rocksdb/db/version_util.h

69 lines
2.6 KiB
C++

// Copyright (c) Facebook, Inc. and its affiliates. 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).
#pragma once
#include "db/version_set.h"
namespace ROCKSDB_NAMESPACE {
// Instead of opening a `DB` to perform certain manifest updates, this
// uses the underlying `VersionSet` API to read and modify the MANIFEST. This
// allows us to use the user's real options, while not having to worry about
// the DB persisting new SST files via flush/compaction or attempting to read/
// compact files which may fail, particularly for the file we intend to remove
// (the user may want to remove an already deleted file from MANIFEST).
class OfflineManifestWriter {
public:
OfflineManifestWriter(const DBOptions& options, const std::string& db_path)
: wc_(options.delayed_write_rate),
wb_(options.db_write_buffer_size),
immutable_db_options_(WithDbPath(options, db_path)),
tc_(NewLRUCache(1 << 20 /* capacity */,
options.table_cache_numshardbits)),
versions_(db_path, &immutable_db_options_, sopt_, tc_.get(), &wb_, &wc_,
/*block_cache_tracer=*/nullptr, /*io_tracer=*/nullptr,
/*db_session_id*/ "") {}
Status Recover(const std::vector<ColumnFamilyDescriptor>& column_families) {
return versions_.Recover(column_families);
}
Status LogAndApply(ColumnFamilyData* cfd, VersionEdit* edit) {
// Use `mutex` to imitate a locked DB mutex when calling `LogAndApply()`.
InstrumentedMutex mutex;
mutex.Lock();
Status s = versions_.LogAndApply(cfd, *cfd->GetLatestMutableCFOptions(),
edit, &mutex, nullptr /* db_directory */,
false /* new_descriptor_log */);
mutex.Unlock();
return s;
}
VersionSet& Versions() { return versions_; }
const ImmutableDBOptions& IOptions() { return immutable_db_options_; }
private:
WriteController wc_;
WriteBufferManager wb_;
ImmutableDBOptions immutable_db_options_;
std::shared_ptr<Cache> tc_;
EnvOptions sopt_;
VersionSet versions_;
static ImmutableDBOptions WithDbPath(const DBOptions& options,
const std::string& db_path) {
ImmutableDBOptions rv(options);
if (rv.db_paths.empty()) {
// `VersionSet` expects options that have been through
// `SanitizeOptions()`, which would sanitize an empty `db_paths`.
rv.db_paths.emplace_back(db_path, 0 /* target_size */);
}
return rv;
}
};
} // namespace ROCKSDB_NAMESPACE