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LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened.

(Based on a suggestion by cmumford.)

"open" benchmark on my workstation speeds up significantly since we
can now avoid three fdatasync calls and a compaction per open:

  Before: ~80000 microseconds
  After:    ~130 microseconds

Details:

(1) Added Options::reuse_logs (currently defaults to false) to control
new behavior.  The intention is to change the default to true after some
baking.

(2) Added Env::NewAppendableFile() whose default implementation returns
a not-supported error.

(3) VersionSet::Recovery attempts to reuse the MANIFEST from which
it is recovering.

(4) DBImpl recovery attempts to reuse the last log file and memtable.

(5) db_test.cc now tests a new configuration that sets reuse_logs to true.

(6) fault_injection_test also tests a reuse_logs==true config.

(7) Added a new recovery_test.
baseline
Sanjay Ghemawat 10 years ago
committed by Chris Mumford
parent
commit
ac1d69da31
22 changed files with 707 additions and 155 deletions
  1. +4
    -0
      Makefile
  2. +1
    -1
      db/corruption_test.cc
  3. +7
    -0
      db/db_bench.cc
  4. +109
    -69
      db/db_impl.cc
  5. +4
    -4
      db/db_impl.h
  6. +20
    -1
      db/db_test.cc
  7. +80
    -68
      db/fault_injection_test.cc
  8. +21
    -3
      db/log_test.cc
  9. +13
    -4
      db/log_writer.cc
  10. +6
    -0
      db/log_writer.h
  11. +324
    -0
      db/recovery_test.cc
  12. +36
    -1
      db/version_set.cc
  13. +3
    -1
      db/version_set.h
  14. +13
    -0
      helpers/memenv/memenv.cc
  15. +11
    -2
      helpers/memenv/memenv_test.cc
  16. +18
    -0
      include/leveldb/env.h
  17. +6
    -0
      include/leveldb/options.h
  18. +3
    -0
      include/leveldb/status.h
  19. +4
    -0
      util/env.cc
  20. +13
    -0
      util/env_posix.cc
  21. +1
    -1
      util/options.cc
  22. +10
    -0
      util/testutil.h

+ 4
- 0
Makefile View File

@ -57,6 +57,7 @@ TESTS = \
issue200_test \
log_test \
memenv_test \
recovery_test \
skiplist_test \
table_test \
version_edit_test \
@ -177,6 +178,9 @@ issue200_test: issues/issue200_test.o $(LIBOBJECTS) $(TESTHARNESS)
log_test: db/log_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) $(LDFLAGS) db/log_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
recovery_test: db/recovery_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) $(LDFLAGS) db/recovery_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
table_test: table/table_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(CXX) $(LDFLAGS) table/table_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

+ 1
- 1
db/corruption_test.cc View File

@ -36,7 +36,7 @@ class CorruptionTest {
tiny_cache_ = NewLRUCache(100);
options_.env = &env_;
options_.block_cache = tiny_cache_;
dbname_ = test::TmpDir() + "/db_test";
dbname_ = test::TmpDir() + "/corruption_test";
DestroyDB(dbname_, options_);
db_ = NULL;

+ 7
- 0
db/db_bench.cc View File

@ -100,6 +100,9 @@ static int FLAGS_bloom_bits = -1;
// benchmark will fail.
static bool FLAGS_use_existing_db = false;
// If true, reuse existing log/MANIFEST files when re-opening a database.
static bool FLAGS_reuse_logs = false;
// Use the db with the following name.
static const char* FLAGS_db = NULL;
@ -700,6 +703,7 @@ class Benchmark {
options.write_buffer_size = FLAGS_write_buffer_size;
options.max_open_files = FLAGS_open_files;
options.filter_policy = filter_policy_;
options.reuse_logs = FLAGS_reuse_logs;
Status s = DB::Open(options, FLAGS_db, &db_);
if (!s.ok()) {
fprintf(stderr, "open error: %s\n", s.ToString().c_str());
@ -954,6 +958,9 @@ int main(int argc, char** argv) {
} else if (sscanf(argv[i], "--use_existing_db=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_use_existing_db = n;
} else if (sscanf(argv[i], "--reuse_logs=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_reuse_logs = n;
} else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
FLAGS_num = n;
} else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {

+ 109
- 69
db/db_impl.cc View File

@ -125,7 +125,7 @@ DBImpl::DBImpl(const Options& raw_options, const std::string& dbname)
db_lock_(NULL),
shutting_down_(NULL),
bg_cv_(&mutex_),
mem_(new MemTable(internal_comparator_)),
mem_(NULL),
imm_(NULL),
logfile_(NULL),
logfile_number_(0),
@ -134,7 +134,6 @@ DBImpl::DBImpl(const Options& raw_options, const std::string& dbname)
tmp_batch_(new WriteBatch),
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.
@ -271,7 +270,7 @@ void DBImpl::DeleteObsoleteFiles() {
}
}
Status DBImpl::Recover(VersionEdit* edit) {
Status DBImpl::Recover(VersionEdit* edit, bool *save_manifest) {
mutex_.AssertHeld();
// Ignore error from CreateDir since the creation of the DB is
@ -301,66 +300,69 @@ Status DBImpl::Recover(VersionEdit* edit) {
}
}
s = versions_->Recover();
if (s.ok()) {
SequenceNumber max_sequence(0);
// Recover from all newer log files than the ones named in the
// descriptor (new log files may have been added by the previous
// incarnation without registering them in the descriptor).
//
// Note that PrevLogNumber() is no longer used, but we pay
// attention to it in case we are recovering a database
// produced by an older version of leveldb.
const uint64_t min_log = versions_->LogNumber();
const uint64_t prev_log = versions_->PrevLogNumber();
std::vector<std::string> filenames;
s = env_->GetChildren(dbname_, &filenames);
s = versions_->Recover(save_manifest);
if (!s.ok()) {
return s;
}
SequenceNumber max_sequence(0);
// Recover from all newer log files than the ones named in the
// descriptor (new log files may have been added by the previous
// incarnation without registering them in the descriptor).
//
// Note that PrevLogNumber() is no longer used, but we pay
// attention to it in case we are recovering a database
// produced by an older version of leveldb.
const uint64_t min_log = versions_->LogNumber();
const uint64_t prev_log = versions_->PrevLogNumber();
std::vector<std::string> filenames;
s = env_->GetChildren(dbname_, &filenames);
if (!s.ok()) {
return s;
}
std::set<uint64_t> expected;
versions_->AddLiveFiles(&expected);
uint64_t number;
FileType type;
std::vector<uint64_t> logs;
for (size_t i = 0; i < filenames.size(); i++) {
if (ParseFileName(filenames[i], &number, &type)) {
expected.erase(number);
if (type == kLogFile && ((number >= min_log) || (number == prev_log)))
logs.push_back(number);
}
}
if (!expected.empty()) {
char buf[50];
snprintf(buf, sizeof(buf), "%d missing files; e.g.",
static_cast<int>(expected.size()));
return Status::Corruption(buf, TableFileName(dbname_, *(expected.begin())));
}
// Recover in the order in which the logs were generated
std::sort(logs.begin(), logs.end());
for (size_t i = 0; i < logs.size(); i++) {
s = RecoverLogFile(logs[i], (i == logs.size() - 1), save_manifest, edit,
&max_sequence);
if (!s.ok()) {
return s;
}
std::set<uint64_t> expected;
versions_->AddLiveFiles(&expected);
uint64_t number;
FileType type;
std::vector<uint64_t> logs;
for (size_t i = 0; i < filenames.size(); i++) {
if (ParseFileName(filenames[i], &number, &type)) {
expected.erase(number);
if (type == kLogFile && ((number >= min_log) || (number == prev_log)))
logs.push_back(number);
}
}
if (!expected.empty()) {
char buf[50];
snprintf(buf, sizeof(buf), "%d missing files; e.g.",
static_cast<int>(expected.size()));
return Status::Corruption(buf, TableFileName(dbname_, *(expected.begin())));
}
// Recover in the order in which the logs were generated
std::sort(logs.begin(), logs.end());
for (size_t i = 0; i < logs.size(); i++) {
s = RecoverLogFile(logs[i], edit, &max_sequence);
// The previous incarnation may not have written any MANIFEST
// records after allocating this log number. So we manually
// update the file number allocation counter in VersionSet.
versions_->MarkFileNumberUsed(logs[i]);
}
// The previous incarnation may not have written any MANIFEST
// records after allocating this log number. So we manually
// update the file number allocation counter in VersionSet.
versions_->MarkFileNumberUsed(logs[i]);
}
if (s.ok()) {
if (versions_->LastSequence() < max_sequence) {
versions_->SetLastSequence(max_sequence);
}
}
if (versions_->LastSequence() < max_sequence) {
versions_->SetLastSequence(max_sequence);
}
return s;
return Status::OK();
}
Status DBImpl::RecoverLogFile(uint64_t log_number,
VersionEdit* edit,
Status DBImpl::RecoverLogFile(uint64_t log_number, bool last_log,
bool* save_manifest, VersionEdit* edit,
SequenceNumber* max_sequence) {
struct LogReporter : public log::Reader::Reporter {
Env* env;
@ -405,6 +407,7 @@ Status DBImpl::RecoverLogFile(uint64_t log_number,
std::string scratch;
Slice record;
WriteBatch batch;
int compactions = 0;
MemTable* mem = NULL;
while (reader.ReadRecord(&record, &scratch) &&
status.ok()) {
@ -432,25 +435,52 @@ Status DBImpl::RecoverLogFile(uint64_t log_number,
}
if (mem->ApproximateMemoryUsage() > options_.write_buffer_size) {
compactions++;
*save_manifest = true;
status = WriteLevel0Table(mem, edit, NULL);
mem->Unref();
mem = NULL;
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, NULL);
// Reflect errors immediately so that conditions like full
// file-systems cause the DB::Open() to fail.
delete file;
// See if we should keep reusing the last log file.
if (status.ok() && options_.reuse_logs && last_log && compactions == 0) {
assert(logfile_ == NULL);
assert(log_ == NULL);
assert(mem_ == NULL);
uint64_t lfile_size;
if (env_->GetFileSize(fname, &lfile_size).ok() &&
env_->NewAppendableFile(fname, &logfile_).ok()) {
Log(options_.info_log, "Reusing old log %s \n", fname.c_str());
log_ = new log::Writer(logfile_, lfile_size);
logfile_number_ = log_number;
if (mem != NULL) {
mem_ = mem;
mem = NULL;
} else {
// mem can be NULL if lognum exists but was empty.
mem_ = new MemTable(internal_comparator_);
mem_->Ref();
}
}
}
if (mem != NULL) {
// mem did not get reused; compact it.
if (status.ok()) {
*save_manifest = true;
status = WriteLevel0Table(mem, edit, NULL);
}
mem->Unref();
}
if (mem != NULL) mem->Unref();
delete file;
return status;
}
@ -1449,8 +1479,11 @@ Status DB::Open(const Options& options, const std::string& dbname,
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()) {
// Recover handles create_if_missing, error_if_exists
bool save_manifest = false;
Status s = impl->Recover(&edit, &save_manifest);
if (s.ok() && impl->mem_ == NULL) {
// Create new log and a corresponding memtable.
uint64_t new_log_number = impl->versions_->NewFileNumber();
WritableFile* lfile;
s = options.env->NewWritableFile(LogFileName(dbname, new_log_number),
@ -1460,15 +1493,22 @@ Status DB::Open(const Options& options, const std::string& dbname,
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->mem_ = new MemTable(impl->internal_comparator_);
impl->mem_->Ref();
}
}
if (s.ok() && save_manifest) {
edit.SetPrevLogNumber(0); // No older logs needed after recovery.
edit.SetLogNumber(impl->logfile_number_);
s = impl->versions_->LogAndApply(&edit, &impl->mutex_);
}
if (s.ok()) {
impl->DeleteObsoleteFiles();
impl->MaybeScheduleCompaction();
}
impl->mutex_.Unlock();
if (s.ok()) {
assert(impl->mem_ != NULL);
*dbptr = impl;
} else {
delete impl;

+ 4
- 4
db/db_impl.h View File

@ -78,7 +78,8 @@ class DBImpl : public DB {
// Recover the descriptor from persistent storage. May do a significant
// amount of work to recover recently logged updates. Any changes to
// be made to the descriptor are added to *edit.
Status Recover(VersionEdit* edit) EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status Recover(VersionEdit* edit, bool* save_manifest)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
void MaybeIgnoreError(Status* s) const;
@ -90,9 +91,8 @@ class DBImpl : public DB {
// Errors are recorded in bg_error_.
void CompactMemTable() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status RecoverLogFile(uint64_t log_number,
VersionEdit* edit,
SequenceNumber* max_sequence)
Status RecoverLogFile(uint64_t log_number, bool last_log, bool* save_manifest,
VersionEdit* edit, SequenceNumber* max_sequence)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base)

+ 20
- 1
db/db_test.cc View File

@ -193,6 +193,7 @@ class DBTest {
// Sequence of option configurations to try
enum OptionConfig {
kDefault,
kReuse,
kFilter,
kUncompressed,
kEnd
@ -237,7 +238,11 @@ class DBTest {
// Return the current option configuration.
Options CurrentOptions() {
Options options;
options.reuse_logs = false;
switch (option_config_) {
case kReuse:
options.reuse_logs = true;
break;
case kFilter:
options.filter_policy = filter_policy_;
break;
@ -1080,6 +1085,14 @@ TEST(DBTest, ApproximateSizes) {
// 0 because GetApproximateSizes() does not account for memtable space
ASSERT_TRUE(Between(Size("", Key(50)), 0, 0));
if (options.reuse_logs) {
// Recovery will reuse memtable, and GetApproximateSizes() does not
// account for memtable usage;
Reopen(&options);
ASSERT_TRUE(Between(Size("", Key(50)), 0, 0));
continue;
}
// Check sizes across recovery by reopening a few times
for (int run = 0; run < 3; run++) {
Reopen(&options);
@ -1123,6 +1136,11 @@ TEST(DBTest, ApproximateSizes_MixOfSmallAndLarge) {
ASSERT_OK(Put(Key(6), RandomString(&rnd, 300000)));
ASSERT_OK(Put(Key(7), RandomString(&rnd, 10000)));
if (options.reuse_logs) {
// Need to force a memtable compaction since recovery does not do so.
ASSERT_OK(dbfull()->TEST_CompactMemTable());
}
// Check sizes across recovery by reopening a few times
for (int run = 0; run < 3; run++) {
Reopen(&options);
@ -2084,7 +2102,8 @@ void BM_LogAndApply(int iters, int num_base_files) {
InternalKeyComparator cmp(BytewiseComparator());
Options options;
VersionSet vset(dbname, &options, NULL, &cmp);
ASSERT_OK(vset.Recover());
bool save_manifest;
ASSERT_OK(vset.Recover(&save_manifest));
VersionEdit vbase;
uint64_t fnum = 1;
for (int i = 0; i < num_base_files; i++) {

+ 80
- 68
db/fault_injection_test.cc View File

@ -106,7 +106,7 @@ struct FileState {
// is written to or sync'ed.
class TestWritableFile : public WritableFile {
public:
TestWritableFile(const std::string& fname,
TestWritableFile(const FileState& state,
WritableFile* f,
FaultInjectionTestEnv* env);
virtual ~TestWritableFile();
@ -130,6 +130,8 @@ class FaultInjectionTestEnv : public EnvWrapper {
virtual ~FaultInjectionTestEnv() { }
virtual Status NewWritableFile(const std::string& fname,
WritableFile** result);
virtual Status NewAppendableFile(const std::string& fname,
WritableFile** result);
virtual Status DeleteFile(const std::string& f);
virtual Status RenameFile(const std::string& s, const std::string& t);
@ -154,15 +156,14 @@ class FaultInjectionTestEnv : public EnvWrapper {
bool filesystem_active_; // Record flushes, syncs, writes
};
TestWritableFile::TestWritableFile(const std::string& fname,
TestWritableFile::TestWritableFile(const FileState& state,
WritableFile* f,
FaultInjectionTestEnv* env)
: state_(fname),
: state_(state),
target_(f),
writable_file_opened_(true),
env_(env) {
assert(f != NULL);
state_.pos_ = 0;
}
TestWritableFile::~TestWritableFile() {
@ -228,9 +229,12 @@ Status FaultInjectionTestEnv::NewWritableFile(const std::string& fname,
WritableFile* actual_writable_file;
Status s = target()->NewWritableFile(fname, &actual_writable_file);
if (s.ok()) {
*result = new TestWritableFile(fname, actual_writable_file, this);
// WritableFile doesn't append to files, so if the same file is opened again
// then it will be truncated - so forget our saved state.
FileState state(fname);
state.pos_ = 0;
*result = new TestWritableFile(state, actual_writable_file, this);
// NewWritableFile doesn't append to files, so if the same file is
// opened again then it will be truncated - so forget our saved
// state.
UntrackFile(fname);
MutexLock l(&mutex_);
new_files_since_last_dir_sync_.insert(fname);
@ -238,6 +242,26 @@ Status FaultInjectionTestEnv::NewWritableFile(const std::string& fname,
return s;
}
Status FaultInjectionTestEnv::NewAppendableFile(const std::string& fname,
WritableFile** result) {
WritableFile* actual_writable_file;
Status s = target()->NewAppendableFile(fname, &actual_writable_file);
if (s.ok()) {
FileState state(fname);
state.pos_ = 0;
{
MutexLock l(&mutex_);
if (db_file_state_.count(fname) == 0) {
new_files_since_last_dir_sync_.insert(fname);
} else {
state = db_file_state_[fname];
}
}
*result = new TestWritableFile(state, actual_writable_file, this);
}
return s;
}
Status FaultInjectionTestEnv::DropUnsyncedFileData() {
Status s;
MutexLock l(&mutex_);
@ -301,9 +325,10 @@ Status FaultInjectionTestEnv::RenameFile(const std::string& s,
}
void FaultInjectionTestEnv::ResetState() {
// Since we are not destroying the database, the existing files
// should keep their recorded synced/flushed state. Therefore
// we do not reset db_file_state_ and new_files_since_last_dir_sync_.
MutexLock l(&mutex_);
db_file_state_.clear();
new_files_since_last_dir_sync_.clear();
SetFilesystemActive(true);
}
@ -342,51 +367,28 @@ class FaultInjectionTest {
Options options_;
DB* db_;
FaultInjectionTest() : env_(NULL), tiny_cache_(NULL), db_(NULL) { NewDB(); }
~FaultInjectionTest() { ASSERT_OK(TearDown()); }
Status NewDB() {
assert(db_ == NULL);
assert(tiny_cache_ == NULL);
assert(env_ == NULL);
env_ = new FaultInjectionTestEnv();
options_ = Options();
FaultInjectionTest()
: env_(new FaultInjectionTestEnv),
tiny_cache_(NewLRUCache(100)),
db_(NULL) {
dbname_ = test::TmpDir() + "/fault_test";
DestroyDB(dbname_, Options()); // Destroy any db from earlier run
options_.reuse_logs = true;
options_.env = env_;
options_.paranoid_checks = true;
tiny_cache_ = NewLRUCache(100);
options_.block_cache = tiny_cache_;
dbname_ = test::TmpDir() + "/fault_test";
options_.create_if_missing = true;
Status s = OpenDB();
options_.create_if_missing = false;
return s;
}
Status SetUp() {
Status s = TearDown();
if (s.ok()) {
s = NewDB();
}
return s;
}
Status TearDown() {
~FaultInjectionTest() {
CloseDB();
Status s = DestroyDB(dbname_, Options());
DestroyDB(dbname_, Options());
delete tiny_cache_;
tiny_cache_ = NULL;
delete env_;
env_ = NULL;
}
return s;
void ReuseLogs(bool reuse) {
options_.reuse_logs = reuse;
}
void Build(int start_idx, int num_vals) {
@ -506,33 +508,43 @@ class FaultInjectionTest {
ResetDBState(reset_method);
ASSERT_OK(OpenDB());
}
};
TEST(FaultInjectionTest, FaultTest) {
Random rnd(0);
ASSERT_OK(SetUp());
for (size_t idx = 0; idx < kNumIterations; idx++) {
int num_pre_sync = rnd.Uniform(kMaxNumValues);
int num_post_sync = rnd.Uniform(kMaxNumValues);
PartialCompactTestPreFault(num_pre_sync, num_post_sync);
PartialCompactTestReopenWithFault(RESET_DROP_UNSYNCED_DATA,
num_pre_sync,
num_post_sync);
NoWriteTestPreFault();
NoWriteTestReopenWithFault(RESET_DROP_UNSYNCED_DATA);
void DoTest() {
Random rnd(0);
ASSERT_OK(OpenDB());
for (size_t idx = 0; idx < kNumIterations; idx++) {
int num_pre_sync = rnd.Uniform(kMaxNumValues);
int num_post_sync = rnd.Uniform(kMaxNumValues);
PartialCompactTestPreFault(num_pre_sync, num_post_sync);
PartialCompactTestReopenWithFault(RESET_DROP_UNSYNCED_DATA,
num_pre_sync,
num_post_sync);
NoWriteTestPreFault();
NoWriteTestReopenWithFault(RESET_DROP_UNSYNCED_DATA);
PartialCompactTestPreFault(num_pre_sync, num_post_sync);
// No new files created so we expect all values since no files will be
// dropped.
PartialCompactTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES,
num_pre_sync + num_post_sync,
0);
NoWriteTestPreFault();
NoWriteTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES);
}
}
};
PartialCompactTestPreFault(num_pre_sync, num_post_sync);
// No new files created so we expect all values since no files will be
// dropped.
PartialCompactTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES,
num_pre_sync + num_post_sync,
0);
TEST(FaultInjectionTest, FaultTestNoLogReuse) {
ReuseLogs(false);
DoTest();
}
NoWriteTestPreFault();
NoWriteTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES);
}
TEST(FaultInjectionTest, FaultTestWithLogReuse) {
ReuseLogs(true);
DoTest();
}
} // namespace leveldb

+ 21
- 3
db/log_test.cc View File

@ -104,7 +104,7 @@ class LogTest {
StringSource source_;
ReportCollector report_;
bool reading_;
Writer writer_;
Writer* writer_;
Reader reader_;
// Record metadata for testing initial offset functionality
@ -113,14 +113,23 @@ class LogTest {
public:
LogTest() : reading_(false),
writer_(&dest_),
writer_(new Writer(&dest_)),
reader_(&source_, &report_, true/*checksum*/,
0/*initial_offset*/) {
}
~LogTest() {
delete writer_;
}
void ReopenForAppend() {
delete writer_;
writer_ = new Writer(&dest_, dest_.contents_.size());
}
void Write(const std::string& msg) {
ASSERT_TRUE(!reading_) << "Write() after starting to read";
writer_.AddRecord(Slice(msg));
writer_->AddRecord(Slice(msg));
}
size_t WrittenBytes() const {
@ -318,6 +327,15 @@ TEST(LogTest, AlignedEof) {
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, OpenForAppend) {
Write("hello");
ReopenForAppend();
Write("world");
ASSERT_EQ("hello", Read());
ASSERT_EQ("world", Read());
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, RandomRead) {
const int N = 500;
Random write_rnd(301);

+ 13
- 4
db/log_writer.cc View File

@ -12,15 +12,24 @@
namespace leveldb {
namespace log {
Writer::Writer(WritableFile* dest)
: dest_(dest),
block_offset_(0) {
static void InitTypeCrc(uint32_t* type_crc) {
for (int i = 0; i <= kMaxRecordType; i++) {
char t = static_cast<char>(i);
type_crc_[i] = crc32c::Value(&t, 1);
type_crc[i] = crc32c::Value(&t, 1);
}
}
Writer::Writer(WritableFile* dest)
: dest_(dest),
block_offset_(0) {
InitTypeCrc(type_crc_);
}
Writer::Writer(WritableFile* dest, uint64_t dest_length)
: dest_(dest), block_offset_(dest_length % kBlockSize) {
InitTypeCrc(type_crc_);
}
Writer::~Writer() {
}

+ 6
- 0
db/log_writer.h View File

@ -22,6 +22,12 @@ class Writer {
// "*dest" must be initially empty.
// "*dest" must remain live while this Writer is in use.
explicit Writer(WritableFile* dest);
// Create a writer that will append data to "*dest".
// "*dest" must have initial length "dest_length".
// "*dest" must remain live while this Writer is in use.
Writer(WritableFile* dest, uint64_t dest_length);
~Writer();
Status AddRecord(const Slice& slice);

+ 324
- 0
db/recovery_test.cc View File

@ -0,0 +1,324 @@
// Copyright (c) 2014 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 "db/filename.h"
#include "db/version_set.h"
#include "db/write_batch_internal.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/write_batch.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace leveldb {
class RecoveryTest {
public:
RecoveryTest() : env_(Env::Default()), db_(NULL) {
dbname_ = test::TmpDir() + "/recovery_test";
DestroyDB(dbname_, Options());
Open();
}
~RecoveryTest() {
Close();
DestroyDB(dbname_, Options());
}
DBImpl* dbfull() const { return reinterpret_cast<DBImpl*>(db_); }
Env* env() const { return env_; }
bool CanAppend() {
WritableFile* tmp;
Status s = env_->NewAppendableFile(CurrentFileName(dbname_), &tmp);
delete tmp;
if (s.IsNotSupportedError()) {
return false;
} else {
return true;
}
}
void Close() {
delete db_;
db_ = NULL;
}
void Open(Options* options = NULL) {
Close();
Options opts;
if (options != NULL) {
opts = *options;
} else {
opts.reuse_logs = true; // TODO(sanjay): test both ways
opts.create_if_missing = true;
}
if (opts.env == NULL) {
opts.env = env_;
}
ASSERT_OK(DB::Open(opts, dbname_, &db_));
ASSERT_EQ(1, NumLogs());
}
Status Put(const std::string& k, const std::string& v) {
return db_->Put(WriteOptions(), k, v);
}
std::string Get(const std::string& k, const Snapshot* snapshot = NULL) {
std::string result;
Status s = db_->Get(ReadOptions(), k, &result);
if (s.IsNotFound()) {
result = "NOT_FOUND";
} else if (!s.ok()) {
result = s.ToString();
}
return result;
}
std::string ManifestFileName() {
std::string current;
ASSERT_OK(ReadFileToString(env_, CurrentFileName(dbname_), &current));
size_t len = current.size();
if (len > 0 && current[len-1] == '\n') {
current.resize(len - 1);
}
return dbname_ + "/" + current;
}
std::string LogName(uint64_t number) {
return LogFileName(dbname_, number);
}
size_t DeleteLogFiles() {
std::vector<uint64_t> logs = GetFiles(kLogFile);
for (size_t i = 0; i < logs.size(); i++) {
ASSERT_OK(env_->DeleteFile(LogName(logs[i]))) << LogName(logs[i]);
}
return logs.size();
}
uint64_t FirstLogFile() {
return GetFiles(kLogFile)[0];
}
std::vector<std::uint64_t> GetFiles(FileType t) {
std::vector<std::string> filenames;
ASSERT_OK(env_->GetChildren(dbname_, &filenames));
std::vector<std::uint64_t> result;
for (size_t i = 0; i < filenames.size(); i++) {
uint64_t number;
FileType type;
if (ParseFileName(filenames[i], &number, &type) && type == t) {
result.push_back(number);
}
}
return result;
}
int NumLogs() {
return GetFiles(kLogFile).size();
}
int NumTables() {
return GetFiles(kTableFile).size();
}
uint64_t FileSize(const std::string& fname) {
uint64_t result;
ASSERT_OK(env_->GetFileSize(fname, &result)) << fname;
return result;
}
void CompactMemTable() {
dbfull()->TEST_CompactMemTable();
}
// Directly construct a log file that sets key to val.
void MakeLogFile(uint64_t lognum, SequenceNumber seq, Slice key, Slice val) {
std::string fname = LogFileName(dbname_, lognum);
WritableFile* file;
ASSERT_OK(env_->NewWritableFile(fname, &file));
log::Writer writer(file);
WriteBatch batch;
batch.Put(key, val);
WriteBatchInternal::SetSequence(&batch, seq);
ASSERT_OK(writer.AddRecord(WriteBatchInternal::Contents(&batch)));
ASSERT_OK(file->Flush());
delete file;
}
private:
std::string dbname_;
Env* env_;
DB* db_;
};
TEST(RecoveryTest, ManifestReused) {
if (!CanAppend()) {
fprintf(stderr, "skipping test because env does not support appending\n");
return;
}
ASSERT_OK(Put("foo", "bar"));
Close();
std::string old_manifest = ManifestFileName();
Open();
ASSERT_EQ(old_manifest, ManifestFileName());
ASSERT_EQ("bar", Get("foo"));
Open();
ASSERT_EQ(old_manifest, ManifestFileName());
ASSERT_EQ("bar", Get("foo"));
}
TEST(RecoveryTest, LargeManifestCompacted) {
if (!CanAppend()) {
fprintf(stderr, "skipping test because env does not support appending\n");
return;
}
ASSERT_OK(Put("foo", "bar"));
Close();
std::string old_manifest = ManifestFileName();
// Pad with zeroes to make manifest file very big.
{
uint64_t len = FileSize(old_manifest);
WritableFile* file;
ASSERT_OK(env()->NewAppendableFile(old_manifest, &file));
std::string zeroes(3*1048576 - static_cast<size_t>(len), 0);
ASSERT_OK(file->Append(zeroes));
ASSERT_OK(file->Flush());
delete file;
}
Open();
std::string new_manifest = ManifestFileName();
ASSERT_NE(old_manifest, new_manifest);
ASSERT_GT(10000, FileSize(new_manifest));
ASSERT_EQ("bar", Get("foo"));
Open();
ASSERT_EQ(new_manifest, ManifestFileName());
ASSERT_EQ("bar", Get("foo"));
}
TEST(RecoveryTest, NoLogFiles) {
ASSERT_OK(Put("foo", "bar"));
ASSERT_EQ(1, DeleteLogFiles());
Open();
ASSERT_EQ("NOT_FOUND", Get("foo"));
Open();
ASSERT_EQ("NOT_FOUND", Get("foo"));
}
TEST(RecoveryTest, LogFileReuse) {
if (!CanAppend()) {
fprintf(stderr, "skipping test because env does not support appending\n");
return;
}
for (int i = 0; i < 2; i++) {
ASSERT_OK(Put("foo", "bar"));
if (i == 0) {
// Compact to ensure current log is empty
CompactMemTable();
}
Close();
ASSERT_EQ(1, NumLogs());
uint64_t number = FirstLogFile();
if (i == 0) {
ASSERT_EQ(0, FileSize(LogName(number)));
} else {
ASSERT_LT(0, FileSize(LogName(number)));
}
Open();
ASSERT_EQ(1, NumLogs());
ASSERT_EQ(number, FirstLogFile()) << "did not reuse log file";
ASSERT_EQ("bar", Get("foo"));
Open();
ASSERT_EQ(1, NumLogs());
ASSERT_EQ(number, FirstLogFile()) << "did not reuse log file";
ASSERT_EQ("bar", Get("foo"));
}
}
TEST(RecoveryTest, MultipleMemTables) {
// Make a large log.
const int kNum = 1000;
for (int i = 0; i < kNum; i++) {
char buf[100];
snprintf(buf, sizeof(buf), "%050d", i);
ASSERT_OK(Put(buf, buf));
}
ASSERT_EQ(0, NumTables());
Close();
ASSERT_EQ(0, NumTables());
ASSERT_EQ(1, NumLogs());
uint64_t old_log_file = FirstLogFile();
// Force creation of multiple memtables by reducing the write buffer size.
Options opt;
opt.reuse_logs = true;
opt.write_buffer_size = (kNum*100) / 2;
Open(&opt);
ASSERT_LE(2, NumTables());
ASSERT_EQ(1, NumLogs());
ASSERT_NE(old_log_file, FirstLogFile()) << "must not reuse log";
for (int i = 0; i < kNum; i++) {
char buf[100];
snprintf(buf, sizeof(buf), "%050d", i);
ASSERT_EQ(buf, Get(buf));
}
}
TEST(RecoveryTest, MultipleLogFiles) {
ASSERT_OK(Put("foo", "bar"));
Close();
ASSERT_EQ(1, NumLogs());
// Make a bunch of uncompacted log files.
uint64_t old_log = FirstLogFile();
MakeLogFile(old_log+1, 1000, "hello", "world");
MakeLogFile(old_log+2, 1001, "hi", "there");
MakeLogFile(old_log+3, 1002, "foo", "bar2");
// Recover and check that all log files were processed.
Open();
ASSERT_LE(1, NumTables());
ASSERT_EQ(1, NumLogs());
uint64_t new_log = FirstLogFile();
ASSERT_LE(old_log+3, new_log);
ASSERT_EQ("bar2", Get("foo"));
ASSERT_EQ("world", Get("hello"));
ASSERT_EQ("there", Get("hi"));
// Test that previous recovery produced recoverable state.
Open();
ASSERT_LE(1, NumTables());
ASSERT_EQ(1, NumLogs());
if (CanAppend()) {
ASSERT_EQ(new_log, FirstLogFile());
}
ASSERT_EQ("bar2", Get("foo"));
ASSERT_EQ("world", Get("hello"));
ASSERT_EQ("there", Get("hi"));
// Check that introducing an older log file does not cause it to be re-read.
Close();
MakeLogFile(old_log+1, 2000, "hello", "stale write");
Open();
ASSERT_LE(1, NumTables());
ASSERT_EQ(1, NumLogs());
if (CanAppend()) {
ASSERT_EQ(new_log, FirstLogFile());
}
ASSERT_EQ("bar2", Get("foo"));
ASSERT_EQ("world", Get("hello"));
ASSERT_EQ("there", Get("hi"));
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

+ 36
- 1
db/version_set.cc View File

@ -893,7 +893,7 @@ Status VersionSet::LogAndApply(VersionEdit* edit, port::Mutex* mu) {
return s;
}
Status VersionSet::Recover() {
Status VersionSet::Recover(bool *save_manifest) {
struct LogReporter : public log::Reader::Reporter {
Status* status;
virtual void Corruption(size_t bytes, const Status& s) {
@ -1003,11 +1003,46 @@ Status VersionSet::Recover() {
last_sequence_ = last_sequence;
log_number_ = log_number;
prev_log_number_ = prev_log_number;
// See if we can reuse the existing MANIFEST file.
if (ReuseManifest(dscname, current)) {
// No need to save new manifest
} else {
*save_manifest = true;
}
}
return s;
}
bool VersionSet::ReuseManifest(const std::string& dscname,
const std::string& dscbase) {
FileType manifest_type;
uint64_t manifest_number;
uint64_t manifest_size;
if (!ParseFileName(dscbase, &manifest_number, &manifest_type) ||
manifest_type != kDescriptorFile ||
!env_->GetFileSize(dscname, &manifest_size).ok() ||
// Make new compacted MANIFEST if old one is too big
manifest_size >= kTargetFileSize) {
return false;
}
assert(descriptor_file_ == NULL);
assert(descriptor_log_ == NULL);
Status r = env_->NewAppendableFile(dscname, &descriptor_file_);
if (!r.ok()) {
Log(options_->info_log, "Reuse MANIFEST: %s\n", r.ToString().c_str());
assert(descriptor_file_ == NULL);
return false;
}
Log(options_->info_log, "Reusing MANIFEST %s\n", dscname.c_str());
descriptor_log_ = new log::Writer(descriptor_file_, manifest_size);
manifest_file_number_ = manifest_number;
return true;
}
void VersionSet::MarkFileNumberUsed(uint64_t number) {
if (next_file_number_ <= number) {
next_file_number_ = number + 1;

+ 3
- 1
db/version_set.h View File

@ -179,7 +179,7 @@ class VersionSet {
EXCLUSIVE_LOCKS_REQUIRED(mu);
// Recover the last saved descriptor from persistent storage.
Status Recover();
Status Recover(bool *save_manifest);
// Return the current version.
Version* current() const { return current_; }
@ -274,6 +274,8 @@ class VersionSet {
friend class Compaction;
friend class Version;
bool ReuseManifest(const std::string& dscname, const std::string& dscbase);
void Finalize(Version* v);
void GetRange(const std::vector<FileMetaData*>& inputs,

+ 13
- 0
helpers/memenv/memenv.cc View File

@ -277,6 +277,19 @@ class InMemoryEnv : public EnvWrapper {
return Status::OK();
}
virtual Status NewAppendableFile(const std::string& fname,
WritableFile** result) {
MutexLock lock(&mutex_);
FileState** sptr = &file_map_[fname];
FileState* file = *sptr;
if (file == NULL) {
file = new FileState();
file->Ref();
}
*result = new WritableFileImpl(file);
return Status::OK();
}
virtual bool FileExists(const std::string& fname) {
MutexLock lock(&mutex_);
return file_map_.find(fname) != file_map_.end();

+ 11
- 2
helpers/memenv/memenv_test.cc View File

@ -40,6 +40,8 @@ TEST(MemEnvTest, Basics) {
// Create a file.
ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
ASSERT_EQ(0, file_size);
delete writable_file;
// Check that the file exists.
@ -55,9 +57,16 @@ TEST(MemEnvTest, Basics) {
ASSERT_OK(writable_file->Append("abc"));
delete writable_file;
// Check for expected size.
// Check that append works.
ASSERT_OK(env_->NewAppendableFile("/dir/f", &writable_file));
ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
ASSERT_EQ(3, file_size);
ASSERT_OK(writable_file->Append("hello"));
delete writable_file;
// Check for expected size.
ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
ASSERT_EQ(8, file_size);
// Check that renaming works.
ASSERT_TRUE(!env_->RenameFile("/dir/non_existent", "/dir/g").ok());
@ -65,7 +74,7 @@ TEST(MemEnvTest, Basics) {
ASSERT_TRUE(!env_->FileExists("/dir/f"));
ASSERT_TRUE(env_->FileExists("/dir/g"));
ASSERT_OK(env_->GetFileSize("/dir/g", &file_size));
ASSERT_EQ(3, file_size);
ASSERT_EQ(8, file_size);
// Check that opening non-existent file fails.
SequentialFile* seq_file;

+ 18
- 0
include/leveldb/env.h View File

@ -69,6 +69,21 @@ class Env {
virtual Status NewWritableFile(const std::string& fname,
WritableFile** result) = 0;
// Create an object that either appends to an existing file, or
// writes to a new file (if the file does not exist to begin with).
// On success, stores a pointer to the new file in *result and
// returns OK. On failure stores NULL in *result and returns
// non-OK.
//
// The returned file will only be accessed by one thread at a time.
//
// May return an IsNotSupportedError error if this Env does
// not allow appending to an existing file. Users of Env (including
// the leveldb implementation) must be prepared to deal with
// an Env that does not support appending.
virtual Status NewAppendableFile(const std::string& fname,
WritableFile** result);
// Returns true iff the named file exists.
virtual bool FileExists(const std::string& fname) = 0;
@ -289,6 +304,9 @@ class EnvWrapper : public Env {
Status NewWritableFile(const std::string& f, WritableFile** r) {
return target_->NewWritableFile(f, r);
}
Status NewAppendableFile(const std::string& f, WritableFile** r) {
return target_->NewAppendableFile(f, r);
}
bool FileExists(const std::string& f) { return target_->FileExists(f); }
Status GetChildren(const std::string& dir, std::vector<std::string>* r) {
return target_->GetChildren(dir, r);

+ 6
- 0
include/leveldb/options.h View File

@ -128,6 +128,12 @@ struct Options {
// efficiently detect that and will switch to uncompressed mode.
CompressionType compression;
// EXPERIMENTAL: If true, append to existing MANIFEST and log files
// when a database is opened. This can significantly speed up open.
//
// Default: currently false, but may become true later.
bool reuse_logs;
// If non-NULL, use the specified filter policy to reduce disk reads.
// Many applications will benefit from passing the result of
// NewBloomFilterPolicy() here.

+ 3
- 0
include/leveldb/status.h View File

@ -60,6 +60,9 @@ class Status {
// Returns true iff the status indicates an IOError.
bool IsIOError() const { return code() == kIOError; }
// Returns true iff the status indicates a NotSupportedError.
bool IsNotSupportedError() const { return code() == kNotSupported; }
// Return a string representation of this status suitable for printing.
// Returns the string "OK" for success.
std::string ToString() const;

+ 4
- 0
util/env.cc View File

@ -9,6 +9,10 @@ namespace leveldb {
Env::~Env() {
}
Status Env::NewAppendableFile(const std::string& fname, WritableFile** result) {
return Status::NotSupported("NewAppendableFile", fname);
}
SequentialFile::~SequentialFile() {
}

+ 13
- 0
util/env_posix.cc View File

@ -350,6 +350,19 @@ class PosixEnv : public Env {
return s;
}
virtual Status NewAppendableFile(const std::string& fname,
WritableFile** result) {
Status s;
FILE* f = fopen(fname.c_str(), "a");
if (f == NULL) {
*result = NULL;
s = IOError(fname, errno);
} else {
*result = new PosixWritableFile(fname, f);
}
return s;
}
virtual bool FileExists(const std::string& fname) {
return access(fname.c_str(), F_OK) == 0;
}

+ 1
- 1
util/options.cc View File

@ -22,8 +22,8 @@ Options::Options()
block_size(4096),
block_restart_interval(16),
compression(kSnappyCompression),
reuse_logs(false),
filter_policy(NULL) {
}
} // namespace leveldb

+ 10
- 0
util/testutil.h View File

@ -45,6 +45,16 @@ class ErrorEnv : public EnvWrapper {
}
return target()->NewWritableFile(fname, result);
}
virtual Status NewAppendableFile(const std::string& fname,
WritableFile** result) {
if (writable_file_error_) {
++num_writable_file_errors_;
*result = NULL;
return Status::IOError(fname, "fake error");
}
return target()->NewAppendableFile(fname, result);
}
};
} // namespace test

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