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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 <cassert> | |
9 | #include <cstdint> | |
10 | #include <memory> | |
11 | #include <unordered_map> | |
12 | ||
13 | #include "file/file_prefetch_buffer.h" | |
14 | #include "rocksdb/rocksdb_namespace.h" | |
15 | ||
16 | namespace ROCKSDB_NAMESPACE { | |
17 | ||
18 | // A class that owns a collection of FilePrefetchBuffers using the file number | |
19 | // as key. Used for implementing compaction readahead for blob files. Designed | |
20 | // to be accessed by a single thread only: every (sub)compaction needs its own | |
21 | // buffers since they are guaranteed to read different blobs from different | |
22 | // positions even when reading the same file. | |
23 | class PrefetchBufferCollection { | |
24 | public: | |
25 | explicit PrefetchBufferCollection(uint64_t readahead_size) | |
26 | : readahead_size_(readahead_size) { | |
27 | assert(readahead_size_ > 0); | |
28 | } | |
29 | ||
30 | FilePrefetchBuffer* GetOrCreatePrefetchBuffer(uint64_t file_number); | |
31 | ||
32 | private: | |
33 | uint64_t readahead_size_; | |
34 | std::unordered_map<uint64_t, std::unique_ptr<FilePrefetchBuffer>> | |
35 | prefetch_buffers_; // maps file number to prefetch buffer | |
36 | }; | |
37 | ||
38 | } // namespace ROCKSDB_NAMESPACE |