rocksdb/utilities/options/options_util.cc
sdong 876c2dbff4 Allow readahead when reading option files. (#6372)
Summary:
Right, when reading from option files, no readahead is used and 8KB buffer is used. It might introduce high latency if the file system provide high latency and doesn't do readahead. Instead, introduce a readahead to the file. When calling inside DB, infer the value from options.log_readahead. Otherwise, a default 512KB readahead size is used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6372

Test Plan: Add --log_readahead_size in db_bench. Run it with several options and observe read size from option files using strace.

Differential Revision: D19727739

fbshipit-source-id: e6d8053b0a64259abc087f1f388b9cd66fa8a583
2020-02-07 15:18:26 -08:00

115 lines
3.9 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#ifndef ROCKSDB_LITE
#include "rocksdb/utilities/options_util.h"
#include "env/composite_env_wrapper.h"
#include "file/filename.h"
#include "options/options_parser.h"
#include "rocksdb/options.h"
namespace rocksdb {
Status LoadOptionsFromFile(const std::string& file_name, Env* env,
DBOptions* db_options,
std::vector<ColumnFamilyDescriptor>* cf_descs,
bool ignore_unknown_options,
std::shared_ptr<Cache>* cache) {
RocksDBOptionsParser parser;
LegacyFileSystemWrapper fs(env);
Status s = parser.Parse(file_name, &fs, ignore_unknown_options,
0 /* file_readahead_size */);
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]});
if (cache != nullptr) {
TableFactory* tf = cf_opts[i].table_factory.get();
if (tf != nullptr && tf->GetOptions() != nullptr &&
tf->Name() == BlockBasedTableFactory().Name()) {
auto* loaded_bbt_opt =
reinterpret_cast<BlockBasedTableOptions*>(tf->GetOptions());
loaded_bbt_opt->block_cache = *cache;
}
}
}
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,
bool ignore_unknown_options,
std::shared_ptr<Cache>* cache) {
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, ignore_unknown_options, cache);
}
Status CheckOptionsCompatibility(
const std::string& dbpath, Env* env, const DBOptions& db_options,
const std::vector<ColumnFamilyDescriptor>& cf_descs,
bool ignore_unknown_options) {
std::string options_file_name;
Status s = GetLatestOptionsFileName(dbpath, env, &options_file_name);
if (!s.ok()) {
return s;
}
std::vector<std::string> cf_names;
std::vector<ColumnFamilyOptions> cf_opts;
for (const auto& cf_desc : cf_descs) {
cf_names.push_back(cf_desc.name);
cf_opts.push_back(cf_desc.options);
}
const OptionsSanityCheckLevel kDefaultLevel = kSanityLevelLooselyCompatible;
LegacyFileSystemWrapper fs(env);
return RocksDBOptionsParser::VerifyRocksDBOptionsFromFile(
db_options, cf_names, cf_opts, dbpath + "/" + options_file_name, &fs,
kDefaultLevel, ignore_unknown_options);
}
} // namespace rocksdb
#endif // !ROCKSDB_LITE