fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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33 lines
1.3 KiB
33 lines
1.3 KiB
5 years ago
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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "table/block_based/block_based_table_reader.h"
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namespace ROCKSDB_NAMESPACE {
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class BlockPrefetcher {
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public:
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explicit BlockPrefetcher(size_t compaction_readahead_size)
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: compaction_readahead_size_(compaction_readahead_size) {}
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void PrefetchIfNeeded(const BlockBasedTable::Rep* rep,
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const BlockHandle& handle, size_t readahead_size,
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bool is_for_compaction);
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FilePrefetchBuffer* prefetch_buffer() { return prefetch_buffer_.get(); }
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private:
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// Readahead size used in compaction, its value is used only if
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// lookup_context_.caller = kCompaction.
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size_t compaction_readahead_size_;
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size_t readahead_size_ = BlockBasedTable::kInitAutoReadaheadSize;
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size_t readahead_limit_ = 0;
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int64_t num_file_reads_ = 0;
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std::unique_ptr<FilePrefetchBuffer> prefetch_buffer_;
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};
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} // namespace ROCKSDB_NAMESPACE
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