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1444 Zeilen
42 KiB
1444 Zeilen
42 KiB
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "db/db_impl.h"
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#include <algorithm>
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#include <set>
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#include <string>
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#include <stdint.h>
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#include <stdio.h>
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#include <vector>
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#include "db/builder.h"
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#include "db/db_iter.h"
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#include "db/dbformat.h"
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#include "db/filename.h"
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#include "db/log_reader.h"
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#include "db/log_writer.h"
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#include "db/memtable.h"
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#include "db/table_cache.h"
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#include "db/version_set.h"
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#include "db/write_batch_internal.h"
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#include "leveldb/db.h"
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#include "leveldb/env.h"
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#include "leveldb/status.h"
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#include "leveldb/table.h"
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#include "leveldb/table_builder.h"
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#include "port/port.h"
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#include "table/block.h"
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#include "table/merger.h"
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#include "table/two_level_iterator.h"
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#include "util/coding.h"
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#include "util/logging.h"
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#include "util/mutexlock.h"
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namespace leveldb {
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// Information kept for every waiting writer
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struct DBImpl::Writer {
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Status status;
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WriteBatch* batch;
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bool sync;
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bool done;
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port::CondVar cv;
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explicit Writer(port::Mutex* mu) : cv(mu) { }
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};
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struct DBImpl::CompactionState {
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Compaction* const compaction;
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// Sequence numbers < smallest_snapshot are not significant since we
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// will never have to service a snapshot below smallest_snapshot.
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// Therefore if we have seen a sequence number S <= smallest_snapshot,
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// we can drop all entries for the same key with sequence numbers < S.
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SequenceNumber smallest_snapshot;
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// Files produced by compaction
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struct Output {
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uint64_t number;
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uint64_t file_size;
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InternalKey smallest, largest;
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};
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std::vector<Output> outputs;
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// State kept for output being generated
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WritableFile* outfile;
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TableBuilder* builder;
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uint64_t total_bytes;
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Output* current_output() { return &outputs[outputs.size()-1]; }
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explicit CompactionState(Compaction* c)
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: compaction(c),
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outfile(NULL),
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builder(NULL),
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total_bytes(0) {
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}
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};
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// Fix user-supplied options to be reasonable
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template <class T,class V>
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static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
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if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
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if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
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}
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Options SanitizeOptions(const std::string& dbname,
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const InternalKeyComparator* icmp,
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const Options& src) {
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Options result = src;
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result.comparator = icmp;
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ClipToRange(&result.max_open_files, 20, 50000);
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ClipToRange(&result.write_buffer_size, 64<<10, 1<<30);
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ClipToRange(&result.block_size, 1<<10, 4<<20);
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if (result.info_log == NULL) {
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// Open a log file in the same directory as the db
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src.env->CreateDir(dbname); // In case it does not exist
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src.env->RenameFile(InfoLogFileName(dbname), OldInfoLogFileName(dbname));
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Status s = src.env->NewLogger(InfoLogFileName(dbname), &result.info_log);
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if (!s.ok()) {
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// No place suitable for logging
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result.info_log = NULL;
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}
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}
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if (result.block_cache == NULL) {
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result.block_cache = NewLRUCache(8 << 20);
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}
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return result;
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}
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DBImpl::DBImpl(const Options& options, const std::string& dbname)
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: env_(options.env),
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internal_comparator_(options.comparator),
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options_(SanitizeOptions(dbname, &internal_comparator_, options)),
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owns_info_log_(options_.info_log != options.info_log),
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owns_cache_(options_.block_cache != options.block_cache),
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dbname_(dbname),
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db_lock_(NULL),
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shutting_down_(NULL),
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bg_cv_(&mutex_),
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mem_(new MemTable(internal_comparator_)),
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imm_(NULL),
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logfile_(NULL),
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logfile_number_(0),
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log_(NULL),
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tmp_batch_(new WriteBatch),
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bg_compaction_scheduled_(false),
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manual_compaction_(NULL) {
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mem_->Ref();
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has_imm_.Release_Store(NULL);
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// Reserve ten files or so for other uses and give the rest to TableCache.
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const int table_cache_size = options.max_open_files - 10;
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table_cache_ = new TableCache(dbname_, &options_, table_cache_size);
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versions_ = new VersionSet(dbname_, &options_, table_cache_,
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&internal_comparator_);
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}
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DBImpl::~DBImpl() {
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// Wait for background work to finish
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mutex_.Lock();
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shutting_down_.Release_Store(this); // Any non-NULL value is ok
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while (bg_compaction_scheduled_) {
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bg_cv_.Wait();
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}
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mutex_.Unlock();
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if (db_lock_ != NULL) {
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env_->UnlockFile(db_lock_);
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}
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delete versions_;
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if (mem_ != NULL) mem_->Unref();
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if (imm_ != NULL) imm_->Unref();
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delete tmp_batch_;
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delete log_;
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delete logfile_;
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delete table_cache_;
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if (owns_info_log_) {
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delete options_.info_log;
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}
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if (owns_cache_) {
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delete options_.block_cache;
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}
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}
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Status DBImpl::NewDB() {
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VersionEdit new_db;
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new_db.SetComparatorName(user_comparator()->Name());
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new_db.SetLogNumber(0);
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new_db.SetNextFile(2);
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new_db.SetLastSequence(0);
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const std::string manifest = DescriptorFileName(dbname_, 1);
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WritableFile* file;
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Status s = env_->NewWritableFile(manifest, &file);
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if (!s.ok()) {
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return s;
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}
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{
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log::Writer log(file);
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std::string record;
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new_db.EncodeTo(&record);
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s = log.AddRecord(record);
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if (s.ok()) {
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s = file->Close();
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}
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}
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delete file;
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if (s.ok()) {
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// Make "CURRENT" file that points to the new manifest file.
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s = SetCurrentFile(env_, dbname_, 1);
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} else {
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env_->DeleteFile(manifest);
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}
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return s;
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}
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void DBImpl::MaybeIgnoreError(Status* s) const {
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if (s->ok() || options_.paranoid_checks) {
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// No change needed
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} else {
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Log(options_.info_log, "Ignoring error %s", s->ToString().c_str());
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*s = Status::OK();
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}
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}
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void DBImpl::DeleteObsoleteFiles() {
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// Make a set of all of the live files
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std::set<uint64_t> live = pending_outputs_;
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versions_->AddLiveFiles(&live);
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std::vector<std::string> filenames;
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env_->GetChildren(dbname_, &filenames); // Ignoring errors on purpose
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uint64_t number;
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FileType type;
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for (size_t i = 0; i < filenames.size(); i++) {
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if (ParseFileName(filenames[i], &number, &type)) {
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bool keep = true;
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switch (type) {
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case kLogFile:
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keep = ((number >= versions_->LogNumber()) ||
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(number == versions_->PrevLogNumber()));
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break;
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case kDescriptorFile:
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// Keep my manifest file, and any newer incarnations'
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// (in case there is a race that allows other incarnations)
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keep = (number >= versions_->ManifestFileNumber());
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break;
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case kTableFile:
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keep = (live.find(number) != live.end());
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break;
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case kTempFile:
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// Any temp files that are currently being written to must
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// be recorded in pending_outputs_, which is inserted into "live"
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keep = (live.find(number) != live.end());
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break;
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case kCurrentFile:
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case kDBLockFile:
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case kInfoLogFile:
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keep = true;
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break;
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}
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if (!keep) {
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if (type == kTableFile) {
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table_cache_->Evict(number);
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}
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Log(options_.info_log, "Delete type=%d #%lld\n",
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int(type),
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static_cast<unsigned long long>(number));
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env_->DeleteFile(dbname_ + "/" + filenames[i]);
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}
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}
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}
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}
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Status DBImpl::Recover(VersionEdit* edit) {
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mutex_.AssertHeld();
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// Ignore error from CreateDir since the creation of the DB is
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// committed only when the descriptor is created, and this directory
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// may already exist from a previous failed creation attempt.
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env_->CreateDir(dbname_);
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assert(db_lock_ == NULL);
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Status s = env_->LockFile(LockFileName(dbname_), &db_lock_);
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if (!s.ok()) {
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return s;
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}
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if (!env_->FileExists(CurrentFileName(dbname_))) {
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if (options_.create_if_missing) {
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s = NewDB();
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if (!s.ok()) {
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return s;
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}
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} else {
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return Status::InvalidArgument(
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dbname_, "does not exist (create_if_missing is false)");
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}
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} else {
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if (options_.error_if_exists) {
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return Status::InvalidArgument(
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dbname_, "exists (error_if_exists is true)");
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}
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}
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s = versions_->Recover();
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if (s.ok()) {
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SequenceNumber max_sequence(0);
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// Recover from all newer log files than the ones named in the
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// descriptor (new log files may have been added by the previous
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// incarnation without registering them in the descriptor).
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//
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// Note that PrevLogNumber() is no longer used, but we pay
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// attention to it in case we are recovering a database
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// produced by an older version of leveldb.
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const uint64_t min_log = versions_->LogNumber();
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const uint64_t prev_log = versions_->PrevLogNumber();
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std::vector<std::string> filenames;
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s = env_->GetChildren(dbname_, &filenames);
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if (!s.ok()) {
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return s;
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}
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uint64_t number;
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FileType type;
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std::vector<uint64_t> logs;
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for (size_t i = 0; i < filenames.size(); i++) {
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if (ParseFileName(filenames[i], &number, &type)
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&& type == kLogFile
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&& ((number >= min_log) || (number == prev_log))) {
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logs.push_back(number);
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}
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}
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// Recover in the order in which the logs were generated
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std::sort(logs.begin(), logs.end());
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for (size_t i = 0; i < logs.size(); i++) {
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s = RecoverLogFile(logs[i], edit, &max_sequence);
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// The previous incarnation may not have written any MANIFEST
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// records after allocating this log number. So we manually
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// update the file number allocation counter in VersionSet.
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versions_->MarkFileNumberUsed(logs[i]);
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}
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if (s.ok()) {
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if (versions_->LastSequence() < max_sequence) {
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versions_->SetLastSequence(max_sequence);
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}
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}
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}
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return s;
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}
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Status DBImpl::RecoverLogFile(uint64_t log_number,
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VersionEdit* edit,
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SequenceNumber* max_sequence) {
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struct LogReporter : public log::Reader::Reporter {
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Env* env;
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Logger* info_log;
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const char* fname;
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Status* status; // NULL if options_.paranoid_checks==false
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virtual void Corruption(size_t bytes, const Status& s) {
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Log(info_log, "%s%s: dropping %d bytes; %s",
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(this->status == NULL ? "(ignoring error) " : ""),
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fname, static_cast<int>(bytes), s.ToString().c_str());
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if (this->status != NULL && this->status->ok()) *this->status = s;
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}
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};
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mutex_.AssertHeld();
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// Open the log file
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std::string fname = LogFileName(dbname_, log_number);
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SequentialFile* file;
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Status status = env_->NewSequentialFile(fname, &file);
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if (!status.ok()) {
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MaybeIgnoreError(&status);
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return status;
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}
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// Create the log reader.
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LogReporter reporter;
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reporter.env = env_;
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reporter.info_log = options_.info_log;
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reporter.fname = fname.c_str();
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reporter.status = (options_.paranoid_checks ? &status : NULL);
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// We intentially make log::Reader do checksumming even if
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// paranoid_checks==false so that corruptions cause entire commits
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// to be skipped instead of propagating bad information (like overly
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// large sequence numbers).
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log::Reader reader(file, &reporter, true/*checksum*/,
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0/*initial_offset*/);
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Log(options_.info_log, "Recovering log #%llu",
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(unsigned long long) log_number);
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// Read all the records and add to a memtable
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std::string scratch;
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Slice record;
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WriteBatch batch;
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MemTable* mem = NULL;
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while (reader.ReadRecord(&record, &scratch) &&
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status.ok()) {
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if (record.size() < 12) {
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reporter.Corruption(
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record.size(), Status::Corruption("log record too small"));
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continue;
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}
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WriteBatchInternal::SetContents(&batch, record);
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if (mem == NULL) {
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mem = new MemTable(internal_comparator_);
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mem->Ref();
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}
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status = WriteBatchInternal::InsertInto(&batch, mem);
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MaybeIgnoreError(&status);
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if (!status.ok()) {
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break;
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}
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const SequenceNumber last_seq =
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WriteBatchInternal::Sequence(&batch) +
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WriteBatchInternal::Count(&batch) - 1;
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if (last_seq > *max_sequence) {
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*max_sequence = last_seq;
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}
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if (mem->ApproximateMemoryUsage() > options_.write_buffer_size) {
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status = WriteLevel0Table(mem, edit, NULL);
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if (!status.ok()) {
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// Reflect errors immediately so that conditions like full
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// file-systems cause the DB::Open() to fail.
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break;
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}
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mem->Unref();
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mem = NULL;
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}
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}
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if (status.ok() && mem != NULL) {
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status = WriteLevel0Table(mem, edit, NULL);
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// Reflect errors immediately so that conditions like full
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// file-systems cause the DB::Open() to fail.
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}
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if (mem != NULL) mem->Unref();
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delete file;
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return status;
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}
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Status DBImpl::WriteLevel0Table(MemTable* mem, VersionEdit* edit,
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Version* base) {
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mutex_.AssertHeld();
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const uint64_t start_micros = env_->NowMicros();
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FileMetaData meta;
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meta.number = versions_->NewFileNumber();
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pending_outputs_.insert(meta.number);
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Iterator* iter = mem->NewIterator();
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Log(options_.info_log, "Level-0 table #%llu: started",
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(unsigned long long) meta.number);
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Status s;
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{
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mutex_.Unlock();
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s = BuildTable(dbname_, env_, options_, table_cache_, iter, &meta);
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mutex_.Lock();
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}
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Log(options_.info_log, "Level-0 table #%llu: %lld bytes %s",
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(unsigned long long) meta.number,
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(unsigned long long) meta.file_size,
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s.ToString().c_str());
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delete iter;
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pending_outputs_.erase(meta.number);
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// Note that if file_size is zero, the file has been deleted and
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// should not be added to the manifest.
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int level = 0;
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if (s.ok() && meta.file_size > 0) {
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const Slice min_user_key = meta.smallest.user_key();
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const Slice max_user_key = meta.largest.user_key();
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if (base != NULL) {
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level = base->PickLevelForMemTableOutput(min_user_key, max_user_key);
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}
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edit->AddFile(level, meta.number, meta.file_size,
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meta.smallest, meta.largest);
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}
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CompactionStats stats;
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stats.micros = env_->NowMicros() - start_micros;
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stats.bytes_written = meta.file_size;
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stats_[level].Add(stats);
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return s;
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}
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Status DBImpl::CompactMemTable() {
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mutex_.AssertHeld();
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assert(imm_ != NULL);
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// Save the contents of the memtable as a new Table
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VersionEdit edit;
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Version* base = versions_->current();
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base->Ref();
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Status s = WriteLevel0Table(imm_, &edit, base);
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base->Unref();
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if (s.ok() && shutting_down_.Acquire_Load()) {
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s = Status::IOError("Deleting DB during memtable compaction");
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}
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// Replace immutable memtable with the generated Table
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if (s.ok()) {
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edit.SetPrevLogNumber(0);
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edit.SetLogNumber(logfile_number_); // Earlier logs no longer needed
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s = versions_->LogAndApply(&edit, &mutex_);
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}
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if (s.ok()) {
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// Commit to the new state
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imm_->Unref();
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imm_ = NULL;
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has_imm_.Release_Store(NULL);
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DeleteObsoleteFiles();
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}
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return s;
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}
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void DBImpl::CompactRange(const Slice* begin, const Slice* end) {
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int max_level_with_files = 1;
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{
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MutexLock l(&mutex_);
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Version* base = versions_->current();
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for (int level = 1; level < config::kNumLevels; level++) {
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if (base->OverlapInLevel(level, begin, end)) {
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max_level_with_files = level;
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}
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}
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}
|
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TEST_CompactMemTable(); // TODO(sanjay): Skip if memtable does not overlap
|
|
for (int level = 0; level < max_level_with_files; level++) {
|
|
TEST_CompactRange(level, begin, end);
|
|
}
|
|
}
|
|
|
|
void DBImpl::TEST_CompactRange(int level, const Slice* begin,const Slice* end) {
|
|
assert(level >= 0);
|
|
assert(level + 1 < config::kNumLevels);
|
|
|
|
InternalKey begin_storage, end_storage;
|
|
|
|
ManualCompaction manual;
|
|
manual.level = level;
|
|
manual.done = false;
|
|
if (begin == NULL) {
|
|
manual.begin = NULL;
|
|
} else {
|
|
begin_storage = InternalKey(*begin, kMaxSequenceNumber, kValueTypeForSeek);
|
|
manual.begin = &begin_storage;
|
|
}
|
|
if (end == NULL) {
|
|
manual.end = NULL;
|
|
} else {
|
|
end_storage = InternalKey(*end, 0, static_cast<ValueType>(0));
|
|
manual.end = &end_storage;
|
|
}
|
|
|
|
MutexLock l(&mutex_);
|
|
while (!manual.done) {
|
|
while (manual_compaction_ != NULL) {
|
|
bg_cv_.Wait();
|
|
}
|
|
manual_compaction_ = &manual;
|
|
MaybeScheduleCompaction();
|
|
while (manual_compaction_ == &manual) {
|
|
bg_cv_.Wait();
|
|
}
|
|
}
|
|
}
|
|
|
|
Status DBImpl::TEST_CompactMemTable() {
|
|
// NULL batch means just wait for earlier writes to be done
|
|
Status s = Write(WriteOptions(), NULL);
|
|
if (s.ok()) {
|
|
// Wait until the compaction completes
|
|
MutexLock l(&mutex_);
|
|
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);
|
|
InternalKey manual_end;
|
|
if (is_manual) {
|
|
ManualCompaction* m = manual_compaction_;
|
|
c = versions_->CompactRange(m->level, m->begin, m->end);
|
|
m->done = (c == NULL);
|
|
if (c != NULL) {
|
|
manual_end = c->input(0, c->num_input_files(0) - 1)->largest;
|
|
}
|
|
Log(options_.info_log,
|
|
"Manual compaction at level-%d from %s .. %s; will stop at %s\n",
|
|
m->level,
|
|
(m->begin ? m->begin->DebugString().c_str() : "(begin)"),
|
|
(m->end ? m->end->DebugString().c_str() : "(end)"),
|
|
(m->done ? "(end)" : manual_end.DebugString().c_str()));
|
|
} 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(), &mutex_);
|
|
VersionSet::LevelSummaryStorage tmp;
|
|
Log(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);
|
|
c->ReleaseInputs();
|
|
DeleteObsoleteFiles();
|
|
}
|
|
delete c;
|
|
|
|
if (status.ok()) {
|
|
// Done
|
|
} else if (shutting_down_.Acquire_Load()) {
|
|
// Ignore compaction errors found during shutting down
|
|
} else {
|
|
Log(options_.info_log,
|
|
"Compaction error: %s", status.ToString().c_str());
|
|
if (options_.paranoid_checks && bg_error_.ok()) {
|
|
bg_error_ = status;
|
|
}
|
|
}
|
|
|
|
if (is_manual) {
|
|
ManualCompaction* m = manual_compaction_;
|
|
if (!status.ok()) {
|
|
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.
|
|
m->tmp_storage = manual_end;
|
|
m->begin = &m->tmp_storage;
|
|
}
|
|
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(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(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);
|
|
}
|
|
return versions_->LogAndApply(compact->compaction->edit(), &mutex_);
|
|
}
|
|
|
|
Status DBImpl::DoCompactionWork(CompactionState* compact) {
|
|
const uint64_t start_micros = env_->NowMicros();
|
|
int64_t imm_micros = 0; // Micros spent doing imm_ compactions
|
|
|
|
Log(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(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(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;
|
|
}
|
|
} // namespace
|
|
|
|
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) {
|
|
Status s;
|
|
MutexLock l(&mutex_);
|
|
SequenceNumber snapshot;
|
|
if (options.snapshot != NULL) {
|
|
snapshot = reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_;
|
|
} else {
|
|
snapshot = versions_->LastSequence();
|
|
}
|
|
|
|
MemTable* mem = mem_;
|
|
MemTable* imm = imm_;
|
|
Version* current = versions_->current();
|
|
mem->Ref();
|
|
if (imm != NULL) imm->Ref();
|
|
current->Ref();
|
|
|
|
bool have_stat_update = false;
|
|
Version::GetStats stats;
|
|
|
|
// Unlock while reading from files and memtables
|
|
{
|
|
mutex_.Unlock();
|
|
// First look in the memtable, then in the immutable memtable (if any).
|
|
LookupKey lkey(key, snapshot);
|
|
if (mem->Get(lkey, value, &s)) {
|
|
// Done
|
|
} else if (imm != NULL && imm->Get(lkey, value, &s)) {
|
|
// Done
|
|
} else {
|
|
s = current->Get(options, lkey, value, &stats);
|
|
have_stat_update = true;
|
|
}
|
|
mutex_.Lock();
|
|
}
|
|
|
|
if (have_stat_update && current->UpdateStats(stats)) {
|
|
MaybeScheduleCompaction();
|
|
}
|
|
mem->Unref();
|
|
if (imm != NULL) imm->Unref();
|
|
current->Unref();
|
|
return s;
|
|
}
|
|
|
|
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* my_batch) {
|
|
Writer w(&mutex_);
|
|
w.batch = my_batch;
|
|
w.sync = options.sync;
|
|
w.done = false;
|
|
|
|
MutexLock l(&mutex_);
|
|
writers_.push_back(&w);
|
|
while (!w.done && &w != writers_.front()) {
|
|
w.cv.Wait();
|
|
}
|
|
if (w.done) {
|
|
return w.status;
|
|
}
|
|
|
|
// May temporarily unlock and wait.
|
|
Status status = MakeRoomForWrite(my_batch == NULL);
|
|
uint64_t last_sequence = versions_->LastSequence();
|
|
Writer* last_writer = &w;
|
|
if (status.ok() && my_batch != NULL) { // NULL batch is for compactions
|
|
WriteBatch* updates = BuildBatchGroup(&last_writer);
|
|
WriteBatchInternal::SetSequence(updates, last_sequence + 1);
|
|
last_sequence += WriteBatchInternal::Count(updates);
|
|
|
|
// Add to log and apply to memtable. We can release the lock
|
|
// during this phase since &w is currently responsible for logging
|
|
// and protects against concurrent loggers and concurrent writes
|
|
// into mem_.
|
|
{
|
|
mutex_.Unlock();
|
|
status = log_->AddRecord(WriteBatchInternal::Contents(updates));
|
|
if (status.ok() && options.sync) {
|
|
status = logfile_->Sync();
|
|
}
|
|
if (status.ok()) {
|
|
status = WriteBatchInternal::InsertInto(updates, mem_);
|
|
}
|
|
mutex_.Lock();
|
|
}
|
|
if (updates == tmp_batch_) tmp_batch_->Clear();
|
|
|
|
versions_->SetLastSequence(last_sequence);
|
|
}
|
|
|
|
while (true) {
|
|
Writer* ready = writers_.front();
|
|
writers_.pop_front();
|
|
if (ready != &w) {
|
|
ready->status = status;
|
|
ready->done = true;
|
|
ready->cv.Signal();
|
|
}
|
|
if (ready == last_writer) break;
|
|
}
|
|
|
|
// Notify new head of write queue
|
|
if (!writers_.empty()) {
|
|
writers_.front()->cv.Signal();
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
// REQUIRES: Writer list must be non-empty
|
|
// REQUIRES: First writer must have a non-NULL batch
|
|
WriteBatch* DBImpl::BuildBatchGroup(Writer** last_writer) {
|
|
assert(!writers_.empty());
|
|
Writer* first = writers_.front();
|
|
WriteBatch* result = first->batch;
|
|
assert(result != NULL);
|
|
|
|
size_t size = WriteBatchInternal::ByteSize(first->batch);
|
|
|
|
// Allow the group to grow up to a maximum size, but if the
|
|
// original write is small, limit the growth so we do not slow
|
|
// down the small write too much.
|
|
size_t max_size = 1 << 20;
|
|
if (size <= (128<<10)) {
|
|
max_size = size + (128<<10);
|
|
}
|
|
|
|
*last_writer = first;
|
|
std::deque<Writer*>::iterator iter = writers_.begin();
|
|
++iter; // Advance past "first"
|
|
for (; iter != writers_.end(); ++iter) {
|
|
Writer* w = *iter;
|
|
if (w->sync && !first->sync) {
|
|
// Do not include a sync write into a batch handled by a non-sync write.
|
|
break;
|
|
}
|
|
|
|
if (w->batch != NULL) {
|
|
size += WriteBatchInternal::ByteSize(w->batch);
|
|
if (size > max_size) {
|
|
// Do not make batch too big
|
|
break;
|
|
}
|
|
|
|
// Append to *reuslt
|
|
if (result == first->batch) {
|
|
// Switch to temporary batch instead of disturbing caller's batch
|
|
result = tmp_batch_;
|
|
assert(WriteBatchInternal::Count(result) == 0);
|
|
WriteBatchInternal::Append(result, first->batch);
|
|
}
|
|
WriteBatchInternal::Append(result, w->batch);
|
|
}
|
|
*last_writer = w;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
// REQUIRES: mutex_ is held
|
|
// REQUIRES: this thread is currently at the front of the writer queue
|
|
Status DBImpl::MakeRoomForWrite(bool force) {
|
|
mutex_.AssertHeld();
|
|
assert(!writers_.empty());
|
|
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(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;
|
|
}
|
|
delete log_;
|
|
delete logfile_;
|
|
logfile_ = lfile;
|
|
logfile_number_ = new_log_number;
|
|
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 >= 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;
|
|
} else if (in == "sstables") {
|
|
*value = versions_->current()->DebugString();
|
|
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->logfile_number_ = new_log_number;
|
|
impl->log_ = new log::Writer(lfile);
|
|
s = impl->versions_->LogAndApply(&edit, &impl->mutex_);
|
|
}
|
|
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;
|
|
const std::string lockname = LockFileName(dbname);
|
|
Status result = env->LockFile(lockname, &lock);
|
|
if (result.ok()) {
|
|
uint64_t number;
|
|
FileType type;
|
|
for (size_t i = 0; i < filenames.size(); i++) {
|
|
if (ParseFileName(filenames[i], &number, &type) &&
|
|
type != kDBLockFile) { // Lock file will be deleted at end
|
|
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(lockname);
|
|
env->DeleteDir(dbname); // Ignore error in case dir contains other files
|
|
}
|
|
return result;
|
|
}
|
|
|
|
} // namespace leveldb
|