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).
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
#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"
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
namespace ROCKSDB_NAMESPACE {
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
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) {
if (smallest != nullptr) {
pinned_bounds_.emplace_back();
auto& parsed_smallest = pinned_bounds_.back();
if (!ParseInternalKey(smallest->Encode(), &parsed_smallest)) {
assert(false);
}
smallest_ = &parsed_smallest;
}
if (largest != nullptr) {
pinned_bounds_.emplace_back();
auto& parsed_largest = pinned_bounds_.back();
if (!ParseInternalKey(largest->Encode(), &parsed_largest)) {
assert(false);
}
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.
} 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;
}
largest_ = &parsed_largest;
}
}
bool TruncatedRangeDelIterator::Valid() const {
return iter_->Valid() &&
(smallest_ == nullptr ||
icmp_->Compare(*smallest_, iter_->parsed_end_key()) < 0) &&
(largest_ == nullptr ||
icmp_->Compare(iter_->parsed_start_key(), *largest_) < 0);
}
void TruncatedRangeDelIterator::Next() { iter_->TopNext(); }
void TruncatedRangeDelIterator::Prev() { iter_->TopPrev(); }
void TruncatedRangeDelIterator::InternalNext() { iter_->Next(); }
// NOTE: target is a user key
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);
}
// NOTE: target is a user key
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) {
std::unique_ptr<TruncatedRangeDelIterator> truncated_iter(
new 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();
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
}
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();
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
}
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;
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
}
}
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;
}
}
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
}
return false;
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
}
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::unique_ptr<TruncatedRangeDelIterator>(new 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);
Compaction Support for Range Deletion Summary: This diff introduces RangeDelAggregator, which takes ownership of iterators provided to it via AddTombstones(). The tombstones are organized in a two-level map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data copy by holding Slices returned by the iterator, which remain valid thanks to pinning. For compaction, we create a hierarchical range tombstone iterator with structure matching the iterator over compaction input data. An aggregator based on that iterator is used by CompactionIterator to determine which keys are covered by range tombstones. In case of merge operand, the same aggregator is used by MergeHelper. Upon finishing each file in the compaction, relevant range tombstones are added to the output file's range tombstone metablock and file boundaries are updated accordingly. To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete() considers tombstones in the key's snapshot stripe. When this function is used outside of compaction, it also checks newer stripes, which can contain covering tombstones. Currently the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges within a stripe such that binary search can be used. RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range to a new table's range tombstone meta-block. Since range tombstones may fall in the gap between files, we may need to extend some files' key-ranges. The strategy is (1) first file extends as far left as possible and other files do not extend left, (2) all files extend right until either the start of the next file or the end of the last range tombstone in the gap, whichever comes first. One other notable change is adding release/move semantics to ScopedArenaIterator such that it can be used to transfer ownership of an arena-allocated iterator, similar to how unique_ptr is used for malloc'd data. Depends on D61473 Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927 Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark Reviewed By: lightmark Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 21:04:56 +02:00
}
void CompactionRangeDelAggregator::AddTombstones(
std::unique_ptr<FragmentedRangeTombstoneIterator> input_iter,
const InternalKey* smallest, const InternalKey* largest) {
if (input_iter == nullptr || input_iter->empty()) {
return;
}
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));
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());
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;
Recommit "Avoid adding tombstones of the same file to RangeDelAggregator multiple times" Summary: The origin commit #3635 will hurt performance for users who aren't using range deletions, because unneeded std::set operations, so it was reverted by commit 44653c7b7aabe821e671946e732dda7ae6b43d1b. (see #3672) To fix this, move the set to and add a check in , i.e., file will be added only if is non-nullptr. The db_bench command which find the performance regression: > ./db_bench --benchmarks=fillrandom,seekrandomwhilewriting --threads=1 --num=1000000 --reads=150000 --key_size=66 > --value_size=1262 --statistics=0 --compression_ratio=0.5 --histogram=1 --seek_nexts=1 --stats_per_interval=1 > --stats_interval_seconds=600 --max_background_flushes=4 --num_multi_db=1 --max_background_compactions=16 --seed=1522388277 > -write_buffer_size=1048576 --level0_file_num_compaction_trigger=10000 --compression_type=none Before and after the modification, I re-run this command on the machine, the results of are as follows: **fillrandom** Table | P50 | P75 | P99 | P99.9 | P99.99 | ---- | --- | --- | --- | ----- | ------ | before commit | 5.92 | 8.57 | 19.63 | 980.97 | 12196.00 | after commit | 5.91 | 8.55 | 19.34 | 965.56 | 13513.56 | **seekrandomwhilewriting** Table | P50 | P75 | P99 | P99.9 | P99.99 | ---- | --- | --- | --- | ----- | ------ | before commit | 1418.62 | 1867.01 | 3823.28 | 4980.99 | 9240.00 | after commit | 1450.54 | 1880.61 | 3962.87 | 5429.60 | 7542.86 | Closes https://github.com/facebook/rocksdb/pull/3800 Differential Revision: D7874245 Pulled By: ajkr fbshipit-source-id: 2e8bec781b3f7399246babd66395c88619534a17
2018-05-05 01:37:39 +02:00
}
return it->second.ShouldDelete(parsed, mode);
Recommit "Avoid adding tombstones of the same file to RangeDelAggregator multiple times" Summary: The origin commit #3635 will hurt performance for users who aren't using range deletions, because unneeded std::set operations, so it was reverted by commit 44653c7b7aabe821e671946e732dda7ae6b43d1b. (see #3672) To fix this, move the set to and add a check in , i.e., file will be added only if is non-nullptr. The db_bench command which find the performance regression: > ./db_bench --benchmarks=fillrandom,seekrandomwhilewriting --threads=1 --num=1000000 --reads=150000 --key_size=66 > --value_size=1262 --statistics=0 --compression_ratio=0.5 --histogram=1 --seek_nexts=1 --stats_per_interval=1 > --stats_interval_seconds=600 --max_background_flushes=4 --num_multi_db=1 --max_background_compactions=16 --seed=1522388277 > -write_buffer_size=1048576 --level0_file_num_compaction_trigger=10000 --compression_type=none Before and after the modification, I re-run this command on the machine, the results of are as follows: **fillrandom** Table | P50 | P75 | P99 | P99.9 | P99.99 | ---- | --- | --- | --- | ----- | ------ | before commit | 5.92 | 8.57 | 19.63 | 980.97 | 12196.00 | after commit | 5.91 | 8.55 | 19.34 | 965.56 | 13513.56 | **seekrandomwhilewriting** Table | P50 | P75 | P99 | P99.9 | P99.99 | ---- | --- | --- | --- | ----- | ------ | before commit | 1418.62 | 1867.01 | 3823.28 | 4980.99 | 9240.00 | after commit | 1450.54 | 1880.61 | 3962.87 | 5429.60 | 7542.86 | Closes https://github.com/facebook/rocksdb/pull/3800 Differential Revision: D7874245 Pulled By: ajkr fbshipit-source-id: 2e8bec781b3f7399246babd66395c88619534a17
2018-05-05 01:37:39 +02:00
}
namespace {
class TruncatedRangeDelMergingIter : public InternalIterator {
public:
TruncatedRangeDelMergingIter(
const InternalKeyComparator* icmp, const Slice* lower_bound,
const Slice* upper_bound, bool upper_bound_inclusive,
const std::vector<std::unique_ptr<TruncatedRangeDelIterator>>& children)
: icmp_(icmp),
lower_bound_(lower_bound),
upper_bound_(upper_bound),
upper_bound_inclusive_(upper_bound_inclusive),
heap_(StartKeyMinComparator(icmp)) {
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() && BeforeEndKey(heap_.top());
}
Status status() const override { return Status::OK(); }
void SeekToFirst() override {
heap_.clear();
for (auto& child : children_) {
if (lower_bound_ != nullptr) {
child->Seek(*lower_bound_);
} 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();
cur_start_key_.Set(top->start_key().user_key, top->seq(),
kTypeRangeDeletion);
return cur_start_key_.Encode();
}
Slice value() const override {
auto* top = heap_.top();
assert(top->end_key().sequence == kMaxSequenceNumber);
return top->end_key().user_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 BeforeEndKey(const TruncatedRangeDelIterator* iter) const {
if (upper_bound_ == nullptr) {
return true;
}
int cmp = icmp_->user_comparator()->Compare(iter->start_key().user_key,
*upper_bound_);
return upper_bound_inclusive_ ? cmp <= 0 : cmp < 0;
}
const InternalKeyComparator* icmp_;
const Slice* lower_bound_;
const Slice* upper_bound_;
bool upper_bound_inclusive_;
BinaryHeap<TruncatedRangeDelIterator*, StartKeyMinComparator> heap_;
std::vector<TruncatedRangeDelIterator*> children_;
mutable InternalKey cur_start_key_;
};
} // namespace
std::unique_ptr<FragmentedRangeTombstoneIterator>
CompactionRangeDelAggregator::NewIterator(const Slice* lower_bound,
const Slice* upper_bound,
bool upper_bound_inclusive) {
InvalidateRangeDelMapPositions();
std::unique_ptr<TruncatedRangeDelMergingIter> merging_iter(
new TruncatedRangeDelMergingIter(icmp_, lower_bound, upper_bound,
upper_bound_inclusive, parent_iters_));
auto fragmented_tombstone_list =
std::make_shared<FragmentedRangeTombstoneList>(
std::move(merging_iter), *icmp_, true /* for_compaction */,
*snapshots_);
return std::unique_ptr<FragmentedRangeTombstoneIterator>(
new FragmentedRangeTombstoneIterator(
fragmented_tombstone_list, *icmp_,
kMaxSequenceNumber /* upper_bound */));
}
} // namespace ROCKSDB_NAMESPACE