Make an API to get database identity from the IDENTITY file

Summary: This would enable rocksdb users to get the db identity without depending on implementation details(storing that in IDENTITY file)

Test Plan: db/db_test (has identity checks)

Reviewers: dhruba, haobo, igor, kailiu

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14463
main
Mayank Agarwal 11 years ago
parent fa88cbc71e
commit 18802689b8
  1. 27
      db/db_impl.cc
  2. 2
      db/db_impl.h
  3. 28
      db/db_test.cc
  4. 10
      include/rocksdb/db.h

@ -3497,6 +3497,33 @@ void DBImpl::GetLiveFilesMetaData(std::vector<LiveFileMetaData> *metadata) {
return versions_->GetLiveFilesMetaData(metadata);
}
Status DBImpl::GetDbIdentity(std::string& identity) {
std::string idfilename = IdentityFileName(dbname_);
unique_ptr<SequentialFile> idfile;
const EnvOptions soptions;
Status s = env_->NewSequentialFile(idfilename, &idfile, soptions);
if (!s.ok()) {
return s;
}
uint64_t file_size;
s = env_->GetFileSize(idfilename, &file_size);
if (!s.ok()) {
return s;
}
char buffer[file_size];
Slice id;
s = idfile->Read(file_size, &id, buffer);
if (!s.ok()) {
return s;
}
identity.assign(id.ToString());
// If last character is '\n' remove it from identity
if (identity.size() > 0 && identity.back() == '\n') {
identity.pop_back();
}
return s;
}
// 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) {

@ -85,6 +85,8 @@ class DBImpl : public DB {
virtual void GetLiveFilesMetaData(
std::vector<LiveFileMetaData> *metadata);
virtual Status GetDbIdentity(std::string& identity);
// Extra methods (for testing) that are not in the public DB interface
// Compact any files in the named level that overlap [*begin, *end]

@ -1731,31 +1731,23 @@ TEST(DBTest, ManifestRollOver) {
TEST(DBTest, IdentityAcrossRestarts) {
do {
std::string idfilename = IdentityFileName(dbname_);
unique_ptr<SequentialFile> idfile;
const EnvOptions soptions;
ASSERT_OK(env_->NewSequentialFile(idfilename, &idfile, soptions));
char buffer1[100];
Slice id1;
ASSERT_OK(idfile->Read(100, &id1, buffer1));
std::string id1;
ASSERT_OK(db_->GetDbIdentity(id1));
Options options = CurrentOptions();
Reopen(&options);
char buffer2[100];
Slice id2;
ASSERT_OK(env_->NewSequentialFile(idfilename, &idfile, soptions));
ASSERT_OK(idfile->Read(100, &id2, buffer2));
std::string id2;
ASSERT_OK(db_->GetDbIdentity(id2));
// id1 should match id2 because identity was not regenerated
ASSERT_EQ(id1.ToString(), id2.ToString());
ASSERT_EQ(id1.compare(id2), 0);
std::string idfilename = IdentityFileName(dbname_);
ASSERT_OK(env_->DeleteFile(idfilename));
Reopen(&options);
char buffer3[100];
Slice id3;
ASSERT_OK(env_->NewSequentialFile(idfilename, &idfile, soptions));
ASSERT_OK(idfile->Read(100, &id3, buffer3));
// id1 should NOT match id2 because identity was regenerated
ASSERT_NE(id1.ToString(0), id3.ToString());
std::string id3;
ASSERT_OK(db_->GetDbIdentity(id3));
// id1 should NOT match id3 because identity was regenerated
ASSERT_NE(id1.compare(id3), 0);
} while (ChangeCompactOptions());
}

@ -273,7 +273,7 @@ class DB {
// Sets iter to an iterator that is positioned at a write-batch containing
// seq_number. If the sequence number is non existent, it returns an iterator
// at the first available seq_no after the requested seq_no
// Returns Status::Ok if iterator is valid
// Returns Status::OK if iterator is valid
// Must set WAL_ttl_seconds or WAL_size_limit_MB to large values to
// use this api, else the WAL files will get
// cleared aggressively and the iterator might keep getting invalid before
@ -292,6 +292,14 @@ class DB {
std::vector<LiveFileMetaData> *metadata) {
}
// Sets the globally unique ID created at database creation time by invoking
// Env::GenerateUniqueId(), in identity. Returns Status::OK if identity could
// be set properly
virtual Status GetDbIdentity(std::string& identity) {
identity.clear();
return Status::OK();
}
private:
// No copying allowed
DB(const DB&);

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