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// 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).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
#pragma once
#include <memory>
#include "db/version_edit.h"
#include "rocksdb/file_system.h"
#include "rocksdb/metadata.h"
#include "rocksdb/slice_transform.h"
namespace ROCKSDB_NAMESPACE {
struct ImmutableCFOptions;
class TableCache;
class VersionStorageInfo;
class VersionEdit;
struct FileMetaData;
class InternalStats;
class Version;
class VersionSet;
class VersionEditHandler;
class ColumnFamilyData;
class CacheReservationManager;
// A helper class so we can efficiently apply a whole sequence
// of edits to a particular state without creating intermediate
// Versions that contain full copies of the intermediate state.
class VersionBuilder {
public:
VersionBuilder(const FileOptions& file_options,
const ImmutableCFOptions* ioptions, TableCache* table_cache,
VersionStorageInfo* base_vstorage, VersionSet* version_set,
std::shared_ptr<CacheReservationManager>
file_metadata_cache_res_mgr = nullptr,
ColumnFamilyData* cfd = nullptr,
VersionEditHandler* version_edit_handler = nullptr,
bool track_found_and_missing_files = false,
bool allow_incomplete_valid_version = false);
~VersionBuilder();
bool CheckConsistencyForNumLevels();
Status Apply(const VersionEdit* edit);
// Save the current Version to the provided `vstorage`.
Status SaveTo(VersionStorageInfo* vstorage) const;
// Load all the table handlers for the current Version in the builder.
Status LoadTableHandlers(InternalStats* internal_stats, int max_threads,
bool prefetch_index_and_filter_in_cache,
bool is_initial_load,
const MutableCFOptions& mutable_cf_options,
size_t max_file_size_for_l0_meta_pin,
const ReadOptions& read_options);
//============APIs only used by VersionEditHandlerPointInTime ============//
// Creates a save point for the Version that has been built so far. Subsequent
// VersionEdits applied to the builder will not affect the Version in this
// save point. VersionBuilder currently only supports creating one save point,
// so when `CreateOrReplaceSavePoint` is called again, the previous save point
// is cleared. `ClearSavePoint` can be called explicitly to clear
// the save point too.
void CreateOrReplaceSavePoint();
// The builder can find all the files to build a `Version`. Or if
// `allow_incomplete_valid_version_` is true and the version history is never
// edited in an atomic group, and only a suffix of L0 SST files and their
// associated blob files are missing.
// From the users' perspective, missing a suffix of L0 files means missing the
// user's most recently written data. So the remaining available files still
// presents a valid point in time view, although for some previous time.
// This validity check result will be cached and reused if the Version is not
// updated between two validity checks.
bool ValidVersionAvailable();
bool HasMissingFiles() const;
// When applying a sequence of VersionEdit, intermediate files are the ones
// that are added and then deleted. The caller should clear this intermediate
// files tracking after calling this API. So that the tracking for subsequent
// VersionEdits can start over with a clean state.
std::vector<std::string>& GetAndClearIntermediateFiles();
// Clearing all the found files in this Version.
void ClearFoundFiles();
// Save the Version in the save point to the provided `vstorage`.
// Non-OK status will be returned if there is not a valid save point.
Status SaveSavePointTo(VersionStorageInfo* vstorage) const;
// Load all the table handlers for the Version in the save point.
// Non-OK status will be returned if there is not a valid save point.
Status LoadSavePointTableHandlers(InternalStats* internal_stats,
int max_threads,
bool prefetch_index_and_filter_in_cache,
bool is_initial_load,
const MutableCFOptions& mutable_cf_options,
size_t max_file_size_for_l0_meta_pin,
const ReadOptions& read_options);
void ClearSavePoint();
//======= End of APIs only used by VersionEditPointInTime==========//
private:
class Rep;
std::unique_ptr<Rep> savepoint_;
std::unique_ptr<Rep> rep_;
};
// A wrapper of version builder which references the current version in
// constructor and unref it in the destructor.
// Both of the constructor and destructor need to be called inside DB Mutex.
class BaseReferencedVersionBuilder {
public:
explicit BaseReferencedVersionBuilder(
ColumnFamilyData* cfd, VersionEditHandler* version_edit_handler = nullptr,
bool track_found_and_missing_files = false,
bool allow_incomplete_valid_version = false);
BaseReferencedVersionBuilder(
ColumnFamilyData* cfd, Version* v,
VersionEditHandler* version_edit_handler = nullptr,
bool track_found_and_missing_files = false,
bool allow_incomplete_valid_version = false);
~BaseReferencedVersionBuilder();
VersionBuilder* version_builder() const { return version_builder_.get(); }
private:
std::unique_ptr<VersionBuilder> version_builder_;
Version* version_;
};
} // namespace ROCKSDB_NAMESPACE
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