// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.

#pragma once
#include <stddef.h>
#include <stdint.h>
#include <string>

namespace rocksdb {
struct CompactionJobStats {
  CompactionJobStats() { Reset(); }
  void Reset();
  // Aggregate the CompactionJobStats from another instance with this one
  void Add(const CompactionJobStats& stats);

  // the elapsed time in micro of this compaction.
  uint64_t elapsed_micros;

  // the number of compaction input records.
  uint64_t num_input_records;
  // the number of compaction input files.
  size_t num_input_files;
  // the number of compaction input files at the output level.
  size_t num_input_files_at_output_level;

  // the number of compaction output records.
  uint64_t num_output_records;
  // the number of compaction output files.
  size_t num_output_files;

  // true if the compaction is a manual compaction
  bool is_manual_compaction;

  // the size of the compaction input in bytes.
  uint64_t total_input_bytes;
  // the size of the compaction output in bytes.
  uint64_t total_output_bytes;

  // number of records being replaced by newer record associated with same key.
  // this could be a new value or a deletion entry for that key so this field
  // sums up all updated and deleted keys
  uint64_t num_records_replaced;

  // the sum of the uncompressed input keys in bytes.
  uint64_t total_input_raw_key_bytes;
  // the sum of the uncompressed input values in bytes.
  uint64_t total_input_raw_value_bytes;

  // the number of deletion entries before compaction. Deletion entries
  // can disappear after compaction because they expired
  uint64_t num_input_deletion_records;
  // number of deletion records that were found obsolete and discarded
  // because it is not possible to delete any more keys with this entry
  // (i.e. all possible deletions resulting from it have been completed)
  uint64_t num_expired_deletion_records;

  // number of corrupt keys (ParseInternalKey returned false when applied to
  // the key) encountered and written out.
  uint64_t num_corrupt_keys;

  // Following counters are only populated if
  // options.report_bg_io_stats = true;

  // Time spent on file's Append() call.
  uint64_t file_write_nanos;

  // Time spent on sync file range.
  uint64_t file_range_sync_nanos;

  // Time spent on file fsync.
  uint64_t file_fsync_nanos;

  // Time spent on preparing file write (falocate, etc)
  uint64_t file_prepare_write_nanos;

  // 0-terminated strings storing the first 8 bytes of the smallest and
  // largest key in the output.
  static const size_t kMaxPrefixLength = 8;

  std::string smallest_output_key_prefix;
  std::string largest_output_key_prefix;

  // number of single-deletes which do not meet a put
  uint64_t num_single_del_fallthru;

  // number of single-deletes which meet something other than a put
  uint64_t num_single_del_mismatch;
};
}  // namespace rocksdb