Merge branch 'master' of https://github.com/facebook/rocksdb
commit
08314321fa
@ -0,0 +1,383 @@ |
||||
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
|
||||
// This source code is licensed under the BSD-style license found in the
|
||||
// LICENSE file in the root directory of this source tree. An additional grant
|
||||
// of patent rights can be found in the PATENTS file in the same directory.
|
||||
|
||||
#ifndef ROCKSDB_LITE |
||||
#include "db/forward_iterator.h" |
||||
|
||||
#include <string> |
||||
#include <utility> |
||||
#include <limits> |
||||
#include "db/db_impl.h" |
||||
#include "db/db_iter.h" |
||||
#include "db/column_family.h" |
||||
#include "rocksdb/env.h" |
||||
#include "rocksdb/slice.h" |
||||
#include "rocksdb/slice_transform.h" |
||||
#include "table/merger.h" |
||||
#include "db/dbformat.h" |
||||
|
||||
namespace rocksdb { |
||||
|
||||
// Usage:
|
||||
// LevelIterator iter;
|
||||
// iter.SetFileIndex(file_index);
|
||||
// iter.Seek(target);
|
||||
// iter.Next()
|
||||
class LevelIterator : public Iterator { |
||||
public: |
||||
LevelIterator(const ColumnFamilyData* const cfd, |
||||
const ReadOptions& read_options, |
||||
const std::vector<FileMetaData*>& files) |
||||
: cfd_(cfd), read_options_(read_options), files_(files), valid_(false), |
||||
file_index_(std::numeric_limits<uint32_t>::max()) {} |
||||
|
||||
void SetFileIndex(uint32_t file_index) { |
||||
assert(file_index < files_.size()); |
||||
if (file_index != file_index_) { |
||||
file_index_ = file_index; |
||||
file_iter_.reset(cfd_->table_cache()->NewIterator( |
||||
read_options_, *(cfd_->soptions()), cfd_->internal_comparator(), |
||||
*(files_[file_index_]), nullptr /* table_reader_ptr */, false)); |
||||
} |
||||
valid_ = false; |
||||
} |
||||
void SeekToLast() override { |
||||
status_ = Status::NotSupported("LevelIterator::SeekToLast()"); |
||||
valid_ = false; |
||||
} |
||||
void Prev() { |
||||
status_ = Status::NotSupported("LevelIterator::Prev()"); |
||||
valid_ = false; |
||||
} |
||||
bool Valid() const override { |
||||
return valid_; |
||||
} |
||||
void SeekToFirst() override { |
||||
SetFileIndex(0); |
||||
file_iter_->SeekToFirst(); |
||||
valid_ = file_iter_->Valid(); |
||||
} |
||||
void Seek(const Slice& internal_key) override { |
||||
assert(file_iter_ != nullptr); |
||||
file_iter_->Seek(internal_key); |
||||
valid_ = file_iter_->Valid(); |
||||
assert(valid_); |
||||
} |
||||
void Next() override { |
||||
assert(valid_); |
||||
file_iter_->Next(); |
||||
while (!file_iter_->Valid()) { |
||||
if (file_index_ + 1 >= files_.size()) { |
||||
valid_ = false; |
||||
return; |
||||
} |
||||
SetFileIndex(file_index_ + 1); |
||||
file_iter_->SeekToFirst(); |
||||
} |
||||
valid_ = file_iter_->Valid(); |
||||
} |
||||
Slice key() const override { |
||||
assert(valid_); |
||||
return file_iter_->key(); |
||||
} |
||||
Slice value() const override { |
||||
assert(valid_); |
||||
return file_iter_->value(); |
||||
} |
||||
Status status() const override { |
||||
return status_; |
||||
} |
||||
|
||||
private: |
||||
const ColumnFamilyData* const cfd_; |
||||
const ReadOptions& read_options_; |
||||
const std::vector<FileMetaData*>& files_; |
||||
|
||||
bool valid_; |
||||
uint32_t file_index_; |
||||
Status status_; |
||||
std::unique_ptr<Iterator> file_iter_; |
||||
}; |
||||
|
||||
ForwardIterator::ForwardIterator(DBImpl* db, const ReadOptions& read_options, |
||||
ColumnFamilyData* cfd) |
||||
: db_(db), |
||||
read_options_(read_options), |
||||
cfd_(cfd), |
||||
prefix_extractor_(cfd->options()->prefix_extractor.get()), |
||||
user_comparator_(cfd->user_comparator()), |
||||
immutable_min_heap_(MinIterComparator(&cfd_->internal_comparator())), |
||||
sv_(nullptr), |
||||
mutable_iter_(nullptr), |
||||
current_(nullptr), |
||||
valid_(false), |
||||
is_prev_set_(false) {} |
||||
|
||||
ForwardIterator::~ForwardIterator() { |
||||
Cleanup(); |
||||
} |
||||
|
||||
void ForwardIterator::Cleanup() { |
||||
delete mutable_iter_; |
||||
for (auto* m : imm_iters_) { |
||||
delete m; |
||||
} |
||||
imm_iters_.clear(); |
||||
for (auto* f : l0_iters_) { |
||||
delete f; |
||||
} |
||||
l0_iters_.clear(); |
||||
for (auto* l : level_iters_) { |
||||
delete l; |
||||
} |
||||
level_iters_.clear(); |
||||
|
||||
if (sv_ != nullptr && sv_->Unref()) { |
||||
DBImpl::DeletionState deletion_state; |
||||
db_->mutex_.Lock(); |
||||
sv_->Cleanup(); |
||||
db_->FindObsoleteFiles(deletion_state, false, true); |
||||
db_->mutex_.Unlock(); |
||||
delete sv_; |
||||
if (deletion_state.HaveSomethingToDelete()) { |
||||
db_->PurgeObsoleteFiles(deletion_state); |
||||
} |
||||
} |
||||
} |
||||
|
||||
bool ForwardIterator::Valid() const { |
||||
return valid_; |
||||
} |
||||
|
||||
void ForwardIterator::SeekToFirst() { |
||||
if (sv_ == nullptr || |
||||
sv_ ->version_number != cfd_->GetSuperVersionNumber()) { |
||||
RebuildIterators(); |
||||
} |
||||
SeekInternal(Slice(), true); |
||||
} |
||||
|
||||
void ForwardIterator::Seek(const Slice& internal_key) { |
||||
if (sv_ == nullptr || |
||||
sv_ ->version_number != cfd_->GetSuperVersionNumber()) { |
||||
RebuildIterators(); |
||||
} |
||||
SeekInternal(internal_key, false); |
||||
} |
||||
|
||||
void ForwardIterator::SeekInternal(const Slice& internal_key, |
||||
bool seek_to_first) { |
||||
// mutable
|
||||
seek_to_first ? mutable_iter_->SeekToFirst() : |
||||
mutable_iter_->Seek(internal_key); |
||||
|
||||
// immutable
|
||||
// TODO(ljin): NeedToSeekImmutable has negative impact on performance
|
||||
// if it turns to need to seek immutable often. We probably want to have
|
||||
// an option to turn it off.
|
||||
if (seek_to_first || NeedToSeekImmutable(internal_key)) { |
||||
{ |
||||
auto tmp = MinIterHeap(MinIterComparator(&cfd_->internal_comparator())); |
||||
immutable_min_heap_.swap(tmp); |
||||
} |
||||
for (auto* m : imm_iters_) { |
||||
seek_to_first ? m->SeekToFirst() : m->Seek(internal_key); |
||||
if (m->Valid()) { |
||||
immutable_min_heap_.push(m); |
||||
} |
||||
} |
||||
|
||||
auto* files = sv_->current->files_; |
||||
for (uint32_t i = 0; i < files[0].size(); ++i) { |
||||
if (seek_to_first) { |
||||
l0_iters_[i]->SeekToFirst(); |
||||
} else { |
||||
// If the target key passes over the larget key, we are sure Next()
|
||||
// won't go over this file.
|
||||
if (user_comparator_->Compare(ExtractUserKey(internal_key), |
||||
files[0][i]->largest.user_key()) > 0) { |
||||
continue; |
||||
} |
||||
l0_iters_[i]->Seek(internal_key); |
||||
} |
||||
if (l0_iters_[i]->Valid()) { |
||||
immutable_min_heap_.push(l0_iters_[i]); |
||||
} |
||||
} |
||||
for (int32_t level = 1; level < sv_->current->NumberLevels(); ++level) { |
||||
if (files[level].empty()) { |
||||
continue; |
||||
} |
||||
assert(level_iters_[level - 1] != nullptr); |
||||
uint32_t f_idx = 0; |
||||
if (!seek_to_first) { |
||||
f_idx = FindFileInRange( |
||||
files[level], internal_key, 0, files[level].size()); |
||||
} |
||||
if (f_idx < files[level].size()) { |
||||
level_iters_[level - 1]->SetFileIndex(f_idx); |
||||
seek_to_first ? level_iters_[level - 1]->SeekToFirst() : |
||||
level_iters_[level - 1]->Seek(internal_key); |
||||
if (level_iters_[level - 1]->Valid()) { |
||||
immutable_min_heap_.push(level_iters_[level - 1]); |
||||
} |
||||
} |
||||
} |
||||
|
||||
if (seek_to_first || immutable_min_heap_.empty()) { |
||||
is_prev_set_ = false; |
||||
} else { |
||||
prev_key_.SetKey(internal_key); |
||||
is_prev_set_ = true; |
||||
} |
||||
} |
||||
|
||||
UpdateCurrent(); |
||||
} |
||||
|
||||
void ForwardIterator::Next() { |
||||
assert(valid_); |
||||
|
||||
if (sv_ == nullptr || |
||||
sv_ ->version_number != cfd_->GetSuperVersionNumber()) { |
||||
std::string current_key = key().ToString(); |
||||
Slice old_key(current_key.data(), current_key.size()); |
||||
|
||||
RebuildIterators(); |
||||
SeekInternal(old_key, false); |
||||
if (!valid_ || key().compare(old_key) != 0) { |
||||
return; |
||||
} |
||||
} else if (current_ != mutable_iter_) { |
||||
// It is going to advance immutable iterator
|
||||
prev_key_.SetKey(current_->key()); |
||||
is_prev_set_ = true; |
||||
} |
||||
|
||||
current_->Next(); |
||||
if (current_->Valid() && current_ != mutable_iter_) { |
||||
immutable_min_heap_.push(current_); |
||||
} |
||||
UpdateCurrent(); |
||||
} |
||||
|
||||
Slice ForwardIterator::key() const { |
||||
assert(valid_); |
||||
return current_->key(); |
||||
} |
||||
|
||||
Slice ForwardIterator::value() const { |
||||
assert(valid_); |
||||
return current_->value(); |
||||
} |
||||
|
||||
Status ForwardIterator::status() const { |
||||
if (!status_.ok()) { |
||||
return status_; |
||||
} else if (!mutable_iter_->status().ok()) { |
||||
return mutable_iter_->status(); |
||||
} |
||||
return Status::OK(); |
||||
} |
||||
|
||||
void ForwardIterator::RebuildIterators() { |
||||
// Clean up
|
||||
Cleanup(); |
||||
// New
|
||||
sv_ = cfd_->GetReferencedSuperVersion(&(db_->mutex_)); |
||||
mutable_iter_ = sv_->mem->NewIterator(read_options_); |
||||
sv_->imm->AddIterators(read_options_, &imm_iters_); |
||||
const auto& l0_files = sv_->current->files_[0]; |
||||
l0_iters_.reserve(l0_files.size()); |
||||
for (const auto* l0 : l0_files) { |
||||
l0_iters_.push_back(cfd_->table_cache()->NewIterator( |
||||
read_options_, *cfd_->soptions(), cfd_->internal_comparator(), *l0)); |
||||
} |
||||
level_iters_.reserve(sv_->current->NumberLevels() - 1); |
||||
for (int32_t level = 1; level < sv_->current->NumberLevels(); ++level) { |
||||
if (sv_->current->files_[level].empty()) { |
||||
level_iters_.push_back(nullptr); |
||||
} else { |
||||
level_iters_.push_back(new LevelIterator(cfd_, read_options_, |
||||
sv_->current->files_[level])); |
||||
} |
||||
} |
||||
|
||||
current_ = nullptr; |
||||
is_prev_set_ = false; |
||||
} |
||||
|
||||
void ForwardIterator::UpdateCurrent() { |
||||
if (immutable_min_heap_.empty() && !mutable_iter_->Valid()) { |
||||
current_ = nullptr; |
||||
} else if (immutable_min_heap_.empty()) { |
||||
current_ = mutable_iter_; |
||||
} else if (!mutable_iter_->Valid()) { |
||||
current_ = immutable_min_heap_.top(); |
||||
immutable_min_heap_.pop(); |
||||
} else { |
||||
current_ = immutable_min_heap_.top(); |
||||
assert(current_ != nullptr); |
||||
assert(current_->Valid()); |
||||
int cmp = cfd_->internal_comparator().InternalKeyComparator::Compare( |
||||
mutable_iter_->key(), current_->key()) > 0; |
||||
assert(cmp != 0); |
||||
if (cmp > 0) { |
||||
immutable_min_heap_.pop(); |
||||
} else { |
||||
current_ = mutable_iter_; |
||||
} |
||||
} |
||||
valid_ = (current_ != nullptr); |
||||
if (!status_.ok()) { |
||||
status_ = Status::OK(); |
||||
} |
||||
} |
||||
|
||||
bool ForwardIterator::NeedToSeekImmutable(const Slice& target) { |
||||
if (!is_prev_set_) { |
||||
return true; |
||||
} |
||||
Slice prev_key = prev_key_.GetKey(); |
||||
if (prefix_extractor_ && prefix_extractor_->Transform(target).compare( |
||||
prefix_extractor_->Transform(prev_key)) != 0) { |
||||
return true; |
||||
} |
||||
if (cfd_->internal_comparator().InternalKeyComparator::Compare( |
||||
prev_key, target) >= 0) { |
||||
return true; |
||||
} |
||||
if (immutable_min_heap_.empty() || |
||||
cfd_->internal_comparator().InternalKeyComparator::Compare( |
||||
target, current_ == mutable_iter_ ? immutable_min_heap_.top()->key() |
||||
: current_->key()) > 0) { |
||||
return true; |
||||
} |
||||
return false; |
||||
} |
||||
|
||||
uint32_t ForwardIterator::FindFileInRange( |
||||
const std::vector<FileMetaData*>& files, const Slice& internal_key, |
||||
uint32_t left, uint32_t right) { |
||||
while (left < right) { |
||||
uint32_t mid = (left + right) / 2; |
||||
const FileMetaData* f = files[mid]; |
||||
if (cfd_->internal_comparator().InternalKeyComparator::Compare( |
||||
f->largest.Encode(), internal_key) < 0) { |
||||
// Key at "mid.largest" is < "target". Therefore all
|
||||
// files at or before "mid" are uninteresting.
|
||||
left = mid + 1; |
||||
} else { |
||||
// Key at "mid.largest" is >= "target". Therefore all files
|
||||
// after "mid" are uninteresting.
|
||||
right = mid; |
||||
} |
||||
} |
||||
return right; |
||||
} |
||||
|
||||
} // namespace rocksdb
|
||||
|
||||
#endif // ROCKSDB_LITE
|
@ -0,0 +1,105 @@ |
||||
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
|
||||
// This source code is licensed under the BSD-style license found in the
|
||||
// LICENSE file in the root directory of this source tree. An additional grant
|
||||
// of patent rights can be found in the PATENTS file in the same directory.
|
||||
#pragma once |
||||
|
||||
#ifndef ROCKSDB_LITE |
||||
|
||||
#include <string> |
||||
#include <vector> |
||||
#include <queue> |
||||
|
||||
#include "rocksdb/db.h" |
||||
#include "rocksdb/iterator.h" |
||||
#include "rocksdb/options.h" |
||||
#include "db/dbformat.h" |
||||
|
||||
namespace rocksdb { |
||||
|
||||
class DBImpl; |
||||
class Env; |
||||
struct SuperVersion; |
||||
class ColumnFamilyData; |
||||
class LevelIterator; |
||||
struct FileMetaData; |
||||
|
||||
class MinIterComparator { |
||||
public: |
||||
explicit MinIterComparator(const Comparator* comparator) : |
||||
comparator_(comparator) {} |
||||
|
||||
bool operator()(Iterator* a, Iterator* b) { |
||||
return comparator_->Compare(a->key(), b->key()) > 0; |
||||
} |
||||
private: |
||||
const Comparator* comparator_; |
||||
}; |
||||
|
||||
typedef std::priority_queue<Iterator*, |
||||
std::vector<Iterator*>, |
||||
MinIterComparator> MinIterHeap; |
||||
|
||||
/**
|
||||
* ForwardIterator is a special type of iterator that only supports Seek() |
||||
* and Next(). It is expected to perform better than TailingIterator by |
||||
* removing the encapsulation and making all information accessible within |
||||
* the iterator. At the current implementation, snapshot is taken at the |
||||
* time Seek() is called. The Next() followed do not see new values after. |
||||
*/ |
||||
class ForwardIterator : public Iterator { |
||||
public: |
||||
ForwardIterator(DBImpl* db, const ReadOptions& read_options, |
||||
ColumnFamilyData* cfd); |
||||
virtual ~ForwardIterator(); |
||||
|
||||
void SeekToLast() override { |
||||
status_ = Status::NotSupported("ForwardIterator::SeekToLast()"); |
||||
valid_ = false; |
||||
} |
||||
void Prev() { |
||||
status_ = Status::NotSupported("ForwardIterator::Prev"); |
||||
valid_ = false; |
||||
} |
||||
|
||||
virtual bool Valid() const override; |
||||
void SeekToFirst() override; |
||||
virtual void Seek(const Slice& target) override; |
||||
virtual void Next() override; |
||||
virtual Slice key() const override; |
||||
virtual Slice value() const override; |
||||
virtual Status status() const override; |
||||
|
||||
private: |
||||
void Cleanup(); |
||||
void RebuildIterators(); |
||||
void SeekInternal(const Slice& internal_key, bool seek_to_first); |
||||
void UpdateCurrent(); |
||||
bool NeedToSeekImmutable(const Slice& internal_key); |
||||
uint32_t FindFileInRange( |
||||
const std::vector<FileMetaData*>& files, const Slice& internal_key, |
||||
uint32_t left, uint32_t right); |
||||
|
||||
DBImpl* const db_; |
||||
const ReadOptions read_options_; |
||||
ColumnFamilyData* const cfd_; |
||||
const SliceTransform* const prefix_extractor_; |
||||
const Comparator* user_comparator_; |
||||
MinIterHeap immutable_min_heap_; |
||||
|
||||
SuperVersion* sv_; |
||||
Iterator* mutable_iter_; |
||||
std::vector<Iterator*> imm_iters_; |
||||
std::vector<Iterator*> l0_iters_; |
||||
std::vector<LevelIterator*> level_iters_; |
||||
Iterator* current_; |
||||
// internal iterator status
|
||||
Status status_; |
||||
bool valid_; |
||||
|
||||
IterKey prev_key_; |
||||
bool is_prev_set_; |
||||
}; |
||||
|
||||
} // namespace rocksdb
|
||||
#endif // ROCKSDB_LITE
|
Loading…
Reference in new issue