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Revision 0f0076ed5abd1540dd0b7af5d51cde529c178d52 authored by Haobo Xu on 13 June 2014, 02:03:22 UTC, committed by Haobo Xu on 19 June 2014, 01:16:07 UTC 
[RocksDB] Reduce memory footprint of the blockbased table hash index.
 
Summary:
Currently, the in-memory hash index of blockbased table uses a precise hash map to track the prefix to block range mapping. In some use cases, especially when prefix itself is big, the memory overhead becomes a problem. This diff introduces a fixed hash bucket array that does not store the prefix and allows prefix collision, which is similar to the plaintable hash index, in order to reduce the memory consumption.
Just a quick draft, still testing and refining.

Test Plan: unit test and shadow testing

Reviewers: dhruba, kailiu, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19047
1 parent 3525aac
Raw File
plain_table_factory.cc 
// 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.

#ifndef ROCKSDB_LITE
#include "table/plain_table_factory.h"

#include <memory>
#include <stdint.h>
#include "db/dbformat.h"
#include "table/plain_table_builder.h"
#include "table/plain_table_reader.h"
#include "port/port.h"

namespace rocksdb {

Status PlainTableFactory::NewTableReader(const Options& options,
                                         const EnvOptions& soptions,
                                         const InternalKeyComparator& icomp,
                                         unique_ptr<RandomAccessFile>&& file,
                                         uint64_t file_size,
                                         unique_ptr<TableReader>* table) const {
  return PlainTableReader::Open(options, soptions, icomp, std::move(file),
                                file_size, table, bloom_bits_per_key_,
                                hash_table_ratio_, index_sparseness_,
                                huge_page_tlb_size_);
}

TableBuilder* PlainTableFactory::NewTableBuilder(
    const Options& options, const InternalKeyComparator& internal_comparator,
    WritableFile* file, CompressionType compression_type) const {
  return new PlainTableBuilder(options, file, user_key_len_);
}

extern TableFactory* NewPlainTableFactory(uint32_t user_key_len,
                                          int bloom_bits_per_key,
                                          double hash_table_ratio,
                                          size_t index_sparseness,
                                          size_t huge_page_tlb_size) {
  return new PlainTableFactory(user_key_len, bloom_bits_per_key,
                               hash_table_ratio, index_sparseness,
                               huge_page_tlb_size);
}

extern TableFactory* NewTotalOrderPlainTableFactory(uint32_t user_key_len,
                                                    int bloom_bits_per_key,
                                                    size_t index_sparseness,
                                                    size_t huge_page_tlb_size) {
  return new PlainTableFactory(user_key_len, bloom_bits_per_key, 0,
                               index_sparseness, huge_page_tlb_size);
}

}  // namespace rocksdb
#endif  // ROCKSDB_LITE
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