Du kannst nicht mehr als 25 Themen auswählen
Themen müssen entweder mit einem Buchstaben oder einer Ziffer beginnen. Sie können Bindestriche („-“) enthalten und bis zu 35 Zeichen lang sein.
450 Zeilen
13 KiB
450 Zeilen
13 KiB
// 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.
|
|
//
|
|
// We recover the contents of the descriptor from the other files we find.
|
|
// (1) Any log files are first converted to tables
|
|
// (2) We scan every table to compute
|
|
// (a) smallest/largest for the table
|
|
// (b) largest sequence number in the table
|
|
// (3) We generate descriptor contents:
|
|
// - log number is set to zero
|
|
// - next-file-number is set to 1 + largest file number we found
|
|
// - last-sequence-number is set to largest sequence# found across
|
|
// all tables (see 2c)
|
|
// - compaction pointers are cleared
|
|
// - every table file is added at level 0
|
|
//
|
|
// Possible optimization 1:
|
|
// (a) Compute total size and use to pick appropriate max-level M
|
|
// (b) Sort tables by largest sequence# in the table
|
|
// (c) For each table: if it overlaps earlier table, place in level-0,
|
|
// else place in level-M.
|
|
// Possible optimization 2:
|
|
// Store per-table metadata (smallest, largest, largest-seq#, ...)
|
|
// in the table's meta section to speed up ScanTable.
|
|
|
|
#include "db/builder.h"
|
|
#include "db/db_impl.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_edit.h"
|
|
#include "db/write_batch_internal.h"
|
|
#include "leveldb/comparator.h"
|
|
#include "leveldb/db.h"
|
|
#include "leveldb/env.h"
|
|
|
|
namespace leveldb {
|
|
|
|
namespace {
|
|
|
|
class Repairer {
|
|
public:
|
|
Repairer(const std::string& dbname, const Options& options)
|
|
: dbname_(dbname),
|
|
env_(options.env),
|
|
icmp_(options.comparator),
|
|
ipolicy_(options.filter_policy),
|
|
options_(SanitizeOptions(dbname, &icmp_, &ipolicy_, options)),
|
|
owns_info_log_(options_.info_log != options.info_log),
|
|
owns_cache_(options_.block_cache != options.block_cache),
|
|
next_file_number_(1) {
|
|
// TableCache can be small since we expect each table to be opened once.
|
|
table_cache_ = new TableCache(dbname_, options_, 10);
|
|
}
|
|
|
|
~Repairer() {
|
|
delete table_cache_;
|
|
if (owns_info_log_) {
|
|
delete options_.info_log;
|
|
}
|
|
if (owns_cache_) {
|
|
delete options_.block_cache;
|
|
}
|
|
}
|
|
|
|
Status Run() {
|
|
Status status = FindFiles();
|
|
if (status.ok()) {
|
|
ConvertLogFilesToTables();
|
|
ExtractMetaData();
|
|
status = WriteDescriptor();
|
|
}
|
|
if (status.ok()) {
|
|
unsigned long long bytes = 0;
|
|
for (size_t i = 0; i < tables_.size(); i++) {
|
|
bytes += tables_[i].meta.file_size;
|
|
}
|
|
Log(options_.info_log,
|
|
"**** Repaired leveldb %s; "
|
|
"recovered %d files; %llu bytes. "
|
|
"Some data may have been lost. "
|
|
"****",
|
|
dbname_.c_str(), static_cast<int>(tables_.size()), bytes);
|
|
}
|
|
return status;
|
|
}
|
|
|
|
private:
|
|
struct TableInfo {
|
|
FileMetaData meta;
|
|
SequenceNumber max_sequence;
|
|
};
|
|
|
|
Status FindFiles() {
|
|
std::vector<std::string> filenames;
|
|
Status status = env_->GetChildren(dbname_, &filenames);
|
|
if (!status.ok()) {
|
|
return status;
|
|
}
|
|
if (filenames.empty()) {
|
|
return Status::IOError(dbname_, "repair found no files");
|
|
}
|
|
|
|
uint64_t number;
|
|
FileType type;
|
|
for (size_t i = 0; i < filenames.size(); i++) {
|
|
if (ParseFileName(filenames[i], &number, &type)) {
|
|
if (type == kDescriptorFile) {
|
|
manifests_.push_back(filenames[i]);
|
|
} else {
|
|
if (number + 1 > next_file_number_) {
|
|
next_file_number_ = number + 1;
|
|
}
|
|
if (type == kLogFile) {
|
|
logs_.push_back(number);
|
|
} else if (type == kTableFile) {
|
|
table_numbers_.push_back(number);
|
|
} else {
|
|
// Ignore other files
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return status;
|
|
}
|
|
|
|
void ConvertLogFilesToTables() {
|
|
for (size_t i = 0; i < logs_.size(); i++) {
|
|
std::string logname = LogFileName(dbname_, logs_[i]);
|
|
Status status = ConvertLogToTable(logs_[i]);
|
|
if (!status.ok()) {
|
|
Log(options_.info_log, "Log #%llu: ignoring conversion error: %s",
|
|
(unsigned long long)logs_[i], status.ToString().c_str());
|
|
}
|
|
ArchiveFile(logname);
|
|
}
|
|
}
|
|
|
|
Status ConvertLogToTable(uint64_t log) {
|
|
struct LogReporter : public log::Reader::Reporter {
|
|
Env* env;
|
|
Logger* info_log;
|
|
uint64_t lognum;
|
|
virtual void Corruption(size_t bytes, const Status& s) {
|
|
// We print error messages for corruption, but continue repairing.
|
|
Log(info_log, "Log #%llu: dropping %d bytes; %s",
|
|
(unsigned long long)lognum, static_cast<int>(bytes),
|
|
s.ToString().c_str());
|
|
}
|
|
};
|
|
|
|
// Open the log file
|
|
std::string logname = LogFileName(dbname_, log);
|
|
SequentialFile* lfile;
|
|
Status status = env_->NewSequentialFile(logname, &lfile);
|
|
if (!status.ok()) {
|
|
return status;
|
|
}
|
|
|
|
// Create the log reader.
|
|
LogReporter reporter;
|
|
reporter.env = env_;
|
|
reporter.info_log = options_.info_log;
|
|
reporter.lognum = log;
|
|
// We intentionally make log::Reader do checksumming so that
|
|
// corruptions cause entire commits to be skipped instead of
|
|
// propagating bad information (like overly large sequence
|
|
// numbers).
|
|
log::Reader reader(lfile, &reporter, false /*do not checksum*/,
|
|
0 /*initial_offset*/);
|
|
|
|
// Read all the records and add to a memtable
|
|
std::string scratch;
|
|
Slice record;
|
|
WriteBatch batch;
|
|
MemTable* mem = new MemTable(icmp_);
|
|
mem->Ref();
|
|
int counter = 0;
|
|
while (reader.ReadRecord(&record, &scratch)) {
|
|
if (record.size() < 12) {
|
|
reporter.Corruption(record.size(),
|
|
Status::Corruption("log record too small"));
|
|
continue;
|
|
}
|
|
WriteBatchInternal::SetContents(&batch, record);
|
|
status = WriteBatchInternal::InsertInto(&batch, mem);
|
|
if (status.ok()) {
|
|
counter += WriteBatchInternal::Count(&batch);
|
|
} else {
|
|
Log(options_.info_log, "Log #%llu: ignoring %s",
|
|
(unsigned long long)log, status.ToString().c_str());
|
|
status = Status::OK(); // Keep going with rest of file
|
|
}
|
|
}
|
|
delete lfile;
|
|
|
|
// Do not record a version edit for this conversion to a Table
|
|
// since ExtractMetaData() will also generate edits.
|
|
FileMetaData meta;
|
|
meta.number = next_file_number_++;
|
|
Iterator* iter = mem->NewIterator();
|
|
status = BuildTable(dbname_, env_, options_, table_cache_, iter, &meta);
|
|
delete iter;
|
|
mem->Unref();
|
|
mem = nullptr;
|
|
if (status.ok()) {
|
|
if (meta.file_size > 0) {
|
|
table_numbers_.push_back(meta.number);
|
|
}
|
|
}
|
|
Log(options_.info_log, "Log #%llu: %d ops saved to Table #%llu %s",
|
|
(unsigned long long)log, counter, (unsigned long long)meta.number,
|
|
status.ToString().c_str());
|
|
return status;
|
|
}
|
|
|
|
void ExtractMetaData() {
|
|
for (size_t i = 0; i < table_numbers_.size(); i++) {
|
|
ScanTable(table_numbers_[i]);
|
|
}
|
|
}
|
|
|
|
Iterator* NewTableIterator(const FileMetaData& meta) {
|
|
// Same as compaction iterators: if paranoid_checks are on, turn
|
|
// on checksum verification.
|
|
ReadOptions r;
|
|
r.verify_checksums = options_.paranoid_checks;
|
|
return table_cache_->NewIterator(r, meta.number, meta.file_size);
|
|
}
|
|
|
|
void ScanTable(uint64_t number) {
|
|
TableInfo t;
|
|
t.meta.number = number;
|
|
std::string fname = TableFileName(dbname_, number);
|
|
Status status = env_->GetFileSize(fname, &t.meta.file_size);
|
|
if (!status.ok()) {
|
|
// Try alternate file name.
|
|
fname = SSTTableFileName(dbname_, number);
|
|
Status s2 = env_->GetFileSize(fname, &t.meta.file_size);
|
|
if (s2.ok()) {
|
|
status = Status::OK();
|
|
}
|
|
}
|
|
if (!status.ok()) {
|
|
ArchiveFile(TableFileName(dbname_, number));
|
|
ArchiveFile(SSTTableFileName(dbname_, number));
|
|
Log(options_.info_log, "Table #%llu: dropped: %s",
|
|
(unsigned long long)t.meta.number, status.ToString().c_str());
|
|
return;
|
|
}
|
|
|
|
// Extract metadata by scanning through table.
|
|
int counter = 0;
|
|
Iterator* iter = NewTableIterator(t.meta);
|
|
bool empty = true;
|
|
ParsedInternalKey parsed;
|
|
t.max_sequence = 0;
|
|
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
|
|
Slice key = iter->key();
|
|
if (!ParseInternalKey(key, &parsed)) {
|
|
Log(options_.info_log, "Table #%llu: unparsable key %s",
|
|
(unsigned long long)t.meta.number, EscapeString(key).c_str());
|
|
continue;
|
|
}
|
|
|
|
counter++;
|
|
if (empty) {
|
|
empty = false;
|
|
t.meta.smallest.DecodeFrom(key);
|
|
}
|
|
t.meta.largest.DecodeFrom(key);
|
|
if (parsed.sequence > t.max_sequence) {
|
|
t.max_sequence = parsed.sequence;
|
|
}
|
|
}
|
|
if (!iter->status().ok()) {
|
|
status = iter->status();
|
|
}
|
|
delete iter;
|
|
Log(options_.info_log, "Table #%llu: %d entries %s",
|
|
(unsigned long long)t.meta.number, counter, status.ToString().c_str());
|
|
|
|
if (status.ok()) {
|
|
tables_.push_back(t);
|
|
} else {
|
|
RepairTable(fname, t); // RepairTable archives input file.
|
|
}
|
|
}
|
|
|
|
void RepairTable(const std::string& src, TableInfo t) {
|
|
// We will copy src contents to a new table and then rename the
|
|
// new table over the source.
|
|
|
|
// Create builder.
|
|
std::string copy = TableFileName(dbname_, next_file_number_++);
|
|
WritableFile* file;
|
|
Status s = env_->NewWritableFile(copy, &file);
|
|
if (!s.ok()) {
|
|
return;
|
|
}
|
|
TableBuilder* builder = new TableBuilder(options_, file);
|
|
|
|
// Copy data.
|
|
Iterator* iter = NewTableIterator(t.meta);
|
|
int counter = 0;
|
|
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
|
|
builder->Add(iter->key(), iter->value());
|
|
counter++;
|
|
}
|
|
delete iter;
|
|
|
|
ArchiveFile(src);
|
|
if (counter == 0) {
|
|
builder->Abandon(); // Nothing to save
|
|
} else {
|
|
s = builder->Finish();
|
|
if (s.ok()) {
|
|
t.meta.file_size = builder->FileSize();
|
|
}
|
|
}
|
|
delete builder;
|
|
builder = nullptr;
|
|
|
|
if (s.ok()) {
|
|
s = file->Close();
|
|
}
|
|
delete file;
|
|
file = nullptr;
|
|
|
|
if (counter > 0 && s.ok()) {
|
|
std::string orig = TableFileName(dbname_, t.meta.number);
|
|
s = env_->RenameFile(copy, orig);
|
|
if (s.ok()) {
|
|
Log(options_.info_log, "Table #%llu: %d entries repaired",
|
|
(unsigned long long)t.meta.number, counter);
|
|
tables_.push_back(t);
|
|
}
|
|
}
|
|
if (!s.ok()) {
|
|
env_->DeleteFile(copy);
|
|
}
|
|
}
|
|
|
|
Status WriteDescriptor() {
|
|
std::string tmp = TempFileName(dbname_, 1);
|
|
WritableFile* file;
|
|
Status status = env_->NewWritableFile(tmp, &file);
|
|
if (!status.ok()) {
|
|
return status;
|
|
}
|
|
|
|
SequenceNumber max_sequence = 0;
|
|
for (size_t i = 0; i < tables_.size(); i++) {
|
|
if (max_sequence < tables_[i].max_sequence) {
|
|
max_sequence = tables_[i].max_sequence;
|
|
}
|
|
}
|
|
|
|
edit_.SetComparatorName(icmp_.user_comparator()->Name());
|
|
edit_.SetLogNumber(0);
|
|
edit_.SetNextFile(next_file_number_);
|
|
edit_.SetLastSequence(max_sequence);
|
|
|
|
for (size_t i = 0; i < tables_.size(); i++) {
|
|
// TODO(opt): separate out into multiple levels
|
|
const TableInfo& t = tables_[i];
|
|
edit_.AddFile(0, t.meta.number, t.meta.file_size, t.meta.smallest,
|
|
t.meta.largest);
|
|
}
|
|
|
|
// fprintf(stderr, "NewDescriptor:\n%s\n", edit_.DebugString().c_str());
|
|
{
|
|
log::Writer log(file);
|
|
std::string record;
|
|
edit_.EncodeTo(&record);
|
|
status = log.AddRecord(record);
|
|
}
|
|
if (status.ok()) {
|
|
status = file->Close();
|
|
}
|
|
delete file;
|
|
file = nullptr;
|
|
|
|
if (!status.ok()) {
|
|
env_->DeleteFile(tmp);
|
|
} else {
|
|
// Discard older manifests
|
|
for (size_t i = 0; i < manifests_.size(); i++) {
|
|
ArchiveFile(dbname_ + "/" + manifests_[i]);
|
|
}
|
|
|
|
// Install new manifest
|
|
status = env_->RenameFile(tmp, DescriptorFileName(dbname_, 1));
|
|
if (status.ok()) {
|
|
status = SetCurrentFile(env_, dbname_, 1);
|
|
} else {
|
|
env_->DeleteFile(tmp);
|
|
}
|
|
}
|
|
return status;
|
|
}
|
|
|
|
void ArchiveFile(const std::string& fname) {
|
|
// Move into another directory. E.g., for
|
|
// dir/foo
|
|
// rename to
|
|
// dir/lost/foo
|
|
const char* slash = strrchr(fname.c_str(), '/');
|
|
std::string new_dir;
|
|
if (slash != nullptr) {
|
|
new_dir.assign(fname.data(), slash - fname.data());
|
|
}
|
|
new_dir.append("/lost");
|
|
env_->CreateDir(new_dir); // Ignore error
|
|
std::string new_file = new_dir;
|
|
new_file.append("/");
|
|
new_file.append((slash == nullptr) ? fname.c_str() : slash + 1);
|
|
Status s = env_->RenameFile(fname, new_file);
|
|
Log(options_.info_log, "Archiving %s: %s\n", fname.c_str(),
|
|
s.ToString().c_str());
|
|
}
|
|
|
|
const std::string dbname_;
|
|
Env* const env_;
|
|
InternalKeyComparator const icmp_;
|
|
InternalFilterPolicy const ipolicy_;
|
|
const Options options_;
|
|
bool owns_info_log_;
|
|
bool owns_cache_;
|
|
TableCache* table_cache_;
|
|
VersionEdit edit_;
|
|
|
|
std::vector<std::string> manifests_;
|
|
std::vector<uint64_t> table_numbers_;
|
|
std::vector<uint64_t> logs_;
|
|
std::vector<TableInfo> tables_;
|
|
uint64_t next_file_number_;
|
|
};
|
|
} // namespace
|
|
|
|
Status RepairDB(const std::string& dbname, const Options& options) {
|
|
Repairer repairer(dbname, options);
|
|
return repairer.Run();
|
|
}
|
|
|
|
} // namespace leveldb
|