mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-30 04:41:49 +00:00
39 lines
1.3 KiB
C
39 lines
1.3 KiB
C
|
// 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).
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
|
||
|
|
#include <cassert>
|
||
|
|
#include <cstdint>
|
||
|
|
#include <memory>
|
||
|
|
#include <unordered_map>
|
||
|
|
|
||
|
|
#include "file/file_prefetch_buffer.h"
|
||
|
|
#include "rocksdb/rocksdb_namespace.h"
|
||
|
|
|
||
|
|
namespace ROCKSDB_NAMESPACE {
|
||
|
|
|
||
|
|
// A class that owns a collection of FilePrefetchBuffers using the file number
|
||
|
|
// as key. Used for implementing compaction readahead for blob files. Designed
|
||
|
|
// to be accessed by a single thread only: every (sub)compaction needs its own
|
||
|
|
// buffers since they are guaranteed to read different blobs from different
|
||
|
|
// positions even when reading the same file.
|
||
|
|
class PrefetchBufferCollection {
|
||
|
|
public:
|
||
|
|
explicit PrefetchBufferCollection(uint64_t readahead_size)
|
||
|
|
: readahead_size_(readahead_size) {
|
||
|
|
assert(readahead_size_ > 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
FilePrefetchBuffer* GetOrCreatePrefetchBuffer(uint64_t file_number);
|
||
|
|
|
||
|
|
private:
|
||
|
|
uint64_t readahead_size_;
|
||
|
|
std::unordered_map<uint64_t, std::unique_ptr<FilePrefetchBuffer>>
|
||
|
|
prefetch_buffers_; // maps file number to prefetch buffer
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace ROCKSDB_NAMESPACE
|