Summary: Adding option to save PlainTable index and bloom filter in SST file. If there is no bloom block and/or index block, PlainTableReader builds new ones. Otherwise PlainTableReader just use these blocks. Test Plan: make all check Reviewers: sdong Reviewed By: sdong Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D19527main
Stanislau Hlebik
11 years ago
parent
92d73cbe78
commit
9d70cce047
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// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#include "table/bloom_block.h" |
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#include <string> |
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#include "rocksdb/slice.h" |
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#include "util/dynamic_bloom.h" |
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namespace rocksdb { |
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void BloomBlockBuilder::AddKeysHashes(const std::vector<uint32_t> keys_hashes) { |
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for (auto hash : keys_hashes) { |
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bloom_.AddHash(hash); |
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} |
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} |
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Slice BloomBlockBuilder::Finish() { return bloom_.GetRawData(); } |
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const std::string BloomBlockBuilder::kBloomBlock = "kBloomBlock"; |
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} // namespace rocksdb
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// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once |
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#include <vector> |
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#include <string> |
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#include "util/dynamic_bloom.h" |
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namespace rocksdb { |
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class Logger; |
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class BloomBlockBuilder { |
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public: |
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static const std::string kBloomBlock; |
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explicit BloomBlockBuilder(uint32_t num_probes = 6) |
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: bloom_(num_probes, nullptr) {} |
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void SetTotalBits(Arena* arena, uint32_t total_bits, uint32_t locality, |
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size_t huge_page_tlb_size, Logger* logger) { |
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bloom_.SetTotalBits(arena, total_bits, locality, huge_page_tlb_size, |
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logger); |
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} |
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uint32_t GetNumBlocks() const { return bloom_.GetNumBlocks(); } |
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void AddKeysHashes(const std::vector<uint32_t> keys_hashes); |
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Slice Finish(); |
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private: |
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DynamicBloom bloom_; |
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}; |
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}; // namespace rocksdb
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// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#include "table/plain_table_index.h" |
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#include "util/coding.h" |
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#include "util/hash.h" |
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namespace rocksdb { |
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namespace { |
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inline uint32_t GetBucketIdFromHash(uint32_t hash, uint32_t num_buckets) { |
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assert(num_buckets > 0); |
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return hash % num_buckets; |
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} |
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} |
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void PlainTableIndex::InitFromRawData(Slice data) { |
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assert(GetVarint32(&data, &index_size_)); |
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assert(index_size_ > 0); |
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assert(GetVarint32(&data, &num_prefixes_)); |
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sub_index_size_ = data.size() - index_size_ * kOffsetLen; |
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char* index_data_begin = const_cast<char*>(data.data()); |
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index_ = reinterpret_cast<uint32_t*>(index_data_begin); |
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sub_index_ = reinterpret_cast<char*>(index_ + index_size_); |
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} |
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PlainTableIndex::IndexSearchResult PlainTableIndex::GetOffset( |
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uint32_t prefix_hash, uint32_t* bucket_value) const { |
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int bucket = GetBucketIdFromHash(prefix_hash, index_size_); |
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*bucket_value = index_[bucket]; |
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if ((*bucket_value & kSubIndexMask) == kSubIndexMask) { |
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*bucket_value ^= kSubIndexMask; |
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return kSubindex; |
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} |
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if (*bucket_value >= kMaxFileSize) { |
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return kNoPrefixForBucket; |
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} else { |
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// point directly to the file
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return kDirectToFile; |
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} |
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} |
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void PlainTableIndexBuilder::IndexRecordList::AddRecord(murmur_t hash, |
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uint32_t offset) { |
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if (num_records_in_current_group_ == kNumRecordsPerGroup) { |
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current_group_ = AllocateNewGroup(); |
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num_records_in_current_group_ = 0; |
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} |
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auto& new_record = current_group_[num_records_in_current_group_++]; |
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new_record.hash = hash; |
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new_record.offset = offset; |
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new_record.next = nullptr; |
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} |
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void PlainTableIndexBuilder::AddKeyPrefix(Slice key_prefix_slice, |
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uint64_t key_offset) { |
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if (is_first_record_ || prev_key_prefix_ != key_prefix_slice.ToString()) { |
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++num_prefixes_; |
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if (!is_first_record_) { |
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keys_per_prefix_hist_.Add(num_keys_per_prefix_); |
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} |
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num_keys_per_prefix_ = 0; |
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prev_key_prefix_ = key_prefix_slice.ToString(); |
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prev_key_prefix_hash_ = GetSliceHash(key_prefix_slice); |
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due_index_ = true; |
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} |
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if (due_index_) { |
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// Add an index key for every kIndexIntervalForSamePrefixKeys keys
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record_list_.AddRecord(prev_key_prefix_hash_, key_offset); |
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due_index_ = false; |
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} |
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num_keys_per_prefix_++; |
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if (index_sparseness_ == 0 || num_keys_per_prefix_ % index_sparseness_ == 0) { |
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due_index_ = true; |
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} |
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is_first_record_ = false; |
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} |
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Slice PlainTableIndexBuilder::Finish() { |
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AllocateIndex(); |
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std::vector<IndexRecord*> hash_to_offsets(index_size_, nullptr); |
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std::vector<uint32_t> entries_per_bucket(index_size_, 0); |
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BucketizeIndexes(&hash_to_offsets, &entries_per_bucket); |
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keys_per_prefix_hist_.Add(num_keys_per_prefix_); |
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Log(options_.info_log, "Number of Keys per prefix Histogram: %s", |
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keys_per_prefix_hist_.ToString().c_str()); |
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// From the temp data structure, populate indexes.
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return FillIndexes(hash_to_offsets, entries_per_bucket); |
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} |
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void PlainTableIndexBuilder::AllocateIndex() { |
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if (prefix_extractor_ == nullptr || hash_table_ratio_ <= 0) { |
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// Fall back to pure binary search if the user fails to specify a prefix
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// extractor.
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index_size_ = 1; |
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} else { |
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double hash_table_size_multipier = 1.0 / hash_table_ratio_; |
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index_size_ = num_prefixes_ * hash_table_size_multipier + 1; |
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assert(index_size_ > 0); |
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} |
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} |
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void PlainTableIndexBuilder::BucketizeIndexes( |
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std::vector<IndexRecord*>* hash_to_offsets, |
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std::vector<uint32_t>* entries_per_bucket) { |
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bool first = true; |
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uint32_t prev_hash = 0; |
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size_t num_records = record_list_.GetNumRecords(); |
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for (size_t i = 0; i < num_records; i++) { |
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IndexRecord* index_record = record_list_.At(i); |
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uint32_t cur_hash = index_record->hash; |
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if (first || prev_hash != cur_hash) { |
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prev_hash = cur_hash; |
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first = false; |
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} |
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uint32_t bucket = GetBucketIdFromHash(cur_hash, index_size_); |
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IndexRecord* prev_bucket_head = (*hash_to_offsets)[bucket]; |
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index_record->next = prev_bucket_head; |
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(*hash_to_offsets)[bucket] = index_record; |
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(*entries_per_bucket)[bucket]++; |
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} |
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sub_index_size_ = 0; |
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for (auto entry_count : *entries_per_bucket) { |
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if (entry_count <= 1) { |
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continue; |
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} |
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// Only buckets with more than 1 entry will have subindex.
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sub_index_size_ += VarintLength(entry_count); |
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// total bytes needed to store these entries' in-file offsets.
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sub_index_size_ += entry_count * PlainTableIndex::kOffsetLen; |
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} |
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} |
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Slice PlainTableIndexBuilder::FillIndexes( |
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const std::vector<IndexRecord*>& hash_to_offsets, |
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const std::vector<uint32_t>& entries_per_bucket) { |
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Log(options_.info_log, "Reserving %zu bytes for plain table's sub_index", |
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sub_index_size_); |
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auto total_allocate_size = GetTotalSize(); |
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char* allocated = arena_->AllocateAligned( |
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total_allocate_size, huge_page_tlb_size_, options_.info_log.get()); |
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auto temp_ptr = EncodeVarint32(allocated, index_size_); |
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uint32_t* index = |
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reinterpret_cast<uint32_t*>(EncodeVarint32(temp_ptr, num_prefixes_)); |
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char* sub_index = reinterpret_cast<char*>(index + index_size_); |
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size_t sub_index_offset = 0; |
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for (uint32_t i = 0; i < index_size_; i++) { |
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uint32_t num_keys_for_bucket = entries_per_bucket[i]; |
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switch (num_keys_for_bucket) { |
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case 0: |
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// No key for bucket
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index[i] = PlainTableIndex::kMaxFileSize; |
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break; |
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case 1: |
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// point directly to the file offset
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index[i] = hash_to_offsets[i]->offset; |
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break; |
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default: |
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// point to second level indexes.
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index[i] = sub_index_offset | PlainTableIndex::kSubIndexMask; |
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char* prev_ptr = &sub_index[sub_index_offset]; |
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char* cur_ptr = EncodeVarint32(prev_ptr, num_keys_for_bucket); |
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sub_index_offset += (cur_ptr - prev_ptr); |
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char* sub_index_pos = &sub_index[sub_index_offset]; |
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IndexRecord* record = hash_to_offsets[i]; |
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int j; |
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for (j = num_keys_for_bucket - 1; j >= 0 && record; |
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j--, record = record->next) { |
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EncodeFixed32(sub_index_pos + j * sizeof(uint32_t), record->offset); |
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} |
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assert(j == -1 && record == nullptr); |
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sub_index_offset += PlainTableIndex::kOffsetLen * num_keys_for_bucket; |
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assert(sub_index_offset <= sub_index_size_); |
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break; |
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} |
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} |
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assert(sub_index_offset == sub_index_size_); |
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Log(options_.info_log, "hash table size: %d, suffix_map length %zu", |
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index_size_, sub_index_size_); |
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return Slice(allocated, GetTotalSize()); |
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} |
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const std::string PlainTableIndexBuilder::kPlainTableIndexBlock = |
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"PlainTableIndexBlock"; |
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}; // namespace rocksdb
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@ -0,0 +1,221 @@ |
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// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once |
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#include <string> |
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#include <vector> |
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#include "db/dbformat.h" |
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#include "rocksdb/options.h" |
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#include "util/murmurhash.h" |
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#include "util/hash.h" |
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#include "util/arena.h" |
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#include "util/histogram.h" |
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namespace rocksdb { |
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// PlainTableIndex contains buckets size of index_size_, each is a
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// 32-bit integer. The lower 31 bits contain an offset value (explained below)
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// and the first bit of the integer indicates type of the offset.
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//
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// +--------------+------------------------------------------------------+
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// | Flag (1 bit) | Offset to binary search buffer or file (31 bits) +
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// +--------------+------------------------------------------------------+
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//
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// Explanation for the "flag bit":
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//
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// 0 indicates that the bucket contains only one prefix (no conflict when
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// hashing this prefix), whose first row starts from this offset of the
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// file.
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// 1 indicates that the bucket contains more than one prefixes, or there
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// are too many rows for one prefix so we need a binary search for it. In
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// this case, the offset indicates the offset of sub_index_ holding the
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// binary search indexes of keys for those rows. Those binary search indexes
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// are organized in this way:
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//
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// The first 4 bytes, indicate how many indexes (N) are stored after it. After
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// it, there are N 32-bit integers, each points of an offset of the file,
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// which
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// points to starting of a row. Those offsets need to be guaranteed to be in
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// ascending order so the keys they are pointing to are also in ascending
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// order
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// to make sure we can use them to do binary searches. Below is visual
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// presentation of a bucket.
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//
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// <begin>
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// number_of_records: varint32
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// record 1 file offset: fixedint32
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// record 2 file offset: fixedint32
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// ....
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// record N file offset: fixedint32
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// <end>
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class PlainTableIndex { |
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public: |
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enum IndexSearchResult { |
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kNoPrefixForBucket = 0, |
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kDirectToFile = 1, |
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kSubindex = 2 |
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}; |
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explicit PlainTableIndex(Slice data) { InitFromRawData(data); } |
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PlainTableIndex() |
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: index_size_(0), |
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sub_index_size_(0), |
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num_prefixes_(0), |
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index_(nullptr), |
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sub_index_(nullptr) {} |
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IndexSearchResult GetOffset(uint32_t prefix_hash, |
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uint32_t* bucket_value) const; |
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void InitFromRawData(Slice data); |
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const char* GetSubIndexBasePtrAndUpperBound(uint32_t offset, |
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uint32_t* upper_bound) const { |
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const char* index_ptr = &sub_index_[offset]; |
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return GetVarint32Ptr(index_ptr, index_ptr + 4, upper_bound); |
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} |
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uint32_t GetIndexSize() const { return index_size_; } |
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uint32_t GetSubIndexSize() const { return sub_index_size_; } |
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uint32_t GetNumPrefixes() const { return num_prefixes_; } |
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static const uint64_t kMaxFileSize = (1u << 31) - 1; |
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static const uint32_t kSubIndexMask = 0x80000000; |
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static const size_t kOffsetLen = sizeof(uint32_t); |
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private: |
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uint32_t index_size_; |
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size_t sub_index_size_; |
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uint32_t num_prefixes_; |
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uint32_t* index_; |
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char* sub_index_; |
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}; |
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// PlainTableIndexBuilder is used to create plain table index.
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// After calling Finish(), it returns Slice, which is usually
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// used either to initialize PlainTableIndex or
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// to save index to sst file.
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// For more details about the index, please refer to:
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// https://github.com/facebook/rocksdb/wiki/PlainTable-Format
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// #wiki-in-memory-index-format
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class PlainTableIndexBuilder { |
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public: |
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PlainTableIndexBuilder(Arena* arena, const Options& options, |
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uint32_t index_sparseness, double hash_table_ratio, |
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double huge_page_tlb_size) |
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: arena_(arena), |
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options_(options), |
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record_list_(kRecordsPerGroup), |
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is_first_record_(true), |
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due_index_(false), |
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num_prefixes_(0), |
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num_keys_per_prefix_(0), |
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prev_key_prefix_hash_(0), |
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index_sparseness_(index_sparseness), |
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prefix_extractor_(options.prefix_extractor.get()), |
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hash_table_ratio_(hash_table_ratio), |
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huge_page_tlb_size_(huge_page_tlb_size) {} |
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void AddKeyPrefix(Slice key_prefix_slice, uint64_t key_offset); |
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Slice Finish(); |
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uint32_t GetTotalSize() const { |
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return VarintLength(index_size_) + VarintLength(num_prefixes_) + |
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PlainTableIndex::kOffsetLen * index_size_ + sub_index_size_; |
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} |
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static const std::string kPlainTableIndexBlock; |
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private: |
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struct IndexRecord { |
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uint32_t hash; // hash of the prefix
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uint32_t offset; // offset of a row
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IndexRecord* next; |
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}; |
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// Helper class to track all the index records
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class IndexRecordList { |
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public: |
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explicit IndexRecordList(size_t num_records_per_group) |
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: kNumRecordsPerGroup(num_records_per_group), |
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current_group_(nullptr), |
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num_records_in_current_group_(num_records_per_group) {} |
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~IndexRecordList() { |
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for (size_t i = 0; i < groups_.size(); i++) { |
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delete[] groups_[i]; |
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} |
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} |
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void AddRecord(murmur_t hash, uint32_t offset); |
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size_t GetNumRecords() const { |
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return (groups_.size() - 1) * kNumRecordsPerGroup + |
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num_records_in_current_group_; |
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} |
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IndexRecord* At(size_t index) { |
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return &(groups_[index / kNumRecordsPerGroup] |
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[index % kNumRecordsPerGroup]); |
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} |
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private: |
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IndexRecord* AllocateNewGroup() { |
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IndexRecord* result = new IndexRecord[kNumRecordsPerGroup]; |
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groups_.push_back(result); |
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return result; |
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} |
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// Each group in `groups_` contains fix-sized records (determined by
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// kNumRecordsPerGroup). Which can help us minimize the cost if resizing
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// occurs.
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const size_t kNumRecordsPerGroup; |
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IndexRecord* current_group_; |
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// List of arrays allocated
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std::vector<IndexRecord*> groups_; |
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size_t num_records_in_current_group_; |
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}; |
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void AllocateIndex(); |
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// Internal helper function to bucket index record list to hash buckets.
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void BucketizeIndexes(std::vector<IndexRecord*>* hash_to_offsets, |
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std::vector<uint32_t>* entries_per_bucket); |
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// Internal helper class to fill the indexes and bloom filters to internal
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// data structures.
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Slice FillIndexes(const std::vector<IndexRecord*>& hash_to_offsets, |
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const std::vector<uint32_t>& entries_per_bucket); |
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Arena* arena_; |
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Options options_; |
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HistogramImpl keys_per_prefix_hist_; |
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IndexRecordList record_list_; |
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bool is_first_record_; |
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bool due_index_; |
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uint32_t num_prefixes_; |
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uint32_t num_keys_per_prefix_; |
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uint32_t prev_key_prefix_hash_; |
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uint32_t index_sparseness_; |
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uint32_t index_size_; |
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size_t sub_index_size_; |
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const SliceTransform* prefix_extractor_; |
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double hash_table_ratio_; |
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double huge_page_tlb_size_; |
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std::string prev_key_prefix_; |
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static const size_t kRecordsPerGroup = 256; |
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}; |
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}; // namespace rocksdb
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