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rocksdb/db/forward_iterator.cc
yiwu-arbug f1239d5f10 Avoid per-key upper bound check in BlockBasedTableIterator (#5142) 
Summary:
This is second attempt for #5101. Original commit message:
`BlockBasedTableIterator` avoid reading next block on `Next()` if it detects the iterator will be out of bound, by checking against index key. The optimization was added in #2239, and by the time it only check the bound per block. It seems later change make it a per-key check, which introduce unnecessary key comparisons.

This patch come with two fixes:

Fix 1: To optimize checking for bounds, we need comparing the bounds with index key as well. However BlockBasedTableIterator doesn't know whether its index iterator is internally using user keys or internal keys. The patch fixes that by extending InternalIterator with a user_key() function that is overridden by In IndexBlockIter.

Fix 2: In #5101 we return `IsOutOfBound()=true` when block index key is out of bound. But the index key can be larger than smallest key of the next file on the level. That file can be within upper bound and should not be filtered out.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5142

Differential Revision: D14907113

Pulled By: siying

fbshipit-source-id: ac95775c5b4e7b700f76ab43e39f45402c98fbfb
2019-04-16 11:37:47 -07:00

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#ifndef ROCKSDB_LITE
#include "db/forward_iterator.h"
#include <limits>
#include <string>
#include <utility>
#include "db/column_family.h"
#include "db/db_impl.h"
#include "db/db_iter.h"
#include "db/dbformat.h"
#include "db/job_context.h"
#include "db/range_del_aggregator.h"
#include "db/range_tombstone_fragmenter.h"
#include "rocksdb/env.h"
#include "rocksdb/slice.h"
#include "rocksdb/slice_transform.h"
#include "table/merging_iterator.h"
#include "util/string_util.h"
#include "util/sync_point.h"
namespace rocksdb {
// Usage:
// ForwardLevelIterator iter;
// iter.SetFileIndex(file_index);
// iter.Seek(target); // or iter.SeekToFirst();
// iter.Next()
class ForwardLevelIterator : public InternalIterator {
public:
ForwardLevelIterator(const ColumnFamilyData* const cfd,
const ReadOptions& read_options,
const std::vector<FileMetaData*>& files,
const SliceTransform* prefix_extractor)
: cfd_(cfd),
read_options_(read_options),
files_(files),
valid_(false),
file_index_(std::numeric_limits<uint32_t>::max()),
file_iter_(nullptr),
pinned_iters_mgr_(nullptr),
prefix_extractor_(prefix_extractor) {}
~ForwardLevelIterator() override {
// Reset current pointer
if (pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled()) {
pinned_iters_mgr_->PinIterator(file_iter_);
} else {
delete file_iter_;
}
}
void SetFileIndex(uint32_t file_index) {
assert(file_index < files_.size());
status_ = Status::OK();
if (file_index != file_index_) {
file_index_ = file_index;
Reset();
}
}
void Reset() {
assert(file_index_ < files_.size());
// Reset current pointer
if (pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled()) {
pinned_iters_mgr_->PinIterator(file_iter_);
} else {
delete file_iter_;
}
ReadRangeDelAggregator range_del_agg(&cfd_->internal_comparator(),
kMaxSequenceNumber /* upper_bound */);
file_iter_ = cfd_->table_cache()->NewIterator(
read_options_, *(cfd_->soptions()), cfd_->internal_comparator(),
*files_[file_index_],
read_options_.ignore_range_deletions ? nullptr : &range_del_agg,
prefix_extractor_, nullptr /* table_reader_ptr */, nullptr, false);
file_iter_->SetPinnedItersMgr(pinned_iters_mgr_);
valid_ = false;
if (!range_del_agg.IsEmpty()) {
status_ = Status::NotSupported(
"Range tombstones unsupported with ForwardIterator");
}
}
void SeekToLast() override {
status_ = Status::NotSupported("ForwardLevelIterator::SeekToLast()");
valid_ = false;
}
void Prev() override {
status_ = Status::NotSupported("ForwardLevelIterator::Prev()");
valid_ = false;
}
bool Valid() const override {
return valid_;
}
void SeekToFirst() override {
assert(file_iter_ != nullptr);
if (!status_.ok()) {
assert(!valid_);
return;
}
file_iter_->SeekToFirst();
valid_ = file_iter_->Valid();
}
void Seek(const Slice& internal_key) override {
assert(file_iter_ != nullptr);
// This deviates from the usual convention for InternalIterator::Seek() in
// that it doesn't discard pre-existing error status. That's because this
// Seek() is only supposed to be called immediately after SetFileIndex()
// (which discards pre-existing error status), and SetFileIndex() may set
// an error status, which we shouldn't discard.
if (!status_.ok()) {
assert(!valid_);
return;
}
file_iter_->Seek(internal_key);
valid_ = file_iter_->Valid();
}
void SeekForPrev(const Slice& /*internal_key*/) override {
status_ = Status::NotSupported("ForwardLevelIterator::SeekForPrev()");
valid_ = false;
}
void Next() override {
assert(valid_);
file_iter_->Next();
for (;;) {
valid_ = file_iter_->Valid();
if (!file_iter_->status().ok()) {
assert(!valid_);
return;
}
if (valid_) {
return;
}
if (file_index_ + 1 >= files_.size()) {
valid_ = false;
return;
}
SetFileIndex(file_index_ + 1);
if (!status_.ok()) {
assert(!valid_);
return;
}
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_) {
return file_iter_->status();
}
return Status::OK();
}
bool IsKeyPinned() const override {
return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
file_iter_->IsKeyPinned();
}
bool IsValuePinned() const override {
return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
file_iter_->IsValuePinned();
}
void SetPinnedItersMgr(PinnedIteratorsManager* pinned_iters_mgr) override {
pinned_iters_mgr_ = pinned_iters_mgr;
if (file_iter_) {
file_iter_->SetPinnedItersMgr(pinned_iters_mgr_);
}
}
private:
const ColumnFamilyData* const cfd_;
const ReadOptions& read_options_;
const std::vector<FileMetaData*>& files_;
bool valid_;
uint32_t file_index_;
Status status_;
InternalIterator* file_iter_;
PinnedIteratorsManager* pinned_iters_mgr_;
const SliceTransform* prefix_extractor_;
};
ForwardIterator::ForwardIterator(DBImpl* db, const ReadOptions& read_options,
ColumnFamilyData* cfd,
SuperVersion* current_sv)
: db_(db),
read_options_(read_options),
cfd_(cfd),
prefix_extractor_(current_sv->mutable_cf_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),
status_(Status::OK()),
immutable_status_(Status::OK()),
has_iter_trimmed_for_upper_bound_(false),
current_over_upper_bound_(false),
is_prev_set_(false),
is_prev_inclusive_(false),
pinned_iters_mgr_(nullptr) {
if (sv_) {
RebuildIterators(false);
}
}
ForwardIterator::~ForwardIterator() {
Cleanup(true);
}
void ForwardIterator::SVCleanup(DBImpl* db, SuperVersion* sv,
bool background_purge_on_iterator_cleanup) {
if (sv->Unref()) {
// Job id == 0 means that this is not our background process, but rather
// user thread
JobContext job_context(0);
db->mutex_.Lock();
sv->Cleanup();
db->FindObsoleteFiles(&job_context, false, true);
if (background_purge_on_iterator_cleanup) {
db->ScheduleBgLogWriterClose(&job_context);
}
db->mutex_.Unlock();
delete sv;
if (job_context.HaveSomethingToDelete()) {
db->PurgeObsoleteFiles(job_context, background_purge_on_iterator_cleanup);
}
job_context.Clean();
}
}
namespace {
struct SVCleanupParams {
DBImpl* db;
SuperVersion* sv;
bool background_purge_on_iterator_cleanup;
};
}
// Used in PinnedIteratorsManager to release pinned SuperVersion
void ForwardIterator::DeferredSVCleanup(void* arg) {
auto d = reinterpret_cast<SVCleanupParams*>(arg);
ForwardIterator::SVCleanup(
d->db, d->sv, d->background_purge_on_iterator_cleanup);
delete d;
}
void ForwardIterator::SVCleanup() {
if (sv_ == nullptr) {
return;
}
bool background_purge =
read_options_.background_purge_on_iterator_cleanup ||
db_->immutable_db_options().avoid_unnecessary_blocking_io;
if (pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled()) {
// pinned_iters_mgr_ tells us to make sure that all visited key-value slices
// are alive until pinned_iters_mgr_->ReleasePinnedData() is called.
// The slices may point into some memtables owned by sv_, so we need to keep
// sv_ referenced until pinned_iters_mgr_ unpins everything.
auto p = new SVCleanupParams{db_, sv_, background_purge};
pinned_iters_mgr_->PinPtr(p, &ForwardIterator::DeferredSVCleanup);
} else {
SVCleanup(db_, sv_, background_purge);
}
}
void ForwardIterator::Cleanup(bool release_sv) {
if (mutable_iter_ != nullptr) {
DeleteIterator(mutable_iter_, true /* is_arena */);
}
for (auto* m : imm_iters_) {
DeleteIterator(m, true /* is_arena */);
}
imm_iters_.clear();
for (auto* f : l0_iters_) {
DeleteIterator(f);
}
l0_iters_.clear();
for (auto* l : level_iters_) {
DeleteIterator(l);
}
level_iters_.clear();
if (release_sv) {
SVCleanup();
}
}
bool ForwardIterator::Valid() const {
// See UpdateCurrent().
return valid_ ? !current_over_upper_bound_ : false;
}
void ForwardIterator::SeekToFirst() {
if (sv_ == nullptr) {
RebuildIterators(true);
} else if (sv_->version_number != cfd_->GetSuperVersionNumber()) {
RenewIterators();
} else if (immutable_status_.IsIncomplete()) {
ResetIncompleteIterators();
}
SeekInternal(Slice(), true);
}
bool ForwardIterator::IsOverUpperBound(const Slice& internal_key) const {
return !(read_options_.iterate_upper_bound == nullptr ||
cfd_->internal_comparator().user_comparator()->Compare(
ExtractUserKey(internal_key),
*read_options_.iterate_upper_bound) < 0);
}
void ForwardIterator::Seek(const Slice& internal_key) {
if (sv_ == nullptr) {
RebuildIterators(true);
} else if (sv_->version_number != cfd_->GetSuperVersionNumber()) {
RenewIterators();
} else if (immutable_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)) {
immutable_status_ = Status::OK();
if (has_iter_trimmed_for_upper_bound_ &&
(
// prev_ is not set yet
is_prev_set_ == false ||
// We are doing SeekToFirst() and internal_key.size() = 0
seek_to_first ||
// prev_key_ > internal_key
cfd_->internal_comparator().InternalKeyComparator::Compare(
prev_key_.GetInternalKey(), internal_key) > 0)) {
// Some iterators are trimmed. Need to rebuild.
RebuildIterators(true);
// Already seeked mutable iter, so seek again
seek_to_first ? mutable_iter_->SeekToFirst()
: mutable_iter_->Seek(internal_key);
}
{
auto tmp = MinIterHeap(MinIterComparator(&cfd_->internal_comparator()));
immutable_min_heap_.swap(tmp);
}
for (size_t i = 0; i < imm_iters_.size(); i++) {
auto* m = imm_iters_[i];
seek_to_first ? m->SeekToFirst() : m->Seek(internal_key);
if (!m->status().ok()) {
immutable_status_ = m->status();
} else if (m->Valid()) {
immutable_min_heap_.push(m);
}
}
Slice target_user_key;
if (!seek_to_first) {
target_user_key = ExtractUserKey(internal_key);
}
const VersionStorageInfo* vstorage = sv_->current->storage_info();
const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
for (size_t i = 0; i < l0.size(); ++i) {
if (!l0_iters_[i]) {
continue;
}
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(target_user_key,
l0[i]->largest.user_key()) > 0) {
if (read_options_.iterate_upper_bound != nullptr) {
has_iter_trimmed_for_upper_bound_ = true;
DeleteIterator(l0_iters_[i]);
l0_iters_[i] = nullptr;
}
continue;
}
l0_iters_[i]->Seek(internal_key);
}
if (!l0_iters_[i]->status().ok()) {
immutable_status_ = l0_iters_[i]->status();
} else if (l0_iters_[i]->Valid() &&
!IsOverUpperBound(l0_iters_[i]->key())) {
immutable_min_heap_.push(l0_iters_[i]);
} else {
has_iter_trimmed_for_upper_bound_ = true;
DeleteIterator(l0_iters_[i]);
l0_iters_[i] = nullptr;
}
}
for (int32_t level = 1; level < vstorage->num_levels(); ++level) {
const std::vector<FileMetaData*>& level_files =
vstorage->LevelFiles(level);
if (level_files.empty()) {
continue;
}
if (level_iters_[level - 1] == nullptr) {
continue;
}
uint32_t f_idx = 0;
if (!seek_to_first) {
f_idx = FindFileInRange(level_files, internal_key, 0,
static_cast<uint32_t>(level_files.size()));
}
// 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().ok()) {
immutable_status_ = level_iters_[level - 1]->status();
} else if (level_iters_[level - 1]->Valid() &&
!IsOverUpperBound(level_iters_[level - 1]->key())) {
immutable_min_heap_.push(level_iters_[level - 1]);
} else {
// Nothing in this level is interesting. Remove.
has_iter_trimmed_for_upper_bound_ = true;
DeleteIterator(level_iters_[level - 1]);
level_iters_[level - 1] = nullptr;
}
}
}
if (seek_to_first) {
is_prev_set_ = false;
} else {
prev_key_.SetInternalKey(internal_key);
is_prev_set_ = true;
is_prev_inclusive_ = true;
}
TEST_SYNC_POINT_CALLBACK("ForwardIterator::SeekInternal:Immutable", this);
} else if (current_ && current_ != mutable_iter_) {
// current_ is one of immutable iterators, push it back to the heap
immutable_min_heap_.push(current_);
}
UpdateCurrent();
TEST_SYNC_POINT_CALLBACK("ForwardIterator::SeekInternal:Return", this);
}
void ForwardIterator::Next() {
assert(valid_);
bool update_prev_key = false;
if (sv_ == nullptr ||
sv_->version_number != cfd_->GetSuperVersionNumber()) {
std::string current_key = key().ToString();
Slice old_key(current_key.data(), current_key.size());
if (sv_ == nullptr) {
RebuildIterators(true);
} else {
RenewIterators();
}
SeekInternal(old_key, false);
if (!valid_ || key().compare(old_key) != 0) {
return;
}
} else if (current_ != mutable_iter_) {
// It is going to advance immutable iterator
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_.GetUserKey())
.compare(prefix_extractor_->Transform(current_->key())) == 0;
} else {
update_prev_key = true;
}
if (update_prev_key) {
prev_key_.SetInternalKey(current_->key());
is_prev_set_ = true;
is_prev_inclusive_ = false;
}
}
current_->Next();
if (current_ != mutable_iter_) {
if (!current_->status().ok()) {
immutable_status_ = current_->status();
} else if ((current_->Valid()) && (!IsOverUpperBound(current_->key()))) {
immutable_min_heap_.push(current_);
} else {
if ((current_->Valid()) && (IsOverUpperBound(current_->key()))) {
// remove the current iterator
DeleteCurrentIter();
current_ = nullptr;
}
if (update_prev_key) {
mutable_iter_->Seek(prev_key_.GetInternalKey());
}
}
}
UpdateCurrent();
TEST_SYNC_POINT_CALLBACK("ForwardIterator::Next:Return", this);
}
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 immutable_status_;
}
Status ForwardIterator::GetProperty(std::string prop_name, std::string* prop) {
assert(prop != nullptr);
if (prop_name == "rocksdb.iterator.super-version-number") {
*prop = ToString(sv_->version_number);
return Status::OK();
}
return Status::InvalidArgument();
}
void ForwardIterator::SetPinnedItersMgr(
PinnedIteratorsManager* pinned_iters_mgr) {
pinned_iters_mgr_ = pinned_iters_mgr;
UpdateChildrenPinnedItersMgr();
}
void ForwardIterator::UpdateChildrenPinnedItersMgr() {
// Set PinnedIteratorsManager for mutable memtable iterator.
if (mutable_iter_) {
mutable_iter_->SetPinnedItersMgr(pinned_iters_mgr_);
}
// Set PinnedIteratorsManager for immutable memtable iterators.
for (InternalIterator* child_iter : imm_iters_) {
if (child_iter) {
child_iter->SetPinnedItersMgr(pinned_iters_mgr_);
}
}
// Set PinnedIteratorsManager for L0 files iterators.
for (InternalIterator* child_iter : l0_iters_) {
if (child_iter) {
child_iter->SetPinnedItersMgr(pinned_iters_mgr_);
}
}
// Set PinnedIteratorsManager for L1+ levels iterators.
for (ForwardLevelIterator* child_iter : level_iters_) {
if (child_iter) {
child_iter->SetPinnedItersMgr(pinned_iters_mgr_);
}
}
}
bool ForwardIterator::IsKeyPinned() const {
return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
current_->IsKeyPinned();
}
bool ForwardIterator::IsValuePinned() const {
return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
current_->IsValuePinned();
}
void ForwardIterator::RebuildIterators(bool refresh_sv) {
// Clean up
Cleanup(refresh_sv);
if (refresh_sv) {
// New
sv_ = cfd_->GetReferencedSuperVersion(&(db_->mutex_));
}
ReadRangeDelAggregator range_del_agg(&cfd_->internal_comparator(),
kMaxSequenceNumber /* upper_bound */);
mutable_iter_ = sv_->mem->NewIterator(read_options_, &arena_);
sv_->imm->AddIterators(read_options_, &imm_iters_, &arena_);
if (!read_options_.ignore_range_deletions) {
std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter(
sv_->mem->NewRangeTombstoneIterator(
read_options_, sv_->current->version_set()->LastSequence()));
range_del_agg.AddTombstones(std::move(range_del_iter));
sv_->imm->AddRangeTombstoneIterators(read_options_, &arena_,
&range_del_agg);
}
has_iter_trimmed_for_upper_bound_ = false;
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) {
if ((read_options_.iterate_upper_bound != nullptr) &&
cfd_->internal_comparator().user_comparator()->Compare(
l0->smallest.user_key(), *read_options_.iterate_upper_bound) > 0) {
// No need to set has_iter_trimmed_for_upper_bound_: this ForwardIterator
// will never be interested in files with smallest key above
// iterate_upper_bound, since iterate_upper_bound can't be changed.
l0_iters_.push_back(nullptr);
continue;
}
l0_iters_.push_back(cfd_->table_cache()->NewIterator(
read_options_, *cfd_->soptions(), cfd_->internal_comparator(), *l0,
read_options_.ignore_range_deletions ? nullptr : &range_del_agg,
sv_->mutable_cf_options.prefix_extractor.get()));
}
BuildLevelIterators(vstorage);
current_ = nullptr;
is_prev_set_ = false;
UpdateChildrenPinnedItersMgr();
if (!range_del_agg.IsEmpty()) {
status_ = Status::NotSupported(
"Range tombstones unsupported with ForwardIterator");
valid_ = false;
}
}
void ForwardIterator::RenewIterators() {
SuperVersion* svnew;
assert(sv_);
svnew = cfd_->GetReferencedSuperVersion(&(db_->mutex_));
if (mutable_iter_ != nullptr) {
DeleteIterator(mutable_iter_, true /* is_arena */);
}
for (auto* m : imm_iters_) {
DeleteIterator(m, true /* is_arena */);
}
imm_iters_.clear();
mutable_iter_ = svnew->mem->NewIterator(read_options_, &arena_);
svnew->imm->AddIterators(read_options_, &imm_iters_, &arena_);
ReadRangeDelAggregator range_del_agg(&cfd_->internal_comparator(),
kMaxSequenceNumber /* upper_bound */);
if (!read_options_.ignore_range_deletions) {
std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter(
svnew->mem->NewRangeTombstoneIterator(
read_options_, sv_->current->version_set()->LastSequence()));
range_del_agg.AddTombstones(std::move(range_del_iter));
svnew->imm->AddRangeTombstoneIterators(read_options_, &arena_,
&range_del_agg);
}
const auto* vstorage = sv_->current->storage_info();
const auto& l0_files = vstorage->LevelFiles(0);
const auto* vstorage_new = svnew->current->storage_info();
const auto& l0_files_new = vstorage_new->LevelFiles(0);
size_t iold, inew;
bool found;
std::vector<InternalIterator*> l0_iters_new;
l0_iters_new.reserve(l0_files_new.size());
for (inew = 0; inew < l0_files_new.size(); inew++) {
found = false;
for (iold = 0; iold < l0_files.size(); iold++) {
if (l0_files[iold] == l0_files_new[inew]) {
found = true;
break;
}
}
if (found) {
if (l0_iters_[iold] == nullptr) {
l0_iters_new.push_back(nullptr);
TEST_SYNC_POINT_CALLBACK("ForwardIterator::RenewIterators:Null", this);
} else {
l0_iters_new.push_back(l0_iters_[iold]);
l0_iters_[iold] = nullptr;
TEST_SYNC_POINT_CALLBACK("ForwardIterator::RenewIterators:Copy", this);
}
continue;
}
l0_iters_new.push_back(cfd_->table_cache()->NewIterator(
read_options_, *cfd_->soptions(), cfd_->internal_comparator(),
*l0_files_new[inew],
read_options_.ignore_range_deletions ? nullptr : &range_del_agg,
svnew->mutable_cf_options.prefix_extractor.get()));
}
for (auto* f : l0_iters_) {
DeleteIterator(f);
}
l0_iters_.clear();
l0_iters_ = l0_iters_new;
for (auto* l : level_iters_) {
DeleteIterator(l);
}
level_iters_.clear();
BuildLevelIterators(vstorage_new);
current_ = nullptr;
is_prev_set_ = false;
SVCleanup();
sv_ = svnew;
UpdateChildrenPinnedItersMgr();
if (!range_del_agg.IsEmpty()) {
status_ = Status::NotSupported(
"Range tombstones unsupported with ForwardIterator");
valid_ = false;
}
}
void ForwardIterator::BuildLevelIterators(const VersionStorageInfo* vstorage) {
level_iters_.reserve(vstorage->num_levels() - 1);
for (int32_t level = 1; level < vstorage->num_levels(); ++level) {
const auto& level_files = vstorage->LevelFiles(level);
if ((level_files.empty()) ||
((read_options_.iterate_upper_bound != nullptr) &&
(user_comparator_->Compare(*read_options_.iterate_upper_bound,
level_files[0]->smallest.user_key()) <
0))) {
level_iters_.push_back(nullptr);
if (!level_files.empty()) {
has_iter_trimmed_for_upper_bound_ = true;
}
} else {
level_iters_.push_back(new ForwardLevelIterator(
cfd_, read_options_, level_files,
sv_->mutable_cf_options.prefix_extractor.get()));
}
}
}
void ForwardIterator::ResetIncompleteIterators() {
const auto& l0_files = sv_->current->storage_info()->LevelFiles(0);
for (size_t i = 0; i < l0_iters_.size(); ++i) {
assert(i < l0_files.size());
if (!l0_iters_[i] || !l0_iters_[i]->status().IsIncomplete()) {
continue;
}
DeleteIterator(l0_iters_[i]);
l0_iters_[i] = cfd_->table_cache()->NewIterator(
read_options_, *cfd_->soptions(), cfd_->internal_comparator(),
*l0_files[i], nullptr /* range_del_agg */,
sv_->mutable_cf_options.prefix_extractor.get());
l0_iters_[i]->SetPinnedItersMgr(pinned_iters_mgr_);
}
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 && immutable_status_.ok();
if (!status_.ok()) {
status_ = Status::OK();
}
// Upper bound doesn't apply to the memtable iterator. We want Valid() to
// return false when all iterators are over iterate_upper_bound, but can't
// just set valid_ to false, as that would effectively disable the tailing
// optimization (Seek() would be called on all immutable iterators regardless
// of whether the target key is greater than prev_key_).
current_over_upper_bound_ = valid_ && IsOverUpperBound(current_->key());
}
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_ || !immutable_status_.ok()) {
return true;
}
Slice prev_key = prev_key_.GetInternalKey();
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;
}
void ForwardIterator::DeleteCurrentIter() {
const VersionStorageInfo* vstorage = sv_->current->storage_info();
const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
for (size_t i = 0; i < l0.size(); ++i) {
if (!l0_iters_[i]) {
continue;
}
if (l0_iters_[i] == current_) {
has_iter_trimmed_for_upper_bound_ = true;
DeleteIterator(l0_iters_[i]);
l0_iters_[i] = nullptr;
return;
}
}
for (int32_t level = 1; level < vstorage->num_levels(); ++level) {
if (level_iters_[level - 1] == nullptr) {
continue;
}
if (level_iters_[level - 1] == current_) {
has_iter_trimmed_for_upper_bound_ = true;
DeleteIterator(level_iters_[level - 1]);
level_iters_[level - 1] = nullptr;
}
}
}
bool ForwardIterator::TEST_CheckDeletedIters(int* pdeleted_iters,
int* pnum_iters) {
bool retval = false;
int deleted_iters = 0;
int num_iters = 0;
const VersionStorageInfo* vstorage = sv_->current->storage_info();
const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
for (size_t i = 0; i < l0.size(); ++i) {
if (!l0_iters_[i]) {
retval = true;
deleted_iters++;
} else {
num_iters++;
}
}
for (int32_t level = 1; level < vstorage->num_levels(); ++level) {
if ((level_iters_[level - 1] == nullptr) &&
(!vstorage->LevelFiles(level).empty())) {
retval = true;
deleted_iters++;
} else if (!vstorage->LevelFiles(level).empty()) {
num_iters++;
}
}
if ((!retval) && num_iters <= 1) {
retval = true;
}
if (pdeleted_iters) {
*pdeleted_iters = deleted_iters;
}
if (pnum_iters) {
*pnum_iters = num_iters;
}
return retval;
}
uint32_t ForwardIterator::FindFileInRange(
const std::vector<FileMetaData*>& files, const Slice& internal_key,
uint32_t left, uint32_t right) {
auto cmp = [&](const FileMetaData* f, const Slice& key) -> bool {
return cfd_->internal_comparator().InternalKeyComparator::Compare(
f->largest.Encode(), key) < 0;
};
const auto &b = files.begin();
return static_cast<uint32_t>(std::lower_bound(b + left,
b + right, internal_key, cmp) - b);
}
void ForwardIterator::DeleteIterator(InternalIterator* iter, bool is_arena) {
if (iter == nullptr) {
return;
}
if (pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled()) {
pinned_iters_mgr_->PinIterator(iter, is_arena);
} else {
if (is_arena) {
iter->~InternalIterator();
} else {
delete iter;
}
}
}
} // namespace rocksdb
#endif // ROCKSDB_LITE
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