rocksdb/utilities/options/options_util.cc
Yueh-Hsuan Chiang e11f676e34 Add OptionsUtil::LoadOptionsFromFile() API
Summary:
This patch adds OptionsUtil::LoadOptionsFromFile() and
OptionsUtil::LoadLatestOptionsFromDB(), which allow developers
to construct DBOptions and ColumnFamilyOptions from a RocksDB
options file.  Note that most pointer-typed options such as
merge_operator will not be constructed.

With this API, developers no longer need to remember all the
options in order to reopen an existing rocksdb instance like
the following:

  DBOptions db_options;
  std::vector<std::string> cf_names;
  std::vector<ColumnFamilyOptions> cf_opts;

  // Load primitive-typed options from an existing DB
  OptionsUtil::LoadLatestOptionsFromDB(
      dbname, &db_options, &cf_names, &cf_opts);

  // Initialize necessary pointer-typed options
  cf_opts[0].merge_operator.reset(new MyMergeOperator());
  ...

  // Construct the vector of ColumnFamilyDescriptor
  std::vector<ColumnFamilyDescriptor> cf_descs;
  for (size_t i = 0; i < cf_opts.size(); ++i) {
    cf_descs.emplace_back(cf_names[i], cf_opts[i]);
  }

  // Open the DB
  DB* db = nullptr;
  std::vector<ColumnFamilyHandle*> cf_handles;
  auto s = DB::Open(db_options, dbname, cf_descs,
                    &handles, &db);

Test Plan:
Augment existing tests in column_family_test
options_test
db_test

Reviewers: igor, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49095
2015-11-12 06:52:43 -08:00

77 lines
2.3 KiB
C++

// Copyright (c) 2014, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#ifndef ROCKSDB_LITE
#include "rocksdb/utilities/options_util.h"
#include "db/filename.h"
#include "rocksdb/options.h"
#include "util/options_parser.h"
namespace rocksdb {
Status LoadOptionsFromFile(const std::string& file_name, Env* env,
DBOptions* db_options,
std::vector<ColumnFamilyDescriptor>* cf_descs) {
RocksDBOptionsParser parser;
Status s = parser.Parse(file_name, env);
if (!s.ok()) {
return s;
}
*db_options = *parser.db_opt();
const std::vector<std::string>& cf_names = *parser.cf_names();
const std::vector<ColumnFamilyOptions>& cf_opts = *parser.cf_opts();
cf_descs->clear();
for (size_t i = 0; i < cf_opts.size(); ++i) {
cf_descs->push_back({cf_names[i], cf_opts[i]});
}
return Status::OK();
}
Status GetLatestOptionsFileName(const std::string& dbpath,
Env* env, std::string* options_file_name) {
Status s;
std::string latest_file_name;
uint64_t latest_time_stamp = 0;
std::vector<std::string> file_names;
s = env->GetChildren(dbpath, &file_names);
if (!s.ok()) {
return s;
}
for (auto& file_name : file_names) {
uint64_t time_stamp;
FileType type;
if (ParseFileName(file_name, &time_stamp, &type) && type == kOptionsFile) {
if (time_stamp > latest_time_stamp) {
latest_time_stamp = time_stamp;
latest_file_name = file_name;
}
}
}
if (latest_file_name.size() == 0) {
return Status::NotFound("No options files found in the DB directory.");
}
*options_file_name = latest_file_name;
return Status::OK();
}
Status LoadLatestOptions(const std::string& dbpath, Env* env,
DBOptions* db_options,
std::vector<ColumnFamilyDescriptor>* cf_descs) {
std::string options_file_name;
Status s = GetLatestOptionsFileName(dbpath, env, &options_file_name);
if (!s.ok()) {
return s;
}
return LoadOptionsFromFile(dbpath + "/" + options_file_name, env,
db_options, cf_descs);
}
} // namespace rocksdb
#endif // !ROCKSDB_LITE