ceph/src/rocksdb/file/readahead_file_info.h

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 #pragma once
   7
   8 #include <cstddef>
   9 #include <cstdint>
  10
  11 #include "rocksdb/rocksdb_namespace.h"
  12
  13 namespace ROCKSDB_NAMESPACE {
  14
  15 // struct ReadaheadFileInfo contains readahead information that is passed from
  16 // one file to another file per level during iterations. This information helps
  17 // iterators to carry forward the internal automatic prefetching readahead value
  18 // to next file during sequential reads instead of starting from the scratch.
  19
  20 struct ReadaheadFileInfo {
  21   struct ReadaheadInfo {
  22     size_t readahead_size = 0;
  23     int64_t num_file_reads = 0;
  24   };
  25
  26   // Used by Data block iterators to update readahead info.
  27   ReadaheadInfo data_block_readahead_info;
  28
  29   // Used by Index block iterators to update readahead info.
  30   ReadaheadInfo index_block_readahead_info;
  31 };
  32
  33 }  // namespace ROCKSDB_NAMESPACE