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rust-rocksdb/librocksdb-sys/rocksdb/db/range_del_aggregator.cc

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// Copyright (c) 2018-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).
#include "db/range_del_aggregator.h"
#include "db/compaction/compaction_iteration_stats.h"
#include "db/dbformat.h"
#include "db/pinned_iterators_manager.h"
#include "db/range_del_aggregator.h"
#include "db/range_tombstone_fragmenter.h"
#include "db/version_edit.h"
#include "rocksdb/comparator.h"
#include "rocksdb/types.h"
#include "table/internal_iterator.h"
#include "table/scoped_arena_iterator.h"
#include "table/table_builder.h"
#include "util/heap.h"
#include "util/kv_map.h"
#include "util/vector_iterator.h"
namespace ROCKSDB_NAMESPACE {
TruncatedRangeDelIterator::TruncatedRangeDelIterator(
std::unique_ptr<FragmentedRangeTombstoneIterator> iter,
const InternalKeyComparator* icmp, const InternalKey* smallest,
const InternalKey* largest)
: iter_(std::move(iter)),
icmp_(icmp),
smallest_ikey_(smallest),
largest_ikey_(largest) {
// Set up bounds such that range tombstones from this iterator are
// truncated to range [smallest_, largest_).
if (smallest != nullptr) {
pinned_bounds_.emplace_back();
auto& parsed_smallest = pinned_bounds_.back();
Status pik_status = ParseInternalKey(smallest->Encode(), &parsed_smallest,
false /* log_err_key */); // TODO
pik_status.PermitUncheckedError();
parsed_smallest.type = kTypeMaxValid;
assert(pik_status.ok());
smallest_ = &parsed_smallest;
}
if (largest != nullptr) {
pinned_bounds_.emplace_back();
auto& parsed_largest = pinned_bounds_.back();
Status pik_status = ParseInternalKey(largest->Encode(), &parsed_largest,
false /* log_err_key */); // TODO
pik_status.PermitUncheckedError();
assert(pik_status.ok());
if (parsed_largest.type == kTypeRangeDeletion &&
parsed_largest.sequence == kMaxSequenceNumber) {
// The file boundary has been artificially extended by a range tombstone.
// We do not need to adjust largest to properly truncate range
// tombstones that extend past the boundary.
} else if (parsed_largest.sequence == 0) {
// The largest key in the sstable has a sequence number of 0. Since we
// guarantee that no internal keys with the same user key and sequence
// number can exist in a DB, we know that the largest key in this sstable
// cannot exist as the smallest key in the next sstable. This further
// implies that no range tombstone in this sstable covers largest;
// otherwise, the file boundary would have been artificially extended.
//
// Therefore, we will never truncate a range tombstone at largest, so we
// can leave it unchanged.
// TODO: maybe use kMaxValid here to ensure range tombstone having
// distinct key from point keys.
} else {
// The same user key may straddle two sstable boundaries. To ensure that
// the truncated end key can cover the largest key in this sstable, reduce
// its sequence number by 1.
parsed_largest.sequence -= 1;
// This line is not needed for correctness, but it ensures that the
// truncated end key is not covering keys from the next SST file.
parsed_largest.type = kTypeMaxValid;
}
largest_ = &parsed_largest;
}
}
bool TruncatedRangeDelIterator::Valid() const {
assert(iter_ != nullptr);
return iter_->Valid() &&
(smallest_ == nullptr ||
icmp_->Compare(*smallest_, iter_->parsed_end_key()) < 0) &&
(largest_ == nullptr ||
icmp_->Compare(iter_->parsed_start_key(), *largest_) < 0);
}
// NOTE: target is a user key, with timestamp if enabled.
void TruncatedRangeDelIterator::Seek(const Slice& target) {
if (largest_ != nullptr &&
icmp_->Compare(*largest_, ParsedInternalKey(target, kMaxSequenceNumber,
kTypeRangeDeletion)) <= 0) {
iter_->Invalidate();
return;
}
if (smallest_ != nullptr &&
icmp_->user_comparator()->Compare(target, smallest_->user_key) < 0) {
iter_->Seek(smallest_->user_key);
return;
}
iter_->Seek(target);
}
void TruncatedRangeDelIterator::SeekInternalKey(const Slice& target) {
if (largest_ && icmp_->Compare(*largest_, target) <= 0) {
iter_->Invalidate();
return;
}
if (smallest_ && icmp_->Compare(target, *smallest_) < 0) {
// Since target < smallest, target < largest_.
// This seek must land on a range tombstone where end_key() > target,
// so there is no need to check again.
iter_->Seek(smallest_->user_key);
} else {
iter_->Seek(ExtractUserKey(target));
while (Valid() && icmp_->Compare(end_key(), target) <= 0) {
Next();
}
}
}
// NOTE: target is a user key, with timestamp if enabled.
void TruncatedRangeDelIterator::SeekForPrev(const Slice& target) {
if (smallest_ != nullptr &&
icmp_->Compare(ParsedInternalKey(target, 0, kTypeRangeDeletion),
*smallest_) < 0) {
iter_->Invalidate();
return;
}
if (largest_ != nullptr &&
icmp_->user_comparator()->Compare(largest_->user_key, target) < 0) {
iter_->SeekForPrev(largest_->user_key);
return;
}
iter_->SeekForPrev(target);
}
void TruncatedRangeDelIterator::SeekToFirst() {
if (smallest_ != nullptr) {
iter_->Seek(smallest_->user_key);
return;
}
iter_->SeekToTopFirst();
}
void TruncatedRangeDelIterator::SeekToLast() {
if (largest_ != nullptr) {
iter_->SeekForPrev(largest_->user_key);
return;
}
iter_->SeekToTopLast();
}
std::map<SequenceNumber, std::unique_ptr<TruncatedRangeDelIterator>>
TruncatedRangeDelIterator::SplitBySnapshot(
const std::vector<SequenceNumber>& snapshots) {
using FragmentedIterPair =
std::pair<const SequenceNumber,
std::unique_ptr<FragmentedRangeTombstoneIterator>>;
auto split_untruncated_iters = iter_->SplitBySnapshot(snapshots);
std::map<SequenceNumber, std::unique_ptr<TruncatedRangeDelIterator>>
split_truncated_iters;
std::for_each(
split_untruncated_iters.begin(), split_untruncated_iters.end(),
[&](FragmentedIterPair& iter_pair) {
auto truncated_iter = std::make_unique<TruncatedRangeDelIterator>(
std::move(iter_pair.second), icmp_, smallest_ikey_, largest_ikey_);
split_truncated_iters.emplace(iter_pair.first,
std::move(truncated_iter));
});
return split_truncated_iters;
}
ForwardRangeDelIterator::ForwardRangeDelIterator(
const InternalKeyComparator* icmp)
: icmp_(icmp),
unused_idx_(0),
active_seqnums_(SeqMaxComparator()),
active_iters_(EndKeyMinComparator(icmp)),
inactive_iters_(StartKeyMinComparator(icmp)) {}
bool ForwardRangeDelIterator::ShouldDelete(const ParsedInternalKey& parsed) {
// Move active iterators that end before parsed.
while (!active_iters_.empty() &&
icmp_->Compare((*active_iters_.top())->end_key(), parsed) <= 0) {
TruncatedRangeDelIterator* iter = PopActiveIter();
do {
iter->Next();
} while (iter->Valid() && icmp_->Compare(iter->end_key(), parsed) <= 0);
PushIter(iter, parsed);
assert(active_iters_.size() == active_seqnums_.size());
}
// Move inactive iterators that start before parsed.
while (!inactive_iters_.empty() &&
icmp_->Compare(inactive_iters_.top()->start_key(), parsed) <= 0) {
TruncatedRangeDelIterator* iter = PopInactiveIter();
while (iter->Valid() && icmp_->Compare(iter->end_key(), parsed) <= 0) {
iter->Next();
}
PushIter(iter, parsed);
assert(active_iters_.size() == active_seqnums_.size());
}
return active_seqnums_.empty()
? false
: (*active_seqnums_.begin())->seq() > parsed.sequence;
}
void ForwardRangeDelIterator::Invalidate() {
unused_idx_ = 0;
active_iters_.clear();
active_seqnums_.clear();
inactive_iters_.clear();
}
ReverseRangeDelIterator::ReverseRangeDelIterator(
const InternalKeyComparator* icmp)
: icmp_(icmp),
unused_idx_(0),
active_seqnums_(SeqMaxComparator()),
active_iters_(StartKeyMaxComparator(icmp)),
inactive_iters_(EndKeyMaxComparator(icmp)) {}
bool ReverseRangeDelIterator::ShouldDelete(const ParsedInternalKey& parsed) {
// Move active iterators that start after parsed.
while (!active_iters_.empty() &&
icmp_->Compare(parsed, (*active_iters_.top())->start_key()) < 0) {
TruncatedRangeDelIterator* iter = PopActiveIter();
do {
iter->Prev();
} while (iter->Valid() && icmp_->Compare(parsed, iter->start_key()) < 0);
PushIter(iter, parsed);
assert(active_iters_.size() == active_seqnums_.size());
}
// Move inactive iterators that end after parsed.
while (!inactive_iters_.empty() &&
icmp_->Compare(parsed, inactive_iters_.top()->end_key()) < 0) {
TruncatedRangeDelIterator* iter = PopInactiveIter();
while (iter->Valid() && icmp_->Compare(parsed, iter->start_key()) < 0) {
iter->Prev();
}
PushIter(iter, parsed);
assert(active_iters_.size() == active_seqnums_.size());
}
return active_seqnums_.empty()
? false
: (*active_seqnums_.begin())->seq() > parsed.sequence;
}
void ReverseRangeDelIterator::Invalidate() {
unused_idx_ = 0;
active_iters_.clear();
active_seqnums_.clear();
inactive_iters_.clear();
}
bool RangeDelAggregator::StripeRep::ShouldDelete(
const ParsedInternalKey& parsed, RangeDelPositioningMode mode) {
if (!InStripe(parsed.sequence) || IsEmpty()) {
return false;
}
switch (mode) {
case RangeDelPositioningMode::kForwardTraversal:
InvalidateReverseIter();
// Pick up previously unseen iterators.
for (auto it = std::next(iters_.begin(), forward_iter_.UnusedIdx());
it != iters_.end(); ++it, forward_iter_.IncUnusedIdx()) {
auto& iter = *it;
forward_iter_.AddNewIter(iter.get(), parsed);
}
return forward_iter_.ShouldDelete(parsed);
case RangeDelPositioningMode::kBackwardTraversal:
InvalidateForwardIter();
// Pick up previously unseen iterators.
for (auto it = std::next(iters_.begin(), reverse_iter_.UnusedIdx());
it != iters_.end(); ++it, reverse_iter_.IncUnusedIdx()) {
auto& iter = *it;
reverse_iter_.AddNewIter(iter.get(), parsed);
}
return reverse_iter_.ShouldDelete(parsed);
default:
assert(false);
return false;
}
}
bool RangeDelAggregator::StripeRep::IsRangeOverlapped(const Slice& start,
const Slice& end) {
Invalidate();
// Set the internal start/end keys so that:
// - if start_ikey has the same user key and sequence number as the
// current end key, start_ikey will be considered greater; and
// - if end_ikey has the same user key and sequence number as the current
// start key, end_ikey will be considered greater.
ParsedInternalKey start_ikey(start, kMaxSequenceNumber,
static_cast<ValueType>(0));
ParsedInternalKey end_ikey(end, 0, static_cast<ValueType>(0));
for (auto& iter : iters_) {
bool checked_candidate_tombstones = false;
for (iter->SeekForPrev(start);
iter->Valid() && icmp_->Compare(iter->start_key(), end_ikey) <= 0;
iter->Next()) {
checked_candidate_tombstones = true;
if (icmp_->Compare(start_ikey, iter->end_key()) < 0 &&
icmp_->Compare(iter->start_key(), end_ikey) <= 0) {
return true;
}
}
if (!checked_candidate_tombstones) {
// Do an additional check for when the end of the range is the begin
// key of a tombstone, which we missed earlier since SeekForPrev'ing
// to the start was invalid.
iter->SeekForPrev(end);
if (iter->Valid() && icmp_->Compare(start_ikey, iter->end_key()) < 0 &&
icmp_->Compare(iter->start_key(), end_ikey) <= 0) {
return true;
}
}
}
return false;
}
void ReadRangeDelAggregator::AddTombstones(
std::unique_ptr<FragmentedRangeTombstoneIterator> input_iter,
const InternalKey* smallest, const InternalKey* largest) {
if (input_iter == nullptr || input_iter->empty()) {
return;
}
rep_.AddTombstones(std::make_unique<TruncatedRangeDelIterator>(
std::move(input_iter), icmp_, smallest, largest));
}
bool ReadRangeDelAggregator::ShouldDeleteImpl(const ParsedInternalKey& parsed,
RangeDelPositioningMode mode) {
return rep_.ShouldDelete(parsed, mode);
}
bool ReadRangeDelAggregator::IsRangeOverlapped(const Slice& start,
const Slice& end) {
InvalidateRangeDelMapPositions();
return rep_.IsRangeOverlapped(start, end);
}
void CompactionRangeDelAggregator::AddTombstones(
std::unique_ptr<FragmentedRangeTombstoneIterator> input_iter,
const InternalKey* smallest, const InternalKey* largest) {
if (input_iter == nullptr || input_iter->empty()) {
return;
}
// This bounds output of CompactionRangeDelAggregator::NewIterator.
if (!trim_ts_.empty()) {
assert(icmp_->user_comparator()->timestamp_size() > 0);
input_iter->SetTimestampUpperBound(&trim_ts_);
}
assert(input_iter->lower_bound() == 0);
assert(input_iter->upper_bound() == kMaxSequenceNumber);
parent_iters_.emplace_back(new TruncatedRangeDelIterator(
std::move(input_iter), icmp_, smallest, largest));
Slice* ts_upper_bound = nullptr;
if (!ts_upper_bound_.empty()) {
assert(icmp_->user_comparator()->timestamp_size() > 0);
ts_upper_bound = &ts_upper_bound_;
}
auto split_iters = parent_iters_.back()->SplitBySnapshot(*snapshots_);
for (auto& split_iter : split_iters) {
auto it = reps_.find(split_iter.first);
if (it == reps_.end()) {
bool inserted;
SequenceNumber upper_bound = split_iter.second->upper_bound();
SequenceNumber lower_bound = split_iter.second->lower_bound();
std::tie(it, inserted) = reps_.emplace(
split_iter.first, StripeRep(icmp_, upper_bound, lower_bound));
assert(inserted);
}
assert(it != reps_.end());
// ts_upper_bound is used to bound ShouldDelete() to only consider
// range tombstones under full_history_ts_low_ and trim_ts_. Keys covered by
// range tombstones that are above full_history_ts_low_ should not be
// dropped prematurely: user may read with a timestamp between the range
// tombstone and the covered key. Note that we cannot set timestamp
// upperbound on the original `input_iter` since `input_iter`s are later
// used in CompactionRangeDelAggregator::NewIterator to output range
// tombstones for persistence. We do not want to only persist range
// tombstones with timestamp lower than ts_upper_bound.
split_iter.second->SetTimestampUpperBound(ts_upper_bound);
it->second.AddTombstones(std::move(split_iter.second));
}
}
bool CompactionRangeDelAggregator::ShouldDelete(const ParsedInternalKey& parsed,
RangeDelPositioningMode mode) {
auto it = reps_.lower_bound(parsed.sequence);
if (it == reps_.end()) {
return false;
}
return it->second.ShouldDelete(parsed, mode);
}
namespace {
// Produce a sorted (by start internal key) stream of range tombstones from
// `children`. lower_bound and upper_bound on internal key can be
// optionally specified. Range tombstones that ends before lower_bound or starts
// after upper_bound are excluded.
// If user-defined timestamp is enabled, lower_bound and upper_bound should
// contain timestamp.
class TruncatedRangeDelMergingIter : public InternalIterator {
public:
TruncatedRangeDelMergingIter(
const InternalKeyComparator* icmp, const Slice* lower_bound,
const Slice* upper_bound,
const std::vector<std::unique_ptr<TruncatedRangeDelIterator>>& children)
: icmp_(icmp),
lower_bound_(lower_bound),
upper_bound_(upper_bound),
heap_(StartKeyMinComparator(icmp)),
ts_sz_(icmp_->user_comparator()->timestamp_size()) {
for (auto& child : children) {
if (child != nullptr) {
assert(child->lower_bound() == 0);
assert(child->upper_bound() == kMaxSequenceNumber);
children_.push_back(child.get());
}
}
}
bool Valid() const override {
return !heap_.empty() && !AfterEndKey(heap_.top());
}
Status status() const override { return Status::OK(); }
void SeekToFirst() override {
heap_.clear();
for (auto& child : children_) {
if (lower_bound_ != nullptr) {
child->Seek(ExtractUserKey(*lower_bound_));
// Since the above `Seek()` operates on a user key while `lower_bound_`
// is an internal key, we may need to advance `child` farther for it to
// be in bounds.
while (child->Valid() && BeforeStartKey(child)) {
child->InternalNext();
}
} else {
child->SeekToFirst();
}
if (child->Valid()) {
heap_.push(child);
}
}
}
void Next() override {
auto* top = heap_.top();
top->InternalNext();
if (top->Valid()) {
heap_.replace_top(top);
} else {
heap_.pop();
}
}
Slice key() const override {
auto* top = heap_.top();
if (ts_sz_) {
cur_start_key_.Set(top->start_key().user_key, top->seq(),
kTypeRangeDeletion, top->timestamp());
} else {
cur_start_key_.Set(top->start_key().user_key, top->seq(),
kTypeRangeDeletion);
}
assert(top->start_key().user_key.size() >= ts_sz_);
return cur_start_key_.Encode();
}
Slice value() const override {
auto* top = heap_.top();
if (!ts_sz_) {
return top->end_key().user_key;
}
assert(top->timestamp().size() == ts_sz_);
cur_end_key_.clear();
cur_end_key_.append(top->end_key().user_key.data(),
top->end_key().user_key.size() - ts_sz_);
cur_end_key_.append(top->timestamp().data(), ts_sz_);
return cur_end_key_;
}
// Unused InternalIterator methods
void Prev() override { assert(false); }
void Seek(const Slice& /* target */) override { assert(false); }
void SeekForPrev(const Slice& /* target */) override { assert(false); }
void SeekToLast() override { assert(false); }
private:
bool BeforeStartKey(const TruncatedRangeDelIterator* iter) const {
if (lower_bound_ == nullptr) {
return false;
}
return icmp_->Compare(iter->end_key(), *lower_bound_) <= 0;
}
bool AfterEndKey(const TruncatedRangeDelIterator* iter) const {
if (upper_bound_ == nullptr) {
return false;
}
return icmp_->Compare(iter->start_key(), *upper_bound_) > 0;
}
const InternalKeyComparator* icmp_;
const Slice* lower_bound_;
const Slice* upper_bound_;
BinaryHeap<TruncatedRangeDelIterator*, StartKeyMinComparator> heap_;
std::vector<TruncatedRangeDelIterator*> children_;
mutable InternalKey cur_start_key_;
mutable std::string cur_end_key_;
size_t ts_sz_;
};
} // anonymous namespace
std::unique_ptr<FragmentedRangeTombstoneIterator>
CompactionRangeDelAggregator::NewIterator(const Slice* lower_bound,
const Slice* upper_bound) {
InvalidateRangeDelMapPositions();
auto merging_iter = std::make_unique<TruncatedRangeDelMergingIter>(
icmp_, lower_bound, upper_bound, parent_iters_);
auto fragmented_tombstone_list =
std::make_shared<FragmentedRangeTombstoneList>(
std::move(merging_iter), *icmp_, true /* for_compaction */,
*snapshots_);
return std::make_unique<FragmentedRangeTombstoneIterator>(
fragmented_tombstone_list, *icmp_, kMaxSequenceNumber /* upper_bound */);
}
} // namespace ROCKSDB_NAMESPACE