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rocksdb/db/range_del_aggregator.cc

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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
8 years ago
// Copyright (c) 2016-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
8 years ago
#include "db/range_del_aggregator.h"
#include "util/heap.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
8 years ago
#include <algorithm>
namespace rocksdb {
struct TombstoneStartKeyComparator {
explicit TombstoneStartKeyComparator(const InternalKeyComparator* c)
: cmp(c) {}
bool operator()(const TruncatedRangeTombstone& a,
const TruncatedRangeTombstone& b) const {
return cmp->Compare(a.start_key_, b.start_key_) < 0;
}
const InternalKeyComparator* cmp;
};
struct ParsedInternalKeyComparator {
explicit ParsedInternalKeyComparator(const InternalKeyComparator* c)
: cmp(c) {}
bool operator()(const ParsedInternalKey& a,
const ParsedInternalKey& b) const {
return cmp->Compare(a, b) < 0;
}
const InternalKeyComparator* cmp;
};
// An UncollapsedRangeDelMap is quick to create but slow to answer ShouldDelete
// queries.
class UncollapsedRangeDelMap : public RangeDelMap {
typedef std::vector<TruncatedRangeTombstone> Rep;
class Iterator : public RangeDelIterator {
const Rep& rep_;
Rep::const_iterator iter_;
public:
Iterator(const Rep& rep) : rep_(rep), iter_(rep.begin()) {}
bool Valid() const override { return iter_ != rep_.end(); }
void Next() override { iter_++; }
void Seek(const Slice&) override {
fprintf(stderr,
"UncollapsedRangeDelMap::Iterator::Seek(Slice&) unimplemented\n");
abort();
}
void Seek(const ParsedInternalKey&) override {
fprintf(stderr,
"UncollapsedRangeDelMap::Iterator::Seek(ParsedInternalKey&) "
"unimplemented\n");
abort();
}
RangeTombstone Tombstone() const override { return iter_->Tombstone(); }
};
Rep rep_;
const InternalKeyComparator* icmp_;
public:
explicit UncollapsedRangeDelMap(const InternalKeyComparator* icmp)
: icmp_(icmp) {}
bool ShouldDelete(const ParsedInternalKey& parsed,
RangeDelPositioningMode mode) override {
(void)mode;
assert(mode == RangeDelPositioningMode::kFullScan);
for (const auto& tombstone : rep_) {
if (icmp_->Compare(parsed, tombstone.start_key_) < 0) {
continue;
}
if (parsed.sequence < tombstone.seq_ &&
icmp_->Compare(parsed, tombstone.end_key_) < 0) {
return true;
}
}
return false;
}
bool IsRangeOverlapped(const ParsedInternalKey& start,
const ParsedInternalKey& end) override {
for (const auto& tombstone : rep_) {
if (icmp_->Compare(start, tombstone.end_key_) < 0 &&
icmp_->Compare(tombstone.start_key_, end) <= 0 &&
icmp_->Compare(tombstone.start_key_, tombstone.end_key_) < 0) {
return true;
}
}
return false;
}
void AddTombstone(TruncatedRangeTombstone tombstone) override {
rep_.emplace_back(tombstone);
}
size_t Size() const override { return rep_.size(); }
void InvalidatePosition() override {} // no-op
std::unique_ptr<RangeDelIterator> NewIterator() override {
std::sort(rep_.begin(), rep_.end(), TombstoneStartKeyComparator(icmp_));
return std::unique_ptr<RangeDelIterator>(new Iterator(this->rep_));
}
};
// A CollapsedRangeDelMap is slow to create but quick to answer ShouldDelete
// queries.
//
// An explanation of the design follows. Suppose we have tombstones [b, n) @ 1,
// [e, h) @ 2, [q, t) @ 2, and [g, k) @ 3. Visually, the tombstones look like
// this:
//
// 3: g---k
// 2: e---h q--t
// 1: b------------n
//
// The CollapsedRangeDelMap representation is based on the observation that
// wherever tombstones overlap, we need only store the tombstone with the
// largest seqno. From the perspective of a read at seqno 4 or greater, this set
// of tombstones is exactly equivalent:
//
// 3: g---k
// 2: e--g q--t
// 1: b--e k--n
//
// Because these tombstones do not overlap, they can be efficiently represented
// in an ordered map from keys to sequence numbers. Each entry should be thought
// of as a transition from one tombstone to the next. In this example, the
// CollapsedRangeDelMap would store the following entries, in order:
//
// b → 1, e → 2, g → 3, k → 1, n → 0, q → 2, t → 0
//
// If a tombstone ends before the next tombstone begins, a sentinel seqno of 0
// is installed to indicate that no tombstone exists. This occurs at keys n and
// t in the example above.
//
// To check whether a key K is covered by a tombstone, the map is binary
// searched for the last key less than K. K is covered iff the map entry has a
// larger seqno than K. As an example, consider the key h @ 4. It would be
// compared against the map entry g → 3 and determined to be uncovered. By
// contrast, the key h @ 2 would be determined to be covered.
class CollapsedRangeDelMap : public RangeDelMap {
typedef std::map<ParsedInternalKey, SequenceNumber,
ParsedInternalKeyComparator>
Rep;
class Iterator : public RangeDelIterator {
void MaybeSeekPastSentinel() {
if (Valid() && iter_->second == 0) {
iter_++;
}
}
const Rep& rep_;
Rep::const_iterator iter_;
public:
Iterator(const Rep& rep) : rep_(rep), iter_(rep.begin()) {}
bool Valid() const override { return iter_ != rep_.end(); }
void Next() override {
iter_++;
MaybeSeekPastSentinel();
}
void Seek(const Slice&) override {
fprintf(stderr, "CollapsedRangeDelMap::Iterator::Seek(Slice&) unimplemented\n");
abort();
}
void Seek(const ParsedInternalKey& target) override {
iter_ = rep_.upper_bound(target);
if (iter_ != rep_.begin()) {
iter_--;
}
MaybeSeekPastSentinel();
}
RangeTombstone Tombstone() const override {
assert(Valid());
assert(std::next(iter_) != rep_.end());
assert(iter_->second != 0);
RangeTombstone tombstone;
tombstone.start_key_ = iter_->first.user_key;
tombstone.end_key_ = std::next(iter_)->first.user_key;
tombstone.seq_ = iter_->second;
return tombstone;
}
};
Rep rep_;
Rep::iterator iter_;
const InternalKeyComparator* icmp_;
public:
explicit CollapsedRangeDelMap(const InternalKeyComparator* icmp)
: rep_(ParsedInternalKeyComparator(icmp)),
icmp_(icmp) {
InvalidatePosition();
}
bool ShouldDelete(const ParsedInternalKey& parsed,
RangeDelPositioningMode mode) override {
if (iter_ == rep_.end() &&
(mode == RangeDelPositioningMode::kForwardTraversal ||
mode == RangeDelPositioningMode::kBackwardTraversal)) {
// invalid (e.g., if AddTombstones() changed the deletions), so need to
// reseek
mode = RangeDelPositioningMode::kBinarySearch;
}
switch (mode) {
case RangeDelPositioningMode::kFullScan:
assert(false);
case RangeDelPositioningMode::kForwardTraversal:
assert(iter_ != rep_.end());
if (iter_ == rep_.begin() &&
icmp_->Compare(parsed, iter_->first) < 0) {
// before start of deletion intervals
return false;
}
while (std::next(iter_) != rep_.end() &&
icmp_->Compare(std::next(iter_)->first, parsed) <= 0) {
++iter_;
}
break;
case RangeDelPositioningMode::kBackwardTraversal:
assert(iter_ != rep_.end());
while (iter_ != rep_.begin() &&
icmp_->Compare(parsed, iter_->first) < 0) {
--iter_;
}
if (iter_ == rep_.begin() &&
icmp_->Compare(parsed, iter_->first) < 0) {
// before start of deletion intervals
return false;
}
break;
case RangeDelPositioningMode::kBinarySearch:
iter_ = rep_.upper_bound(parsed);
if (iter_ == rep_.begin()) {
// before start of deletion intervals
return false;
}
--iter_;
break;
}
assert(iter_ != rep_.end() &&
icmp_->Compare(iter_->first, parsed) <= 0);
assert(std::next(iter_) == rep_.end() ||
icmp_->Compare(parsed, std::next(iter_)->first) < 0);
return parsed.sequence < iter_->second;
}
bool IsRangeOverlapped(const ParsedInternalKey&,
const ParsedInternalKey&) override {
// Unimplemented because the only client of this method, file ingestion,
// uses uncollapsed maps.
fprintf(stderr, "CollapsedRangeDelMap::IsRangeOverlapped unimplemented");
abort();
}
void AddTombstone(TruncatedRangeTombstone t) override {
if (icmp_->Compare(t.start_key_, t.end_key_) >= 0 || t.seq_ == 0) {
// The tombstone covers no keys. Nothing to do.
return;
}
auto it = rep_.upper_bound(t.start_key_);
auto prev_seq = [&]() {
return it == rep_.begin() ? 0 : std::prev(it)->second;
};
// end_seq stores the seqno of the last transition that the new tombstone
// covered. This is the seqno that we'll install if we need to insert a
// transition for the new tombstone's end key.
SequenceNumber end_seq = 0;
// In the diagrams below, the new tombstone is always [c, k) @ 2. The
// existing tombstones are varied to depict different scenarios. Uppercase
// letters are used to indicate points that exist in the map, while
// lowercase letters are used to indicate points that do not exist in the
// map. The location of the iterator is marked with a caret; it may point
// off the end of the diagram to indicate that it is positioned at a
// entry with a larger key whose specific key is irrelevant.
if (t.seq_ > prev_seq()) {
// The new tombstone's start point covers the existing tombstone:
//
// 3: 3: A--C 3: 3:
// 2: c--- OR 2: c--- OR 2: c--- OR 2: c------
// 1: A--C 1: 1: A------ 1: C------
// ^ ^ ^ ^
end_seq = prev_seq();
Rep::iterator pit;
if (it != rep_.begin() && (pit = std::prev(it)) != rep_.begin() &&
icmp_->Compare(pit->first, t.start_key_) == 0 &&
std::prev(pit)->second == t.seq_) {
// The new tombstone starts at the end of an existing tombstone with an
// identical seqno:
//
// 3:
// 2: A--C---
// 1:
// ^
// Merge the tombstones by removing the existing tombstone's end key.
it = rep_.erase(std::prev(it));
} else {
// Insert a new transition at the new tombstone's start point, or raise
// the existing transition at that point to the new tombstone's seqno.
rep_[t.start_key_] = t.seq_; // operator[] will overwrite existing entry
}
} else {
// The new tombstone's start point is covered by an existing tombstone:
//
// 3: A----- OR 3: C------ OR
// 2: c--- 2: c------ 2: C------
// ^ ^ ^
// Do nothing.
}
// Look at all the existing transitions that overlap the new tombstone.
while (it != rep_.end() && icmp_->Compare(it->first, t.end_key_) < 0) {
if (t.seq_ >= it->second) {
// The transition is to an existing tombstone that the new tombstone
// covers. Save the covered tombstone's seqno. We'll need to return to
// it if the new tombstone ends before the existing tombstone.
end_seq = it->second;
if (t.seq_ == prev_seq()) {
// The previous transition is to the seqno of the new tombstone:
//
// 3: 3: 3: --F
// 2: C------ OR 2: C------ OR 2: F----
// 1: F--- 1: ---F 1: H--
// ^ ^ ^
//
// Erase this transition. It's been superseded.
it = rep_.erase(it);
continue; // skip increment; erase positions iterator correctly
} else {
// The previous transition is to a tombstone that covers the new
// tombstone, but this transition is to a tombstone that is covered by
// the new tombstone. That is, this is the end of a run of existing
// tombstones that cover the new tombstone:
//
// 3: A---E OR 3: E-G
// 2: c---- 2: ------
// ^ ^
// Preserve this transition point, but raise it to the new tombstone's
// seqno.
it->second = t.seq_;
}
} else {
// The transition is to an existing tombstone that covers the new
// tombstone:
//
// 4: 4: --F
// 3: F-- OR 3: F--
// 2: ----- 2: -----
// ^ ^
// Do nothing.
}
++it;
}
if (t.seq_ == prev_seq()) {
// The new tombstone is unterminated in the map.
if (it != rep_.end() && t.seq_ == it->second &&
icmp_->Compare(it->first, t.end_key_) == 0) {
// The new tombstone ends at the start of another tombstone with an
// identical seqno. Merge the tombstones by removing the existing
// tombstone's start key.
rep_.erase(it);
} else if (end_seq == prev_seq() ||
(it != rep_.end() && end_seq == it->second)) {
// The new tombstone is implicitly ended because its end point is
// contained within an existing tombstone with the same seqno:
//
// 2: ---k--N
// ^
} else {
// The new tombstone needs an explicit end point.
//
// 3: OR 3: --G OR 3: --G K--
// 2: C-------k 2: G---k 2: G---k
// ^ ^ ^
// Install one that returns to the last seqno we covered. Because end
// keys are exclusive, if there's an existing transition at t.end_key_,
// it takes precedence over the transition that we install here.
rep_.emplace(t.end_key_,
end_seq); // emplace is a noop if existing entry
}
} else {
// The new tombstone is implicitly ended because its end point is covered
// by an existing tombstone with a higher seqno.
//
// 3: I---M OR 3: A-----------M
// 2: ----k 2: c-------k
// ^ ^
// Do nothing.
}
}
size_t Size() const override { return rep_.empty() ? 0 : rep_.size() - 1; }
void InvalidatePosition() override { iter_ = rep_.end(); }
std::unique_ptr<RangeDelIterator> NewIterator() override {
return std::unique_ptr<RangeDelIterator>(new Iterator(this->rep_));
}
};
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
8 years ago
RangeDelAggregator::RangeDelAggregator(
const InternalKeyComparator& icmp,
const std::vector<SequenceNumber>& snapshots,
bool collapse_deletions /* = true */)
: upper_bound_(kMaxSequenceNumber),
icmp_(icmp),
collapse_deletions_(collapse_deletions) {
InitRep(snapshots);
}
RangeDelAggregator::RangeDelAggregator(const InternalKeyComparator& icmp,
SequenceNumber snapshot,
bool collapse_deletions /* = false */)
: upper_bound_(snapshot),
icmp_(icmp),
collapse_deletions_(collapse_deletions) {}
void RangeDelAggregator::InitRep(const std::vector<SequenceNumber>& snapshots) {
assert(rep_ == nullptr);
rep_.reset(new Rep());
rep_->snapshots_ = snapshots;
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
8 years ago
// Data newer than any snapshot falls in this catch-all stripe
rep_->snapshots_.emplace_back(kMaxSequenceNumber);
rep_->pinned_iters_mgr_.StartPinning();
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
8 years ago
}
std::unique_ptr<RangeDelMap> RangeDelAggregator::NewRangeDelMap() {
RangeDelMap* tombstone_map;
if (collapse_deletions_) {
tombstone_map = new CollapsedRangeDelMap(&icmp_);
} else {
tombstone_map = new UncollapsedRangeDelMap(&icmp_);
}
return std::unique_ptr<RangeDelMap>(tombstone_map);
}
bool RangeDelAggregator::ShouldDeleteImpl(const Slice& internal_key,
RangeDelPositioningMode mode) {
assert(rep_ != nullptr);
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
8 years ago
ParsedInternalKey parsed;
if (!ParseInternalKey(internal_key, &parsed)) {
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
8 years ago
}
return ShouldDeleteImpl(parsed, mode);
}
bool RangeDelAggregator::ShouldDeleteImpl(const ParsedInternalKey& parsed,
RangeDelPositioningMode mode) {
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
8 years ago
assert(IsValueType(parsed.type));
assert(rep_ != nullptr);
auto* tombstone_map = GetRangeDelMapIfExists(parsed.sequence);
if (tombstone_map == nullptr || tombstone_map->IsEmpty()) {
return false;
}
return tombstone_map->ShouldDelete(parsed, mode);
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
8 years ago
}
bool RangeDelAggregator::IsRangeOverlapped(const Slice& start,
const Slice& end) {
// Unimplemented because the only client of this method, file ingestion,
// uses uncollapsed maps.
assert(!collapse_deletions_);
if (rep_ == nullptr) {
return false;
}
ParsedInternalKey start_ikey(start, kMaxSequenceNumber, kMaxValue);
ParsedInternalKey end_ikey(end, 0, static_cast<ValueType>(0));
for (const auto& stripe : rep_->stripe_map_) {
if (stripe.second.first->IsRangeOverlapped(start_ikey, end_ikey)) {
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
8 years ago
return true;
}
}
return false;
}
Status RangeDelAggregator::AddTombstones(
std::unique_ptr<InternalIterator> input,
const InternalKey* smallest,
const InternalKey* largest) {
if (input == nullptr) {
return Status::OK();
}
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
8 years ago
input->SeekToFirst();
bool first_iter = 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
8 years ago
while (input->Valid()) {
if (first_iter) {
if (rep_ == nullptr) {
InitRep({upper_bound_});
} else {
InvalidateRangeDelMapPositions();
}
first_iter = false;
}
ParsedInternalKey parsed_key;
bool parsed;
if (input->IsKeyPinned()) {
parsed = ParseInternalKey(input->key(), &parsed_key);
} else {
// The tombstone map holds slices into the iterator's memory. Make a
// copy of the key if it is not pinned.
rep_->pinned_slices_.emplace_back(input->key().data(),
input->key().size());
parsed = ParseInternalKey(rep_->pinned_slices_.back(), &parsed_key);
}
if (!parsed) {
return Status::Corruption("Unable to parse range tombstone InternalKey");
}
Slice end_user_key;
if (input->IsValuePinned()) {
end_user_key = input->value();
} else {
// The tombstone map holds slices into the iterator's memory. Make a
// copy of the value if it is not pinned.
rep_->pinned_slices_.emplace_back(input->value().data(),
input->value().size());
end_user_key = rep_->pinned_slices_.back();
}
ParsedInternalKey start_key(parsed_key.user_key, kMaxSequenceNumber,
kMaxValue);
ParsedInternalKey end_key(end_user_key, kMaxSequenceNumber, kMaxValue);
// Truncate the tombstone to the range [smallest, largest].
if (smallest != nullptr) {
ParsedInternalKey parsed_smallest;
if (ParseInternalKey(smallest->Encode(), &parsed_smallest) &&
icmp_.Compare(start_key, parsed_smallest) < 0) {
start_key.user_key = parsed_smallest.user_key;
start_key.sequence = parsed_smallest.sequence;
}
}
if (largest != nullptr) {
ParsedInternalKey parsed_largest;
if (ParseInternalKey(largest->Encode(), &parsed_largest) &&
icmp_.Compare(end_key, parsed_largest) > 0) {
end_key.user_key = parsed_largest.user_key;
if (parsed_largest.sequence != kMaxSequenceNumber) {
// The same user key straddles two adjacent sstables. To make sure we
// can truncate to a range that includes the largest point key in the
// first sstable, set the tombstone end key's sequence number to 1
// less than the largest key.
assert(parsed_largest.sequence != 0);
end_key.sequence = parsed_largest.sequence - 1;
} else {
// The SST file boundary was artificially extended by a range tombstone.
// We will not see any entries in this SST with this user key, so we
// can leave the seqnum at kMaxSequenceNumber.
}
}
}
TruncatedRangeTombstone tombstone(start_key, end_key, parsed_key.sequence);
GetRangeDelMap(parsed_key.sequence).AddTombstone(std::move(tombstone));
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
8 years ago
input->Next();
}
if (!first_iter) {
rep_->pinned_iters_mgr_.PinIterator(input.release(), false /* arena */);
}
return Status::OK();
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
8 years ago
}
void RangeDelAggregator::InvalidateRangeDelMapPositions() {
if (rep_ == nullptr) {
return;
}
for (auto& stripe : rep_->stripe_map_) {
stripe.second.first->InvalidatePosition();
}
}
RangeDelMap* RangeDelAggregator::GetRangeDelMapIfExists(SequenceNumber seq) {
assert(rep_ != nullptr);
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
8 years ago
// The stripe includes seqnum for the snapshot above and excludes seqnum for
// the snapshot below.
if (rep_->stripe_map_.empty()) {
return nullptr;
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
8 years ago
}
StripeMap::iterator iter = rep_->stripe_map_.lower_bound(seq);
if (iter == rep_->stripe_map_.end()) {
return nullptr;
}
size_t snapshot_idx = iter->second.second;
if (snapshot_idx > 0 && seq <= rep_->snapshots_[snapshot_idx - 1]) {
return nullptr;
}
return iter->second.first.get();
}
RangeDelMap& RangeDelAggregator::GetRangeDelMap(SequenceNumber seq) {
assert(rep_ != nullptr);
// The stripe includes seqnum for the snapshot above and excludes seqnum for
// the snapshot below.
std::vector<SequenceNumber>::iterator iter =
std::lower_bound(rep_->snapshots_.begin(), rep_->snapshots_.end(), seq);
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
8 years ago
// catch-all stripe justifies this assertion in either of above cases
assert(iter != rep_->snapshots_.end());
if (rep_->stripe_map_.find(*iter) == rep_->stripe_map_.end()) {
rep_->stripe_map_.emplace(
*iter,
std::make_pair(NewRangeDelMap(), iter - rep_->snapshots_.begin()));
}
return *rep_->stripe_map_[*iter].first;
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
8 years ago
}
bool RangeDelAggregator::IsEmpty() {
if (rep_ == nullptr) {
return true;
}
for (const auto& stripe : rep_->stripe_map_) {
if (!stripe.second.first->IsEmpty()) {
return false;
}
}
return true;
}
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
7 years ago
bool RangeDelAggregator::AddFile(uint64_t file_number) {
if (rep_ == nullptr) {
return true;
}
return rep_->added_files_.emplace(file_number).second;
}
class MergingRangeDelIter : public RangeDelIterator {
public:
MergingRangeDelIter(const Comparator* c)
: heap_(IterMinHeap(IterComparator(c))), current_(nullptr) {}
void AddIterator(std::unique_ptr<RangeDelIterator> iter) {
if (iter->Valid()) {
heap_.push(iter.get());
iters_.push_back(std::move(iter));
current_ = heap_.top();
}
}
bool Valid() const override { return current_ != nullptr; }
void Next() override {
current_->Next();
if (current_->Valid()) {
heap_.replace_top(current_);
} else {
heap_.pop();
}
current_ = heap_.empty() ? nullptr : heap_.top();
}
void Seek(const Slice& target) override {
ParsedInternalKey ikey(target, kMaxSequenceNumber, kMaxValue);
Seek(ikey);
}
void Seek(const ParsedInternalKey& target) override {
heap_.clear();
for (auto& iter : iters_) {
iter->Seek(target);
if (iter->Valid()) {
heap_.push(iter.get());
}
}
current_ = heap_.empty() ? nullptr : heap_.top();
}
RangeTombstone Tombstone() const override { return current_->Tombstone(); }
private:
struct IterComparator {
IterComparator(const Comparator* c) : cmp(c) {}
bool operator()(const RangeDelIterator* a,
const RangeDelIterator* b) const {
// Note: counterintuitively, returning the tombstone with the larger start
// key puts the tombstone with the smallest key at the top of the heap.
return cmp->Compare(a->Tombstone().start_key_,
b->Tombstone().start_key_) > 0;
}
const Comparator* cmp;
};
typedef BinaryHeap<RangeDelIterator*, IterComparator> IterMinHeap;
std::vector<std::unique_ptr<RangeDelIterator>> iters_;
IterMinHeap heap_;
RangeDelIterator* current_;
};
std::unique_ptr<RangeDelIterator> RangeDelAggregator::NewIterator() {
std::unique_ptr<MergingRangeDelIter> iter(
new MergingRangeDelIter(icmp_.user_comparator()));
if (rep_ != nullptr) {
for (const auto& stripe : rep_->stripe_map_) {
iter->AddIterator(stripe.second.first->NewIterator());
}
}
return std::move(iter);
}
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
8 years ago
} // namespace rocksdb