mirror of https://github.com/facebook/rocksdb.git
Some refactorings on plain table
Summary: Plain table has been working well and this is just a nit-picking patch, which is generated during my coding reading. No real functional changes. only some changes regarding: * Improve some comments from the perspective a "new" code reader. * Change some magic number to constant, which can help us to parameterize them in the future. * Did some style, naming, C++ convention changes. * Fix warnings from new "arc lint" Test Plan: make check Reviewers: sdong, haobo CC: leveldb Differential Revision: https://reviews.facebook.net/D15429
This commit is contained in:
parent
0ab766132b
commit
4b51dffcf8
|
@ -34,29 +34,66 @@
|
|||
|
||||
namespace rocksdb {
|
||||
|
||||
extern const uint64_t kPlainTableMagicNumber;
|
||||
namespace {
|
||||
|
||||
static uint32_t GetSliceHash(Slice const& s) {
|
||||
inline uint32_t GetSliceHash(Slice const& s) {
|
||||
return Hash(s.data(), s.size(), 397) ;
|
||||
}
|
||||
static uint32_t getBucketIdFromHash(uint32_t hash, uint32_t num_buckets) {
|
||||
|
||||
inline uint32_t GetBucketIdFromHash(uint32_t hash, uint32_t num_buckets) {
|
||||
return hash % num_buckets;
|
||||
}
|
||||
|
||||
} // namespace
|
||||
|
||||
// Iterator to iterate IndexedTable
|
||||
class PlainTableIterator : public Iterator {
|
||||
public:
|
||||
explicit PlainTableIterator(PlainTableReader* table);
|
||||
~PlainTableIterator();
|
||||
|
||||
bool Valid() const;
|
||||
|
||||
void SeekToFirst();
|
||||
|
||||
void SeekToLast();
|
||||
|
||||
void Seek(const Slice& target);
|
||||
|
||||
void Next();
|
||||
|
||||
void Prev();
|
||||
|
||||
Slice key() const;
|
||||
|
||||
Slice value() const;
|
||||
|
||||
Status status() const;
|
||||
|
||||
private:
|
||||
PlainTableReader* table_;
|
||||
uint32_t offset_;
|
||||
uint32_t next_offset_;
|
||||
Slice key_;
|
||||
Slice value_;
|
||||
Status status_;
|
||||
// No copying allowed
|
||||
PlainTableIterator(const PlainTableIterator&) = delete;
|
||||
void operator=(const Iterator&) = delete;
|
||||
};
|
||||
|
||||
extern const uint64_t kPlainTableMagicNumber;
|
||||
PlainTableReader::PlainTableReader(const EnvOptions& storage_options,
|
||||
uint64_t file_size, int bloom_bits_per_key,
|
||||
double hash_table_ratio,
|
||||
const TableProperties& table_properties) :
|
||||
hash_table_size_(0), soptions_(storage_options), file_size_(file_size),
|
||||
hash_table_ratio_(hash_table_ratio),
|
||||
bloom_bits_per_key_(bloom_bits_per_key),
|
||||
table_properties_(table_properties), data_start_offset_(0),
|
||||
data_end_offset_(table_properties_.data_size),
|
||||
user_key_len_(table_properties.fixed_key_len) {
|
||||
hash_table_ = nullptr;
|
||||
bloom_ = nullptr;
|
||||
sub_index_ = nullptr;
|
||||
}
|
||||
const TableProperties& table_properties)
|
||||
: soptions_(storage_options),
|
||||
file_size_(file_size),
|
||||
kHashTableRatio(hash_table_ratio),
|
||||
kBloomBitsPerKey(bloom_bits_per_key),
|
||||
table_properties_(table_properties),
|
||||
data_end_offset_(table_properties_.data_size),
|
||||
user_key_len_(table_properties.fixed_key_len) {}
|
||||
|
||||
PlainTableReader::~PlainTableReader() {
|
||||
delete[] hash_table_;
|
||||
|
@ -73,30 +110,20 @@ Status PlainTableReader::Open(const Options& options,
|
|||
double hash_table_ratio) {
|
||||
assert(options.allow_mmap_reads);
|
||||
|
||||
if (file_size > 2147483646) {
|
||||
if (file_size > kMaxFileSize) {
|
||||
return Status::NotSupported("File is too large for PlainTableReader!");
|
||||
}
|
||||
|
||||
TableProperties table_properties;
|
||||
auto s = ReadTableProperties(
|
||||
file.get(),
|
||||
file_size,
|
||||
kPlainTableMagicNumber,
|
||||
options.env,
|
||||
options.info_log.get(),
|
||||
&table_properties
|
||||
);
|
||||
auto s = ReadTableProperties(file.get(), file_size, kPlainTableMagicNumber,
|
||||
options.env, options.info_log.get(),
|
||||
&table_properties);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
|
||||
std::unique_ptr<PlainTableReader> new_reader(new PlainTableReader(
|
||||
soptions,
|
||||
file_size,
|
||||
bloom_num_bits,
|
||||
hash_table_ratio,
|
||||
table_properties
|
||||
));
|
||||
soptions, file_size, bloom_num_bits, hash_table_ratio, table_properties));
|
||||
new_reader->file_ = std::move(file);
|
||||
new_reader->options_ = options;
|
||||
|
||||
|
@ -129,12 +156,11 @@ struct PlainTableReader::IndexRecord {
|
|||
|
||||
// Helper class to track all the index records
|
||||
class PlainTableReader::IndexRecordList {
|
||||
public:
|
||||
explicit IndexRecordList(size_t num_records_per_group) :
|
||||
num_records_per_group_(num_records_per_group),
|
||||
current_group_(nullptr),
|
||||
num_records_in_current_group_(num_records_per_group) {
|
||||
}
|
||||
public:
|
||||
explicit IndexRecordList(size_t num_records_per_group)
|
||||
: kNumRecordsPerGroup(num_records_per_group),
|
||||
current_group_(nullptr),
|
||||
num_records_in_current_group_(num_records_per_group) {}
|
||||
|
||||
~IndexRecordList() {
|
||||
for (size_t i = 0; i < groups_.size(); i++) {
|
||||
|
@ -143,65 +169,59 @@ public:
|
|||
}
|
||||
|
||||
void AddRecord(murmur_t hash, uint32_t offset) {
|
||||
if (num_records_in_current_group_ == num_records_per_group_) {
|
||||
if (num_records_in_current_group_ == kNumRecordsPerGroup) {
|
||||
current_group_ = AllocateNewGroup();
|
||||
num_records_in_current_group_ = 0;
|
||||
}
|
||||
auto& new_record = current_group_[num_records_in_current_group_];
|
||||
auto& new_record = current_group_[num_records_in_current_group_++];
|
||||
new_record.hash = hash;
|
||||
new_record.offset = offset;
|
||||
new_record.next = nullptr;
|
||||
num_records_in_current_group_++;
|
||||
}
|
||||
|
||||
size_t GetNumRecords() {
|
||||
return (groups_.size() - 1) * num_records_per_group_
|
||||
+ num_records_in_current_group_;
|
||||
size_t GetNumRecords() const {
|
||||
return (groups_.size() - 1) * kNumRecordsPerGroup +
|
||||
num_records_in_current_group_;
|
||||
}
|
||||
IndexRecord* At(size_t index) {
|
||||
return &(groups_[index / num_records_per_group_]
|
||||
[index % num_records_per_group_]);
|
||||
return &(groups_[index / kNumRecordsPerGroup][index % kNumRecordsPerGroup]);
|
||||
}
|
||||
|
||||
private:
|
||||
IndexRecord* AllocateNewGroup() {
|
||||
IndexRecord* result = new IndexRecord[num_records_per_group_];
|
||||
IndexRecord* result = new IndexRecord[kNumRecordsPerGroup];
|
||||
groups_.push_back(result);
|
||||
return result;
|
||||
}
|
||||
private:
|
||||
const size_t num_records_per_group_;
|
||||
|
||||
const size_t kNumRecordsPerGroup;
|
||||
IndexRecord* current_group_;
|
||||
// List of arrays allocated
|
||||
std::vector<IndexRecord*> groups_;
|
||||
size_t num_records_in_current_group_;
|
||||
};
|
||||
|
||||
int PlainTableReader::PopulateIndexRecordList(
|
||||
IndexRecordList& record_list) {
|
||||
Slice key_slice;
|
||||
Slice key_prefix_slice;
|
||||
Slice key_suffix_slice;
|
||||
Slice value_slice;
|
||||
int PlainTableReader::PopulateIndexRecordList(IndexRecordList* record_list) {
|
||||
Slice prev_key_prefix_slice;
|
||||
uint32_t prev_key_prefix_hash = 0;
|
||||
uint32_t pos = data_start_offset_;
|
||||
int key_index_within_prefix = 0;
|
||||
bool first = true;
|
||||
std::string prefix_sub_index;
|
||||
bool is_first_record = true;
|
||||
HistogramImpl keys_per_prefix_hist;
|
||||
// Need map to be ordered to make sure sub indexes generated
|
||||
// are in order.
|
||||
|
||||
int num_prefixes = 0;
|
||||
|
||||
while (pos < data_end_offset_) {
|
||||
uint32_t key_offset = pos;
|
||||
Slice key_slice;
|
||||
Slice value_slice;
|
||||
status_ = Next(pos, &key_slice, &value_slice, pos);
|
||||
key_prefix_slice = GetPrefix(key_slice);
|
||||
Slice key_prefix_slice = GetPrefix(key_slice);
|
||||
|
||||
if (first || prev_key_prefix_slice != key_prefix_slice) {
|
||||
num_prefixes++;
|
||||
if (!first) {
|
||||
if (is_first_record || prev_key_prefix_slice != key_prefix_slice) {
|
||||
++num_prefixes;
|
||||
if (!is_first_record) {
|
||||
keys_per_prefix_hist.Add(key_index_within_prefix);
|
||||
}
|
||||
key_index_within_prefix = 0;
|
||||
|
@ -209,12 +229,13 @@ int PlainTableReader::PopulateIndexRecordList(
|
|||
prev_key_prefix_hash = GetSliceHash(key_prefix_slice);
|
||||
}
|
||||
|
||||
if (key_index_within_prefix++ % 16 == 0) {
|
||||
// Add an index key for every 16 keys
|
||||
record_list.AddRecord(prev_key_prefix_hash, key_offset);
|
||||
if (key_index_within_prefix++ % kIndexIntervalForSamePrefixKeys == 0) {
|
||||
// Add an index key for every kIndexIntervalForSamePrefixKeys keys
|
||||
record_list->AddRecord(prev_key_prefix_hash, key_offset);
|
||||
}
|
||||
first = false;
|
||||
is_first_record = false;
|
||||
}
|
||||
|
||||
keys_per_prefix_hist.Add(key_index_within_prefix);
|
||||
Log(options_.info_log, "Number of Keys per prefix Histogram: %s",
|
||||
keys_per_prefix_hist.ToString().c_str());
|
||||
|
@ -222,23 +243,22 @@ int PlainTableReader::PopulateIndexRecordList(
|
|||
return num_prefixes;
|
||||
}
|
||||
|
||||
void PlainTableReader::Allocate(int num_prefixes) {
|
||||
if (hash_table_ != nullptr) {
|
||||
delete[] hash_table_;
|
||||
}
|
||||
if (bloom_bits_per_key_ > 0) {
|
||||
bloom_ = new DynamicBloom(num_prefixes * bloom_bits_per_key_);
|
||||
void PlainTableReader::AllocateIndexAndBloom(int num_prefixes) {
|
||||
delete[] hash_table_;
|
||||
|
||||
if (kBloomBitsPerKey > 0) {
|
||||
bloom_ = new DynamicBloom(num_prefixes * kBloomBitsPerKey);
|
||||
}
|
||||
double hash_table_size_multipier =
|
||||
(hash_table_ratio_ > 1.0) ? 1.0 : 1.0 / hash_table_ratio_;
|
||||
(kHashTableRatio > 1.0) ? 1.0 : 1.0 / kHashTableRatio;
|
||||
hash_table_size_ = num_prefixes * hash_table_size_multipier + 1;
|
||||
hash_table_ = new uint32_t[hash_table_size_];
|
||||
}
|
||||
|
||||
size_t PlainTableReader::BucketizeIndexesAndFillBloom(
|
||||
IndexRecordList& record_list, int num_prefixes,
|
||||
std::vector<IndexRecord*>& hash2offsets,
|
||||
std::vector<uint32_t>& bucket_count) {
|
||||
std::vector<IndexRecord*>* hash_to_offsets,
|
||||
std::vector<uint32_t>* bucket_count) {
|
||||
size_t sub_index_size_needed = 0;
|
||||
bool first = true;
|
||||
uint32_t prev_hash = 0;
|
||||
|
@ -253,32 +273,34 @@ size_t PlainTableReader::BucketizeIndexesAndFillBloom(
|
|||
bloom_->AddHash(cur_hash);
|
||||
}
|
||||
}
|
||||
uint32_t bucket = getBucketIdFromHash(cur_hash, hash_table_size_);
|
||||
IndexRecord* prev_bucket_head = hash2offsets[bucket];
|
||||
uint32_t bucket = GetBucketIdFromHash(cur_hash, hash_table_size_);
|
||||
IndexRecord* prev_bucket_head = (*hash_to_offsets)[bucket];
|
||||
index_record->next = prev_bucket_head;
|
||||
hash2offsets[bucket] = index_record;
|
||||
if (bucket_count[bucket] > 0) {
|
||||
if (bucket_count[bucket] == 1) {
|
||||
(*hash_to_offsets)[bucket] = index_record;
|
||||
auto& item_count = (*bucket_count)[bucket];
|
||||
if (item_count > 0) {
|
||||
if (item_count == 1) {
|
||||
sub_index_size_needed += kOffsetLen + 1;
|
||||
}
|
||||
if (bucket_count[bucket] == 127) {
|
||||
if (item_count == 127) {
|
||||
// Need more than one byte for length
|
||||
sub_index_size_needed++;
|
||||
}
|
||||
sub_index_size_needed += kOffsetLen;
|
||||
}
|
||||
bucket_count[bucket]++;
|
||||
item_count++;
|
||||
}
|
||||
return sub_index_size_needed;
|
||||
}
|
||||
|
||||
void PlainTableReader::FillIndexes(size_t sub_index_size_needed,
|
||||
std::vector<IndexRecord*>& hash2offsets,
|
||||
std::vector<uint32_t>& bucket_count) {
|
||||
void PlainTableReader::FillIndexes(
|
||||
size_t sub_index_size_needed,
|
||||
const std::vector<IndexRecord*>& hash_to_offsets,
|
||||
const std::vector<uint32_t>& bucket_count) {
|
||||
Log(options_.info_log, "Reserving %zu bytes for sub index",
|
||||
sub_index_size_needed);
|
||||
// 4 bytes buffer for variable length size
|
||||
size_t buffer_size = 64;
|
||||
// 8 bytes buffer for variable length size
|
||||
size_t buffer_size = 8 * 8;
|
||||
size_t buffer_used = 0;
|
||||
sub_index_size_needed += buffer_size;
|
||||
sub_index_ = new char[sub_index_size_needed];
|
||||
|
@ -286,7 +308,6 @@ void PlainTableReader::FillIndexes(size_t sub_index_size_needed,
|
|||
char* prev_ptr;
|
||||
char* cur_ptr;
|
||||
uint32_t* sub_index_ptr;
|
||||
IndexRecord* record;
|
||||
for (int i = 0; i < hash_table_size_; i++) {
|
||||
uint32_t num_keys_for_bucket = bucket_count[i];
|
||||
switch (num_keys_for_bucket) {
|
||||
|
@ -296,14 +317,14 @@ void PlainTableReader::FillIndexes(size_t sub_index_size_needed,
|
|||
break;
|
||||
case 1:
|
||||
// point directly to the file offset
|
||||
hash_table_[i] = hash2offsets[i]->offset;
|
||||
hash_table_[i] = hash_to_offsets[i]->offset;
|
||||
break;
|
||||
default:
|
||||
// point to second level indexes.
|
||||
hash_table_[i] = sub_index_offset | kSubIndexMask;
|
||||
prev_ptr = sub_index_ + sub_index_offset;
|
||||
cur_ptr = EncodeVarint32(prev_ptr, num_keys_for_bucket);
|
||||
sub_index_offset += cur_ptr - prev_ptr;
|
||||
sub_index_offset += (cur_ptr - prev_ptr);
|
||||
if (cur_ptr - prev_ptr > 2
|
||||
|| (cur_ptr - prev_ptr == 2 && num_keys_for_bucket <= 127)) {
|
||||
// Need to resize sub_index. Exponentially grow buffer.
|
||||
|
@ -321,10 +342,10 @@ void PlainTableReader::FillIndexes(size_t sub_index_size_needed,
|
|||
}
|
||||
}
|
||||
sub_index_ptr = (uint32_t*) (sub_index_ + sub_index_offset);
|
||||
record = hash2offsets[i];
|
||||
IndexRecord* record = hash_to_offsets[i];
|
||||
int j;
|
||||
for (j = num_keys_for_bucket - 1;
|
||||
j >= 0 && record; j--, record = record->next) {
|
||||
for (j = num_keys_for_bucket - 1; j >= 0 && record;
|
||||
j--, record = record->next) {
|
||||
sub_index_ptr[j] = record->offset;
|
||||
}
|
||||
assert(j == -1 && record == nullptr);
|
||||
|
@ -337,24 +358,6 @@ void PlainTableReader::FillIndexes(size_t sub_index_size_needed,
|
|||
hash_table_size_, sub_index_size_needed);
|
||||
}
|
||||
|
||||
// PopulateIndex() builds index of keys.
|
||||
// hash_table_ contains buckets size of hash_table_size_, each is a 32-bit
|
||||
// integer. The lower 31 bits contain an offset value (explained below) and
|
||||
// the first bit of the integer indicates type of the offset:
|
||||
//
|
||||
// 0 indicates that the bucket contains only one prefix (no conflict when
|
||||
// hashing this prefix), whose first row starts from this offset of the file.
|
||||
// 1 indicates that the bucket contains more than one prefixes, or there
|
||||
// are too many rows for one prefix so we need a binary search for it. In
|
||||
// this case, the offset indicates the offset of sub_index_ holding the
|
||||
// binary search indexes of keys for those rows. Those binary search indexes
|
||||
// are organized in this way:
|
||||
//
|
||||
// The first 4 bytes, indicates how many indexes (N) are stored after it. After
|
||||
// it, there are N 32-bit integers, each points of an offset of the file, which
|
||||
// points to starting of a row. Those offsets need to be guaranteed to be in
|
||||
// ascending order so the keys they are pointing to are also in ascending order
|
||||
// to make sure we can use them to do binary searches.
|
||||
Status PlainTableReader::PopulateIndex() {
|
||||
// Get mmapped memory to file_data_.
|
||||
Status s = file_->Read(0, file_size_, &file_data_, nullptr);
|
||||
|
@ -362,25 +365,24 @@ Status PlainTableReader::PopulateIndex() {
|
|||
return s;
|
||||
}
|
||||
|
||||
IndexRecordList record_list(256);
|
||||
// First, read the whole file, for every 16 rows for a prefix (starting from
|
||||
// the first one), generate a record of (hash, offset) and append it to
|
||||
// IndexRecordList, which is a data structure created to store them.
|
||||
int num_prefixes = PopulateIndexRecordList(record_list);
|
||||
IndexRecordList record_list(kRecordsPerGroup);
|
||||
// First, read the whole file, for every kIndexIntervalForSamePrefixKeys rows
|
||||
// for a prefix (starting from the first one), generate a record of (hash,
|
||||
// offset) and append it to IndexRecordList, which is a data structure created
|
||||
// to store them.
|
||||
int num_prefixes = PopulateIndexRecordList(&record_list);
|
||||
// Calculated hash table and bloom filter size and allocate memory for indexes
|
||||
// and bloom filter based on the number of prefixes.
|
||||
Allocate(num_prefixes);
|
||||
AllocateIndexAndBloom(num_prefixes);
|
||||
|
||||
// Bucketize all the index records to a temp data structure, in which for
|
||||
// each bucket, we generate a linked list of IndexRecord, in reversed order.
|
||||
std::vector<IndexRecord*> hash2offsets(hash_table_size_, nullptr);
|
||||
std::vector<IndexRecord*> hash_to_offsets(hash_table_size_, nullptr);
|
||||
std::vector<uint32_t> bucket_count(hash_table_size_, 0);
|
||||
size_t sub_index_size_needed = BucketizeIndexesAndFillBloom(record_list,
|
||||
num_prefixes,
|
||||
hash2offsets,
|
||||
bucket_count);
|
||||
size_t sub_index_size_needed = BucketizeIndexesAndFillBloom(
|
||||
record_list, num_prefixes, &hash_to_offsets, &bucket_count);
|
||||
// From the temp data structure, populate indexes.
|
||||
FillIndexes(sub_index_size_needed, hash2offsets, bucket_count);
|
||||
FillIndexes(sub_index_size_needed, hash_to_offsets, bucket_count);
|
||||
|
||||
return Status::OK();
|
||||
}
|
||||
|
@ -389,7 +391,7 @@ Status PlainTableReader::GetOffset(const Slice& target, const Slice& prefix,
|
|||
uint32_t prefix_hash, bool& prefix_matched,
|
||||
uint32_t& ret_offset) {
|
||||
prefix_matched = false;
|
||||
int bucket = getBucketIdFromHash(prefix_hash, hash_table_size_);
|
||||
int bucket = GetBucketIdFromHash(prefix_hash, hash_table_size_);
|
||||
uint32_t bucket_value = hash_table_[bucket];
|
||||
if (bucket_value == data_end_offset_) {
|
||||
ret_offset = data_end_offset_;
|
||||
|
|
|
@ -5,6 +5,7 @@
|
|||
#pragma once
|
||||
#include <unordered_map>
|
||||
#include <memory>
|
||||
#include <vector>
|
||||
#include <stdint.h>
|
||||
#include "rocksdb/env.h"
|
||||
#include "rocksdb/iterator.h"
|
||||
|
@ -35,7 +36,7 @@ using std::unordered_map;
|
|||
//
|
||||
// The implementation of IndexedTableReader requires output file is mmaped
|
||||
class PlainTableReader: public TableReader {
|
||||
public:
|
||||
public:
|
||||
static Status Open(const Options& options, const EnvOptions& soptions,
|
||||
unique_ptr<RandomAccessFile> && file, uint64_t file_size,
|
||||
unique_ptr<TableReader>* table, const int bloom_num_bits,
|
||||
|
@ -65,12 +66,12 @@ public:
|
|||
const TableProperties& table_properties);
|
||||
~PlainTableReader();
|
||||
|
||||
private:
|
||||
private:
|
||||
struct IndexRecord;
|
||||
class IndexRecordList;
|
||||
|
||||
uint32_t* hash_table_ = nullptr;
|
||||
int hash_table_size_;
|
||||
int hash_table_size_ = 0;
|
||||
char* sub_index_ = nullptr;
|
||||
|
||||
Options options_;
|
||||
|
@ -82,24 +83,30 @@ private:
|
|||
uint32_t version_;
|
||||
uint32_t file_size_;
|
||||
|
||||
const double hash_table_ratio_;
|
||||
const int bloom_bits_per_key_;
|
||||
DynamicBloom* bloom_;
|
||||
const double kHashTableRatio;
|
||||
const int kBloomBitsPerKey;
|
||||
DynamicBloom* bloom_ = nullptr;
|
||||
|
||||
TableProperties table_properties_;
|
||||
const uint32_t data_start_offset_;
|
||||
const uint32_t data_start_offset_ = 0;
|
||||
const uint32_t data_end_offset_;
|
||||
const size_t user_key_len_;
|
||||
|
||||
static const size_t kNumInternalBytes = 8;
|
||||
static const uint32_t kSubIndexMask = 0x80000000;
|
||||
static const size_t kOffsetLen = sizeof(uint32_t);
|
||||
static const uint64_t kMaxFileSize = 1u << 31;
|
||||
static const size_t kRecordsPerGroup = 256;
|
||||
// To speed up the search for keys with same prefix, we'll add index key for
|
||||
// every N keys, where the "N" is determined by
|
||||
// kIndexIntervalForSamePrefixKeys
|
||||
static const size_t kIndexIntervalForSamePrefixKeys = 16;
|
||||
|
||||
bool IsFixedLength() {
|
||||
bool IsFixedLength() const {
|
||||
return user_key_len_ != PlainTableFactory::kVariableLength;
|
||||
}
|
||||
|
||||
size_t GetFixedInternalKeyLength() {
|
||||
size_t GetFixedInternalKeyLength() const {
|
||||
return user_key_len_ + kNumInternalBytes;
|
||||
}
|
||||
|
||||
|
@ -108,32 +115,67 @@ private:
|
|||
|
||||
// Internal helper function to generate an IndexRecordList object from all
|
||||
// the rows, which contains index records as a list.
|
||||
int PopulateIndexRecordList(IndexRecordList& record_list);
|
||||
int PopulateIndexRecordList(IndexRecordList* record_list);
|
||||
|
||||
// Internal helper function to allocate memory for indexes and bloom filters
|
||||
void Allocate(int num_prefixes);
|
||||
void AllocateIndexAndBloom(int num_prefixes);
|
||||
|
||||
// Internal helper function to bucket index record list to hash buckets.
|
||||
// hash2offsets is sized of of hash_table_size_, each contains a linked list
|
||||
// hash_to_offsets is sized of of hash_table_size_, each contains a linked
|
||||
// list
|
||||
// of offsets for the hash, in reversed order.
|
||||
// bucket_count is sized of hash_table_size_. The value is how many index
|
||||
// records are there in hash2offsets for the same bucket.
|
||||
// records are there in hash_to_offsets for the same bucket.
|
||||
size_t BucketizeIndexesAndFillBloom(
|
||||
IndexRecordList& record_list, int num_prefixes,
|
||||
std::vector<IndexRecord*>& hash2offsets,
|
||||
std::vector<uint32_t>& bucket_count);
|
||||
std::vector<IndexRecord*>* hash_to_offsets,
|
||||
std::vector<uint32_t>* bucket_count);
|
||||
|
||||
// Internal helper class to fill the indexes and bloom filters to internal
|
||||
// data structures. hash2offsets and bucket_count are bucketized indexes and
|
||||
// counts generated by BucketizeIndexesAndFillBloom().
|
||||
// data structures. hash_to_offsets and bucket_count are bucketized indexes
|
||||
// and counts generated by BucketizeIndexesAndFillBloom().
|
||||
void FillIndexes(size_t sub_index_size_needed,
|
||||
std::vector<IndexRecord*>& hash2offsets,
|
||||
std::vector<uint32_t>& bucket_count);
|
||||
const std::vector<IndexRecord*>& hash_to_offsets,
|
||||
const std::vector<uint32_t>& bucket_count);
|
||||
|
||||
// Populate the internal indexes. It must be called before
|
||||
// any query to the table.
|
||||
// This query will populate the hash table hash_table_, the second
|
||||
// level of indexes sub_index_ and bloom filter filter_slice_ if enabled.
|
||||
// PopulateIndex() builds index of keys. It must be called before any query
|
||||
// to the table.
|
||||
//
|
||||
// hash_table_ contains buckets size of hash_table_size_, each is a 32-bit
|
||||
// integer. The lower 31 bits contain an offset value (explained below) and
|
||||
// the first bit of the integer indicates type of the offset.
|
||||
//
|
||||
// +--------------+------------------------------------------------------+
|
||||
// | Flag (1 bit) | Offset to binary search buffer or file (31 bits) +
|
||||
// +--------------+------------------------------------------------------+
|
||||
//
|
||||
// Explanation for the "flag bit":
|
||||
//
|
||||
// 0 indicates that the bucket contains only one prefix (no conflict when
|
||||
// hashing this prefix), whose first row starts from this offset of the
|
||||
// file.
|
||||
// 1 indicates that the bucket contains more than one prefixes, or there
|
||||
// are too many rows for one prefix so we need a binary search for it. In
|
||||
// this case, the offset indicates the offset of sub_index_ holding the
|
||||
// binary search indexes of keys for those rows. Those binary search indexes
|
||||
// are organized in this way:
|
||||
//
|
||||
// The first 4 bytes, indicate how many indexes (N) are stored after it. After
|
||||
// it, there are N 32-bit integers, each points of an offset of the file,
|
||||
// which
|
||||
// points to starting of a row. Those offsets need to be guaranteed to be in
|
||||
// ascending order so the keys they are pointing to are also in ascending
|
||||
// order
|
||||
// to make sure we can use them to do binary searches. Below is visual
|
||||
// presentation of a bucket.
|
||||
//
|
||||
// <begin>
|
||||
// number_of_records: varint32
|
||||
// record 1 file offset: fixedint32
|
||||
// record 2 file offset: fixedint32
|
||||
// ....
|
||||
// record N file offset: fixedint32
|
||||
// <end>
|
||||
Status PopulateIndex();
|
||||
|
||||
// Check bloom filter to see whether it might contain this prefix.
|
||||
|
@ -163,41 +205,4 @@ private:
|
|||
explicit PlainTableReader(const TableReader&) = delete;
|
||||
void operator=(const TableReader&) = delete;
|
||||
};
|
||||
|
||||
// Iterator to iterate IndexedTable
|
||||
class PlainTableIterator: public Iterator {
|
||||
public:
|
||||
explicit PlainTableIterator(PlainTableReader* table);
|
||||
~PlainTableIterator();
|
||||
|
||||
bool Valid() const;
|
||||
|
||||
void SeekToFirst();
|
||||
|
||||
void SeekToLast();
|
||||
|
||||
void Seek(const Slice& target);
|
||||
|
||||
void Next();
|
||||
|
||||
void Prev();
|
||||
|
||||
Slice key() const;
|
||||
|
||||
Slice value() const;
|
||||
|
||||
Status status() const;
|
||||
|
||||
private:
|
||||
PlainTableReader* table_;
|
||||
uint32_t offset_;
|
||||
uint32_t next_offset_;
|
||||
Slice key_;
|
||||
Slice value_;
|
||||
Status status_;
|
||||
// No copying allowed
|
||||
PlainTableIterator(const PlainTableIterator&) = delete;
|
||||
void operator=(const Iterator&) = delete;
|
||||
};
|
||||
|
||||
} // namespace rocksdb
|
||||
|
|
|
@ -874,9 +874,9 @@ static bool Between(uint64_t val, uint64_t low, uint64_t high) {
|
|||
}
|
||||
|
||||
// Tests against all kinds of tables
|
||||
class GeneralTableTest { };
|
||||
class BlockBasedTableTest { };
|
||||
class PlainTableTest { };
|
||||
class GeneralTableTest {};
|
||||
class BlockBasedTableTest {};
|
||||
class PlainTableTest {};
|
||||
|
||||
// This test include all the basic checks except those for index size and block
|
||||
// size, which will be conducted in separated unit tests.
|
||||
|
@ -1184,8 +1184,9 @@ TEST(BlockBasedTableTest, BlockCacheLeak) {
|
|||
Options opt;
|
||||
opt.block_size = 1024;
|
||||
opt.compression = kNoCompression;
|
||||
opt.block_cache = NewLRUCache(16*1024*1024); // big enough so we don't ever
|
||||
// lose cached values.
|
||||
opt.block_cache =
|
||||
NewLRUCache(16 * 1024 * 1024); // big enough so we don't ever
|
||||
// lose cached values.
|
||||
|
||||
TableConstructor c(BytewiseComparator());
|
||||
c.Add("k01", "hello");
|
||||
|
@ -1209,21 +1210,17 @@ TEST(BlockBasedTableTest, BlockCacheLeak) {
|
|||
ASSERT_OK(iter->status());
|
||||
|
||||
ASSERT_OK(c.Reopen(opt));
|
||||
for (const std::string& key: keys) {
|
||||
for (const std::string& key : keys) {
|
||||
ASSERT_TRUE(c.table_reader()->TEST_KeyInCache(ReadOptions(), key));
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
extern const uint64_t kPlainTableMagicNumber;
|
||||
TEST(PlainTableTest, BasicPlainTableProperties) {
|
||||
PlainTableFactory factory(8, 8, 0);
|
||||
StringSink sink;
|
||||
std::unique_ptr<TableBuilder> builder(factory.GetTableBuilder(
|
||||
Options(),
|
||||
&sink,
|
||||
kNoCompression
|
||||
));
|
||||
std::unique_ptr<TableBuilder> builder(
|
||||
factory.GetTableBuilder(Options(), &sink, kNoCompression));
|
||||
|
||||
for (char c = 'a'; c <= 'z'; ++c) {
|
||||
std::string key(16, c);
|
||||
|
@ -1235,14 +1232,9 @@ TEST(PlainTableTest, BasicPlainTableProperties) {
|
|||
StringSource source(sink.contents(), 72242, true);
|
||||
|
||||
TableProperties props;
|
||||
auto s = ReadTableProperties(
|
||||
&source,
|
||||
sink.contents().size(),
|
||||
kPlainTableMagicNumber,
|
||||
Env::Default(),
|
||||
nullptr,
|
||||
&props
|
||||
);
|
||||
auto s = ReadTableProperties(&source, sink.contents().size(),
|
||||
kPlainTableMagicNumber, Env::Default(), nullptr,
|
||||
&props);
|
||||
ASSERT_OK(s);
|
||||
|
||||
ASSERT_EQ(0ul, props.index_size);
|
||||
|
@ -1253,7 +1245,6 @@ TEST(PlainTableTest, BasicPlainTableProperties) {
|
|||
ASSERT_EQ(1ul, props.num_data_blocks);
|
||||
}
|
||||
|
||||
|
||||
TEST(GeneralTableTest, ApproximateOffsetOfPlain) {
|
||||
TableConstructor c(BytewiseComparator());
|
||||
c.Add("k01", "hello");
|
||||
|
|
Loading…
Reference in New Issue