import quincy beta 17.1.0

[ceph.git] / ceph / src / rocksdb / table / block_based / block_prefetcher.h

diff --git a/ceph/src/rocksdb/table/block_based/block_prefetcher.h b/ceph/src/rocksdb/table/block_based/block_prefetcher.h
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+++ b/ceph/src/rocksdb/table/block_based/block_prefetcher.h
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+//  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).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+#pragma once
+#include "table/block_based/block_based_table_reader.h"
+
+namespace ROCKSDB_NAMESPACE {
+class BlockPrefetcher {
+ public:
+  explicit BlockPrefetcher(size_t compaction_readahead_size)
+      : compaction_readahead_size_(compaction_readahead_size) {}
+  void PrefetchIfNeeded(const BlockBasedTable::Rep* rep,
+                        const BlockHandle& handle, size_t readahead_size,
+                        bool is_for_compaction);
+  FilePrefetchBuffer* prefetch_buffer() { return prefetch_buffer_.get(); }
+
+ private:
+  // Readahead size used in compaction, its value is used only if
+  // lookup_context_.caller = kCompaction.
+  size_t compaction_readahead_size_;
+
+  size_t readahead_size_ = BlockBasedTable::kInitAutoReadaheadSize;
+  size_t readahead_limit_ = 0;
+  int64_t num_file_reads_ = 0;
+  std::unique_ptr<FilePrefetchBuffer> prefetch_buffer_;
+};
+}  // namespace ROCKSDB_NAMESPACE