import_column_family_job.h

//  Copyright (c) Meta Platforms, Inc. and affiliates.
//
//  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 <string>
#include <unordered_set>
#include <vector>

#include "db/column_family.h"
#include "db/external_sst_file_ingestion_job.h"
#include "db/snapshot_impl.h"
#include "options/db_options.h"
#include "rocksdb/db.h"
#include "rocksdb/metadata.h"
#include "rocksdb/sst_file_writer.h"
#include "util/autovector.h"

namespace ROCKSDB_NAMESPACE {
struct EnvOptions;
class SystemClock;

// Imports a set of sst files as is into a new column family. Logic is similar
// to ExternalSstFileIngestionJob.
class ImportColumnFamilyJob {
  // All file information of an imported CF, mainly used to
  // calculate whether there is overlap between CFs
  struct ColumnFamilyIngestFileInfo {
    // Smallest internal key in cf
    InternalKey smallest_internal_key;
    // Largest internal key in cf
    InternalKey largest_internal_key;
  };

 public:
  ImportColumnFamilyJob(
      VersionSet* versions, ColumnFamilyData* cfd,
      const ImmutableDBOptions& db_options, const EnvOptions& env_options,
      const ImportColumnFamilyOptions& import_options,
      const std::vector<std::vector<LiveFileMetaData*>>& metadatas,
      const std::shared_ptr<IOTracer>& io_tracer)
      : clock_(db_options.clock),
        versions_(versions),
        cfd_(cfd),
        db_options_(db_options),
        fs_(db_options_.fs, io_tracer),
        env_options_(env_options),
        import_options_(import_options),
        metadatas_(metadatas),
        io_tracer_(io_tracer) {}

  // Prepare the job by copying external files into the DB.
  Status Prepare(uint64_t next_file_number, SuperVersion* sv);

  // Will execute the import job and prepare edit() to be applied.
  // REQUIRES: Mutex held
  Status Run();

  // Cleanup after successful/failed job
  void Cleanup(const Status& status);

  VersionEdit* edit() { return &edit_; }

  const std::vector<std::vector<IngestedFileInfo>>& files_to_import() const {
    return files_to_import_;
  }

 private:
  // Open the external file and populate `file_to_import` with all the
  // external information we need to import this file.
  Status GetIngestedFileInfo(const std::string& external_file,
                             uint64_t new_file_number, SuperVersion* sv,
                             const LiveFileMetaData& file_meta,
                             IngestedFileInfo* file_to_import);

  SystemClock* clock_;
  VersionSet* versions_;
  ColumnFamilyData* cfd_;
  const ImmutableDBOptions& db_options_;
  const FileSystemPtr fs_;
  const EnvOptions& env_options_;
  std::vector<std::vector<IngestedFileInfo>> files_to_import_;
  VersionEdit edit_;
  const ImportColumnFamilyOptions& import_options_;
  const std::vector<std::vector<LiveFileMetaData*>> metadatas_;
  const std::shared_ptr<IOTracer> io_tracer_;
};

}  // namespace ROCKSDB_NAMESPACE