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

Browse Source 
(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.
This commit is contained in:
Sanjay Ghemawat
2014-12-11 08:13:18 -08:00
committed by Chris Mumford
parent 77948e7eec
commit ac1d69da31
22 changed files with 707 additions and 155 deletions
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13
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();

13
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;