NextGraph
/
rocksdb
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

remove malloc when create data and index iterator in Get

Browse Source 
Summary:
  Define Block::Iter to be an independent class to be used by block_based_table_reader
  When creating data and index iterator, update an existing iterator rather than new one
  Thus malloc and free could be reduced

Benchmark,
Base:
commit 76286ee67e
commands:
--db=/dev/shm/rocksdb --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --write_buffer_size=134217728 --max_write_buffer_number=2 --target_file_size_base=33554432 --max_bytes_for_level_base=1073741824 --verify_checksum=false --max_background_compactions=4 --use_plain_table=0 --memtablerep=prefix_hash --open_files=-1 --mmap_read=1 --mmap_write=0 --bloom_bits=10 --bloom_locality=1 --memtable_bloom_bits=500000 --compression_type=lz4 --num=2621440 --use_hash_search=1 --block_size=1024 --block_restart_interval=1 --use_existing_db=1 --threads=1 --benchmarks=readrandom —disable_auto_compactions=1

malloc: 3.30% -> 1.42%
free: 3.59%->1.61%

Test Plan:
  make all check
  run db_stress
  valgrind ./db_test ./table_test

Reviewers: ljin, yhchiang, dhruba, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20655
main
Feng Zhu 11 years ago
parent 76286ee67e
commit 8f09d53fd1
4 changed files with 416 additions and 291 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 475
      table/block.cc
  2. 128
      table/block.h
  3. 94
      table/block_based_table_reader.cc
  4. 10
      table/block_based_table_reader.h

475
table/block.cc
Unescape View File

@ -17,44 +17,14 @@
#include <vector>
#include "rocksdb/comparator.h"
#include "table/format.h"
#include "table/block_hash_index.h"
#include "table/block_prefix_index.h"
#include "table/format.h"
#include "util/coding.h"
#include "util/logging.h"
#include "db/dbformat.h"
namespace rocksdb {
uint32_t Block::NumRestarts() const {
assert(size_ >= 2*sizeof(uint32_t));
return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
}
Block::Block(const BlockContents& contents)
: data_(contents.data.data()),
size_(contents.data.size()),
owned_(contents.heap_allocated),
cachable_(contents.cachable),
compression_type_(contents.compression_type) {
if (size_ < sizeof(uint32_t)) {
size_ = 0; // Error marker
} else {
restart_offset_ = size_ - (1 + NumRestarts()) * sizeof(uint32_t);
if (restart_offset_ > size_ - sizeof(uint32_t)) {
// The size is too small for NumRestarts() and therefore
// restart_offset_ wrapped around.
size_ = 0;
}
}
}
Block::~Block() {
if (owned_) {
delete[] data_;
}
}
// Helper routine: decode the next block entry starting at "p",
// storing the number of shared key bytes, non_shared key bytes,
// and the length of the value in "*shared", "*non_shared", and
@ -85,142 +55,85 @@ static inline const char* DecodeEntry(const char* p, const char* limit,
return p;
}
class Block::Iter : public Iterator {
private:
const Comparator* const comparator_;
const char* const data_; // underlying block contents
uint32_t const restarts_; // Offset of restart array (list of fixed32)
uint32_t const num_restarts_; // Number of uint32_t entries in restart array
// current_ is offset in data_ of current entry. >= restarts_ if !Valid
uint32_t current_;
uint32_t restart_index_; // Index of restart block in which current_ falls
IterKey key_;
Slice value_;
Status status_;
BlockHashIndex* hash_index_;
BlockPrefixIndex* prefix_index_;
inline int Compare(const Slice& a, const Slice& b) const {
return comparator_->Compare(a, b);
}
// Return the offset in data_ just past the end of the current entry.
inline uint32_t NextEntryOffset() const {
return (value_.data() + value_.size()) - data_;
}
uint32_t GetRestartPoint(uint32_t index) {
assert(index < num_restarts_);
return DecodeFixed32(data_ + restarts_ + index * sizeof(uint32_t));
}
void BlockIter::Next() {
assert(Valid());
ParseNextKey();
}
void SeekToRestartPoint(uint32_t index) {
key_.Clear();
restart_index_ = index;
// current_ will be fixed by ParseNextKey();
void BlockIter::Prev() {
assert(Valid());
// ParseNextKey() starts at the end of value_, so set value_ accordingly
uint32_t offset = GetRestartPoint(index);
value_ = Slice(data_ + offset, 0);
// Scan backwards to a restart point before current_
const uint32_t original = current_;
while (GetRestartPoint(restart_index_) >= original) {
if (restart_index_ == 0) {
// No more entries
current_ = restarts_;
restart_index_ = num_restarts_;
return;
}
restart_index_--;
}
public:
Iter(const Comparator* comparator, const char* data, uint32_t restarts,
uint32_t num_restarts, BlockHashIndex* hash_index,
BlockPrefixIndex* prefix_index)
: comparator_(comparator),
data_(data),
restarts_(restarts),
num_restarts_(num_restarts),
current_(restarts_),
restart_index_(num_restarts_),
hash_index_(hash_index),
prefix_index_(prefix_index) {
assert(num_restarts_ > 0);
}
SeekToRestartPoint(restart_index_);
do {
// Loop until end of current entry hits the start of original entry
} while (ParseNextKey() && NextEntryOffset() < original);
}
virtual bool Valid() const { return current_ < restarts_; }
virtual Status status() const { return status_; }
virtual Slice key() const {
assert(Valid());
return key_.GetKey();
void BlockIter::Seek(const Slice& target) {
if (data_ == nullptr) { // Not init yet
return;
}
virtual Slice value() const {
assert(Valid());
return value_;
}
virtual void Next() {
assert(Valid());
ParseNextKey();
uint32_t index = 0;
bool ok = false;
if (prefix_index_) {
ok = PrefixSeek(target, &index);
} else {
ok = hash_index_ ? HashSeek(target, &index)
: BinarySeek(target, 0, num_restarts_ - 1, &index);
}
virtual void Prev() {
assert(Valid());
// Scan backwards to a restart point before current_
const uint32_t original = current_;
while (GetRestartPoint(restart_index_) >= original) {
if (restart_index_ == 0) {
// No more entries
current_ = restarts_;
restart_index_ = num_restarts_;
return;
}
restart_index_--;
}
SeekToRestartPoint(restart_index_);
do {
// Loop until end of current entry hits the start of original entry
} while (ParseNextKey() && NextEntryOffset() < original);
if (!ok) {
return;
}
SeekToRestartPoint(index);
// Linear search (within restart block) for first key >= target
virtual void Seek(const Slice& target) {
uint32_t index = 0;
bool ok = false;
if (prefix_index_) {
ok = PrefixSeek(target, &index);
} else {
ok = hash_index_ ? HashSeek(target, &index)
: BinarySeek(target, 0, num_restarts_ - 1, &index);
}
if (!ok) {
while (true) {
if (!ParseNextKey() || Compare(key_.GetKey(), target) >= 0) {
return;
}
SeekToRestartPoint(index);
// Linear search (within restart block) for first key >= target
while (true) {
if (!ParseNextKey() || Compare(key_.GetKey(), target) >= 0) {
return;
}
}
}
virtual void SeekToFirst() {
SeekToRestartPoint(0);
ParseNextKey();
}
}
virtual void SeekToLast() {
SeekToRestartPoint(num_restarts_ - 1);
while (ParseNextKey() && NextEntryOffset() < restarts_) {
// Keep skipping
}
void BlockIter::SeekToFirst() {
if (data_ == nullptr) { // Not init yet
return;
}
SeekToRestartPoint(0);
ParseNextKey();
}
private:
void CorruptionError() {
current_ = restarts_;
restart_index_ = num_restarts_;
status_ = Status::Corruption("bad entry in block");
key_.Clear();
value_.clear();
void BlockIter::SeekToLast() {
if (data_ == nullptr) { // Not init yet
return;
}
SeekToRestartPoint(num_restarts_ - 1);
while (ParseNextKey() && NextEntryOffset() < restarts_) {
// Keep skipping
}
}
void BlockIter::CorruptionError() {
current_ = restarts_;
restart_index_ = num_restarts_;
status_ = Status::Corruption("bad entry in block");
key_.Clear();
value_.clear();
}
bool ParseNextKey() {
bool BlockIter::ParseNextKey() {
current_ = NextEntryOffset();
const char* p = data_ + current_;
const char* limit = data_ + restarts_; // Restarts come right after data
@ -248,150 +161,194 @@ class Block::Iter : public Iterator {
}
}
// Binary search in restart array to find the first restart point
// with a key >= target (TODO: this comment is inaccurate)
bool BinarySeek(const Slice& target, uint32_t left, uint32_t right,
// Binary search in restart array to find the first restart point
// with a key >= target (TODO: this comment is inaccurate)
bool BlockIter::BinarySeek(const Slice& target, uint32_t left, uint32_t right,
uint32_t* index) {
assert(left <= right);
while (left < right) {
uint32_t mid = (left + right + 1) / 2;
uint32_t region_offset = GetRestartPoint(mid);
uint32_t shared, non_shared, value_length;
const char* key_ptr =
DecodeEntry(data_ + region_offset, data_ + restarts_, &shared,
&non_shared, &value_length);
if (key_ptr == nullptr || (shared != 0)) {
CorruptionError();
return false;
}
Slice mid_key(key_ptr, non_shared);
int cmp = Compare(mid_key, target);
if (cmp < 0) {
// Key at "mid" is smaller than "target". Therefore all
// blocks before "mid" are uninteresting.
left = mid;
} else if (cmp > 0) {
// Key at "mid" is >= "target". Therefore all blocks at or
// after "mid" are uninteresting.
right = mid - 1;
} else {
left = right = mid;
}
}
assert(left <= right);
*index = left;
return true;
}
// Compare target key and the block key of the block of `block_index`.
// Return -1 if error.
int CompareBlockKey(uint32_t block_index, const Slice& target) {
uint32_t region_offset = GetRestartPoint(block_index);
while (left < right) {
uint32_t mid = (left + right + 1) / 2;
uint32_t region_offset = GetRestartPoint(mid);
uint32_t shared, non_shared, value_length;
const char* key_ptr = DecodeEntry(data_ + region_offset, data_ + restarts_,
&shared, &non_shared, &value_length);
const char* key_ptr =
DecodeEntry(data_ + region_offset, data_ + restarts_, &shared,
&non_shared, &value_length);
if (key_ptr == nullptr || (shared != 0)) {
CorruptionError();
return 1; // Return target is smaller
return false;
}
Slice mid_key(key_ptr, non_shared);
int cmp = Compare(mid_key, target);
if (cmp < 0) {
// Key at "mid" is smaller than "target". Therefore all
// blocks before "mid" are uninteresting.
left = mid;
} else if (cmp > 0) {
// Key at "mid" is >= "target". Therefore all blocks at or
// after "mid" are uninteresting.
right = mid - 1;
} else {
left = right = mid;
}
Slice block_key(key_ptr, non_shared);
return Compare(block_key, target);
}
// Binary search in block_ids to find the first block
// with a key >= target
bool BinaryBlockIndexSeek(const Slice& target, uint32_t* block_ids,
uint32_t left, uint32_t right,
uint32_t* index) {
assert(left <= right);
uint32_t left_bound = left;
*index = left;
return true;
}
while (left <= right) {
uint32_t mid = (left + right) / 2;
// Compare target key and the block key of the block of `block_index`.
// Return -1 if error.
int BlockIter::CompareBlockKey(uint32_t block_index, const Slice& target) {
uint32_t region_offset = GetRestartPoint(block_index);
uint32_t shared, non_shared, value_length;
const char* key_ptr = DecodeEntry(data_ + region_offset, data_ + restarts_,
&shared, &non_shared, &value_length);
if (key_ptr == nullptr || (shared != 0)) {
CorruptionError();
return 1; // Return target is smaller
}
Slice block_key(key_ptr, non_shared);
return Compare(block_key, target);
}
int cmp = CompareBlockKey(block_ids[mid], target);
if (!status_.ok()) {
return false;
}
if (cmp < 0) {
// Key at "target" is larger than "mid". Therefore all
// blocks before or at "mid" are uninteresting.
left = mid + 1;
} else {
// Key at "target" is <= "mid". Therefore all blocks
// after "mid" are uninteresting.
// If there is only one block left, we found it.
if (left == right) break;
right = mid;
}
}
// Binary search in block_ids to find the first block
// with a key >= target
bool BlockIter::BinaryBlockIndexSeek(const Slice& target, uint32_t* block_ids,
uint32_t left, uint32_t right,
uint32_t* index) {
assert(left <= right);
uint32_t left_bound = left;
if (left == right) {
// In one of the two following cases:
// (1) left is the first one of block_ids
// (2) there is a gap of blocks between block of `left` and `left-1`.
// we can further distinguish the case of key in the block or key not
// existing, by comparing the target key and the key of the previous
// block to the left of the block found.
if (block_ids[left] > 0 &&
(left == left_bound || block_ids[left - 1] != block_ids[left] - 1) &&
CompareBlockKey(block_ids[left] - 1, target) > 0) {
current_ = restarts_;
return false;
}
while (left <= right) {
uint32_t mid = (left + right) / 2;
*index = block_ids[left];
return true;
} else {
assert(left > right);
// Mark iterator invalid
current_ = restarts_;
int cmp = CompareBlockKey(block_ids[mid], target);
if (!status_.ok()) {
return false;
}
if (cmp < 0) {
// Key at "target" is larger than "mid". Therefore all
// blocks before or at "mid" are uninteresting.
left = mid + 1;
} else {
// Key at "target" is <= "mid". Therefore all blocks
// after "mid" are uninteresting.
// If there is only one block left, we found it.
if (left == right) break;
right = mid;
}
}
bool HashSeek(const Slice& target, uint32_t* index) {
assert(hash_index_);
auto restart_index = hash_index_->GetRestartIndex(target);
if (restart_index == nullptr) {
if (left == right) {
// In one of the two following cases:
// (1) left is the first one of block_ids
// (2) there is a gap of blocks between block of `left` and `left-1`.
// we can further distinguish the case of key in the block or key not
// existing, by comparing the target key and the key of the previous
// block to the left of the block found.
if (block_ids[left] > 0 &&
(left == left_bound || block_ids[left - 1] != block_ids[left] - 1) &&
CompareBlockKey(block_ids[left] - 1, target) > 0) {
current_ = restarts_;
return false;
}
// the elements in restart_array[index : index + num_blocks]
// are all with same prefix. We'll do binary search in that small range.
auto left = restart_index->first_index;
auto right = restart_index->first_index + restart_index->num_blocks - 1;
return BinarySeek(target, left, right, index);
*index = block_ids[left];
return true;
} else {
assert(left > right);
// Mark iterator invalid
current_ = restarts_;
return false;
}
}
bool BlockIter::HashSeek(const Slice& target, uint32_t* index) {
assert(hash_index_);
auto restart_index = hash_index_->GetRestartIndex(target);
if (restart_index == nullptr) {
current_ = restarts_;
return false;
}
bool PrefixSeek(const Slice& target, uint32_t* index) {
assert(prefix_index_);
uint32_t* block_ids = nullptr;
uint32_t num_blocks = prefix_index_->GetBlocks(target, &block_ids);
// the elements in restart_array[index : index + num_blocks]
// are all with same prefix. We'll do binary search in that small range.
auto left = restart_index->first_index;
auto right = restart_index->first_index + restart_index->num_blocks - 1;
return BinarySeek(target, left, right, index);
}
bool BlockIter::PrefixSeek(const Slice& target, uint32_t* index) {
assert(prefix_index_);
uint32_t* block_ids = nullptr;
uint32_t num_blocks = prefix_index_->GetBlocks(target, &block_ids);
if (num_blocks == 0) {
current_ = restarts_;
return false;
} else {
return BinaryBlockIndexSeek(target, block_ids, 0, num_blocks - 1, index);
if (num_blocks == 0) {
current_ = restarts_;
return false;
} else {
return BinaryBlockIndexSeek(target, block_ids, 0, num_blocks - 1, index);
}
}
uint32_t Block::NumRestarts() const {
assert(size_ >= 2*sizeof(uint32_t));
return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
}
Block::Block(const BlockContents& contents)
: data_(contents.data.data()),
size_(contents.data.size()),
owned_(contents.heap_allocated),
cachable_(contents.cachable),
compression_type_(contents.compression_type) {
if (size_ < sizeof(uint32_t)) {
size_ = 0; // Error marker
} else {
restart_offset_ = size_ - (1 + NumRestarts()) * sizeof(uint32_t);
if (restart_offset_ > size_ - sizeof(uint32_t)) {
// The size is too small for NumRestarts() and therefore
// restart_offset_ wrapped around.
size_ = 0;
}
}
};
}
Block::~Block() {
if (owned_) {
delete[] data_;
}
}
Iterator* Block::NewIterator(const Comparator* cmp) {
Iterator* Block::NewIterator(const Comparator* cmp, BlockIter* iter) {
if (size_ < 2*sizeof(uint32_t)) {
return NewErrorIterator(Status::Corruption("bad block contents"));
if (iter != nullptr) {
iter->SetStatus(Status::Corruption("bad block contents"));
return iter;
} else {
return NewErrorIterator(Status::Corruption("bad block contents"));
}
}
const uint32_t num_restarts = NumRestarts();
if (num_restarts == 0) {
return NewEmptyIterator();
if (iter != nullptr) {
iter->SetStatus(Status::OK());
return iter;
} else {
return NewEmptyIterator();
}
} else {
return new Iter(cmp, data_, restart_offset_, num_restarts,
if (iter != nullptr) {
iter->Initialize(cmp, data_, restart_offset_, num_restarts,
hash_index_.get(), prefix_index_.get());
} else {
iter = new BlockIter(cmp, data_, restart_offset_, num_restarts,
hash_index_.get(), prefix_index_.get());
}
}
return iter;
}
void Block::SetBlockHashIndex(BlockHashIndex* hash_index) {

128
table/block.h
Unescape View File

@ -13,11 +13,13 @@
#include "rocksdb/iterator.h"
#include "rocksdb/options.h"
#include "db/dbformat.h"
namespace rocksdb {
struct BlockContents;
class Comparator;
class BlockIter;
class BlockHashIndex;
class BlockPrefixIndex;
@ -40,7 +42,11 @@ class Block {
// NOTE: for the hash based lookup, if a key prefix doesn't match any key,
// the iterator will simply be set as "invalid", rather than returning
// the key that is just pass the target key.
Iterator* NewIterator(const Comparator* comparator);
//
// If iter is null, return new Iterator
// If iter is not null, update this one and return it as Iterator*
Iterator* NewIterator(const Comparator* comparator,
BlockIter* iter = nullptr);
void SetBlockHashIndex(BlockHashIndex* hash_index);
void SetBlockPrefixIndex(BlockPrefixIndex* prefix_index);
@ -57,8 +63,126 @@ class Block {
// No copying allowed
Block(const Block&);
void operator=(const Block&);
};
class BlockIter : public Iterator {
public:
BlockIter()
: comparator_(nullptr),
data_(nullptr),
restarts_(0),
num_restarts_(0),
current_(0),
restart_index_(0),
status_(Status::OK()),
hash_index_(nullptr),
prefix_index_(nullptr) {}
BlockIter(const Comparator* comparator, const char* data, uint32_t restarts,
uint32_t num_restarts, BlockHashIndex* hash_index,
BlockPrefixIndex* prefix_index)
: BlockIter() {
Initialize(comparator, data, restarts, num_restarts,
hash_index, prefix_index);
}
void Initialize(const Comparator* comparator, const char* data,
uint32_t restarts, uint32_t num_restarts, BlockHashIndex* hash_index,
BlockPrefixIndex* prefix_index) {
assert(data_ == nullptr); // Ensure it is called only once
assert(num_restarts > 0); // Ensure the param is valid
comparator_ = comparator;
data_ = data;
restarts_ = restarts;
num_restarts_ = num_restarts;
current_ = restarts_;
restart_index_ = num_restarts_;
hash_index_ = hash_index;
prefix_index_ = prefix_index;
}
void SetStatus(Status s) {
status_ = s;
}
virtual bool Valid() const override { return current_ < restarts_; }
virtual Status status() const override { return status_; }
virtual Slice key() const override {
assert(Valid());
return key_.GetKey();
}
virtual Slice value() const override {
assert(Valid());
return value_;
}
virtual void Next() override;
virtual void Prev() override;
virtual void Seek(const Slice& target) override;
virtual void SeekToFirst() override;
virtual void SeekToLast() override;
private:
const Comparator* comparator_;
const char* data_; // underlying block contents
uint32_t restarts_; // Offset of restart array (list of fixed32)
uint32_t num_restarts_; // Number of uint32_t entries in restart array
// current_ is offset in data_ of current entry. >= restarts_ if !Valid
uint32_t current_;
uint32_t restart_index_; // Index of restart block in which current_ falls
IterKey key_;
Slice value_;
Status status_;
BlockHashIndex* hash_index_;
BlockPrefixIndex* prefix_index_;
inline int Compare(const Slice& a, const Slice& b) const {
return comparator_->Compare(a, b);
}
// Return the offset in data_ just past the end of the current entry.
inline uint32_t NextEntryOffset() const {
return (value_.data() + value_.size()) - data_;
}
uint32_t GetRestartPoint(uint32_t index) {
assert(index < num_restarts_);
return DecodeFixed32(data_ + restarts_ + index * sizeof(uint32_t));
}
void SeekToRestartPoint(uint32_t index) {
key_.Clear();
restart_index_ = index;
// current_ will be fixed by ParseNextKey();
// ParseNextKey() starts at the end of value_, so set value_ accordingly
uint32_t offset = GetRestartPoint(index);
value_ = Slice(data_ + offset, 0);
}
void CorruptionError();
bool ParseNextKey();
bool BinarySeek(const Slice& target, uint32_t left, uint32_t right,
uint32_t* index);
int CompareBlockKey(uint32_t block_index, const Slice& target);
bool BinaryBlockIndexSeek(const Slice& target, uint32_t* block_ids,
uint32_t left, uint32_t right,
uint32_t* index);
bool HashSeek(const Slice& target, uint32_t* index);
bool PrefixSeek(const Slice& target, uint32_t* index);
class Iter;
};
} // namespace rocksdb

94
table/block_based_table_reader.cc
Unescape View File

@ -135,7 +135,9 @@ class BlockBasedTable::IndexReader {
virtual ~IndexReader() {}
// Create an iterator for index access.
virtual Iterator* NewIterator() = 0;
// An iter is passed in, if it is not null, update this one and return it
// If it is null, create a new Iterator
virtual Iterator* NewIterator(BlockIter* iter = nullptr) = 0;
// The size of the index.
virtual size_t size() const = 0;
@ -168,8 +170,8 @@ class BinarySearchIndexReader : public IndexReader {
return s;
}
virtual Iterator* NewIterator() override {
return index_block_->NewIterator(comparator_);
virtual Iterator* NewIterator(BlockIter* iter = nullptr) override {
return index_block_->NewIterator(comparator_, iter);
}
virtual size_t size() const override { return index_block_->size(); }
@ -284,8 +286,8 @@ class HashIndexReader : public IndexReader {
return Status::OK();
}
virtual Iterator* NewIterator() override {
return index_block_->NewIterator(comparator_);
virtual Iterator* NewIterator(BlockIter* iter = nullptr) override {
return index_block_->NewIterator(comparator_, iter);
}
virtual size_t size() const override { return index_block_->size(); }
@ -779,10 +781,11 @@ BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
return { filter, cache_handle };
}
Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options,
BlockIter* input_iter) {
// index reader has already been pre-populated.
if (rep_->index_reader) {
return rep_->index_reader->NewIterator();
return rep_->index_reader->NewIterator(input_iter);
}
bool no_io = read_options.read_tier == kBlockCacheTier;
@ -796,7 +799,12 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
BLOCK_CACHE_INDEX_HIT, statistics);
if (cache_handle == nullptr && no_io) {
return NewErrorIterator(Status::Incomplete("no blocking io"));
if (input_iter != nullptr) {
input_iter->SetStatus(Status::Incomplete("no blocking io"));
return input_iter;
} else {
return NewErrorIterator(Status::Incomplete("no blocking io"));
}
}
IndexReader* index_reader = nullptr;
@ -811,7 +819,12 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
if (!s.ok()) {
// make sure if something goes wrong, index_reader shall remain intact.
assert(index_reader == nullptr);
return NewErrorIterator(s);
if (input_iter != nullptr) {
input_iter->SetStatus(s);
return input_iter;
} else {
return NewErrorIterator(s);
}
}
cache_handle = block_cache->Insert(key, index_reader, index_reader->size(),
@ -820,7 +833,8 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
}
assert(cache_handle);
auto iter = index_reader->NewIterator();
Iterator* iter;
iter = index_reader->NewIterator(input_iter);
iter->RegisterCleanup(&ReleaseCachedEntry, block_cache, cache_handle);
return iter;
@ -828,8 +842,11 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
// Convert an index iterator value (i.e., an encoded BlockHandle)
// into an iterator over the contents of the corresponding block.
// If input_iter is null, new a iterator
// If input_iter is not null, update this iter and return it
Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
const ReadOptions& ro, const Slice& index_value) {
const ReadOptions& ro, const Slice& index_value,
BlockIter* input_iter) {
const bool no_io = (ro.read_tier == kBlockCacheTier);
Cache* block_cache = rep->options.block_cache.get();
Cache* block_cache_compressed = rep->options.
@ -843,7 +860,12 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
Status s = handle.DecodeFrom(&input);
if (!s.ok()) {
return NewErrorIterator(s);
if (input_iter != nullptr) {
input_iter->SetStatus(s);
return input_iter;
} else {
return NewErrorIterator(s);
}
}
// If either block cache is enabled, we'll try to read from it.
@ -889,7 +911,12 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
if (block.value == nullptr) {
if (no_io) {
// Could not read from block_cache and can't do IO
return NewErrorIterator(Status::Incomplete("no blocking io"));
if (input_iter != nullptr) {
input_iter->SetStatus(Status::Incomplete("no blocking io"));
return input_iter;
} else {
return NewErrorIterator(Status::Incomplete("no blocking io"));
}
}
s = ReadBlockFromFile(rep->file.get(), rep->footer, ro, handle,
&block.value, rep->options.env);
@ -897,15 +924,20 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
Iterator* iter;
if (block.value != nullptr) {
iter = block.value->NewIterator(&rep->internal_comparator);
iter = block.value->NewIterator(&rep->internal_comparator, input_iter);
if (block.cache_handle != nullptr) {
iter->RegisterCleanup(&ReleaseCachedEntry, block_cache,
block.cache_handle);
block.cache_handle);
} else {
iter->RegisterCleanup(&DeleteHeldResource<Block>, block.value, nullptr);
}
} else {
iter = NewErrorIterator(s);
if (input_iter != nullptr) {
input_iter->SetStatus(s);
iter = input_iter;
} else {
iter = NewErrorIterator(s);
}
}
return iter;
}
@ -1023,12 +1055,14 @@ Status BlockBasedTable::Get(
const Slice& v),
void (*mark_key_may_exist_handler)(void* handle_context)) {
Status s;
Iterator* iiter = NewIndexIterator(read_options);
BlockIter iiter;
NewIndexIterator(read_options, &iiter);
auto filter_entry = GetFilter(read_options.read_tier == kBlockCacheTier);
FilterBlockReader* filter = filter_entry.value;
bool done = false;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
Slice handle_value = iiter->value();
for (iiter.Seek(key); iiter.Valid() && !done; iiter.Next()) {
Slice handle_value = iiter.value();
BlockHandle handle;
bool may_not_exist_in_filter =
@ -1043,39 +1077,43 @@ Status BlockBasedTable::Get(
RecordTick(rep_->options.statistics.get(), BLOOM_FILTER_USEFUL);
break;
} else {
unique_ptr<Iterator> block_iter(
NewDataBlockIterator(rep_, read_options, iiter->value()));
BlockIter biter;
NewDataBlockIterator(rep_, read_options, iiter.value(), &biter);
if (read_options.read_tier && block_iter->status().IsIncomplete()) {
if (read_options.read_tier && biter.status().IsIncomplete()) {
// couldn't get block from block_cache
// Update Saver.state to Found because we are only looking for whether
// we can guarantee the key is not there when "no_io" is set
(*mark_key_may_exist_handler)(handle_context);
break;
}
if (!biter.status().ok()) {
s = biter.status();
break;
}
// Call the *saver function on each entry/block until it returns false
for (block_iter->Seek(key); block_iter->Valid(); block_iter->Next()) {
for (biter.Seek(key); biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(block_iter->key(), &parsed_key)) {
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!(*result_handler)(handle_context, parsed_key,
block_iter->value())) {
biter.value())) {
done = true;
break;
}
}
s = block_iter->status();
s = biter.status();
}
}
filter_entry.Release(rep_->options.block_cache.get());
if (s.ok()) {
s = iiter->status();
s = iiter.status();
}
delete iiter;
return s;
}

10
table/block_based_table_reader.h
Unescape View File

@ -23,6 +23,7 @@
namespace rocksdb {
class Block;
class BlockIter;
class BlockHandle;
class Cache;
class FilterBlockReader;
@ -111,8 +112,10 @@ class BlockBasedTable : public TableReader {
bool compaction_optimized_;
class BlockEntryIteratorState;
// input_iter: if it is not null, update this one and return it as Iterator
static Iterator* NewDataBlockIterator(Rep* rep, const ReadOptions& ro,
const Slice& index_value);
const Slice& index_value,
BlockIter* input_iter = nullptr);
// For the following two functions:
// if `no_io == true`, we will not try to read filter/index from sst file
@ -120,6 +123,8 @@ class BlockBasedTable : public TableReader {
CachableEntry<FilterBlockReader> GetFilter(bool no_io = false) const;
// Get the iterator from the index reader.
// If input_iter is not set, return new Iterator
// If input_iter is set, update it and return it as Iterator
//
// Note: ErrorIterator with Status::Incomplete shall be returned if all the
// following conditions are met:
@ -127,7 +132,8 @@ class BlockBasedTable : public TableReader {
// 2. index is not present in block cache.
// 3. We disallowed any io to be performed, that is, read_options ==
// kBlockCacheTier
Iterator* NewIndexIterator(const ReadOptions& read_options);
Iterator* NewIndexIterator(const ReadOptions& read_options,
BlockIter* input_iter = nullptr);
// Read block cache from block caches (if set): block_cache and
// block_cache_compressed.

Write Preview
Loading…
Cancel
Save