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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <unordered_map>
#include <memory>
#include <vector>
#include <string>
#include <stdint.h>
#include "db/dbformat.h"
#include "rocksdb/env.h"
#include "rocksdb/iterator.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/table.h"
#include "rocksdb/table_properties.h"
#include "table/table_reader.h"
#include "table/plain_table_factory.h"
#include "table/plain_table_index.h"
#include "util/arena.h"
#include "util/dynamic_bloom.h"
#include "util/file_reader_writer.h"
namespace rocksdb {
class Block;
struct BlockContents;
class BlockHandle;
class Footer;
struct Options;
class RandomAccessFile;
struct ReadOptions;
class TableCache;
class TableReader;
class InternalKeyComparator;
class PlainTableKeyDecoder;
class GetContext;
class InternalIterator;
using std::unique_ptr;
using std::unordered_map;
using std::vector;
extern const uint32_t kPlainTableVariableLength;
struct PlainTableReaderFileInfo {
bool is_mmap_mode;
Slice file_data;
uint32_t data_end_offset;
unique_ptr<RandomAccessFileReader> file;
PlainTableReaderFileInfo(unique_ptr<RandomAccessFileReader>&& _file,
const EnvOptions& storage_options,
uint32_t _data_size_offset)
: is_mmap_mode(storage_options.use_mmap_reads),
file(std::move(_file)) {}
// Based on following output file format shown in plain_table_factory.h
// When opening the output file, IndexedTableReader creates a hash table
// from key prefixes to offset of the output file. IndexedTable will decide
// whether it points to the data offset of the first key with the key prefix
// or the offset of it. If there are too many keys share this prefix, it will
// create a binary search-able index from the suffix to offset on disk.
// The implementation of IndexedTableReader requires output file is mmaped
class PlainTableReader: public TableReader {
static Status Open(const ImmutableCFOptions& ioptions,
const EnvOptions& env_options,
const InternalKeyComparator& internal_comparator,
unique_ptr<RandomAccessFileReader>&& file,
uint64_t file_size, unique_ptr<TableReader>* table,
const int bloom_bits_per_key, double hash_table_ratio,
size_t index_sparseness, size_t huge_page_tlb_size,
bool full_scan_mode);
InternalIterator* NewIterator(const ReadOptions&,
Arena* arena = nullptr,
bool skip_filters = false) override;
void Prepare(const Slice& target) override;
Status Get(const ReadOptions&, const Slice& key, GetContext* get_context,
bool skip_filters = false) override;
uint64_t ApproximateOffsetOf(const Slice& key) override;
uint32_t GetIndexSize() const { return index_.GetIndexSize(); }
void SetupForCompaction() override;
std::shared_ptr<const TableProperties> GetTableProperties() const override {
return table_properties_;
virtual size_t ApproximateMemoryUsage() const override {
return arena_.MemoryAllocatedBytes();
PlainTableReader(const ImmutableCFOptions& ioptions,
unique_ptr<RandomAccessFileReader>&& file,
const EnvOptions& env_options,
const InternalKeyComparator& internal_comparator,
EncodingType encoding_type, uint64_t file_size,
const TableProperties* table_properties);
virtual ~PlainTableReader();
// Check bloom filter to see whether it might contain this prefix.
// The hash of the prefix is given, since it can be reused for index lookup
// too.
virtual bool MatchBloom(uint32_t hash) const;
// PopulateIndex() builds index of keys. It must be called before any query
// to the table.
// props: the table properties object that need to be stored. Ownership of
// the object will be passed.
Status PopulateIndex(TableProperties* props, int bloom_bits_per_key,
double hash_table_ratio, size_t index_sparseness,
size_t huge_page_tlb_size);
Status MmapDataIfNeeded();
const InternalKeyComparator internal_comparator_;
EncodingType encoding_type_;
// represents plain table's current status.
Status status_;
PlainTableIndex index_;
bool full_scan_mode_;
// data_start_offset_ and data_end_offset_ defines the range of the
// sst file that stores data.
const uint32_t data_start_offset_ = 0;
const uint32_t user_key_len_;
const SliceTransform* prefix_extractor_;
static const size_t kNumInternalBytes = 8;
// Bloom filter is used to rule out non-existent key
bool enable_bloom_;
DynamicBloom bloom_;
PlainTableReaderFileInfo file_info_;
Arena arena_;
std::unique_ptr<char[]> index_block_alloc_;
std::unique_ptr<char[]> bloom_block_alloc_;
const ImmutableCFOptions& ioptions_;
uint64_t file_size_;
std::shared_ptr<const TableProperties> table_properties_;
bool IsFixedLength() const {
return user_key_len_ != kPlainTableVariableLength;
size_t GetFixedInternalKeyLength() const {
return user_key_len_ + kNumInternalBytes;
Slice GetPrefix(const Slice& target) const {
assert(target.size() >= 8); // target is internal key
return GetPrefixFromUserKey(GetUserKey(target));
Slice GetPrefix(const ParsedInternalKey& target) const {
return GetPrefixFromUserKey(target.user_key);
Slice GetUserKey(const Slice& key) const {
return Slice(, key.size() - 8);
Slice GetPrefixFromUserKey(const Slice& user_key) const {
if (!IsTotalOrderMode()) {
return prefix_extractor_->Transform(user_key);
} else {
// Use empty slice as prefix if prefix_extractor is not set.
// In that case,
// it falls back to pure binary search and
// total iterator seek is supported.
return Slice();
friend class TableCache;
friend class PlainTableIterator;
// Internal helper function to generate an IndexRecordList object from all
// the rows, which contains index records as a list.
// If bloom_ is not null, all the keys' full-key hash will be added to the
// bloom filter.
Status PopulateIndexRecordList(PlainTableIndexBuilder* index_builder,
vector<uint32_t>* prefix_hashes);
// Internal helper function to allocate memory for bloom filter and fill it
void AllocateAndFillBloom(int bloom_bits_per_key, int num_prefixes,
size_t huge_page_tlb_size,
vector<uint32_t>* prefix_hashes);
void FillBloom(vector<uint32_t>* prefix_hashes);
// Read the key and value at `offset` to parameters for keys, the and
// `seekable`.
// On success, `offset` will be updated as the offset for the next key.
// `parsed_key` will be key in parsed format.
// if `internal_key` is not empty, it will be filled with key with slice
// format.
// if `seekable` is not null, it will return whether we can directly read
// data using this offset.
Status Next(PlainTableKeyDecoder* decoder, uint32_t* offset,
ParsedInternalKey* parsed_key, Slice* internal_key, Slice* value,
bool* seekable = nullptr) const;
// Get file offset for key target.
// return value prefix_matched is set to true if the offset is confirmed
// for a key with the same prefix as target.
Status GetOffset(PlainTableKeyDecoder* decoder, const Slice& target,
const Slice& prefix, uint32_t prefix_hash,
bool& prefix_matched, uint32_t* offset) const;
bool IsTotalOrderMode() const { return (prefix_extractor_ == nullptr); }
// No copying allowed
explicit PlainTableReader(const TableReader&) = delete;
void operator=(const TableReader&) = delete;
} // namespace rocksdb
#endif // ROCKSDB_LITE