4d2ba38b65
Summary: Rename Version::Builder to VersionBuilder and expose its definition to a header. Make VerisonBuilder not reference Version or ColumnFamilyData, only working with VersionStorageInfo. Add version_builder_test which has a simple test. Test Plan: make all check Reviewers: rven, yhchiang, igor, ljin Reviewed By: igor Subscribers: leveldb, dhruba Differential Revision: https://reviews.facebook.net/D27969
562 lines
16 KiB
C++
562 lines
16 KiB
C++
// 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 <limits>
|
|
#include <string>
|
|
#include <utility>
|
|
|
|
#include "db/job_context.h"
|
|
#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;
|
|
Reset();
|
|
}
|
|
valid_ = false;
|
|
}
|
|
void Reset() {
|
|
assert(file_index_ < files_.size());
|
|
file_iter_.reset(cfd_->table_cache()->NewIterator(
|
|
read_options_, *(cfd_->soptions()), cfd_->internal_comparator(),
|
|
files_[file_index_]->fd, nullptr /* table_reader_ptr */, 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();
|
|
}
|
|
void Next() override {
|
|
assert(valid_);
|
|
file_iter_->Next();
|
|
for (;;) {
|
|
if (file_iter_->status().IsIncomplete() || file_iter_->Valid()) {
|
|
valid_ = !file_iter_->status().IsIncomplete();
|
|
return;
|
|
}
|
|
if (file_index_ + 1 >= files_.size()) {
|
|
valid_ = false;
|
|
return;
|
|
}
|
|
SetFileIndex(file_index_ + 1);
|
|
file_iter_->SeekToFirst();
|
|
}
|
|
}
|
|
Slice key() const override {
|
|
assert(valid_);
|
|
return file_iter_->key();
|
|
}
|
|
Slice value() const override {
|
|
assert(valid_);
|
|
return file_iter_->value();
|
|
}
|
|
Status status() const override {
|
|
if (!status_.ok()) {
|
|
return status_;
|
|
} else if (file_iter_ && !file_iter_->status().ok()) {
|
|
return file_iter_->status();
|
|
}
|
|
return Status::OK();
|
|
}
|
|
|
|
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, SuperVersion* current_sv)
|
|
: 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_(current_sv),
|
|
mutable_iter_(nullptr),
|
|
current_(nullptr),
|
|
valid_(false),
|
|
is_prev_set_(false),
|
|
is_prev_inclusive_(false) {
|
|
if (sv_) {
|
|
RebuildIterators(false);
|
|
}
|
|
}
|
|
|
|
ForwardIterator::~ForwardIterator() {
|
|
Cleanup(true);
|
|
}
|
|
|
|
void ForwardIterator::Cleanup(bool release_sv) {
|
|
if (mutable_iter_ != nullptr) {
|
|
mutable_iter_->~Iterator();
|
|
}
|
|
for (auto* m : imm_iters_) {
|
|
m->~Iterator();
|
|
}
|
|
imm_iters_.clear();
|
|
for (auto* f : l0_iters_) {
|
|
delete f;
|
|
}
|
|
l0_iters_.clear();
|
|
for (auto* l : level_iters_) {
|
|
delete l;
|
|
}
|
|
level_iters_.clear();
|
|
|
|
if (release_sv) {
|
|
if (sv_ != nullptr && sv_->Unref()) {
|
|
JobContext job_context;
|
|
db_->mutex_.Lock();
|
|
sv_->Cleanup();
|
|
db_->FindObsoleteFiles(&job_context, false, true);
|
|
db_->mutex_.Unlock();
|
|
delete sv_;
|
|
if (job_context.HaveSomethingToDelete()) {
|
|
db_->PurgeObsoleteFiles(job_context);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
bool ForwardIterator::Valid() const {
|
|
return valid_;
|
|
}
|
|
|
|
void ForwardIterator::SeekToFirst() {
|
|
if (sv_ == nullptr ||
|
|
sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
|
|
RebuildIterators(true);
|
|
} else if (status_.IsIncomplete()) {
|
|
ResetIncompleteIterators();
|
|
}
|
|
SeekInternal(Slice(), true);
|
|
}
|
|
|
|
void ForwardIterator::Seek(const Slice& internal_key) {
|
|
if (sv_ == nullptr ||
|
|
sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
|
|
RebuildIterators(true);
|
|
} else if (status_.IsIncomplete()) {
|
|
ResetIncompleteIterators();
|
|
}
|
|
SeekInternal(internal_key, false);
|
|
}
|
|
|
|
void ForwardIterator::SeekInternal(const Slice& internal_key,
|
|
bool seek_to_first) {
|
|
assert(mutable_iter_);
|
|
// 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);
|
|
}
|
|
}
|
|
|
|
Slice user_key;
|
|
if (!seek_to_first) {
|
|
user_key = ExtractUserKey(internal_key);
|
|
}
|
|
const VersionStorageInfo* vstorage = sv_->current->storage_info();
|
|
const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
|
|
for (uint32_t i = 0; i < l0.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(user_key,
|
|
l0[i]->largest.user_key()) > 0) {
|
|
continue;
|
|
}
|
|
l0_iters_[i]->Seek(internal_key);
|
|
}
|
|
|
|
if (l0_iters_[i]->status().IsIncomplete()) {
|
|
// if any of the immutable iterators is incomplete (no-io option was
|
|
// used), we are unable to reliably find the smallest key
|
|
assert(read_options_.read_tier == kBlockCacheTier);
|
|
status_ = l0_iters_[i]->status();
|
|
valid_ = false;
|
|
return;
|
|
} else if (l0_iters_[i]->Valid()) {
|
|
immutable_min_heap_.push(l0_iters_[i]);
|
|
}
|
|
}
|
|
|
|
int32_t search_left_bound = 0;
|
|
int32_t search_right_bound = FileIndexer::kLevelMaxIndex;
|
|
for (int32_t level = 1; level < vstorage->NumberLevels(); ++level) {
|
|
const std::vector<FileMetaData*>& level_files =
|
|
vstorage->LevelFiles(level);
|
|
if (level_files.empty()) {
|
|
search_left_bound = 0;
|
|
search_right_bound = FileIndexer::kLevelMaxIndex;
|
|
continue;
|
|
}
|
|
assert(level_iters_[level - 1] != nullptr);
|
|
uint32_t f_idx = 0;
|
|
const auto& indexer = vstorage->GetIndexer();
|
|
if (!seek_to_first) {
|
|
if (search_left_bound == search_right_bound) {
|
|
f_idx = search_left_bound;
|
|
} else if (search_left_bound < search_right_bound) {
|
|
f_idx = FindFileInRange(
|
|
level_files, internal_key, search_left_bound,
|
|
search_right_bound == FileIndexer::kLevelMaxIndex ?
|
|
level_files.size() : search_right_bound);
|
|
} else {
|
|
// search_left_bound > search_right_bound
|
|
// There are only 2 cases this can happen:
|
|
// (1) target key is smaller than left most file
|
|
// (2) target key is larger than right most file
|
|
assert(search_left_bound == (int32_t)level_files.size() ||
|
|
search_right_bound == -1);
|
|
if (search_right_bound == -1) {
|
|
assert(search_left_bound == 0);
|
|
f_idx = 0;
|
|
} else {
|
|
indexer.GetNextLevelIndex(
|
|
level, level_files.size() - 1,
|
|
1, 1, &search_left_bound, &search_right_bound);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Prepare hints for the next level
|
|
if (f_idx < level_files.size()) {
|
|
int cmp_smallest = user_comparator_->Compare(
|
|
user_key, level_files[f_idx]->smallest.user_key());
|
|
int cmp_largest = -1;
|
|
if (cmp_smallest >= 0) {
|
|
cmp_smallest = user_comparator_->Compare(
|
|
user_key, level_files[f_idx]->smallest.user_key());
|
|
}
|
|
indexer.GetNextLevelIndex(level, f_idx,
|
|
cmp_smallest, cmp_largest,
|
|
&search_left_bound, &search_right_bound);
|
|
} else {
|
|
indexer.GetNextLevelIndex(
|
|
level, level_files.size() - 1,
|
|
1, 1, &search_left_bound, &search_right_bound);
|
|
}
|
|
}
|
|
|
|
// Seek
|
|
if (f_idx < level_files.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]->status().IsIncomplete()) {
|
|
// see above
|
|
assert(read_options_.read_tier == kBlockCacheTier);
|
|
status_ = level_iters_[level - 1]->status();
|
|
valid_ = false;
|
|
return;
|
|
} else if (level_iters_[level - 1]->Valid()) {
|
|
immutable_min_heap_.push(level_iters_[level - 1]);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (seek_to_first) {
|
|
is_prev_set_ = false;
|
|
} else {
|
|
prev_key_.SetKey(internal_key);
|
|
is_prev_set_ = true;
|
|
is_prev_inclusive_ = true;
|
|
}
|
|
} else if (current_ && current_ != mutable_iter_) {
|
|
// current_ is one of immutable iterators, push it back to the heap
|
|
immutable_min_heap_.push(current_);
|
|
}
|
|
|
|
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(true);
|
|
SeekInternal(old_key, false);
|
|
if (!valid_ || key().compare(old_key) != 0) {
|
|
return;
|
|
}
|
|
} else if (current_ != mutable_iter_) {
|
|
// It is going to advance immutable iterator
|
|
|
|
bool update_prev_key = true;
|
|
if (is_prev_set_ && prefix_extractor_) {
|
|
// advance prev_key_ to current_ only if they share the same prefix
|
|
update_prev_key =
|
|
prefix_extractor_->Transform(prev_key_.GetKey()).compare(
|
|
prefix_extractor_->Transform(current_->key())) == 0;
|
|
}
|
|
|
|
if (update_prev_key) {
|
|
prev_key_.SetKey(current_->key());
|
|
is_prev_set_ = true;
|
|
is_prev_inclusive_ = false;
|
|
}
|
|
}
|
|
|
|
current_->Next();
|
|
if (current_ != mutable_iter_) {
|
|
if (current_->status().IsIncomplete()) {
|
|
assert(read_options_.read_tier == kBlockCacheTier);
|
|
status_ = current_->status();
|
|
valid_ = false;
|
|
return;
|
|
} else if (current_->Valid()) {
|
|
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();
|
|
}
|
|
|
|
for (auto *it : imm_iters_) {
|
|
if (it && !it->status().ok()) {
|
|
return it->status();
|
|
}
|
|
}
|
|
for (auto *it : l0_iters_) {
|
|
if (it && !it->status().ok()) {
|
|
return it->status();
|
|
}
|
|
}
|
|
for (auto *it : level_iters_) {
|
|
if (it && !it->status().ok()) {
|
|
return it->status();
|
|
}
|
|
}
|
|
|
|
return Status::OK();
|
|
}
|
|
|
|
void ForwardIterator::RebuildIterators(bool refresh_sv) {
|
|
// Clean up
|
|
Cleanup(refresh_sv);
|
|
if (refresh_sv) {
|
|
// New
|
|
sv_ = cfd_->GetReferencedSuperVersion(&(db_->mutex_));
|
|
}
|
|
mutable_iter_ = sv_->mem->NewIterator(read_options_, &arena_);
|
|
sv_->imm->AddIterators(read_options_, &imm_iters_, &arena_);
|
|
|
|
const auto* vstorage = sv_->current->storage_info();
|
|
const auto& l0_files = vstorage->LevelFiles(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->fd));
|
|
}
|
|
level_iters_.reserve(vstorage->NumberLevels() - 1);
|
|
for (int32_t level = 1; level < vstorage->NumberLevels(); ++level) {
|
|
const auto& level_files = vstorage->LevelFiles(level);
|
|
|
|
if (level_files.empty()) {
|
|
level_iters_.push_back(nullptr);
|
|
} else {
|
|
level_iters_.push_back(
|
|
new LevelIterator(cfd_, read_options_, level_files));
|
|
}
|
|
}
|
|
|
|
current_ = nullptr;
|
|
is_prev_set_ = false;
|
|
}
|
|
|
|
void ForwardIterator::ResetIncompleteIterators() {
|
|
const auto& l0_files = sv_->current->storage_info()->LevelFiles(0);
|
|
for (uint32_t i = 0; i < l0_iters_.size(); ++i) {
|
|
assert(i < l0_files.size());
|
|
if (!l0_iters_[i]->status().IsIncomplete()) {
|
|
continue;
|
|
}
|
|
delete l0_iters_[i];
|
|
l0_iters_[i] = cfd_->table_cache()->NewIterator(
|
|
read_options_, *cfd_->soptions(), cfd_->internal_comparator(),
|
|
l0_files[i]->fd);
|
|
}
|
|
|
|
for (auto* level_iter : level_iters_) {
|
|
if (level_iter && level_iter->status().IsIncomplete()) {
|
|
level_iter->Reset();
|
|
}
|
|
}
|
|
|
|
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());
|
|
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) {
|
|
// We maintain the interval (prev_key_, immutable_min_heap_.top()->key())
|
|
// such that there are no records with keys within that range in
|
|
// immutable_min_heap_. Since immutable structures (SST files and immutable
|
|
// memtables) can't change in this version, we don't need to do a seek if
|
|
// 'target' belongs to that interval (immutable_min_heap_.top() is already
|
|
// at the correct position).
|
|
|
|
if (!valid_ || !current_ || !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) >= (is_prev_inclusive_ ? 1 : 0)) {
|
|
return true;
|
|
}
|
|
|
|
if (immutable_min_heap_.empty() && current_ == mutable_iter_) {
|
|
// Nothing to seek on.
|
|
return false;
|
|
}
|
|
if (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
|