_LOG_INFO(immutable_db_options_.info_log, "=====End of column families list====="); autovector cfds; std::for_each(column_families.begin(), column_families.end(), [&cfds](ColumnFamilyHandle* elem) { auto cfh = static_cast(elem); cfds.emplace_back(cfh->cfd()); }); s = AtomicFlushMemTables(cfds, flush_options, FlushReason::kManualFlush); ROCKS_LOG_INFO(immutable_db_options_.info_log, "Manual atomic flush finished, status: %s\n", "=====Column families:=====", s.ToString().c_str()); for (auto cfh : column_families) { auto cfhi = static_cast(cfh); ROCKS_LOG_INFO(immutable_db_options_.info_log, "%s", cfhi->GetName().c_str()); } ROCKS_LOG_INFO(immutable_db_options_.info_log, "=====End of column families list====="); } return s; } Status DBImpl::RunManualCompaction(ColumnFamilyData* cfd, int input_level, int output_level, uint32_t output_path_id, uint32_t max_subcompactions, const Slice* begin, const Slice* end, bool exclusive, bool disallow_trivial_move) { assert(input_level == ColumnFamilyData::kCompactAllLevels || input_level >= 0); InternalKey begin_storage, end_storage; CompactionArg* ca; bool scheduled = false; bool manual_conflict = false; ManualCompactionState manual; manual.cfd = cfd; manual.input_level = input_level; manual.output_level = output_level; manual.output_path_id = output_path_id; manual.done = false; manual.in_progress = false; manual.incomplete = false; manual.exclusive = exclusive; manual.disallow_trivial_move = disallow_trivial_move; // For universal compaction, we enforce every manual compaction to compact // all files. if (begin == nullptr || cfd->ioptions()->compaction_style == kCompactionStyleUniversal || cfd->ioptions()->compaction_style == kCompactionStyleFIFO) { manual.begin = nullptr; } else { begin_storage.SetMinPossibleForUserKey(*begin); manual.begin = &begin_storage; } if (end == nullptr || cfd->ioptions()->compaction_style == kCompactionStyleUniversal || cfd->ioptions()->compaction_style == kCompactionStyleFIFO) { manual.end = nullptr; } else { end_storage.SetMaxPossibleForUserKey(*end); manual.end = &end_storage; } TEST_SYNC_POINT("DBImpl::RunManualCompaction:0"); TEST_SYNC_POINT("DBImpl::RunManualCompaction:1"); InstrumentedMutexLock l(&mutex_); // When a manual compaction arrives, temporarily disable scheduling of // non-manual compactions and wait until the number of scheduled compaction // jobs drops to zero. This is needed to ensure that this manual compaction // can compact any range of keys/files. // // HasPendingManualCompaction() is true when at least one thread is inside // RunManualCompaction(), i.e. during that time no other compaction will // get scheduled (see MaybeScheduleFlushOrCompaction). // // Note that the following loop doesn't stop more that one thread calling // RunManualCompaction() from getting to the second while loop below. // However, only one of them will actually schedule compaction, while // others will wait on a condition variable until it completes. AddManualCompaction(&manual); TEST_SYNC_POINT_CALLBACK("DBImpl::RunManualCompaction:NotScheduled", &mutex_); if (exclusive) { while (bg_bottom_compaction_scheduled_ > 0 || bg_compaction_scheduled_ > 0) { TEST_SYNC_POINT("DBImpl::RunManualCompaction:WaitScheduled"); ROCKS_LOG_INFO( immutable_db_options_.info_log, "[%s] Manual compaction waiting for all other scheduled background " "compactions to finish", cfd->GetName().c_str()); bg_cv_.Wait(); } } ROCKS_LOG_INFO(immutable_db_options_.info_log, "[%s] Manual compaction starting", cfd->GetName().c_str()); LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, immutable_db_options_.info_log.get()); // We don't check bg_error_ here, because if we get the error in compaction, // the compaction will set manual.status to bg_error_ and set manual.done to // true. while (!manual.done) { assert(HasPendingManualCompaction()); manual_conflict = false; Compaction* compaction = nullptr; if (ShouldntRunManualCompaction(&manual) || (manual.in_progress == true) || scheduled || (((manual.manual_end = &manual.tmp_storage1) != nullptr) && ((compaction = manual.cfd->CompactRange( *manual.cfd->GetLatestMutableCFOptions(), manual.input_level, manual.output_level, manual.output_path_id, max_subcompactions, manual.begin, manual.end, &manual.manual_end, &manual_conflict)) == nullptr && manual_conflict))) { // exclusive manual compactions should not see a conflict during // CompactRange assert(!exclusive || !manual_conflict); // Running either this or some other manual compaction bg_cv_.Wait(); if (scheduled && manual.incomplete == true) { assert(!manual.in_progress); scheduled = false; manual.incomplete = false; } } else if (!scheduled) { if (compaction == nullptr) { manual.done = true; bg_cv_.SignalAll(); continue; } ca = new CompactionArg; ca->db = this; ca->prepicked_compaction = new PrepickedCompaction; ca->prepicked_compaction->manual_compaction_state = &manual; ca->prepicked_compaction->compaction = compaction; if (!RequestCompactionToken( cfd, true, &ca->prepicked_compaction->task_token, &log_buffer)) { // Don't throttle manual compaction, only count outstanding tasks. assert(false); } manual.incomplete = false; bg_compaction_scheduled_++; env_->Schedule(&DBImpl::BGWorkCompaction, ca, Env::Priority::LOW, this, &DBImpl::UnscheduleCallback); scheduled = true; } } log_buffer.FlushBufferToLog(); assert(!manual.in_progress); assert(HasPendingManualCompaction()); RemoveManualCompaction(&manual); bg_cv_.SignalAll(); return manual.status; } void DBImpl::GenerateFlushRequest(const autovector& cfds, FlushRequest* req) { assert(req != nullptr); req->reserve(cfds.size()); for (const auto cfd : cfds) { if (nullptr == cfd) { // cfd may be null, see DBImpl::ScheduleFlushes continue; } uint64_t max_memtable_id = cfd->imm()->GetLatestMemTableID(); req->emplace_back(cfd, max_memtable_id); } } Status DBImpl::FlushMemTable(ColumnFamilyData* cfd, const FlushOptions& flush_options, FlushReason flush_reason, bool writes_stopped) { Status s; uint64_t flush_memtable_id = 0; if (!flush_options.allow_write_stall) { bool flush_needed = true; s = WaitUntilFlushWouldNotStallWrites(cfd, &flush_needed); TEST_SYNC_POINT("DBImpl::FlushMemTable:StallWaitDone"); if (!s.ok() || !flush_needed) { return s; } } FlushRequest flush_req; { WriteContext context; InstrumentedMutexLock guard_lock(&mutex_); WriteThread::Writer w; if (!writes_stopped) { write_thread_.EnterUnbatched(&w, &mutex_); } if (!cfd->mem()->IsEmpty() || !cached_recoverable_state_empty_.load()) { s = SwitchMemtable(cfd, &context); } if (s.ok()) { if (cfd->imm()->NumNotFlushed() != 0 || !cfd->mem()->IsEmpty() || !cached_recoverable_state_empty_.load()) { flush_memtable_id = cfd->imm()->GetLatestMemTableID(); flush_req.emplace_back(cfd, flush_memtable_id); } } if (s.ok() && !flush_req.empty()) { for (auto& elem : flush_req) { ColumnFamilyData* loop_cfd = elem.first; loop_cfd->imm()->FlushRequested(); } SchedulePendingFlush(flush_req, flush_reason); MaybeScheduleFlushOrCompaction(); } if (!writes_stopped) { write_thread_.ExitUnbatched(&w); } } if (s.ok() && flush_options.wait) { autovector cfds; autovector flush_memtable_ids; for (auto& iter : flush_req) { cfds.push_back(iter.first); flush_memtable_ids.push_back(&(iter.second)); } s = WaitForFlushMemTables(cfds, flush_memtable_ids, (flush_reason == FlushReason::kErrorRecovery)); } TEST_SYNC_POINT("FlushMemTableFinished"); return s; } // Flush all elments in 'column_family_datas' // and atomically record the result to the MANIFEST. Status DBImpl::AtomicFlushMemTables( const autovector& column_family_datas, const FlushOptions& flush_options, FlushReason flush_reason, bool writes_stopped) { Status s; if (!flush_options.allow_write_stall) { int num_cfs_to_flush = 0; for (auto cfd : column_family_datas) { bool flush_needed = true; s = WaitUntilFlushWouldNotStallWrites(cfd, &flush_needed); if (!s.ok()) { return s; } else if (flush_needed) { ++num_cfs_to_flush; } } if (0 == num_cfs_to_flush) { return s; } } FlushRequest flush_req; autovector cfds; { WriteContext context; InstrumentedMutexLock guard_lock(&mutex_); WriteThread::Writer w; if (!writes_stopped) { write_thread_.EnterUnbatched(&w, &mutex_); } for (auto cfd : column_family_datas) { if (cfd->IsDropped()) { continue; } if (cfd->imm()->NumNotFlushed() != 0 || !cfd->mem()->IsEmpty() || !cached_recoverable_state_empty_.load()) { cfds.emplace_back(cfd); } } for (auto cfd : cfds) { if (cfd->mem()->IsEmpty() && cached_recoverable_state_empty_.load()) { continue; } cfd->Ref(); s = SwitchMemtable(cfd, &context); cfd->Unref(); if (!s.ok()) { break; } } if (s.ok()) { AssignAtomicFlushSeq(cfds); for (auto cfd : cfds) { cfd->imm()->FlushRequested(); } GenerateFlushRequest(cfds, &flush_req); SchedulePendingFlush(flush_req, flush_reason); MaybeScheduleFlushOrCompaction(); } if (!writes_stopped) { write_thread_.ExitUnbatched(&w); } } TEST_SYNC_POINT("DBImpl::AtomicFlushMemTables:AfterScheduleFlush"); if (s.ok() && flush_options.wait) { autovector flush_memtable_ids; for (auto& iter : flush_req) { flush_memtable_ids.push_back(&(iter.second)); } s = WaitForFlushMemTables(cfds, flush_memtable_ids, (flush_reason == FlushReason::kErrorRecovery)); } return s; } // Calling FlushMemTable(), whether from DB::Flush() or from Backup Engine, can // cause write stall, for example if one memtable is being flushed already. // This method tries to avoid write stall (similar to CompactRange() behavior) // it emulates how the SuperVersion / LSM would change if flush happens, checks // it against various constrains and delays flush if it'd cause write stall. // Called should check status and flush_needed to see if flush already happened. Status DBImpl::WaitUntilFlushWouldNotStallWrites(ColumnFamilyData* cfd, bool* flush_needed) { { *flush_needed = true; InstrumentedMutexLock l(&mutex_); uint64_t orig_active_memtable_id = cfd->mem()->GetID(); WriteStallCondition write_stall_condition = WriteStallCondition::kNormal; do { if (write_stall_condition != WriteStallCondition::kNormal) { // Same error handling as user writes: Don't wait if there's a // background error, even if it's a soft error. We might wait here // indefinitely as the pending flushes/compactions may never finish // successfully, resulting in the stall condition lasting indefinitely if (error_handler_.IsBGWorkStopped()) { return error_handler_.GetBGError(); } TEST_SYNC_POINT("DBImpl::WaitUntilFlushWouldNotStallWrites:StallWait"); ROCKS_LOG_INFO(immutable_db_options_.info_log, "[%s] WaitUntilFlushWouldNotStallWrites" " waiting on stall conditions to clear", cfd->GetName().c_str()); bg_cv_.Wait(); } if (cfd->IsDropped() || shutting_down_.load(std::memory_order_acquire)) { return Status::ShutdownInProgress(); } uint64_t earliest_memtable_id = std::min(cfd->mem()->GetID(), cfd->imm()->GetEarliestMemTableID()); if (earliest_memtable_id > orig_active_memtable_id) { // We waited so long that the memtable we were originally waiting on was // flushed. *flush_needed = false; return Status::OK(); } const auto& mutable_cf_options = *cfd->GetLatestMutableCFOptions(); const auto* vstorage = cfd->current()->storage_info(); // Skip stalling check if we're below auto-flush and auto-compaction // triggers. If it stalled in these conditions, that'd mean the stall // triggers are so low that stalling is needed for any background work. In // that case we shouldn't wait since background work won't be scheduled. if (cfd->imm()->NumNotFlushed() < cfd->ioptions()->min_write_buffer_number_to_merge && vstorage->l0_delay_trigger_count() < mutable_cf_options.level0_file_num_compaction_trigger) { break; } // check whether one extra immutable memtable or an extra L0 file would // cause write stalling mode to be entered. It could still enter stall // mode due to pending compaction bytes, but that's less common write_stall_condition = ColumnFamilyData::GetWriteStallConditionAndCause( cfd->imm()->NumNotFlushed() + 1, vstorage->l0_delay_trigger_count() + 1, vstorage->estimated_compaction_needed_bytes(), mutable_cf_options) .first; } while (write_stall_condition != WriteStallCondition::kNormal); } return Status::OK(); } // Wait for memtables to be flushed for multiple column families. // let N = cfds.size() // for i in [0, N), // 1) if flush_memtable_ids[i] is not null, then the memtables with lower IDs // have to be flushed for THIS column family; // 2) if flush_memtable_ids[i] is null, then all memtables in THIS column // family have to be flushed. // Finish waiting when ALL column families finish flushing memtables. // resuming_from_bg_err indicates whether the caller is trying to resume from // background error or in normal processing. Status DBImpl::WaitForFlushMemTables( const autovector& cfds, const autovector& flush_memtable_ids, bool resuming_from_bg_err) { int num = static_cast(cfds.size()); // Wait until the compaction completes InstrumentedMutexLock l(&mutex_); // If the caller is trying to resume from bg error, then // error_handler_.IsDBStopped() is true. while (resuming_from_bg_err || !error_handler_.IsDBStopped()) { if (shutting_down_.load(std::memory_order_acquire)) { return Status::ShutdownInProgress(); } // If an error has occurred during resumption, then no need to wait. if (!error_handler_.GetRecoveryError().ok()) { break; } // Number of column families that have been dropped. int num_dropped = 0; // Number of column families that have finished flush. int num_finished = 0; for (int i = 0; i < num; ++i) { if (cfds[i]->IsDropped()) { ++num_dropped; } else if (cfds[i]->imm()->NumNotFlushed() == 0 || (flush_memtable_ids[i] != nullptr && cfds[i]->imm()->GetEarliestMemTableID() > *flush_memtable_ids[i])) { ++num_finished; } } if (1 == num_dropped && 1 == num) { return Status::InvalidArgument("Cannot flush a dropped CF"); } // Column families involved in this flush request have either been dropped // or finished flush. Then it's time to finish waiting. if (num_dropped + num_finished == num) { break; } bg_cv_.Wait(); } Status s; // If not resuming from bg error, and an error has caused the DB to stop, // then report the bg error to caller. if (!resuming_from_bg_err && error_handler_.IsDBStopped()) { s = error_handler_.GetBGError(); } return s; } Status DBImpl::EnableAutoCompaction( const std::vector& column_family_handles) { Status s; for (auto cf_ptr : column_family_handles) { Status status = this->SetOptions(cf_ptr, {{"disable_auto_compactions", "false"}}); if (!status.ok()) { s = status; } } return s; } void DBImpl::MaybeScheduleFlushOrCompaction() { mutex_.AssertHeld(); if (!opened_successfully_) { // Compaction may introduce data race to DB open return; } if (bg_work_paused_ > 0) { // we paused the background work return; } else if (error_handler_.IsBGWorkStopped() && !error_handler_.IsRecoveryInProgress()) { // There has been a hard error and this call is not part of the recovery // sequence. Bail out here so we don't get into an endless loop of // scheduling BG work which will again call this function return; } else if (shutting_down_.load(std::memory_order_acquire)) { // DB is being deleted; no more background compactions return; } auto bg_job_limits = GetBGJobLimits(); bool is_flush_pool_empty = env_->GetBackgroundThreads(Env::Priority::HIGH) == 0; while (!is_flush_pool_empty && unscheduled_flushes_ > 0 && bg_flush_scheduled_ < bg_job_limits.max_flushes) { bg_flush_scheduled_++; env_->Schedule(&DBImpl::BGWorkFlush, this, Env::Priority::HIGH, this); } // special case -- if high-pri (flush) thread pool is empty, then schedule // flushes in low-pri (compaction) thread pool. if (is_flush_pool_empty) { while (unscheduled_flushes_ > 0 && bg_flush_scheduled_ + bg_compaction_scheduled_ < bg_job_limits.max_flushes) { bg_flush_scheduled_++; env_->Schedule(&DBImpl::BGWorkFlush, this, Env::Priority::LOW, this); } } if (bg_compaction_paused_ > 0) { // we paused the background compaction return; } else if (error_handler_.IsBGWorkStopped()) { // Compaction is not part of the recovery sequence from a hard error. We // might get here because recovery might do a flush and install a new // super version, which will try to schedule pending compactions. Bail // out here and let the higher level recovery handle compactions return; } if (HasExclusiveManualCompaction()) { // only manual compactions are allowed to run. don't schedule automatic // compactions TEST_SYNC_POINT("DBImpl::MaybeScheduleFlushOrCompaction:Conflict"); return; } while (bg_compaction_scheduled_ < bg_job_limits.max_compactions && unscheduled_compactions_ > 0) { CompactionArg* ca = new CompactionArg; ca->db = this; ca->prepicked_compaction = nullptr; bg_compaction_scheduled_++; unscheduled_compactions_--; env_->Schedule(&DBImpl::BGWorkCompaction, ca, Env::Priority::LOW, this, &DBImpl::UnscheduleCallback); } } DBImpl::BGJobLimits DBImpl::GetBGJobLimits() const { mutex_.AssertHeld(); return GetBGJobLimits(immutable_db_options_.max_background_flushes, mutable_db_options_.max_background_compactions, mutable_db_options_.max_background_jobs, write_controller_.NeedSpeedupCompaction()); } DBImpl::BGJobLimits DBImpl::GetBGJobLimits(int max_background_flushes, int max_background_compactions, int max_background_jobs, bool parallelize_compactions) { BGJobLimits res; if (max_background_flushes == -1 && max_background_compactions == -1) { // for our first stab implementing max_background_jobs, simply allocate a // quarter of the threads to flushes. res.max_flushes = std::max(1, max_background_jobs / 4); res.max_compactions = std::max(1, max_background_jobs - res.max_flushes); } else { // compatibility code in case users haven't migrated to max_background_jobs, // which automatically computes flush/compaction limits res.max_flushes = std::max(1, max_background_flushes); res.max_compactions = std::max(1, max_background_compactions); } if (!parallelize_compactions) { // throttle background compactions until we deem necessary res.max_compactions = 1; } return res; } void DBImpl::AddToCompactionQueue(ColumnFamilyData* cfd) { assert(!cfd->queued_for_compaction()); cfd->Ref(); compaction_queue_.push_back(cfd); cfd->set_queued_for_compaction(true); } ColumnFamilyData* DBImpl::PopFirstFromCompactionQueue() { assert(!compaction_queue_.empty()); auto cfd = *compaction_queue_.begin(); compaction_queue_.pop_front(); assert(cfd->queued_for_compaction()); cfd->set_queued_for_compaction(false); return cfd; } DBImpl::FlushRequest DBImpl::PopFirstFromFlushQueue() { assert(!flush_queue_.empty()); FlushRequest flush_req = flush_queue_.front(); assert(unscheduled_flushes_ >= static_cast(flush_req.size())); unscheduled_flushes_ -= static_cast(flush_req.size()); flush_queue_.pop_front(); // TODO: need to unset flush reason? return flush_req; } ColumnFamilyData* DBImpl::PickCompactionFromQueue( std::unique_ptr* token, LogBuffer* log_buffer) { assert(!compaction_queue_.empty()); assert(*token == nullptr); autovector throttled_candidates; ColumnFamilyData* cfd = nullptr; while (!compaction_queue_.empty()) { auto first_cfd = *compaction_queue_.begin(); compaction_queue_.pop_front(); assert(first_cfd->queued_for_compaction()); if (!RequestCompactionToken(first_cfd, false, token, log_buffer)) { throttled_candidates.push_back(first_cfd); continue; } cfd = first_cfd; cfd->set_queued_for_compaction(false); break; } // Add throttled compaction candidates back to queue in the original order. for (auto iter = throttled_candidates.rbegin(); iter != throttled_candidates.rend(); ++iter) { compaction_queue_.push_front(*iter); } return cfd; } void DBImpl::SchedulePendingFlush(const FlushRequest& flush_req, FlushReason flush_reason) { if (flush_req.empty()) { return; } for (auto& iter : flush_req) { ColumnFamilyData* cfd = iter.first; cfd->Ref(); cfd->SetFlushReason(flush_reason); } unscheduled_flushes_ += static_cast(flush_req.size()); flush_queue_.push_back(flush_req); } void DBImpl::SchedulePendingCompaction(ColumnFamilyData* cfd) { if (!cfd->queued_for_compaction() && cfd->NeedsCompaction()) { AddToCompactionQueue(cfd); ++unscheduled_compactions_; } } void DBImpl::SchedulePendingPurge(std::string fname, std::string dir_to_sync, FileType type, uint64_t number, int job_id) { mutex_.AssertHeld(); PurgeFileInfo file_info(fname, dir_to_sync, type, number, job_id); purge_queue_.push_back(std::move(file_info)); } void DBImpl::BGWorkFlush(void* db) { IOSTATS_SET_THREAD_POOL_ID(Env::Priority::HIGH); TEST_SYNC_POINT("DBImpl::BGWorkFlush"); reinterpret_cast(db)->BackgroundCallFlush(); TEST_SYNC_POINT("DBImpl::BGWorkFlush:done"); } void DBImpl::BGWorkCompaction(void* arg) { CompactionArg ca = *(reinterpret_cast(arg)); delete reinterpret_cast(arg); IOSTATS_SET_THREAD_POOL_ID(Env::Priority::LOW); TEST_SYNC_POINT("DBImpl::BGWorkCompaction"); auto prepicked_compaction = static_cast(ca.prepicked_compaction); reinterpret_cast(ca.db)->BackgroundCallCompaction( prepicked_compaction, Env::Priority::LOW); delete prepicked_compaction; } void DBImpl::BGWorkBottomCompaction(void* arg) { CompactionArg ca = *(static_cast(arg)); delete static_cast(arg); IOSTATS_SET_THREAD_POOL_ID(Env::Priority::BOTTOM); TEST_SYNC_POINT("DBImpl::BGWorkBottomCompaction"); auto* prepicked_compaction = ca.prepicked_compaction; assert(prepicked_compaction && prepicked_compaction->compaction && !prepicked_compaction->manual_compaction_state); ca.db->BackgroundCallCompaction(prepicked_compaction, Env::Priority::BOTTOM); delete prepicked_compaction; } void DBImpl::BGWorkPurge(void* db) { IOSTATS_SET_THREAD_POOL_ID(Env::Priority::HIGH); TEST_SYNC_POINT("DBImpl::BGWorkPurge:start"); reinterpret_cast(db)->BackgroundCallPurge(); TEST_SYNC_POINT("DBImpl::BGWorkPurge:end"); } void DBImpl::UnscheduleCallback(void* arg) { CompactionArg ca = *(reinterpret_cast(arg)); delete reinterpret_cast(arg); if (ca.prepicked_compaction != nullptr) { if (ca.prepicked_compaction->compaction != nullptr) { delete ca.prepicked_compaction->compaction; } delete ca.prepicked_compaction; } TEST_SYNC_POINT("DBImpl::UnscheduleCallback"); } Status DBImpl::BackgroundFlush(bool* made_progress, JobContext* job_context, LogBuffer* log_buffer, FlushReason* reason) { mutex_.AssertHeld(); Status status; *reason = FlushReason::kOthers; // If BG work is stopped due to an error, but a recovery is in progress, // that means this flush is part of the recovery. So allow it to go through if (!error_handler_.IsBGWorkStopped()) { if (shutting_down_.load(std::memory_order_acquire)) { status = Status::ShutdownInProgress(); } } else if (!error_handler_.IsRecoveryInProgress()) { status = error_handler_.GetBGError(); } if (!status.ok()) { return status; } autovector bg_flush_args; std::vector& superversion_contexts = job_context->superversion_contexts; while (!flush_queue_.empty()) { // This cfd is already referenced const FlushRequest& flush_req = PopFirstFromFlushQueue(); superversion_contexts.clear(); superversion_contexts.reserve(flush_req.size()); for (const auto& iter : flush_req) { ColumnFamilyData* cfd = iter.first; if (cfd->IsDropped() || !cfd->imm()->IsFlushPending()) { // can't flush this CF, try next one if (cfd->Unref()) { delete cfd; } continue; } superversion_contexts.emplace_back(SuperVersionContext(true)); bg_flush_args.emplace_back(cfd, iter.second, &(superversion_contexts.back())); } if (!bg_flush_args.empty()) { break; } } if (!bg_flush_args.empty()) { auto bg_job_limits = GetBGJobLimits(); for (const auto& arg : bg_flush_args) { ColumnFamilyData* cfd = arg.cfd_; ROCKS_LOG_BUFFER( log_buffer, "Calling FlushMemTableToOutputFile with column " "family [%s], flush slots available %d, compaction slots available " "%d, " "flush slots scheduled %d, compaction slots scheduled %d", cfd->GetName().c_str(), bg_job_limits.max_flushes, bg_job_limits.max_compactions, bg_flush_scheduled_, bg_compaction_scheduled_); } status = FlushMemTablesToOutputFiles(bg_flush_args, made_progress, job_context, log_buffer); // All the CFDs in the FlushReq must have the same flush reason, so just // grab the first one *reason = bg_flush_args[0].cfd_->GetFlushReason(); for (auto& arg : bg_flush_args) { ColumnFamilyData* cfd = arg.cfd_; if (cfd->Unref()) { delete cfd; arg.cfd_ = nullptr; } } } return status; } void DBImpl::BackgroundCallFlush() { bool made_progress = false; JobContext job_context(next_job_id_.fetch_add(1), true); TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:start"); LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, immutable_db_options_.info_log.get()); { InstrumentedMutexLock l(&mutex_); assert(bg_flush_scheduled_); num_running_flushes_++; auto pending_outputs_inserted_elem = CaptureCurrentFileNumberInPendingOutputs(); FlushReason reason; Status s = BackgroundFlush(&made_progress, &job_context, &log_buffer, &reason); if (!s.ok() && !s.IsShutdownInProgress() && reason != FlushReason::kErrorRecovery) { // Wait a little bit before retrying background flush in // case this is an environmental problem and we do not want to // chew up resources for failed flushes for the duration of // the problem. uint64_t error_cnt = default_cf_internal_stats_->BumpAndGetBackgroundErrorCount(); bg_cv_.SignalAll(); // In case a waiter can proceed despite the error mutex_.Unlock(); ROCKS_LOG_ERROR(immutable_db_options_.info_log, "Waiting after background flush error: %s" "Accumulated background error counts: %" PRIu64, s.ToString().c_str(), error_cnt); log_buffer.FlushBufferToLog(); LogFlush(immutable_db_options_.info_log); env_->SleepForMicroseconds(1000000); mutex_.Lock(); } TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:FlushFinish:0"); ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem); // If flush failed, we want to delete all temporary files that we might have // created. Thus, we force full scan in FindObsoleteFiles() FindObsoleteFiles(&job_context, !s.ok() && !s.IsShutdownInProgress()); // delete unnecessary files if any, this is done outside the mutex if (job_context.HaveSomethingToClean() || job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) { mutex_.Unlock(); TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:FilesFound"); // Have to flush the info logs before bg_flush_scheduled_-- // because if bg_flush_scheduled_ becomes 0 and the lock is // released, the deconstructor of DB can kick in and destroy all the // states of DB so info_log might not be available after that point. // It also applies to access other states that DB owns. log_buffer.FlushBufferToLog(); if (job_context.HaveSomethingToDelete()) { PurgeObsoleteFiles(job_context); } job_context.Clean(); mutex_.Lock(); } TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:ContextCleanedUp"); assert(num_running_flushes_ > 0); num_running_flushes_--; bg_flush_scheduled_--; // See if there's more work to be done MaybeScheduleFlushOrCompaction(); atomic_flush_install_cv_.SignalAll(); bg_cv_.SignalAll(); // IMPORTANT: there should be no code after calling SignalAll. This call may // signal the DB destructor that it's OK to proceed with destruction. In // that case, all DB variables will be dealloacated and referencing them // will cause trouble. } } void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction, Env::Priority bg_thread_pri) { bool made_progress = false; JobContext job_context(next_job_id_.fetch_add(1), true); TEST_SYNC_POINT("BackgroundCallCompaction:0"); LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, immutable_db_options_.info_log.get()); { InstrumentedMutexLock l(&mutex_); // This call will unlock/lock the mutex to wait for current running // IngestExternalFile() calls to finish. WaitForIngestFile(); num_running_compactions_++; auto pending_outputs_inserted_elem = CaptureCurrentFileNumberInPendingOutputs(); assert((bg_thread_pri == Env::Priority::BOTTOM && bg_bottom_compaction_scheduled_) || (bg_thread_pri == Env::Priority::LOW && bg_compaction_scheduled_)); Status s = BackgroundCompaction(&made_progress, &job_context, &log_buffer, prepicked_compaction); TEST_SYNC_POINT("BackgroundCallCompaction:1"); if (s.IsBusy()) { bg_cv_.SignalAll(); // In case a waiter can proceed despite the error mutex_.Unlock(); env_->SleepForMicroseconds(10000); // prevent hot loop mutex_.Lock(); } else if (!s.ok() && !s.IsShutdownInProgress()) { // Wait a little bit before retrying background compaction in // case this is an environmental problem and we do not want to // chew up resources for failed compactions for the duration of // the problem. uint64_t error_cnt = default_cf_internal_stats_->BumpAndGetBackgroundErrorCount(); bg_cv_.SignalAll(); // In case a waiter can proceed despite the error mutex_.Unlock(); log_buffer.FlushBufferToLog(); ROCKS_LOG_ERROR(immutable_db_options_.info_log, "Waiting after background compaction error: %s, " "Accumulated background error counts: %" PRIu64, s.ToString().c_str(), error_cnt); LogFlush(immutable_db_options_.info_log); env_->SleepForMicroseconds(1000000); mutex_.Lock(); } ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem); // If compaction failed, we want to delete all temporary files that we might // have created (they might not be all recorded in job_context in case of a // failure). Thus, we force full scan in FindObsoleteFiles() FindObsoleteFiles(&job_context, !s.ok() && !s.IsShutdownInProgress()); TEST_SYNC_POINT("DBImpl::BackgroundCallCompaction:FoundObsoleteFiles"); // delete unnecessary files if any, this is done outside the mutex if (job_context.HaveSomethingToClean() || job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) { mutex_.Unlock(); // Have to flush the info logs before bg_compaction_scheduled_-- // because if bg_flush_scheduled_ becomes 0 and the lock is // released, the deconstructor of DB can kick in and destroy all the // states of DB so info_log might not be available after that point. // It also applies to access other states that DB owns. log_buffer.FlushBufferToLog(); if (job_context.HaveSomethingToDelete()) { PurgeObsoleteFiles(job_context); TEST_SYNC_POINT("DBImpl::BackgroundCallCompaction:PurgedObsoleteFiles"); } job_context.Clean(); mutex_.Lock(); } assert(num_running_compactions_ > 0); num_running_compactions_--; if (bg_thread_pri == Env::Priority::LOW) { bg_compaction_scheduled_--; } else { assert(bg_thread_pri == Env::Priority::BOTTOM); bg_bottom_compaction_scheduled_--; } versions_->GetColumnFamilySet()->FreeDeadColumnFamilies(); // See if there's more work to be done MaybeScheduleFlushOrCompaction(); if (made_progress || (bg_compaction_scheduled_ == 0 && bg_bottom_compaction_scheduled_ == 0) || HasPendingManualCompaction() || unscheduled_compactions_ == 0) { // signal if // * made_progress -- need to wakeup DelayWrite // * bg_{bottom,}_compaction_scheduled_ == 0 -- need to wakeup ~DBImpl // * HasPendingManualCompaction -- need to wakeup RunManualCompaction // If none of this is true, there is no need to signal since nobody is // waiting for it bg_cv_.SignalAll(); } // IMPORTANT: there should be no code after calling SignalAll. This call may // signal the DB destructor that it's OK to proceed with destruction. In // that case, all DB variables will be dealloacated and referencing them // will cause trouble. } } Status DBImpl::BackgroundCompaction(bool* made_progress, JobContext* job_context, LogBuffer* log_buffer, PrepickedCompaction* prepicked_compaction) { ManualCompactionState* manual_compaction = prepicked_compaction == nullptr ? nullptr : prepicked_compaction->manual_compaction_state; *made_progress = false; mutex_.AssertHeld(); TEST_SYNC_POINT("DBImpl::BackgroundCompaction:Start"); bool is_manual = (manual_compaction != nullptr); std::unique_ptr c; if (prepicked_compaction != nullptr && prepicked_compaction->compaction != nullptr) { c.reset(prepicked_compaction->compaction); } bool is_prepicked = is_manual || c; // (manual_compaction->in_progress == false); bool trivial_move_disallowed = is_manual && manual_compaction->disallow_trivial_move; CompactionJobStats compaction_job_stats; Status status; if (!error_handler_.IsBGWorkStopped()) { if (shutting_down_.load(std::memory_order_acquire)) { status = Status::ShutdownInProgress(); } } else { status = error_handler_.GetBGError(); // If we get here, it means a hard error happened after this compaction // was scheduled by MaybeScheduleFlushOrCompaction(), but before it got // a chance to execute. Since we didn't pop a cfd from the compaction // queue, increment unscheduled_compactions_ unscheduled_compactions_++; } if (!status.ok()) { if (is_manual) { manual_compaction->status = status; manual_compaction->done = true; manual_compaction->in_progress = false; manual_compaction = nullptr; } if (c) { c->ReleaseCompactionFiles(status); c.reset(); } return status; } if (is_manual) { // another thread cannot pick up the same work manual_compaction->in_progress = true; } std::unique_ptr task_token; // InternalKey manual_end_storage; // InternalKey* manual_end = &manual_end_storage; bool sfm_reserved_compact_space = false; if (is_manual) { ManualCompactionState* m = manual_compaction; assert(m->in_progress); if (!c) { m->done = true; m->manual_end = nullptr; ROCKS_LOG_BUFFER(log_buffer, "[%s] Manual compaction from level-%d from %s .. " "%s; nothing to do\n", m->cfd->GetName().c_str(), m->input_level, (m->begin ? m->begin->DebugString().c_str() : "(begin)"), (m->end ? m->end->DebugString().c_str() : "(end)")); } else { // First check if we have enough room to do the compaction bool enough_room = EnoughRoomForCompaction( m->cfd, *(c->inputs()), &sfm_reserved_compact_space, log_buffer); if (!enough_room) { // Then don't do the compaction c->ReleaseCompactionFiles(status); c.reset(); // m's vars will get set properly at the end of this function, // as long as status == CompactionTooLarge status = Status::CompactionTooLarge(); } else { ROCKS_LOG_BUFFER( log_buffer, "[%s] Manual compaction from level-%d to level-%d from %s .. " "%s; will stop at %s\n", m->cfd->GetName().c_str(), m->input_level, c->output_level(), (m->begin ? m->begin->DebugString().c_str() : "(begin)"), (m->end ? m->end->DebugString().c_str() : "(end)"), ((m->done || m->manual_end == nullptr) ? "(end)" : m->manual_end->DebugString().c_str())); } } } else if (!is_prepicked && !compaction_queue_.empty()) { if (HasExclusiveManualCompaction()) { // Can't compact right now, but try again later TEST_SYNC_POINT("DBImpl::BackgroundCompaction()::Conflict"); // Stay in the compaction queue. unscheduled_compactions_++; return Status::OK(); } auto cfd = PickCompactionFromQueue(&task_token, log_buffer); if (cfd == nullptr) { // Can't find any executable task from the compaction queue. // All tasks have been throttled by compaction thread limiter. ++unscheduled_compactions_; return Status::Busy(); } // We unreference here because the following code will take a Ref() on // this cfd if it is going to use it (Compaction class holds a // reference). // This will all happen under a mutex so we don't have to be afraid of // somebody else deleting it. if (cfd->Unref()) { // This was the last reference of the column family, so no need to // compact. delete cfd; return Status::OK(); } // Pick up latest mutable CF Options and use it throughout the // compaction job // Compaction makes a copy of the latest MutableCFOptions. It should be used // throughout the compaction procedure to make sure consistency. It will // eventually be installed into SuperVersion auto* mutable_cf_options = cfd->GetLatestMutableCFOptions(); if (!mutable_cf_options->disable_auto_compactions && !cfd->IsDropped()) { // NOTE: try to avoid unnecessary copy of MutableCFOptions if // compaction is not necessary. Need to make sure mutex is held // until we make a copy in the following code TEST_SYNC_POINT("DBImpl::BackgroundCompaction():BeforePickCompaction"); c.reset(cfd->PickCompaction(*mutable_cf_options, log_buffer)); TEST_SYNC_POINT("DBImpl::BackgroundCompaction():AfterPickCompaction"); if (c != nullptr) { bool enough_room = EnoughRoomForCompaction( cfd, *(c->inputs()), &sfm_reserved_compact_space, log_buffer); if (!enough_room) { // Then don't do the compaction c->ReleaseCompactionFiles(status); c->column_family_data() ->current() ->storage_info() ->ComputeCompactionScore(*(c->immutable_cf_options()), *(c->mutable_cf_options())); AddToCompactionQueue(cfd); ++unscheduled_compactions_; c.reset(); // Don't need to sleep here, because BackgroundCallCompaction // will sleep if !s.ok() status = Status::CompactionTooLarge(); } else { // update statistics MeasureTime(stats_, NUM_FILES_IN_SINGLE_COMPACTION, c->inputs(0)->size()); // There are three things that can change compaction score: // 1) When flush or compaction finish. This case is covered by // InstallSuperVersionAndScheduleWork // 2) When MutableCFOptions changes. This case is also covered by // InstallSuperVersionAndScheduleWork, because this is when the new // options take effect. // 3) When we Pick a new compaction, we "remove" those files being // compacted from the calculation, which then influences compaction // score. Here we check if we need the new compaction even without the // files that are currently being compacted. If we need another // compaction, we might be able to execute it in parallel, so we add // it to the queue and schedule a new thread. if (cfd->NeedsCompaction()) { // Yes, we need more compactions! AddToCompactionQueue(cfd); ++unscheduled_compactions_; MaybeScheduleFlushOrCompaction(); } } } } } if (!c) { // Nothing to do ROCKS_LOG_BUFFER(log_buffer, "Compaction nothing to do"); } else if (c->deletion_compaction()) { // TODO(icanadi) Do we want to honor snapshots here? i.e. not delete old // file if there is alive snapshot pointing to it TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:BeforeCompaction", c->column_family_data()); assert(c->num_input_files(1) == 0); assert(c->level() == 0); assert(c->column_family_data()->ioptions()->compaction_style == kCompactionStyleFIFO); compaction_job_stats.num_input_files = c->num_input_files(0); NotifyOnCompactionBegin(c->column_family_data(), c.get(), status, compaction_job_stats, job_context->job_id); for (const auto& f : *c->inputs(0)) { c->edit()->DeleteFile(c->level(), f->fd.GetNumber()); } status = versions_->LogAndApply(c->column_family_data(), *c->mutable_cf_options(), c->edit(), &mutex_, directories_.GetDbDir()); InstallSuperVersionAndScheduleWork(c->column_family_data(), &job_context->superversion_contexts[0], *c->mutable_cf_options()); ROCKS_LOG_BUFFER(log_buffer, "[%s] Deleted %d files\n", c->column_family_data()->GetName().c_str(), c->num_input_files(0)); *made_progress = true; TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:AfterCompaction", c->column_family_data()); } else if (!trivial_move_disallowed && c->IsTrivialMove()) { TEST_SYNC_POINT("DBImpl::BackgroundCompaction:TrivialMove"); TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:BeforeCompaction", c->column_family_data()); // Instrument for event update // TODO(yhchiang): add op details for showing trivial-move. ThreadStatusUtil::SetColumnFamily( c->column_family_data(), c->column_family_data()->ioptions()->env, immutable_db_options_.enable_thread_tracking); ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION); compaction_job_stats.num_input_files = c->num_input_files(0); NotifyOnCompactionBegin(c->column_family_data(), c.get(), status, compaction_job_stats, job_context->job_id); // Move files to next level int32_t moved_files = 0; int64_t moved_bytes = 0; for (unsigned int l = 0; l < c->num_input_levels(); l++) { if (c->level(l) == c->output_level()) { continue; } for (size_t i = 0; i < c->num_input_files(l); i++) { FileMetaData* f = c->input(l, i); c->edit()->DeleteFile(c->level(l), f->fd.GetNumber()); c->edit()->AddFile(c->output_level(), f->fd.GetNumber(), f->fd.GetPathId(), f->fd.GetFileSize(), f->smallest, f->largest, f->fd.smallest_seqno, f->fd.largest_seqno, f->marked_for_compaction); ROCKS_LOG_BUFFER( log_buffer, "[%s] Moving #%" PRIu64 " to level-%d %" PRIu64 " bytes\n", c->column_family_data()->GetName().c_str(), f->fd.GetNumber(), c->output_level(), f->fd.GetFileSize()); ++moved_files; moved_bytes += f->fd.GetFileSize(); } } status = versions_->LogAndApply(c->column_family_data(), *c->mutable_cf_options(), c->edit(), &mutex_, directories_.GetDbDir()); // Use latest MutableCFOptions InstallSuperVersionAndScheduleWork(c->column_family_data(), &job_context->superversion_contexts[0], *c->mutable_cf_options()); VersionStorageInfo::LevelSummaryStorage tmp; c->column_family_data()->internal_stats()->IncBytesMoved(c->output_level(), moved_bytes); { event_logger_.LogToBuffer(log_buffer) << "job" << job_context->job_id << "event" << "trivial_move" << "destination_level" << c->output_level() << "files" << moved_files << "total_files_size" << moved_bytes; } ROCKS_LOG_BUFFER( log_buffer, "[%s] Moved #%d files to level-%d %" PRIu64 " bytes %s: %s\n", c->column_family_data()->GetName().c_str(), moved_files, c->output_level(), moved_bytes, status.ToString().c_str(), c->column_family_data()->current()->storage_info()->LevelSummary(&tmp)); *made_progress = true; // Clear Instrument ThreadStatusUtil::ResetThreadStatus(); TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:AfterCompaction", c->column_family_data()); } else if (!is_prepicked && c->output_level() > 0 && c->output_level() == c->column_family_data() ->current() ->storage_info() ->MaxOutputLevel( immutable_db_options_.allow_ingest_behind) && env_->GetBackgroundThreads(Env::Priority::BOTTOM) > 0) { // Forward compactions involving last level to the bottom pool if it exists, // such that compactions unlikely to contribute to write stalls can be // delayed or deprioritized. TEST_SYNC_POINT("DBImpl::BackgroundCompaction:ForwardToBottomPriPool"); CompactionArg* ca = new CompactionArg; ca->db = this; ca->prepicked_compaction = new PrepickedCompaction; ca->prepicked_compaction->compaction = c.release(); ca->prepicked_compaction->manual_compaction_state = nullptr; // Transfer requested token, so it doesn't need to do it again. ca->prepicked_compaction->task_token = std::move(task_token); ++bg_bottom_compaction_scheduled_; env_->Schedule(&DBImpl::BGWorkBottomCompaction, ca, Env::Priority::BOTTOM, this, &DBImpl::UnscheduleCallback); } else { TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:BeforeCompaction", c->column_family_data()); int output_level __attribute__((__unused__)); output_level = c->output_level(); TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:NonTrivial", &output_level); std::vector snapshot_seqs; SequenceNumber earliest_write_conflict_snapshot; SnapshotChecker* snapshot_checker; GetSnapshotContext(job_context, &snapshot_seqs, &earliest_write_conflict_snapshot, &snapshot_checker); assert(is_snapshot_supported_ || snapshots_.empty()); CompactionJob compaction_job( job_context->job_id, c.get(), immutable_db_options_, env_options_for_compaction_, versions_.get(), &shutting_down_, preserve_deletes_seqnum_.load(), log_buffer, directories_.GetDbDir(), GetDataDir(c->column_family_data(), c->output_path_id()), stats_, &mutex_, &error_handler_, snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker, table_cache_, &event_logger_, c->mutable_cf_options()->paranoid_file_checks, c->mutable_cf_options()->report_bg_io_stats, dbname_, &compaction_job_stats); compaction_job.Prepare(); NotifyOnCompactionBegin(c->column_family_data(), c.get(), status, compaction_job_stats, job_context->job_id); mutex_.Unlock(); compaction_job.Run(); TEST_SYNC_POINT("DBImpl::BackgroundCompaction:NonTrivial:AfterRun"); mutex_.Lock(); status = compaction_job.Install(*c->mutable_cf_options()); if (status.ok()) { InstallSuperVersionAndScheduleWork(c->column_family_data(), &job_context->superversion_contexts[0], *c->mutable_cf_options()); } *made_progress = true; TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:AfterCompaction", c->column_family_data()); } if (c != nullptr) { c->ReleaseCompactionFiles(status); *made_progress = true; #ifndef ROCKSDB_LITE // Need to make sure SstFileManager does its bookkeeping auto sfm = static_cast( immutable_db_options_.sst_file_manager.get()); if (sfm && sfm_reserved_compact_space) { sfm->OnCompactionCompletion(c.get()); } #endif // ROCKSDB_LITE NotifyOnCompactionCompleted(c->column_family_data(), c.get(), status, compaction_job_stats, job_context->job_id); } if (status.ok() || status.IsCompactionTooLarge()) { // Done } else if (status.IsShutdownInProgress()) { // Ignore compaction errors found during shutting down } else { ROCKS_LOG_WARN(immutable_db_options_.info_log, "Compaction error: %s", status.ToString().c_str()); error_handler_.SetBGError(status, BackgroundErrorReason::kCompaction); if (c != nullptr && !is_manual && !error_handler_.IsBGWorkStopped()) { // Put this cfd back in the compaction queue so we can retry after some // time auto cfd = c->column_family_data(); assert(cfd != nullptr); // Since this compaction failed, we need to recompute the score so it // takes the original input files into account c->column_family_data() ->current() ->storage_info() ->ComputeCompactionScore(*(c->immutable_cf_options()), *(c->mutable_cf_options())); if (!cfd->queued_for_compaction()) { AddToCompactionQueue(cfd); ++unscheduled_compactions_; } } } // this will unref its input_version and column_family_data c.reset(); if (is_manual) { ManualCompactionState* m = manual_compaction; if (!status.ok()) { m->status = status; m->done = true; } // For universal compaction: // Because universal compaction always happens at level 0, so one // compaction will pick up all overlapped files. No files will be // filtered out due to size limit and left for a successive compaction. // So we can safely conclude the current compaction. // // Also note that, if we don't stop here, then the current compaction // writes a new file back to level 0, which will be used in successive // compaction. Hence the manual compaction will never finish. // // Stop the compaction if manual_end points to nullptr -- this means // that we compacted the whole range. manual_end should always point // to nullptr in case of universal compaction if (m->manual_end == nullptr) { m->done = true; } if (!m->done) { // We only compacted part of the requested range. Update *m // to the range that is left to be compacted. // Universal and FIFO compactions should always compact the whole range assert(m->cfd->ioptions()->compaction_style != kCompactionStyleUniversal || m->cfd->ioptions()->num_levels > 1); assert(m->cfd->ioptions()->compaction_style != kCompactionStyleFIFO); m->tmp_storage = *m->manual_end; m->begin = &m->tmp_storage; m->incomplete = true; } m->in_progress = false; // not being processed anymore } TEST_SYNC_POINT("DBImpl::BackgroundCompaction:Finish"); return status; } bool DBImpl::HasPendingManualCompaction() { return (!manual_compaction_dequeue_.empty()); } void DBImpl::AddManualCompaction(DBImpl::ManualCompactionState* m) { manual_compaction_dequeue_.push_back(m); } void DBImpl::RemoveManualCompaction(DBImpl::ManualCompactionState* m) { // Remove from queue std::deque::iterator it = manual_compaction_dequeue_.begin(); while (it != manual_compaction_dequeue_.end()) { if (m == (*it)) { it = manual_compaction_dequeue_.erase(it); return; } it++; } assert(false); return; } bool DBImpl::ShouldntRunManualCompaction(ManualCompactionState* m) { if (num_running_ingest_file_ > 0) { // We need to wait for other IngestExternalFile() calls to finish // before running a manual compaction. return true; } if (m->exclusive) { return (bg_bottom_compaction_scheduled_ > 0 || bg_compaction_scheduled_ > 0); } std::deque::iterator it = manual_compaction_dequeue_.begin(); bool seen = false; while (it != manual_compaction_dequeue_.end()) { if (m == (*it)) { it++; seen = true; continue; } else if (MCOverlap(m, (*it)) && (!seen && !(*it)->in_progress)) { // Consider the other manual compaction *it, conflicts if: // overlaps with m // and (*it) is ahead in the queue and is not yet in progress return true; } it++; } return false; } bool DBImpl::HaveManualCompaction(ColumnFamilyData* cfd) { // Remove from priority queue std::deque::iterator it = manual_compaction_dequeue_.begin(); while (it != manual_compaction_dequeue_.end()) { if ((*it)->exclusive) { return true; } if ((cfd == (*it)->cfd) && (!((*it)->in_progress || (*it)->done))) { // Allow automatic compaction if manual compaction is // in progress return true; } it++; } return false; } bool DBImpl::HasExclusiveManualCompaction() { // Remove from priority queue std::deque::iterator it = manual_compaction_dequeue_.begin(); while (it != manual_compaction_dequeue_.end()) { if ((*it)->exclusive) { return true; } it++; } return false; } bool DBImpl::MCOverlap(ManualCompactionState* m, ManualCompactionState* m1) { if ((m->exclusive) || (m1->exclusive)) { return true; } if (m->cfd != m1->cfd) { return false; } return true; } #ifndef ROCKSDB_LITE void DBImpl::BuildCompactionJobInfo( const ColumnFamilyData* cfd, Compaction* c, const Status& st, const CompactionJobStats& compaction_job_stats, const int job_id, const Version* current, CompactionJobInfo* compaction_job_info) const { assert(compaction_job_info != nullptr); compaction_job_info->cf_id = cfd->GetID(); compaction_job_info->cf_name = cfd->GetName(); compaction_job_info->status = st; compaction_job_info->thread_id = env_->GetThreadID(); compaction_job_info->job_id = job_id; compaction_job_info->base_input_level = c->start_level(); compaction_job_info->output_level = c->output_level(); compaction_job_info->stats = compaction_job_stats; compaction_job_info->table_properties = c->GetOutputTableProperties(); compaction_job_info->compaction_reason = c->compaction_reason(); compaction_job_info->compression = c->output_compression(); for (size_t i = 0; i < c->num_input_levels(); ++i) { for (const auto fmd : *c->inputs(i)) { auto fn = TableFileName(c->immutable_cf_options()->cf_paths, fmd->fd.GetNumber(), fmd->fd.GetPathId()); compaction_job_info->input_files.push_back(fn); if (compaction_job_info->table_properties.count(fn) == 0) { shared_ptr tp; auto s = current->GetTableProperties(&tp, fmd, &fn); if (s.ok()) { compaction_job_info->table_properties[fn] = tp; } } } } for (const auto& newf : c->edit()->GetNewFiles()) { compaction_job_info->output_files.push_back( TableFileName(c->immutable_cf_options()->cf_paths, newf.second.fd.GetNumber(), newf.second.fd.GetPathId())); } } #endif // SuperVersionContext gets created and destructed outside of the lock -- // we use this conveniently to: // * malloc one SuperVersion() outside of the lock -- new_superversion // * delete SuperVersion()s outside of the lock -- superversions_to_free // // However, if InstallSuperVersionAndScheduleWork() gets called twice with the // same sv_context, we can't reuse the SuperVersion() that got // malloced because // first call already used it. In that rare case, we take a hit and create a // new SuperVersion() inside of the mutex. We do similar thing // for superversion_to_free void DBImpl::InstallSuperVersionAndScheduleWork( ColumnFamilyData* cfd, SuperVersionContext* sv_context, const MutableCFOptions& mutable_cf_options) { mutex_.AssertHeld(); // Update max_total_in_memory_state_ size_t old_memtable_size = 0; auto* old_sv = cfd->GetSuperVersion(); if (old_sv) { old_memtable_size = old_sv->mutable_cf_options.write_buffer_size * old_sv->mutable_cf_options.max_write_buffer_number; } // this branch is unlikely to step in if (UNLIKELY(sv_context->new_superversion == nullptr)) { sv_context->NewSuperVersion(); } cfd->InstallSuperVersion(sv_context, &mutex_, mutable_cf_options); // Whenever we install new SuperVersion, we might need to issue new flushes or // compactions. SchedulePendingCompaction(cfd); MaybeScheduleFlushOrCompaction(); // Update max_total_in_memory_state_ max_total_in_memory_state_ = max_total_in_memory_state_ - old_memtable_size + mutable_cf_options.write_buffer_size * mutable_cf_options.max_write_buffer_number; } // ShouldPurge is called by FindObsoleteFiles when doing a full scan, // and db mutex (mutex_) should already be held. This function performs a // linear scan of an vector (files_grabbed_for_purge_) in search of a // certain element. We expect FindObsoleteFiles with full scan to occur once // every 10 hours by default, and the size of the vector is small. // Therefore, the cost is affordable even if the mutex is held. // Actually, the current implementation of FindObsoleteFiles with // full_scan=true can issue I/O requests to obtain list of files in // directories, e.g. env_->getChildren while holding db mutex. // In the future, if we want to reduce the cost of search, we may try to keep // the vector sorted. bool DBImpl::ShouldPurge(uint64_t file_number) const { for (auto fn : files_grabbed_for_purge_) { if (file_number == fn) { return false; } } for (const auto& purge_file_info : purge_queue_) { if (purge_file_info.number == file_number) { return false; } } return true; } // MarkAsGrabbedForPurge is called by FindObsoleteFiles, and db mutex // (mutex_) should already be held. void DBImpl::MarkAsGrabbedForPurge(uint64_t file_number) { files_grabbed_for_purge_.emplace_back(file_number); } void DBImpl::SetSnapshotChecker(SnapshotChecker* snapshot_checker) { InstrumentedMutexLock l(&mutex_); // snapshot_checker_ should only set once. If we need to set it multiple // times, we need to make sure the old one is not deleted while it is still // using by a compaction job. assert(!snapshot_checker_); snapshot_checker_.reset(snapshot_checker); } void DBImpl::GetSnapshotContext( JobContext* job_context, std::vector* snapshot_seqs, SequenceNumber* earliest_write_conflict_snapshot, SnapshotChecker** snapshot_checker_ptr) { mutex_.AssertHeld(); assert(job_context != nullptr); assert(snapshot_seqs != nullptr); assert(earliest_write_conflict_snapshot != nullptr); assert(snapshot_checker_ptr != nullptr); *snapshot_checker_ptr = snapshot_checker_.get(); if (use_custom_gc_ && *snapshot_checker_ptr == nullptr) { *snapshot_checker_ptr = DisableGCSnapshotChecker::Instance(); } if (*snapshot_checker_ptr != nullptr) { // If snapshot_checker is used, that means the flush/compaction may // contain values not visible to snapshot taken after // flush/compaction job starts. Take a snapshot and it will appear // in snapshot_seqs and force compaction iterator to consider such // snapshots. const Snapshot* job_snapshot = GetSnapshotImpl(false /*write_conflict_boundary*/, false /*lock*/); job_context->job_snapshot.reset(new ManagedSnapshot(this, job_snapshot)); } *snapshot_seqs = snapshots_.GetAll(earliest_write_conflict_snapshot); } } // namespace rocksdb