fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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717 lines
22 KiB
717 lines
22 KiB
// 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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#ifndef ROCKSDB_LITE
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#include "table/plain_table_reader.h"
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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/cache.h"
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#include "rocksdb/comparator.h"
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#include "rocksdb/env.h"
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#include "rocksdb/filter_policy.h"
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#include "rocksdb/options.h"
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#include "rocksdb/statistics.h"
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#include "table/block.h"
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#include "table/bloom_block.h"
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#include "table/filter_block.h"
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#include "table/format.h"
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#include "table/meta_blocks.h"
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#include "table/two_level_iterator.h"
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#include "table/plain_table_factory.h"
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#include "table/plain_table_key_coding.h"
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#include "table/get_context.h"
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#include "util/arena.h"
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#include "util/coding.h"
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#include "util/dynamic_bloom.h"
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#include "util/hash.h"
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#include "util/histogram.h"
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#include "util/murmurhash.h"
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#include "util/perf_context_imp.h"
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#include "util/stop_watch.h"
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#include "util/string_util.h"
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namespace rocksdb {
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namespace {
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// Safely getting a uint32_t element from a char array, where, starting from
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// `base`, every 4 bytes are considered as an fixed 32 bit integer.
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inline uint32_t GetFixed32Element(const char* base, size_t offset) {
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return DecodeFixed32(base + offset * sizeof(uint32_t));
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}
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} // namespace
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// Iterator to iterate IndexedTable
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class PlainTableIterator : public Iterator {
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public:
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explicit PlainTableIterator(PlainTableReader* table, bool use_prefix_seek);
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~PlainTableIterator();
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bool Valid() const override;
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void SeekToFirst() override;
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void SeekToLast() override;
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void Seek(const Slice& target) override;
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void Next() override;
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void Prev() override;
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Slice key() const override;
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Slice value() const override;
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Status status() const override;
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private:
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PlainTableReader* table_;
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PlainTableKeyDecoder decoder_;
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bool use_prefix_seek_;
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uint32_t offset_;
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uint32_t next_offset_;
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Slice key_;
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Slice value_;
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Status status_;
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// No copying allowed
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PlainTableIterator(const PlainTableIterator&) = delete;
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void operator=(const Iterator&) = delete;
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};
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extern const uint64_t kPlainTableMagicNumber;
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PlainTableReader::PlainTableReader(const ImmutableCFOptions& ioptions,
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unique_ptr<RandomAccessFile>&& file,
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const EnvOptions& storage_options,
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const InternalKeyComparator& icomparator,
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EncodingType encoding_type,
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uint64_t file_size,
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const TableProperties* table_properties)
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: internal_comparator_(icomparator),
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encoding_type_(encoding_type),
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full_scan_mode_(false),
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data_end_offset_(static_cast<uint32_t>(table_properties->data_size)),
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user_key_len_(static_cast<uint32_t>(table_properties->fixed_key_len)),
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prefix_extractor_(ioptions.prefix_extractor),
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enable_bloom_(false),
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bloom_(6, nullptr),
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ioptions_(ioptions),
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file_(std::move(file)),
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file_size_(file_size),
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table_properties_(nullptr) {}
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PlainTableReader::~PlainTableReader() {
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}
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Status PlainTableReader::Open(const ImmutableCFOptions& ioptions,
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const EnvOptions& env_options,
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const InternalKeyComparator& internal_comparator,
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unique_ptr<RandomAccessFile>&& file,
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uint64_t file_size,
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unique_ptr<TableReader>* table_reader,
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const int bloom_bits_per_key,
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double hash_table_ratio, size_t index_sparseness,
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size_t huge_page_tlb_size, bool full_scan_mode) {
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assert(ioptions.allow_mmap_reads);
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if (file_size > PlainTableIndex::kMaxFileSize) {
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return Status::NotSupported("File is too large for PlainTableReader!");
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}
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TableProperties* props = nullptr;
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auto s = ReadTableProperties(file.get(), file_size, kPlainTableMagicNumber,
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ioptions.env, ioptions.info_log, &props);
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if (!s.ok()) {
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return s;
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}
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assert(hash_table_ratio >= 0.0);
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auto& user_props = props->user_collected_properties;
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auto prefix_extractor_in_file =
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user_props.find(PlainTablePropertyNames::kPrefixExtractorName);
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if (!full_scan_mode && prefix_extractor_in_file != user_props.end()) {
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if (!ioptions.prefix_extractor) {
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return Status::InvalidArgument(
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"Prefix extractor is missing when opening a PlainTable built "
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"using a prefix extractor");
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} else if (prefix_extractor_in_file->second.compare(
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ioptions.prefix_extractor->Name()) != 0) {
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return Status::InvalidArgument(
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"Prefix extractor given doesn't match the one used to build "
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"PlainTable");
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}
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}
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EncodingType encoding_type = kPlain;
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auto encoding_type_prop =
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user_props.find(PlainTablePropertyNames::kEncodingType);
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if (encoding_type_prop != user_props.end()) {
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encoding_type = static_cast<EncodingType>(
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DecodeFixed32(encoding_type_prop->second.c_str()));
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}
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std::unique_ptr<PlainTableReader> new_reader(new PlainTableReader(
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ioptions, std::move(file), env_options, internal_comparator,
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encoding_type, file_size, props));
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s = new_reader->MmapDataFile();
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if (!s.ok()) {
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return s;
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}
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if (!full_scan_mode) {
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s = new_reader->PopulateIndex(props, bloom_bits_per_key, hash_table_ratio,
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index_sparseness, huge_page_tlb_size);
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if (!s.ok()) {
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return s;
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}
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} else {
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// Flag to indicate it is a full scan mode so that none of the indexes
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// can be used.
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new_reader->full_scan_mode_ = true;
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}
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*table_reader = std::move(new_reader);
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return s;
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}
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void PlainTableReader::SetupForCompaction() {
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}
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Iterator* PlainTableReader::NewIterator(const ReadOptions& options,
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Arena* arena) {
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if (options.total_order_seek && !IsTotalOrderMode()) {
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return NewErrorIterator(
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Status::InvalidArgument("total_order_seek not supported"), arena);
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}
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if (arena == nullptr) {
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return new PlainTableIterator(this, prefix_extractor_ != nullptr);
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} else {
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auto mem = arena->AllocateAligned(sizeof(PlainTableIterator));
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return new (mem) PlainTableIterator(this, prefix_extractor_ != nullptr);
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}
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}
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Status PlainTableReader::PopulateIndexRecordList(
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PlainTableIndexBuilder* index_builder, vector<uint32_t>* prefix_hashes) {
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Slice prev_key_prefix_slice;
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uint32_t pos = data_start_offset_;
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bool is_first_record = true;
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Slice key_prefix_slice;
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PlainTableKeyDecoder decoder(encoding_type_, user_key_len_,
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ioptions_.prefix_extractor);
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while (pos < data_end_offset_) {
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uint32_t key_offset = pos;
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ParsedInternalKey key;
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Slice value_slice;
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bool seekable = false;
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Status s = Next(&decoder, &pos, &key, nullptr, &value_slice, &seekable);
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if (!s.ok()) {
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return s;
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}
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key_prefix_slice = GetPrefix(key);
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if (enable_bloom_) {
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bloom_.AddHash(GetSliceHash(key.user_key));
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} else {
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if (is_first_record || prev_key_prefix_slice != key_prefix_slice) {
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if (!is_first_record) {
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prefix_hashes->push_back(GetSliceHash(prev_key_prefix_slice));
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}
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prev_key_prefix_slice = key_prefix_slice;
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}
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}
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index_builder->AddKeyPrefix(GetPrefix(key), key_offset);
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if (!seekable && is_first_record) {
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return Status::Corruption("Key for a prefix is not seekable");
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}
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is_first_record = false;
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}
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prefix_hashes->push_back(GetSliceHash(key_prefix_slice));
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auto s = index_.InitFromRawData(index_builder->Finish());
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return s;
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}
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void PlainTableReader::AllocateAndFillBloom(int bloom_bits_per_key,
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int num_prefixes,
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size_t huge_page_tlb_size,
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vector<uint32_t>* prefix_hashes) {
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if (!IsTotalOrderMode()) {
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uint32_t bloom_total_bits = num_prefixes * bloom_bits_per_key;
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if (bloom_total_bits > 0) {
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enable_bloom_ = true;
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bloom_.SetTotalBits(&arena_, bloom_total_bits, ioptions_.bloom_locality,
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huge_page_tlb_size, ioptions_.info_log);
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FillBloom(prefix_hashes);
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}
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}
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}
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void PlainTableReader::FillBloom(vector<uint32_t>* prefix_hashes) {
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assert(bloom_.IsInitialized());
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for (auto prefix_hash : *prefix_hashes) {
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bloom_.AddHash(prefix_hash);
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}
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}
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Status PlainTableReader::MmapDataFile() {
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// Get mmapped memory to file_data_.
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return file_->Read(0, file_size_, &file_data_, nullptr);
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}
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Status PlainTableReader::PopulateIndex(TableProperties* props,
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int bloom_bits_per_key,
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double hash_table_ratio,
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size_t index_sparseness,
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size_t huge_page_tlb_size) {
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assert(props != nullptr);
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table_properties_.reset(props);
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BlockContents bloom_block_contents;
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auto s = ReadMetaBlock(file_.get(), file_size_, kPlainTableMagicNumber,
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ioptions_.env, BloomBlockBuilder::kBloomBlock,
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&bloom_block_contents);
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bool index_in_file = s.ok();
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BlockContents index_block_contents;
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s = ReadMetaBlock(file_.get(), file_size_, kPlainTableMagicNumber,
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ioptions_.env, PlainTableIndexBuilder::kPlainTableIndexBlock,
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&index_block_contents);
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index_in_file &= s.ok();
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Slice* bloom_block;
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if (index_in_file) {
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bloom_block = &bloom_block_contents.data;
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} else {
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bloom_block = nullptr;
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}
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// index_in_file == true only if there are kBloomBlock and
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// kPlainTableIndexBlock
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// in file
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Slice* index_block;
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if (index_in_file) {
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index_block = &index_block_contents.data;
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} else {
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index_block = nullptr;
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}
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if ((ioptions_.prefix_extractor == nullptr) &&
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(hash_table_ratio != 0)) {
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// ioptions.prefix_extractor is requried for a hash-based look-up.
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return Status::NotSupported(
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"PlainTable requires a prefix extractor enable prefix hash mode.");
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}
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// First, read the whole file, for every kIndexIntervalForSamePrefixKeys rows
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// for a prefix (starting from the first one), generate a record of (hash,
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// offset) and append it to IndexRecordList, which is a data structure created
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// to store them.
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if (!index_in_file) {
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// Allocate bloom filter here for total order mode.
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if (IsTotalOrderMode()) {
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uint32_t num_bloom_bits =
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static_cast<uint32_t>(table_properties_->num_entries) *
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bloom_bits_per_key;
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if (num_bloom_bits > 0) {
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enable_bloom_ = true;
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bloom_.SetTotalBits(&arena_, num_bloom_bits, ioptions_.bloom_locality,
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huge_page_tlb_size, ioptions_.info_log);
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}
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}
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} else {
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enable_bloom_ = true;
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auto num_blocks_property = props->user_collected_properties.find(
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PlainTablePropertyNames::kNumBloomBlocks);
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uint32_t num_blocks = 0;
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if (num_blocks_property != props->user_collected_properties.end()) {
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Slice temp_slice(num_blocks_property->second);
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if (!GetVarint32(&temp_slice, &num_blocks)) {
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num_blocks = 0;
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}
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}
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// cast away const qualifier, because bloom_ won't be changed
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bloom_.SetRawData(
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const_cast<unsigned char*>(
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reinterpret_cast<const unsigned char*>(bloom_block->data())),
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static_cast<uint32_t>(bloom_block->size()) * 8, num_blocks);
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}
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PlainTableIndexBuilder index_builder(&arena_, ioptions_, index_sparseness,
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hash_table_ratio, huge_page_tlb_size);
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std::vector<uint32_t> prefix_hashes;
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if (!index_in_file) {
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s = PopulateIndexRecordList(&index_builder, &prefix_hashes);
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if (!s.ok()) {
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return s;
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}
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} else {
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s = index_.InitFromRawData(*index_block);
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if (!s.ok()) {
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return s;
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}
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}
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if (!index_in_file) {
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// Calculated bloom filter size and allocate memory for
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// bloom filter based on the number of prefixes, then fill it.
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AllocateAndFillBloom(bloom_bits_per_key, index_.GetNumPrefixes(),
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huge_page_tlb_size, &prefix_hashes);
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}
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// Fill two table properties.
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if (!index_in_file) {
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props->user_collected_properties["plain_table_hash_table_size"] =
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ToString(index_.GetIndexSize() * PlainTableIndex::kOffsetLen);
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props->user_collected_properties["plain_table_sub_index_size"] =
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ToString(index_.GetSubIndexSize());
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} else {
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props->user_collected_properties["plain_table_hash_table_size"] =
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ToString(0);
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props->user_collected_properties["plain_table_sub_index_size"] =
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ToString(0);
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}
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return Status::OK();
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}
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Status PlainTableReader::GetOffset(const Slice& target, const Slice& prefix,
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uint32_t prefix_hash, bool& prefix_matched,
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uint32_t* offset) const {
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prefix_matched = false;
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uint32_t prefix_index_offset;
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auto res = index_.GetOffset(prefix_hash, &prefix_index_offset);
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if (res == PlainTableIndex::kNoPrefixForBucket) {
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*offset = data_end_offset_;
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return Status::OK();
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} else if (res == PlainTableIndex::kDirectToFile) {
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*offset = prefix_index_offset;
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return Status::OK();
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}
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// point to sub-index, need to do a binary search
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uint32_t upper_bound;
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const char* base_ptr =
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index_.GetSubIndexBasePtrAndUpperBound(prefix_index_offset, &upper_bound);
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uint32_t low = 0;
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uint32_t high = upper_bound;
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ParsedInternalKey mid_key;
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ParsedInternalKey parsed_target;
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if (!ParseInternalKey(target, &parsed_target)) {
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return Status::Corruption(Slice());
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}
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// The key is between [low, high). Do a binary search between it.
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while (high - low > 1) {
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uint32_t mid = (high + low) / 2;
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uint32_t file_offset = GetFixed32Element(base_ptr, mid);
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size_t tmp;
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Status s = PlainTableKeyDecoder(encoding_type_, user_key_len_,
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ioptions_.prefix_extractor)
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.NextKey(file_data_.data() + file_offset,
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file_data_.data() + data_end_offset_, &mid_key,
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nullptr, &tmp);
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if (!s.ok()) {
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return s;
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}
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int cmp_result = internal_comparator_.Compare(mid_key, parsed_target);
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if (cmp_result < 0) {
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low = mid;
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} else {
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if (cmp_result == 0) {
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// Happen to have found the exact key or target is smaller than the
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// first key after base_offset.
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prefix_matched = true;
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*offset = file_offset;
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return Status::OK();
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} else {
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high = mid;
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}
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}
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}
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// Both of the key at the position low or low+1 could share the same
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// prefix as target. We need to rule out one of them to avoid to go
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// to the wrong prefix.
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ParsedInternalKey low_key;
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size_t tmp;
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uint32_t low_key_offset = GetFixed32Element(base_ptr, low);
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Status s = PlainTableKeyDecoder(encoding_type_, user_key_len_,
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ioptions_.prefix_extractor)
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.NextKey(file_data_.data() + low_key_offset,
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file_data_.data() + data_end_offset_, &low_key,
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nullptr, &tmp);
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if (!s.ok()) {
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return s;
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}
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if (GetPrefix(low_key) == prefix) {
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prefix_matched = true;
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*offset = low_key_offset;
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} else if (low + 1 < upper_bound) {
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// There is possible a next prefix, return it
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prefix_matched = false;
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*offset = GetFixed32Element(base_ptr, low + 1);
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} else {
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// target is larger than a key of the last prefix in this bucket
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// but with a different prefix. Key does not exist.
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*offset = data_end_offset_;
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}
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return Status::OK();
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}
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bool PlainTableReader::MatchBloom(uint32_t hash) const {
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return !enable_bloom_ || bloom_.MayContainHash(hash);
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}
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Status PlainTableReader::Next(PlainTableKeyDecoder* decoder, uint32_t* offset,
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ParsedInternalKey* parsed_key,
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Slice* internal_key, Slice* value,
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bool* seekable) const {
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if (*offset == data_end_offset_) {
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*offset = data_end_offset_;
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return Status::OK();
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}
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if (*offset > data_end_offset_) {
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return Status::Corruption("Offset is out of file size");
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}
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const char* start = file_data_.data() + *offset;
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size_t bytes_for_key;
|
|
Status s =
|
|
decoder->NextKey(start, file_data_.data() + data_end_offset_, parsed_key,
|
|
internal_key, &bytes_for_key, seekable);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
uint32_t value_size;
|
|
const char* value_ptr = GetVarint32Ptr(
|
|
start + bytes_for_key, file_data_.data() + data_end_offset_, &value_size);
|
|
if (value_ptr == nullptr) {
|
|
return Status::Corruption(
|
|
"Unexpected EOF when reading the next value's size.");
|
|
}
|
|
*offset = *offset + static_cast<uint32_t>(value_ptr - start) + value_size;
|
|
if (*offset > data_end_offset_) {
|
|
return Status::Corruption("Unexpected EOF when reading the next value. ");
|
|
}
|
|
*value = Slice(value_ptr, value_size);
|
|
|
|
return Status::OK();
|
|
}
|
|
|
|
void PlainTableReader::Prepare(const Slice& target) {
|
|
if (enable_bloom_) {
|
|
uint32_t prefix_hash = GetSliceHash(GetPrefix(target));
|
|
bloom_.Prefetch(prefix_hash);
|
|
}
|
|
}
|
|
|
|
Status PlainTableReader::Get(const ReadOptions& ro, const Slice& target,
|
|
GetContext* get_context) {
|
|
// Check bloom filter first.
|
|
Slice prefix_slice;
|
|
uint32_t prefix_hash;
|
|
if (IsTotalOrderMode()) {
|
|
if (full_scan_mode_) {
|
|
status_ =
|
|
Status::InvalidArgument("Get() is not allowed in full scan mode.");
|
|
}
|
|
// Match whole user key for bloom filter check.
|
|
if (!MatchBloom(GetSliceHash(GetUserKey(target)))) {
|
|
return Status::OK();
|
|
}
|
|
// in total order mode, there is only one bucket 0, and we always use empty
|
|
// prefix.
|
|
prefix_slice = Slice();
|
|
prefix_hash = 0;
|
|
} else {
|
|
prefix_slice = GetPrefix(target);
|
|
prefix_hash = GetSliceHash(prefix_slice);
|
|
if (!MatchBloom(prefix_hash)) {
|
|
return Status::OK();
|
|
}
|
|
}
|
|
uint32_t offset;
|
|
bool prefix_match;
|
|
Status s =
|
|
GetOffset(target, prefix_slice, prefix_hash, prefix_match, &offset);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
ParsedInternalKey found_key;
|
|
ParsedInternalKey parsed_target;
|
|
if (!ParseInternalKey(target, &parsed_target)) {
|
|
return Status::Corruption(Slice());
|
|
}
|
|
Slice found_value;
|
|
PlainTableKeyDecoder decoder(encoding_type_, user_key_len_,
|
|
ioptions_.prefix_extractor);
|
|
while (offset < data_end_offset_) {
|
|
s = Next(&decoder, &offset, &found_key, nullptr, &found_value);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
if (!prefix_match) {
|
|
// Need to verify prefix for the first key found if it is not yet
|
|
// checked.
|
|
if (GetPrefix(found_key) != prefix_slice) {
|
|
return Status::OK();
|
|
}
|
|
prefix_match = true;
|
|
}
|
|
// TODO(ljin): since we know the key comparison result here,
|
|
// can we enable the fast path?
|
|
if (internal_comparator_.Compare(found_key, parsed_target) >= 0) {
|
|
if (!get_context->SaveValue(found_key, found_value)) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
return Status::OK();
|
|
}
|
|
|
|
uint64_t PlainTableReader::ApproximateOffsetOf(const Slice& key) {
|
|
return 0;
|
|
}
|
|
|
|
PlainTableIterator::PlainTableIterator(PlainTableReader* table,
|
|
bool use_prefix_seek)
|
|
: table_(table),
|
|
decoder_(table_->encoding_type_, table_->user_key_len_,
|
|
table_->prefix_extractor_),
|
|
use_prefix_seek_(use_prefix_seek) {
|
|
next_offset_ = offset_ = table_->data_end_offset_;
|
|
}
|
|
|
|
PlainTableIterator::~PlainTableIterator() {
|
|
}
|
|
|
|
bool PlainTableIterator::Valid() const {
|
|
return offset_ < table_->data_end_offset_
|
|
&& offset_ >= table_->data_start_offset_;
|
|
}
|
|
|
|
void PlainTableIterator::SeekToFirst() {
|
|
next_offset_ = table_->data_start_offset_;
|
|
if (next_offset_ >= table_->data_end_offset_) {
|
|
next_offset_ = offset_ = table_->data_end_offset_;
|
|
} else {
|
|
Next();
|
|
}
|
|
}
|
|
|
|
void PlainTableIterator::SeekToLast() {
|
|
assert(false);
|
|
status_ = Status::NotSupported("SeekToLast() is not supported in PlainTable");
|
|
}
|
|
|
|
void PlainTableIterator::Seek(const Slice& target) {
|
|
// If the user doesn't set prefix seek option and we are not able to do a
|
|
// total Seek(). assert failure.
|
|
if (!use_prefix_seek_) {
|
|
if (table_->full_scan_mode_) {
|
|
status_ =
|
|
Status::InvalidArgument("Seek() is not allowed in full scan mode.");
|
|
offset_ = next_offset_ = table_->data_end_offset_;
|
|
return;
|
|
} else if (table_->GetIndexSize() > 1) {
|
|
assert(false);
|
|
status_ = Status::NotSupported(
|
|
"PlainTable cannot issue non-prefix seek unless in total order "
|
|
"mode.");
|
|
offset_ = next_offset_ = table_->data_end_offset_;
|
|
return;
|
|
}
|
|
}
|
|
|
|
Slice prefix_slice = table_->GetPrefix(target);
|
|
uint32_t prefix_hash = 0;
|
|
// Bloom filter is ignored in total-order mode.
|
|
if (!table_->IsTotalOrderMode()) {
|
|
prefix_hash = GetSliceHash(prefix_slice);
|
|
if (!table_->MatchBloom(prefix_hash)) {
|
|
offset_ = next_offset_ = table_->data_end_offset_;
|
|
return;
|
|
}
|
|
}
|
|
bool prefix_match;
|
|
status_ = table_->GetOffset(target, prefix_slice, prefix_hash, prefix_match,
|
|
&next_offset_);
|
|
if (!status_.ok()) {
|
|
offset_ = next_offset_ = table_->data_end_offset_;
|
|
return;
|
|
}
|
|
|
|
if (next_offset_ < table_-> data_end_offset_) {
|
|
for (Next(); status_.ok() && Valid(); Next()) {
|
|
if (!prefix_match) {
|
|
// Need to verify the first key's prefix
|
|
if (table_->GetPrefix(key()) != prefix_slice) {
|
|
offset_ = next_offset_ = table_->data_end_offset_;
|
|
break;
|
|
}
|
|
prefix_match = true;
|
|
}
|
|
if (table_->internal_comparator_.Compare(key(), target) >= 0) {
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
offset_ = table_->data_end_offset_;
|
|
}
|
|
}
|
|
|
|
void PlainTableIterator::Next() {
|
|
offset_ = next_offset_;
|
|
if (offset_ < table_->data_end_offset_) {
|
|
Slice tmp_slice;
|
|
ParsedInternalKey parsed_key;
|
|
status_ =
|
|
table_->Next(&decoder_, &next_offset_, &parsed_key, &key_, &value_);
|
|
if (!status_.ok()) {
|
|
offset_ = next_offset_ = table_->data_end_offset_;
|
|
}
|
|
}
|
|
}
|
|
|
|
void PlainTableIterator::Prev() {
|
|
assert(false);
|
|
}
|
|
|
|
Slice PlainTableIterator::key() const {
|
|
assert(Valid());
|
|
return key_;
|
|
}
|
|
|
|
Slice PlainTableIterator::value() const {
|
|
assert(Valid());
|
|
return value_;
|
|
}
|
|
|
|
Status PlainTableIterator::status() const {
|
|
return status_;
|
|
}
|
|
|
|
} // namespace rocksdb
|
|
#endif // ROCKSDB_LITE
|
|
|