fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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835 lines
27 KiB
835 lines
27 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/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 "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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namespace rocksdb {
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namespace {
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inline uint32_t GetSliceHash(const Slice& s) {
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return Hash(s.data(), s.size(), 397) ;
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}
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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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// 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;
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void SeekToFirst();
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void SeekToLast();
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void Seek(const Slice& target);
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void Next();
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void Prev();
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Slice key() const;
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Slice value() const;
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Status status() const;
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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 Options& options,
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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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data_end_offset_(table_properties->data_size),
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user_key_len_(table_properties->fixed_key_len),
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prefix_extractor_(options.prefix_extractor.get()),
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enable_bloom_(false),
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bloom_(6, nullptr),
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options_(options),
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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 Options& options,
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const EnvOptions& soptions,
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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(options.allow_mmap_reads);
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if (file_size > 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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options.env, options.info_log.get(), &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 (!options.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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options.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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options, std::move(file), soptions, internal_comparator, encoding_type,
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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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// -- Populate Index
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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->index_size_ = kFullScanModeFlag;
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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 (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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struct PlainTableReader::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 PlainTableReader::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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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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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][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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Status PlainTableReader::PopulateIndexRecordList(IndexRecordList* record_list,
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int* num_prefixes,
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int bloom_bits_per_key,
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size_t index_sparseness) {
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Slice prev_key_prefix_slice;
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uint32_t prev_key_prefix_hash = 0;
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uint32_t pos = data_start_offset_;
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int num_keys_per_prefix = 0;
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bool is_first_record = true;
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HistogramImpl keys_per_prefix_hist;
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// Need map to be ordered to make sure sub indexes generated
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// are in order.
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*num_prefixes = 0;
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PlainTableKeyDecoder decoder(encoding_type_, user_key_len_,
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options_.prefix_extractor.get());
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bool due_index = false;
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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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if (enable_bloom_) {
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// total order mode and bloom filter is enabled.
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bloom_.AddHash(GetSliceHash(key.user_key));
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}
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Slice key_prefix_slice = GetPrefix(key);
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if (is_first_record || prev_key_prefix_slice != key_prefix_slice) {
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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_slice = key_prefix_slice;
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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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if (!seekable) {
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return Status::Corruption("Key for a prefix is not seekable");
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}
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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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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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return Status::OK();
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}
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void PlainTableReader::AllocateIndexAndBloom(int num_prefixes,
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int bloom_bits_per_key,
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double hash_table_ratio,
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size_t huge_page_tlb_size) {
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if (prefix_extractor_ != nullptr) {
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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, options_.bloom_locality,
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huge_page_tlb_size, options_.info_log.get());
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}
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}
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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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}
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}
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size_t PlainTableReader::BucketizeIndexesAndFillBloom(
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IndexRecordList* record_list, 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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if (enable_bloom_ && !IsTotalOrderMode()) {
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bloom_.AddHash(cur_hash);
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}
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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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size_t 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 * kOffsetLen;
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}
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return sub_index_size;
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}
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void PlainTableReader::FillIndexes(
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const size_t kSubIndexSize,
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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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size_t huge_page_tlb_size) {
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Log(options_.info_log, "Reserving %zu bytes for plain table's sub_index",
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kSubIndexSize);
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auto total_allocate_size = sizeof(uint32_t) * index_size_ + kSubIndexSize;
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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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index_ = reinterpret_cast<uint32_t*>(allocated);
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sub_index_ = allocated + sizeof(uint32_t) * index_size_;
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size_t sub_index_offset = 0;
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for (int 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] = data_end_offset_;
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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 | 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 += kOffsetLen * num_keys_for_bucket;
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assert(sub_index_offset <= kSubIndexSize);
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break;
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}
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}
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assert(sub_index_offset == kSubIndexSize);
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Log(options_.info_log, "hash table size: %d, suffix_map length %zu",
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index_size_, kSubIndexSize);
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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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// options.prefix_extractor is requried for a hash-based look-up.
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if ((options_.prefix_extractor.get() == nullptr) && (hash_table_ratio != 0)) {
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// options.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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IndexRecordList record_list(kRecordsPerGroup);
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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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int num_prefixes;
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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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table_properties_->num_entries * 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, options_.bloom_locality,
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huge_page_tlb_size, options_.info_log.get());
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}
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}
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Status s = PopulateIndexRecordList(&record_list, &num_prefixes,
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bloom_bits_per_key, index_sparseness);
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if (!s.ok()) {
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return s;
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}
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// Calculated hash table and bloom filter size and allocate memory for indexes
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// and bloom filter based on the number of prefixes.
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AllocateIndexAndBloom(num_prefixes, bloom_bits_per_key, hash_table_ratio,
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huge_page_tlb_size);
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// Bucketize all the index records to a temp data structure, in which for
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// each bucket, we generate a linked list of IndexRecord, in reversed order.
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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);
|
|
size_t sub_index_size_needed = BucketizeIndexesAndFillBloom(
|
|
&record_list, &hash_to_offsets, &entries_per_bucket);
|
|
// From the temp data structure, populate indexes.
|
|
FillIndexes(sub_index_size_needed, hash_to_offsets, entries_per_bucket,
|
|
huge_page_tlb_size);
|
|
|
|
// Fill two table properties.
|
|
// TODO(sdong): after we have the feature of storing index in file, this
|
|
// properties need to be populated to index_size instead.
|
|
props->user_collected_properties["plain_table_hash_table_size"] =
|
|
std::to_string(index_size_ * 4U);
|
|
props->user_collected_properties["plain_table_sub_index_size"] =
|
|
std::to_string(sub_index_size_needed);
|
|
|
|
return Status::OK();
|
|
}
|
|
|
|
Status PlainTableReader::GetOffset(const Slice& target, const Slice& prefix,
|
|
uint32_t prefix_hash, bool& prefix_matched,
|
|
uint32_t* offset) const {
|
|
prefix_matched = false;
|
|
int bucket = GetBucketIdFromHash(prefix_hash, index_size_);
|
|
uint32_t bucket_value = index_[bucket];
|
|
if (bucket_value == data_end_offset_) {
|
|
*offset = data_end_offset_;
|
|
return Status::OK();
|
|
} else if ((bucket_value & kSubIndexMask) == 0) {
|
|
// point directly to the file
|
|
*offset = bucket_value;
|
|
return Status::OK();
|
|
}
|
|
|
|
// point to sub-index, need to do a binary search
|
|
uint32_t low = 0;
|
|
uint64_t prefix_index_offset = bucket_value ^ kSubIndexMask;
|
|
|
|
const char* index_ptr = &sub_index_[prefix_index_offset];
|
|
uint32_t upper_bound = 0;
|
|
const char* base_ptr = GetVarint32Ptr(index_ptr, index_ptr + 4, &upper_bound);
|
|
uint32_t high = upper_bound;
|
|
ParsedInternalKey mid_key;
|
|
ParsedInternalKey parsed_target;
|
|
if (!ParseInternalKey(target, &parsed_target)) {
|
|
return Status::Corruption(Slice());
|
|
}
|
|
|
|
// The key is between [low, high). Do a binary search between it.
|
|
while (high - low > 1) {
|
|
uint32_t mid = (high + low) / 2;
|
|
uint32_t file_offset = GetFixed32Element(base_ptr, mid);
|
|
size_t tmp;
|
|
Status s = PlainTableKeyDecoder(encoding_type_, user_key_len_,
|
|
options_.prefix_extractor.get())
|
|
.NextKey(file_data_.data() + file_offset,
|
|
file_data_.data() + data_end_offset_, &mid_key,
|
|
nullptr, &tmp);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
int cmp_result = internal_comparator_.Compare(mid_key, parsed_target);
|
|
if (cmp_result < 0) {
|
|
low = mid;
|
|
} else {
|
|
if (cmp_result == 0) {
|
|
// Happen to have found the exact key or target is smaller than the
|
|
// first key after base_offset.
|
|
prefix_matched = true;
|
|
*offset = file_offset;
|
|
return Status::OK();
|
|
} else {
|
|
high = mid;
|
|
}
|
|
}
|
|
}
|
|
// Both of the key at the position low or low+1 could share the same
|
|
// prefix as target. We need to rule out one of them to avoid to go
|
|
// to the wrong prefix.
|
|
ParsedInternalKey low_key;
|
|
size_t tmp;
|
|
uint32_t low_key_offset = GetFixed32Element(base_ptr, low);
|
|
Status s = PlainTableKeyDecoder(encoding_type_, user_key_len_,
|
|
options_.prefix_extractor.get())
|
|
.NextKey(file_data_.data() + low_key_offset,
|
|
file_data_.data() + data_end_offset_, &low_key,
|
|
nullptr, &tmp);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
|
|
if (GetPrefix(low_key) == prefix) {
|
|
prefix_matched = true;
|
|
*offset = low_key_offset;
|
|
} else if (low + 1 < upper_bound) {
|
|
// There is possible a next prefix, return it
|
|
prefix_matched = false;
|
|
*offset = GetFixed32Element(base_ptr, low + 1);
|
|
} else {
|
|
// target is larger than a key of the last prefix in this bucket
|
|
// but with a different prefix. Key does not exist.
|
|
*offset = data_end_offset_;
|
|
}
|
|
return Status::OK();
|
|
}
|
|
|
|
bool PlainTableReader::MatchBloom(uint32_t hash) const {
|
|
return !enable_bloom_ || bloom_.MayContainHash(hash);
|
|
}
|
|
|
|
Slice PlainTableReader::GetPrefix(const ParsedInternalKey& target) const {
|
|
return GetPrefixFromUserKey(target.user_key);
|
|
}
|
|
|
|
Status PlainTableReader::Next(PlainTableKeyDecoder* decoder, uint32_t* offset,
|
|
ParsedInternalKey* parsed_key,
|
|
Slice* internal_key, Slice* value,
|
|
bool* seekable) const {
|
|
if (*offset == data_end_offset_) {
|
|
*offset = data_end_offset_;
|
|
return Status::OK();
|
|
}
|
|
|
|
if (*offset > data_end_offset_) {
|
|
return Status::Corruption("Offset is out of file size");
|
|
}
|
|
|
|
const char* start = file_data_.data() + *offset;
|
|
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 + (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,
|
|
void* arg,
|
|
bool (*saver)(void*, const ParsedInternalKey&,
|
|
const Slice&),
|
|
void (*mark_key_may_exist)(void*)) {
|
|
// Check bloom filter first.
|
|
Slice prefix_slice;
|
|
uint32_t prefix_hash;
|
|
if (IsTotalOrderMode()) {
|
|
if (index_size_ == kFullScanModeFlag) {
|
|
// 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_,
|
|
options_.prefix_extractor.get());
|
|
while (offset < data_end_offset_) {
|
|
Status 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;
|
|
}
|
|
if (internal_comparator_.Compare(found_key, parsed_target) >= 0) {
|
|
if (!(*saver)(arg, 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_->index_size_ == PlainTableReader::kFullScanModeFlag) {
|
|
// 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_->index_size_ > 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
|
|
|