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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).
//
// A checkpoint is an openable snapshot of a database at a point in time.
#pragma once
#include <string>
#include <vector>
#include "rocksdb/status.h"
namespace ROCKSDB_NAMESPACE {
class DB;
class ColumnFamilyHandle;
struct LiveFileMetaData;
struct ExportImportFilesMetaData;
class Checkpoint {
public:
// Creates a Checkpoint object to be used for creating openable snapshots
static Status Create(DB* db, Checkpoint** checkpoint_ptr);
// Builds an openable snapshot of RocksDB. checkpoint_dir should contain an
// absolute path. The specified directory should not exist, since it will be
// created by the API.
// When a checkpoint is created,
// (1) SST and blob files are hard linked if the output directory is on the
// same filesystem as the database, and copied otherwise.
// (2) other required files (like MANIFEST) are always copied.
// log_size_for_flush: if the total log file size is equal or larger than
// this value, then a flush is triggered for all the column families. The
// default value is 0, which means flush is always triggered. If you move
// away from the default, the checkpoint may not contain up-to-date data
// if WAL writing is not always enabled.
// Flush will always trigger if it is 2PC.
// sequence_number_ptr: if it is not nullptr, the value it points to will be
// set to a sequence number guaranteed to be part of the DB, not necessarily
// the latest. The default value of this parameter is nullptr.
// NOTE: db_paths and cf_paths are not supported for creating checkpoints
// and NotSupported will be returned when the DB (without WALs) uses more
// than one directory.
virtual Status CreateCheckpoint(const std::string& checkpoint_dir,
uint64_t log_size_for_flush = 0,
uint64_t* sequence_number_ptr = nullptr);
// Exports all live SST files of a specified Column Family onto export_dir,
// returning SST files information in metadata.
// - SST files will be created as hard links when the directory specified
// is in the same partition as the db directory, copied otherwise.
// - export_dir should not already exist and will be created by this API.
// - Always triggers a flush.
virtual Status ExportColumnFamily(ColumnFamilyHandle* handle,
const std::string& export_dir,
ExportImportFilesMetaData** metadata);
virtual ~Checkpoint() {}
};
} // namespace ROCKSDB_NAMESPACE