mirror of
https://github.com/facebook/rocksdb.git
synced 2024-12-02 10:15:54 +00:00
19ec44fd39
Summary: Add hash index support to data blocks, which helps to reduce the CPU utilization of point-lookup operations. This feature is backward compatible with the data block created without the hash index. It is disabled by default unless `BlockBasedTableOptions::data_block_index_type` is set to `data_block_index_type = kDataBlockBinaryAndHash.` The DB size would be bigger with the hash index option as a hash table is added at the end of each data block. If the hash utilization ratio is 1:1, the space overhead is one byte per key. The hash table utilization ratio is adjustable using `BlockBasedTableOptions::data_block_hash_table_util_ratio`. A lower utilization ratio will improve more on the point-lookup efficiency, but take more space too. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4174 Differential Revision: D8965914 Pulled By: fgwu fbshipit-source-id: 1c6bae5d1fc39c80282d8890a72e9e67bc247198
27 lines
848 B
C++
27 lines
848 B
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).
|
|
//
|
|
// 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 "rocksdb/table.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
uint32_t PackIndexTypeAndNumRestarts(
|
|
BlockBasedTableOptions::DataBlockIndexType index_type,
|
|
uint32_t num_restarts);
|
|
|
|
|
|
void UnPackIndexTypeAndNumRestarts(
|
|
uint32_t block_footer,
|
|
BlockBasedTableOptions::DataBlockIndexType* index_type,
|
|
uint32_t* num_restarts);
|
|
|
|
} // namespace rocksdb
|