| // 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" |
| |
| #include <algorithm> |
| #include <set> |
| #include <string> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <vector> |
| #include "db/builder.h" |
| #include "db/db_iter.h" |
| #include "db/dbformat.h" |
| #include "db/filename.h" |
| #include "db/log_reader.h" |
| #include "db/log_writer.h" |
| #include "db/memtable.h" |
| #include "db/table_cache.h" |
| #include "db/version_set.h" |
| #include "db/write_batch_internal.h" |
| #include "leveldb/db.h" |
| #include "leveldb/env.h" |
| #include "leveldb/status.h" |
| #include "leveldb/table.h" |
| #include "leveldb/table_builder.h" |
| #include "port/port.h" |
| #include "table/block.h" |
| #include "table/merger.h" |
| #include "table/two_level_iterator.h" |
| #include "util/coding.h" |
| #include "util/logging.h" |
| #include "util/mutexlock.h" |
| |
| namespace leveldb { |
| |
| struct DBImpl::CompactionState { |
| Compaction* const compaction; |
| |
| // Sequence numbers < smallest_snapshot are not significant since we |
| // will never have to service a snapshot below smallest_snapshot. |
| // Therefore if we have seen a sequence number S <= smallest_snapshot, |
| // we can drop all entries for the same key with sequence numbers < S. |
| SequenceNumber smallest_snapshot; |
| |
| // Files produced by compaction |
| struct Output { |
| uint64_t number; |
| uint64_t file_size; |
| InternalKey smallest, largest; |
| }; |
| std::vector<Output> outputs; |
| |
| // State kept for output being generated |
| WritableFile* outfile; |
| TableBuilder* builder; |
| |
| uint64_t total_bytes; |
| |
| Output* current_output() { return &outputs[outputs.size()-1]; } |
| |
| explicit CompactionState(Compaction* c) |
| : compaction(c), |
| outfile(NULL), |
| builder(NULL), |
| total_bytes(0) { |
| } |
| }; |
| |
| namespace { |
| class NullWritableFile : public WritableFile { |
| public: |
| virtual Status Append(const Slice& data) { return Status::OK(); } |
| virtual Status Close() { return Status::OK(); } |
| virtual Status Flush() { return Status::OK(); } |
| virtual Status Sync() { return Status::OK(); } |
| }; |
| } |
| |
| // Fix user-supplied options to be reasonable |
| template <class T,class V> |
| static void ClipToRange(T* ptr, V minvalue, V maxvalue) { |
| if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue; |
| if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue; |
| } |
| Options SanitizeOptions(const std::string& dbname, |
| const InternalKeyComparator* icmp, |
| const Options& src) { |
| Options result = src; |
| result.comparator = icmp; |
| ClipToRange(&result.max_open_files, 20, 50000); |
| ClipToRange(&result.write_buffer_size, 64<<10, 1<<30); |
| ClipToRange(&result.block_size, 1<<10, 4<<20); |
| if (result.info_log == NULL) { |
| // Open a log file in the same directory as the db |
| src.env->CreateDir(dbname); // In case it does not exist |
| src.env->RenameFile(InfoLogFileName(dbname), OldInfoLogFileName(dbname)); |
| Status s = src.env->NewWritableFile(InfoLogFileName(dbname), |
| &result.info_log); |
| if (!s.ok()) { |
| // No place suitable for logging |
| result.info_log = new NullWritableFile; |
| } |
| } |
| if (result.block_cache == NULL) { |
| result.block_cache = NewLRUCache(8 << 20); |
| } |
| return result; |
| } |
| |
| DBImpl::DBImpl(const Options& options, const std::string& dbname) |
| : env_(options.env), |
| internal_comparator_(options.comparator), |
| options_(SanitizeOptions(dbname, &internal_comparator_, options)), |
| owns_info_log_(options_.info_log != options.info_log), |
| owns_cache_(options_.block_cache != options.block_cache), |
| dbname_(dbname), |
| db_lock_(NULL), |
| shutting_down_(NULL), |
| bg_cv_(&mutex_), |
| mem_(new MemTable(internal_comparator_)), |
| imm_(NULL), |
| logfile_(NULL), |
| log_(NULL), |
| bg_compaction_scheduled_(false), |
| manual_compaction_(NULL) { |
| mem_->Ref(); |
| has_imm_.Release_Store(NULL); |
| |
| // Reserve ten files or so for other uses and give the rest to TableCache. |
| const int table_cache_size = options.max_open_files - 10; |
| table_cache_ = new TableCache(dbname_, &options_, table_cache_size); |
| |
| versions_ = new VersionSet(dbname_, &options_, table_cache_, |
| &internal_comparator_); |
| } |
| |
| DBImpl::~DBImpl() { |
| // Wait for background work to finish |
| mutex_.Lock(); |
| shutting_down_.Release_Store(this); // Any non-NULL value is ok |
| while (bg_compaction_scheduled_) { |
| bg_cv_.Wait(); |
| } |
| mutex_.Unlock(); |
| |
| if (db_lock_ != NULL) { |
| env_->UnlockFile(db_lock_); |
| } |
| |
| delete versions_; |
| if (mem_ != NULL) mem_->Unref(); |
| if (imm_ != NULL) imm_->Unref(); |
| delete log_; |
| delete logfile_; |
| delete table_cache_; |
| |
| if (owns_info_log_) { |
| delete options_.info_log; |
| } |
| if (owns_cache_) { |
| delete options_.block_cache; |
| } |
| } |
| |
| Status DBImpl::NewDB() { |
| VersionEdit new_db; |
| new_db.SetComparatorName(user_comparator()->Name()); |
| new_db.SetLogNumber(0); |
| new_db.SetNextFile(2); |
| new_db.SetLastSequence(0); |
| |
| const std::string manifest = DescriptorFileName(dbname_, 1); |
| WritableFile* file; |
| Status s = env_->NewWritableFile(manifest, &file); |
| if (!s.ok()) { |
| return s; |
| } |
| { |
| log::Writer log(file); |
| std::string record; |
| new_db.EncodeTo(&record); |
| s = log.AddRecord(record); |
| if (s.ok()) { |
| s = file->Close(); |
| } |
| } |
| delete file; |
| if (s.ok()) { |
| // Make "CURRENT" file that points to the new manifest file. |
| s = SetCurrentFile(env_, dbname_, 1); |
| } else { |
| env_->DeleteFile(manifest); |
| } |
| return s; |
| } |
| |
| void DBImpl::MaybeIgnoreError(Status* s) const { |
| if (s->ok() || options_.paranoid_checks) { |
| // No change needed |
| } else { |
| Log(env_, options_.info_log, "Ignoring error %s", s->ToString().c_str()); |
| *s = Status::OK(); |
| } |
| } |
| |
| void DBImpl::DeleteObsoleteFiles() { |
| // Make a set of all of the live files |
| std::set<uint64_t> live = pending_outputs_; |
| versions_->AddLiveFiles(&live); |
| |
| std::vector<std::string> filenames; |
| env_->GetChildren(dbname_, &filenames); // Ignoring errors on purpose |
| uint64_t number; |
| FileType type; |
| for (size_t i = 0; i < filenames.size(); i++) { |
| if (ParseFileName(filenames[i], &number, &type)) { |
| bool keep = true; |
| switch (type) { |
| case kLogFile: |
| keep = ((number == versions_->LogNumber()) || |
| (number == versions_->PrevLogNumber())); |
| break; |
| case kDescriptorFile: |
| // Keep my manifest file, and any newer incarnations' |
| // (in case there is a race that allows other incarnations) |
| keep = (number >= versions_->ManifestFileNumber()); |
| break; |
| case kTableFile: |
| keep = (live.find(number) != live.end()); |
| break; |
| case kTempFile: |
| // Any temp files that are currently being written to must |
| // be recorded in pending_outputs_, which is inserted into "live" |
| keep = (live.find(number) != live.end()); |
| break; |
| case kCurrentFile: |
| case kDBLockFile: |
| case kInfoLogFile: |
| keep = true; |
| break; |
| } |
| |
| if (!keep) { |
| if (type == kTableFile) { |
| table_cache_->Evict(number); |
| } |
| Log(env_, options_.info_log, "Delete type=%d #%lld\n", |
| int(type), |
| static_cast<unsigned long long>(number)); |
| env_->DeleteFile(dbname_ + "/" + filenames[i]); |
| } |
| } |
| } |
| } |
| |
| Status DBImpl::Recover(VersionEdit* edit) { |
| mutex_.AssertHeld(); |
| |
| // Ignore error from CreateDir since the creation of the DB is |
| // committed only when the descriptor is created, and this directory |
| // may already exist from a previous failed creation attempt. |
| env_->CreateDir(dbname_); |
| assert(db_lock_ == NULL); |
| Status s = env_->LockFile(LockFileName(dbname_), &db_lock_); |
| if (!s.ok()) { |
| return s; |
| } |
| |
| if (!env_->FileExists(CurrentFileName(dbname_))) { |
| if (options_.create_if_missing) { |
| s = NewDB(); |
| if (!s.ok()) { |
| return s; |
| } |
| } else { |
| return Status::InvalidArgument( |
| dbname_, "does not exist (create_if_missing is false)"); |
| } |
| } else { |
| if (options_.error_if_exists) { |
| return Status::InvalidArgument( |
| dbname_, "exists (error_if_exists is true)"); |
| } |
| } |
| |
| s = versions_->Recover(); |
| if (s.ok()) { |
| // Recover from the log files named in the descriptor |
| SequenceNumber max_sequence(0); |
| if (versions_->PrevLogNumber() != 0) { // log#==0 means no prev log |
| s = RecoverLogFile(versions_->PrevLogNumber(), edit, &max_sequence); |
| } |
| if (s.ok() && versions_->LogNumber() != 0) { // log#==0 for initial state |
| s = RecoverLogFile(versions_->LogNumber(), edit, &max_sequence); |
| } |
| if (s.ok()) { |
| if (versions_->LastSequence() < max_sequence) { |
| versions_->SetLastSequence(max_sequence); |
| } |
| } |
| } |
| |
| return s; |
| } |
| |
| Status DBImpl::RecoverLogFile(uint64_t log_number, |
| VersionEdit* edit, |
| SequenceNumber* max_sequence) { |
| struct LogReporter : public log::Reader::Reporter { |
| Env* env; |
| WritableFile* info_log; |
| const char* fname; |
| Status* status; // NULL if options_.paranoid_checks==false |
| virtual void Corruption(size_t bytes, const Status& s) { |
| Log(env, info_log, "%s%s: dropping %d bytes; %s", |
| (this->status == NULL ? "(ignoring error) " : ""), |
| fname, static_cast<int>(bytes), s.ToString().c_str()); |
| if (this->status != NULL && this->status->ok()) *this->status = s; |
| } |
| }; |
| |
| mutex_.AssertHeld(); |
| |
| // Open the log file |
| std::string fname = LogFileName(dbname_, log_number); |
| SequentialFile* file; |
| Status status = env_->NewSequentialFile(fname, &file); |
| if (!status.ok()) { |
| MaybeIgnoreError(&status); |
| return status; |
| } |
| |
| // Create the log reader. |
| LogReporter reporter; |
| reporter.env = env_; |
| reporter.info_log = options_.info_log; |
| reporter.fname = fname.c_str(); |
| reporter.status = (options_.paranoid_checks ? &status : NULL); |
| // We intentially make log::Reader do checksumming even if |
| // paranoid_checks==false so that corruptions cause entire commits |
| // to be skipped instead of propagating bad information (like overly |
| // large sequence numbers). |
| log::Reader reader(file, &reporter, true/*checksum*/, |
| 0/*initial_offset*/); |
| Log(env_, options_.info_log, "Recovering log #%llu", |
| (unsigned long long) log_number); |
| |
| // Read all the records and add to a memtable |
| std::string scratch; |
| Slice record; |
| WriteBatch batch; |
| MemTable* mem = NULL; |
| while (reader.ReadRecord(&record, &scratch) && |
| status.ok()) { |
| if (record.size() < 12) { |
| reporter.Corruption( |
| record.size(), Status::Corruption("log record too small")); |
| continue; |
| } |
| WriteBatchInternal::SetContents(&batch, record); |
| |
| if (mem == NULL) { |
| mem = new MemTable(internal_comparator_); |
| mem->Ref(); |
| } |
| status = WriteBatchInternal::InsertInto(&batch, mem); |
| MaybeIgnoreError(&status); |
| if (!status.ok()) { |
| break; |
| } |
| const SequenceNumber last_seq = |
| WriteBatchInternal::Sequence(&batch) + |
| WriteBatchInternal::Count(&batch) - 1; |
| if (last_seq > *max_sequence) { |
| *max_sequence = last_seq; |
| } |
| |
| if (mem->ApproximateMemoryUsage() > options_.write_buffer_size) { |
| status = WriteLevel0Table(mem, edit); |
| if (!status.ok()) { |
| // Reflect errors immediately so that conditions like full |
| // file-systems cause the DB::Open() to fail. |
| break; |
| } |
| mem->Unref(); |
| mem = NULL; |
| } |
| } |
| |
| if (status.ok() && mem != NULL) { |
| status = WriteLevel0Table(mem, edit); |
| // Reflect errors immediately so that conditions like full |
| // file-systems cause the DB::Open() to fail. |
| } |
| |
| if (mem != NULL) mem->Unref(); |
| delete file; |
| return status; |
| } |
| |
| Status DBImpl::WriteLevel0Table(MemTable* mem, VersionEdit* edit) { |
| mutex_.AssertHeld(); |
| const uint64_t start_micros = env_->NowMicros(); |
| FileMetaData meta; |
| meta.number = versions_->NewFileNumber(); |
| pending_outputs_.insert(meta.number); |
| Iterator* iter = mem->NewIterator(); |
| Log(env_, options_.info_log, "Level-0 table #%llu: started", |
| (unsigned long long) meta.number); |
| |
| Status s; |
| { |
| mutex_.Unlock(); |
| s = BuildTable(dbname_, env_, options_, table_cache_, iter, &meta, edit); |
| mutex_.Lock(); |
| } |
| |
| Log(env_, options_.info_log, "Level-0 table #%llu: %lld bytes %s", |
| (unsigned long long) meta.number, |
| (unsigned long long) meta.file_size, |
| s.ToString().c_str()); |
| delete iter; |
| pending_outputs_.erase(meta.number); |
| |
| CompactionStats stats; |
| stats.micros = env_->NowMicros() - start_micros; |
| stats.bytes_written = meta.file_size; |
| stats_[0].Add(stats); |
| return s; |
| } |
| |
| Status DBImpl::CompactMemTable() { |
| mutex_.AssertHeld(); |
| assert(imm_ != NULL); |
| |
| // Save the contents of the memtable as a new Table |
| VersionEdit edit; |
| Status s = WriteLevel0Table(imm_, &edit); |
| |
| // Replace immutable memtable with the generated Table |
| if (s.ok()) { |
| edit.SetPrevLogNumber(0); |
| s = versions_->LogAndApply(&edit); |
| } |
| |
| if (s.ok()) { |
| // Commit to the new state |
| imm_->Unref(); |
| imm_ = NULL; |
| has_imm_.Release_Store(NULL); |
| DeleteObsoleteFiles(); |
| } |
| |
| return s; |
| } |
| |
| void DBImpl::TEST_CompactRange( |
| int level, |
| const std::string& begin, |
| const std::string& end) { |
| MutexLock l(&mutex_); |
| while (manual_compaction_ != NULL) { |
| bg_cv_.Wait(); |
| } |
| ManualCompaction manual; |
| manual.level = level; |
| manual.begin = begin; |
| manual.end = end; |
| manual_compaction_ = &manual; |
| MaybeScheduleCompaction(); |
| while (manual_compaction_ == &manual) { |
| bg_cv_.Wait(); |
| } |
| } |
| |
| Status DBImpl::TEST_CompactMemTable() { |
| MutexLock l(&mutex_); |
| Status s = MakeRoomForWrite(true /* force compaction */); |
| if (s.ok()) { |
| // Wait until the compaction completes |
| while (imm_ != NULL && bg_error_.ok()) { |
| bg_cv_.Wait(); |
| } |
| if (imm_ != NULL) { |
| s = bg_error_; |
| } |
| } |
| return s; |
| } |
| |
| void DBImpl::MaybeScheduleCompaction() { |
| mutex_.AssertHeld(); |
| if (bg_compaction_scheduled_) { |
| // Already scheduled |
| } else if (shutting_down_.Acquire_Load()) { |
| // DB is being deleted; no more background compactions |
| } else if (imm_ == NULL && |
| manual_compaction_ == NULL && |
| !versions_->NeedsCompaction()) { |
| // No work to be done |
| } else { |
| bg_compaction_scheduled_ = true; |
| env_->Schedule(&DBImpl::BGWork, this); |
| } |
| } |
| |
| void DBImpl::BGWork(void* db) { |
| reinterpret_cast<DBImpl*>(db)->BackgroundCall(); |
| } |
| |
| void DBImpl::BackgroundCall() { |
| MutexLock l(&mutex_); |
| assert(bg_compaction_scheduled_); |
| if (!shutting_down_.Acquire_Load()) { |
| BackgroundCompaction(); |
| } |
| bg_compaction_scheduled_ = false; |
| |
| // Previous compaction may have produced too many files in a level, |
| // so reschedule another compaction if needed. |
| MaybeScheduleCompaction(); |
| bg_cv_.SignalAll(); |
| } |
| |
| void DBImpl::BackgroundCompaction() { |
| mutex_.AssertHeld(); |
| |
| if (imm_ != NULL) { |
| CompactMemTable(); |
| return; |
| } |
| |
| Compaction* c; |
| bool is_manual = (manual_compaction_ != NULL); |
| if (is_manual) { |
| const ManualCompaction* m = manual_compaction_; |
| c = versions_->CompactRange( |
| m->level, |
| InternalKey(m->begin, kMaxSequenceNumber, kValueTypeForSeek), |
| InternalKey(m->end, 0, static_cast<ValueType>(0))); |
| } else { |
| c = versions_->PickCompaction(); |
| } |
| |
| Status status; |
| if (c == NULL) { |
| // Nothing to do |
| } else if (!is_manual && c->IsTrivialMove()) { |
| // Move file to next level |
| assert(c->num_input_files(0) == 1); |
| FileMetaData* f = c->input(0, 0); |
| c->edit()->DeleteFile(c->level(), f->number); |
| c->edit()->AddFile(c->level() + 1, f->number, f->file_size, |
| f->smallest, f->largest); |
| status = versions_->LogAndApply(c->edit()); |
| VersionSet::LevelSummaryStorage tmp; |
| Log(env_, options_.info_log, "Moved #%lld to level-%d %lld bytes %s: %s\n", |
| static_cast<unsigned long long>(f->number), |
| c->level() + 1, |
| static_cast<unsigned long long>(f->file_size), |
| status.ToString().c_str(), |
| versions_->LevelSummary(&tmp)); |
| } else { |
| CompactionState* compact = new CompactionState(c); |
| status = DoCompactionWork(compact); |
| CleanupCompaction(compact); |
| } |
| delete c; |
| |
| if (status.ok()) { |
| // Done |
| } else if (shutting_down_.Acquire_Load()) { |
| // Ignore compaction errors found during shutting down |
| } else { |
| Log(env_, options_.info_log, |
| "Compaction error: %s", status.ToString().c_str()); |
| if (options_.paranoid_checks && bg_error_.ok()) { |
| bg_error_ = status; |
| } |
| } |
| |
| if (is_manual) { |
| // Mark it as done |
| manual_compaction_ = NULL; |
| } |
| } |
| |
| void DBImpl::CleanupCompaction(CompactionState* compact) { |
| mutex_.AssertHeld(); |
| if (compact->builder != NULL) { |
| // May happen if we get a shutdown call in the middle of compaction |
| compact->builder->Abandon(); |
| delete compact->builder; |
| } else { |
| assert(compact->outfile == NULL); |
| } |
| delete compact->outfile; |
| for (size_t i = 0; i < compact->outputs.size(); i++) { |
| const CompactionState::Output& out = compact->outputs[i]; |
| pending_outputs_.erase(out.number); |
| } |
| delete compact; |
| } |
| |
| Status DBImpl::OpenCompactionOutputFile(CompactionState* compact) { |
| assert(compact != NULL); |
| assert(compact->builder == NULL); |
| uint64_t file_number; |
| { |
| mutex_.Lock(); |
| file_number = versions_->NewFileNumber(); |
| pending_outputs_.insert(file_number); |
| CompactionState::Output out; |
| out.number = file_number; |
| out.smallest.Clear(); |
| out.largest.Clear(); |
| compact->outputs.push_back(out); |
| mutex_.Unlock(); |
| } |
| |
| // Make the output file |
| std::string fname = TableFileName(dbname_, file_number); |
| Status s = env_->NewWritableFile(fname, &compact->outfile); |
| if (s.ok()) { |
| compact->builder = new TableBuilder(options_, compact->outfile); |
| } |
| return s; |
| } |
| |
| Status DBImpl::FinishCompactionOutputFile(CompactionState* compact, |
| Iterator* input) { |
| assert(compact != NULL); |
| assert(compact->outfile != NULL); |
| assert(compact->builder != NULL); |
| |
| const uint64_t output_number = compact->current_output()->number; |
| assert(output_number != 0); |
| |
| // Check for iterator errors |
| Status s = input->status(); |
| const uint64_t current_entries = compact->builder->NumEntries(); |
| if (s.ok()) { |
| s = compact->builder->Finish(); |
| } else { |
| compact->builder->Abandon(); |
| } |
| const uint64_t current_bytes = compact->builder->FileSize(); |
| compact->current_output()->file_size = current_bytes; |
| compact->total_bytes += current_bytes; |
| delete compact->builder; |
| compact->builder = NULL; |
| |
| // Finish and check for file errors |
| if (s.ok()) { |
| s = compact->outfile->Sync(); |
| } |
| if (s.ok()) { |
| s = compact->outfile->Close(); |
| } |
| delete compact->outfile; |
| compact->outfile = NULL; |
| |
| if (s.ok() && current_entries > 0) { |
| // Verify that the table is usable |
| Iterator* iter = table_cache_->NewIterator(ReadOptions(), |
| output_number, |
| current_bytes); |
| s = iter->status(); |
| delete iter; |
| if (s.ok()) { |
| Log(env_, options_.info_log, |
| "Generated table #%llu: %lld keys, %lld bytes", |
| (unsigned long long) output_number, |
| (unsigned long long) current_entries, |
| (unsigned long long) current_bytes); |
| } |
| } |
| return s; |
| } |
| |
| |
| Status DBImpl::InstallCompactionResults(CompactionState* compact) { |
| mutex_.AssertHeld(); |
| Log(env_, options_.info_log, "Compacted %d@%d + %d@%d files => %lld bytes", |
| compact->compaction->num_input_files(0), |
| compact->compaction->level(), |
| compact->compaction->num_input_files(1), |
| compact->compaction->level() + 1, |
| static_cast<long long>(compact->total_bytes)); |
| |
| // Add compaction outputs |
| compact->compaction->AddInputDeletions(compact->compaction->edit()); |
| const int level = compact->compaction->level(); |
| for (size_t i = 0; i < compact->outputs.size(); i++) { |
| const CompactionState::Output& out = compact->outputs[i]; |
| compact->compaction->edit()->AddFile( |
| level + 1, |
| out.number, out.file_size, out.smallest, out.largest); |
| pending_outputs_.erase(out.number); |
| } |
| compact->outputs.clear(); |
| |
| Status s = versions_->LogAndApply(compact->compaction->edit()); |
| if (s.ok()) { |
| compact->compaction->ReleaseInputs(); |
| DeleteObsoleteFiles(); |
| } else { |
| // Discard any files we may have created during this failed compaction |
| for (size_t i = 0; i < compact->outputs.size(); i++) { |
| env_->DeleteFile(TableFileName(dbname_, compact->outputs[i].number)); |
| } |
| } |
| return s; |
| } |
| |
| Status DBImpl::DoCompactionWork(CompactionState* compact) { |
| const uint64_t start_micros = env_->NowMicros(); |
| int64_t imm_micros = 0; // Micros spent doing imm_ compactions |
| |
| Log(env_, options_.info_log, "Compacting %d@%d + %d@%d files", |
| compact->compaction->num_input_files(0), |
| compact->compaction->level(), |
| compact->compaction->num_input_files(1), |
| compact->compaction->level() + 1); |
| |
| assert(versions_->NumLevelFiles(compact->compaction->level()) > 0); |
| assert(compact->builder == NULL); |
| assert(compact->outfile == NULL); |
| if (snapshots_.empty()) { |
| compact->smallest_snapshot = versions_->LastSequence(); |
| } else { |
| compact->smallest_snapshot = snapshots_.oldest()->number_; |
| } |
| |
| // Release mutex while we're actually doing the compaction work |
| mutex_.Unlock(); |
| |
| Iterator* input = versions_->MakeInputIterator(compact->compaction); |
| input->SeekToFirst(); |
| Status status; |
| ParsedInternalKey ikey; |
| std::string current_user_key; |
| bool has_current_user_key = false; |
| SequenceNumber last_sequence_for_key = kMaxSequenceNumber; |
| for (; input->Valid() && !shutting_down_.Acquire_Load(); ) { |
| // Prioritize immutable compaction work |
| if (has_imm_.NoBarrier_Load() != NULL) { |
| const uint64_t imm_start = env_->NowMicros(); |
| mutex_.Lock(); |
| if (imm_ != NULL) { |
| CompactMemTable(); |
| bg_cv_.SignalAll(); // Wakeup MakeRoomForWrite() if necessary |
| } |
| mutex_.Unlock(); |
| imm_micros += (env_->NowMicros() - imm_start); |
| } |
| |
| Slice key = input->key(); |
| if (compact->compaction->ShouldStopBefore(key) && |
| compact->builder != NULL) { |
| status = FinishCompactionOutputFile(compact, input); |
| if (!status.ok()) { |
| break; |
| } |
| } |
| |
| // Handle key/value, add to state, etc. |
| bool drop = false; |
| if (!ParseInternalKey(key, &ikey)) { |
| // Do not hide error keys |
| current_user_key.clear(); |
| has_current_user_key = false; |
| last_sequence_for_key = kMaxSequenceNumber; |
| } else { |
| if (!has_current_user_key || |
| user_comparator()->Compare(ikey.user_key, |
| Slice(current_user_key)) != 0) { |
| // First occurrence of this user key |
| current_user_key.assign(ikey.user_key.data(), ikey.user_key.size()); |
| has_current_user_key = true; |
| last_sequence_for_key = kMaxSequenceNumber; |
| } |
| |
| if (last_sequence_for_key <= compact->smallest_snapshot) { |
| // Hidden by an newer entry for same user key |
| drop = true; // (A) |
| } else if (ikey.type == kTypeDeletion && |
| ikey.sequence <= compact->smallest_snapshot && |
| compact->compaction->IsBaseLevelForKey(ikey.user_key)) { |
| // For this user key: |
| // (1) there is no data in higher levels |
| // (2) data in lower levels will have larger sequence numbers |
| // (3) data in layers that are being compacted here and have |
| // smaller sequence numbers will be dropped in the next |
| // few iterations of this loop (by rule (A) above). |
| // Therefore this deletion marker is obsolete and can be dropped. |
| drop = true; |
| } |
| |
| last_sequence_for_key = ikey.sequence; |
| } |
| #if 0 |
| Log(env_, options_.info_log, |
| " Compact: %s, seq %d, type: %d %d, drop: %d, is_base: %d, " |
| "%d smallest_snapshot: %d", |
| ikey.user_key.ToString().c_str(), |
| (int)ikey.sequence, ikey.type, kTypeValue, drop, |
| compact->compaction->IsBaseLevelForKey(ikey.user_key), |
| (int)last_sequence_for_key, (int)compact->smallest_snapshot); |
| #endif |
| |
| if (!drop) { |
| // Open output file if necessary |
| if (compact->builder == NULL) { |
| status = OpenCompactionOutputFile(compact); |
| if (!status.ok()) { |
| break; |
| } |
| } |
| if (compact->builder->NumEntries() == 0) { |
| compact->current_output()->smallest.DecodeFrom(key); |
| } |
| compact->current_output()->largest.DecodeFrom(key); |
| compact->builder->Add(key, input->value()); |
| |
| // Close output file if it is big enough |
| if (compact->builder->FileSize() >= |
| compact->compaction->MaxOutputFileSize()) { |
| status = FinishCompactionOutputFile(compact, input); |
| if (!status.ok()) { |
| break; |
| } |
| } |
| } |
| |
| input->Next(); |
| } |
| |
| if (status.ok() && shutting_down_.Acquire_Load()) { |
| status = Status::IOError("Deleting DB during compaction"); |
| } |
| if (status.ok() && compact->builder != NULL) { |
| status = FinishCompactionOutputFile(compact, input); |
| } |
| if (status.ok()) { |
| status = input->status(); |
| } |
| delete input; |
| input = NULL; |
| |
| CompactionStats stats; |
| stats.micros = env_->NowMicros() - start_micros - imm_micros; |
| for (int which = 0; which < 2; which++) { |
| for (int i = 0; i < compact->compaction->num_input_files(which); i++) { |
| stats.bytes_read += compact->compaction->input(which, i)->file_size; |
| } |
| } |
| for (size_t i = 0; i < compact->outputs.size(); i++) { |
| stats.bytes_written += compact->outputs[i].file_size; |
| } |
| |
| mutex_.Lock(); |
| stats_[compact->compaction->level() + 1].Add(stats); |
| |
| if (status.ok()) { |
| status = InstallCompactionResults(compact); |
| } |
| VersionSet::LevelSummaryStorage tmp; |
| Log(env_, options_.info_log, |
| "compacted to: %s", versions_->LevelSummary(&tmp)); |
| return status; |
| } |
| |
| namespace { |
| struct IterState { |
| port::Mutex* mu; |
| Version* version; |
| MemTable* mem; |
| MemTable* imm; |
| }; |
| |
| static void CleanupIteratorState(void* arg1, void* arg2) { |
| IterState* state = reinterpret_cast<IterState*>(arg1); |
| state->mu->Lock(); |
| state->mem->Unref(); |
| if (state->imm != NULL) state->imm->Unref(); |
| state->version->Unref(); |
| state->mu->Unlock(); |
| delete state; |
| } |
| } |
| |
| Iterator* DBImpl::NewInternalIterator(const ReadOptions& options, |
| SequenceNumber* latest_snapshot) { |
| IterState* cleanup = new IterState; |
| mutex_.Lock(); |
| *latest_snapshot = versions_->LastSequence(); |
| |
| // Collect together all needed child iterators |
| std::vector<Iterator*> list; |
| list.push_back(mem_->NewIterator()); |
| mem_->Ref(); |
| if (imm_ != NULL) { |
| list.push_back(imm_->NewIterator()); |
| imm_->Ref(); |
| } |
| versions_->current()->AddIterators(options, &list); |
| Iterator* internal_iter = |
| NewMergingIterator(&internal_comparator_, &list[0], list.size()); |
| versions_->current()->Ref(); |
| |
| cleanup->mu = &mutex_; |
| cleanup->mem = mem_; |
| cleanup->imm = imm_; |
| cleanup->version = versions_->current(); |
| internal_iter->RegisterCleanup(CleanupIteratorState, cleanup, NULL); |
| |
| mutex_.Unlock(); |
| return internal_iter; |
| } |
| |
| Iterator* DBImpl::TEST_NewInternalIterator() { |
| SequenceNumber ignored; |
| return NewInternalIterator(ReadOptions(), &ignored); |
| } |
| |
| int64_t DBImpl::TEST_MaxNextLevelOverlappingBytes() { |
| MutexLock l(&mutex_); |
| return versions_->MaxNextLevelOverlappingBytes(); |
| } |
| |
| Status DBImpl::Get(const ReadOptions& options, |
| const Slice& key, |
| std::string* value) { |
| // TODO(opt): faster implementation |
| Iterator* iter = NewIterator(options); |
| iter->Seek(key); |
| bool found = false; |
| if (iter->Valid() && user_comparator()->Compare(key, iter->key()) == 0) { |
| Slice v = iter->value(); |
| value->assign(v.data(), v.size()); |
| found = true; |
| } |
| // Non-OK iterator status trumps everything else |
| Status result = iter->status(); |
| if (result.ok() && !found) { |
| result = Status::NotFound(Slice()); // Use an empty error message for speed |
| } |
| delete iter; |
| return result; |
| } |
| |
| Iterator* DBImpl::NewIterator(const ReadOptions& options) { |
| SequenceNumber latest_snapshot; |
| Iterator* internal_iter = NewInternalIterator(options, &latest_snapshot); |
| return NewDBIterator( |
| &dbname_, env_, user_comparator(), internal_iter, |
| (options.snapshot != NULL |
| ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_ |
| : latest_snapshot)); |
| } |
| |
| const Snapshot* DBImpl::GetSnapshot() { |
| MutexLock l(&mutex_); |
| return snapshots_.New(versions_->LastSequence()); |
| } |
| |
| void DBImpl::ReleaseSnapshot(const Snapshot* s) { |
| MutexLock l(&mutex_); |
| snapshots_.Delete(reinterpret_cast<const SnapshotImpl*>(s)); |
| } |
| |
| // Convenience methods |
| Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val) { |
| return DB::Put(o, key, val); |
| } |
| |
| Status DBImpl::Delete(const WriteOptions& options, const Slice& key) { |
| return DB::Delete(options, key); |
| } |
| |
| Status DBImpl::Write(const WriteOptions& options, WriteBatch* updates) { |
| Status status; |
| MutexLock l(&mutex_); |
| status = MakeRoomForWrite(false); // May temporarily release lock and wait |
| uint64_t last_sequence = versions_->LastSequence(); |
| if (status.ok()) { |
| WriteBatchInternal::SetSequence(updates, last_sequence + 1); |
| last_sequence += WriteBatchInternal::Count(updates); |
| versions_->SetLastSequence(last_sequence); |
| |
| // Add to log and apply to memtable |
| status = log_->AddRecord(WriteBatchInternal::Contents(updates)); |
| if (status.ok() && options.sync) { |
| status = logfile_->Sync(); |
| } |
| if (status.ok()) { |
| status = WriteBatchInternal::InsertInto(updates, mem_); |
| } |
| } |
| if (options.post_write_snapshot != NULL) { |
| *options.post_write_snapshot = |
| status.ok() ? snapshots_.New(last_sequence) : NULL; |
| } |
| return status; |
| } |
| |
| Status DBImpl::MakeRoomForWrite(bool force) { |
| mutex_.AssertHeld(); |
| bool allow_delay = !force; |
| Status s; |
| while (true) { |
| if (!bg_error_.ok()) { |
| // Yield previous error |
| s = bg_error_; |
| break; |
| } else if ( |
| allow_delay && |
| versions_->NumLevelFiles(0) >= config::kL0_SlowdownWritesTrigger) { |
| // We are getting close to hitting a hard limit on the number of |
| // L0 files. Rather than delaying a single write by several |
| // seconds when we hit the hard limit, start delaying each |
| // individual write by 1ms to reduce latency variance. Also, |
| // this delay hands over some CPU to the compaction thread in |
| // case it is sharing the same core as the writer. |
| mutex_.Unlock(); |
| env_->SleepForMicroseconds(1000); |
| allow_delay = false; // Do not delay a single write more than once |
| mutex_.Lock(); |
| } else if (!force && |
| (mem_->ApproximateMemoryUsage() <= options_.write_buffer_size)) { |
| // There is room in current memtable |
| break; |
| } else if (imm_ != NULL) { |
| // We have filled up the current memtable, but the previous |
| // one is still being compacted, so we wait. |
| bg_cv_.Wait(); |
| } else if (versions_->NumLevelFiles(0) >= config::kL0_StopWritesTrigger) { |
| // There are too many level-0 files. |
| Log(env_, options_.info_log, "waiting...\n"); |
| bg_cv_.Wait(); |
| } else { |
| // Attempt to switch to a new memtable and trigger compaction of old |
| assert(versions_->PrevLogNumber() == 0); |
| uint64_t new_log_number = versions_->NewFileNumber(); |
| WritableFile* lfile = NULL; |
| s = env_->NewWritableFile(LogFileName(dbname_, new_log_number), &lfile); |
| if (!s.ok()) { |
| break; |
| } |
| VersionEdit edit; |
| edit.SetPrevLogNumber(versions_->LogNumber()); |
| edit.SetLogNumber(new_log_number); |
| s = versions_->LogAndApply(&edit); |
| if (!s.ok()) { |
| delete lfile; |
| env_->DeleteFile(LogFileName(dbname_, new_log_number)); |
| break; |
| } |
| delete log_; |
| delete logfile_; |
| logfile_ = lfile; |
| log_ = new log::Writer(lfile); |
| imm_ = mem_; |
| has_imm_.Release_Store(imm_); |
| mem_ = new MemTable(internal_comparator_); |
| mem_->Ref(); |
| force = false; // Do not force another compaction if have room |
| MaybeScheduleCompaction(); |
| } |
| } |
| return s; |
| } |
| |
| bool DBImpl::GetProperty(const Slice& property, std::string* value) { |
| value->clear(); |
| |
| MutexLock l(&mutex_); |
| Slice in = property; |
| Slice prefix("leveldb."); |
| if (!in.starts_with(prefix)) return false; |
| in.remove_prefix(prefix.size()); |
| |
| if (in.starts_with("num-files-at-level")) { |
| in.remove_prefix(strlen("num-files-at-level")); |
| uint64_t level; |
| bool ok = ConsumeDecimalNumber(&in, &level) && in.empty(); |
| if (!ok || level < 0 || level >= config::kNumLevels) { |
| return false; |
| } else { |
| char buf[100]; |
| snprintf(buf, sizeof(buf), "%d", |
| versions_->NumLevelFiles(static_cast<int>(level))); |
| *value = buf; |
| return true; |
| } |
| } else if (in == "stats") { |
| char buf[200]; |
| snprintf(buf, sizeof(buf), |
| " Compactions\n" |
| "Level Files Size(MB) Time(sec) Read(MB) Write(MB)\n" |
| "--------------------------------------------------\n" |
| ); |
| value->append(buf); |
| for (int level = 0; level < config::kNumLevels; level++) { |
| int files = versions_->NumLevelFiles(level); |
| if (stats_[level].micros > 0 || files > 0) { |
| snprintf( |
| buf, sizeof(buf), |
| "%3d %8d %8.0f %9.0f %8.0f %9.0f\n", |
| level, |
| files, |
| versions_->NumLevelBytes(level) / 1048576.0, |
| stats_[level].micros / 1e6, |
| stats_[level].bytes_read / 1048576.0, |
| stats_[level].bytes_written / 1048576.0); |
| value->append(buf); |
| } |
| } |
| return true; |
| } |
| |
| return false; |
| } |
| |
| void DBImpl::GetApproximateSizes( |
| const Range* range, int n, |
| uint64_t* sizes) { |
| // TODO(opt): better implementation |
| Version* v; |
| { |
| MutexLock l(&mutex_); |
| versions_->current()->Ref(); |
| v = versions_->current(); |
| } |
| |
| for (int i = 0; i < n; i++) { |
| // Convert user_key into a corresponding internal key. |
| InternalKey k1(range[i].start, kMaxSequenceNumber, kValueTypeForSeek); |
| InternalKey k2(range[i].limit, kMaxSequenceNumber, kValueTypeForSeek); |
| uint64_t start = versions_->ApproximateOffsetOf(v, k1); |
| uint64_t limit = versions_->ApproximateOffsetOf(v, k2); |
| sizes[i] = (limit >= start ? limit - start : 0); |
| } |
| |
| { |
| MutexLock l(&mutex_); |
| v->Unref(); |
| } |
| } |
| |
| // Default implementations of convenience methods that subclasses of DB |
| // can call if they wish |
| Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) { |
| WriteBatch batch; |
| batch.Put(key, value); |
| return Write(opt, &batch); |
| } |
| |
| Status DB::Delete(const WriteOptions& opt, const Slice& key) { |
| WriteBatch batch; |
| batch.Delete(key); |
| return Write(opt, &batch); |
| } |
| |
| DB::~DB() { } |
| |
| Status DB::Open(const Options& options, const std::string& dbname, |
| DB** dbptr) { |
| *dbptr = NULL; |
| |
| DBImpl* impl = new DBImpl(options, dbname); |
| impl->mutex_.Lock(); |
| VersionEdit edit; |
| Status s = impl->Recover(&edit); // Handles create_if_missing, error_if_exists |
| if (s.ok()) { |
| uint64_t new_log_number = impl->versions_->NewFileNumber(); |
| WritableFile* lfile; |
| s = options.env->NewWritableFile(LogFileName(dbname, new_log_number), |
| &lfile); |
| if (s.ok()) { |
| edit.SetLogNumber(new_log_number); |
| impl->logfile_ = lfile; |
| impl->log_ = new log::Writer(lfile); |
| s = impl->versions_->LogAndApply(&edit); |
| } |
| if (s.ok()) { |
| impl->DeleteObsoleteFiles(); |
| impl->MaybeScheduleCompaction(); |
| } |
| } |
| impl->mutex_.Unlock(); |
| if (s.ok()) { |
| *dbptr = impl; |
| } else { |
| delete impl; |
| } |
| return s; |
| } |
| |
| Snapshot::~Snapshot() { |
| } |
| |
| Status DestroyDB(const std::string& dbname, const Options& options) { |
| Env* env = options.env; |
| std::vector<std::string> filenames; |
| // Ignore error in case directory does not exist |
| env->GetChildren(dbname, &filenames); |
| if (filenames.empty()) { |
| return Status::OK(); |
| } |
| |
| FileLock* lock; |
| Status result = env->LockFile(LockFileName(dbname), &lock); |
| if (result.ok()) { |
| uint64_t number; |
| FileType type; |
| for (size_t i = 0; i < filenames.size(); i++) { |
| if (ParseFileName(filenames[i], &number, &type)) { |
| Status del = env->DeleteFile(dbname + "/" + filenames[i]); |
| if (result.ok() && !del.ok()) { |
| result = del; |
| } |
| } |
| } |
| env->UnlockFile(lock); // Ignore error since state is already gone |
| env->DeleteFile(LockFileName(dbname)); |
| env->DeleteDir(dbname); // Ignore error in case dir contains other files |
| } |
| return result; |
| } |
| |
| } |