2946cadc46
Summary: as requested in D62259 Closes https://github.com/facebook/rocksdb/pull/1434 Differential Revision: D4099047 Pulled By: ajkr fbshipit-source-id: a258cfb
89 lines
4.1 KiB
C++
89 lines
4.1 KiB
C++
// Copyright (c) 2016-present, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under the BSD-style license found in the
|
|
// LICENSE file in the root directory of this source tree. An additional grant
|
|
// of patent rights can be found in the PATENTS file in the same directory.
|
|
|
|
#pragma once
|
|
|
|
#include <map>
|
|
#include <string>
|
|
#include <vector>
|
|
|
|
#include "db/dbformat.h"
|
|
#include "db/pinned_iterators_manager.h"
|
|
#include "db/version_edit.h"
|
|
#include "include/rocksdb/comparator.h"
|
|
#include "include/rocksdb/types.h"
|
|
#include "table/internal_iterator.h"
|
|
#include "table/scoped_arena_iterator.h"
|
|
#include "table/table_builder.h"
|
|
#include "util/kv_map.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
// A RangeDelAggregator aggregates range deletion tombstones as they are
|
|
// encountered in memtables/SST files. It provides methods that check whether a
|
|
// key is covered by range tombstones or write the relevant tombstones to a new
|
|
// SST file.
|
|
class RangeDelAggregator {
|
|
public:
|
|
// @param snapshots These are used to organize the tombstones into snapshot
|
|
// stripes, which is the seqnum range between consecutive snapshots,
|
|
// including the higher snapshot and excluding the lower one. Currently,
|
|
// this is used by ShouldDelete() to prevent deletion of keys that are
|
|
// covered by range tombstones in other snapshot stripes. In case of writes
|
|
// (flush/compaction), all DB snapshots are provided such that no keys are
|
|
// removed that are uncovered according to any DB snapshot. In case of read
|
|
// (get/iterator), only the user snapshot is provided such that the seqnum
|
|
// space is divided into two stripes, where only tombstones in the older
|
|
// stripe are considered by ShouldDelete().
|
|
RangeDelAggregator(const InternalKeyComparator& icmp,
|
|
const std::vector<SequenceNumber>& snapshots);
|
|
|
|
// Returns whether the key should be deleted, which is the case when it is
|
|
// covered by a range tombstone residing in the same snapshot stripe.
|
|
bool ShouldDelete(const Slice& internal_key, bool for_compaction = false);
|
|
bool ShouldAddTombstones(bool bottommost_level = false);
|
|
|
|
// Adds tombstones to the tombstone aggregation structure maintained by this
|
|
// object.
|
|
// @return non-OK status if any of the tombstone keys are corrupted.
|
|
Status AddTombstones(ScopedArenaIterator input);
|
|
Status AddTombstones(std::unique_ptr<InternalIterator> input);
|
|
|
|
// Writes tombstones covering a range to a table builder.
|
|
// @param extend_before_min_key If true, the range of tombstones to be added
|
|
// to the TableBuilder starts from the beginning of the key-range;
|
|
// otherwise, it starts from meta->smallest.
|
|
// @param next_table_min_key If nullptr, the range of tombstones to be added
|
|
// to the TableBuilder ends at the end of the key-range; otherwise, it
|
|
// ends at next_table_min_key.
|
|
// @param meta The file's metadata. We modify the begin and end keys according
|
|
// to the range tombstones added to this file such that the read path does
|
|
// not miss range tombstones that cover gaps before/after/between files in
|
|
// a level.
|
|
// @param bottommost_level If true, we will filter out any tombstones
|
|
// belonging to the oldest snapshot stripe, because all keys potentially
|
|
// covered by this tombstone are guaranteed to have been deleted by
|
|
// compaction.
|
|
void AddToBuilder(TableBuilder* builder, bool extend_before_min_key,
|
|
const Slice* next_table_min_key, FileMetaData* meta,
|
|
bool bottommost_level = false);
|
|
|
|
private:
|
|
// Maps tombstone start key -> tombstone object
|
|
typedef std::map<std::string, RangeTombstone, stl_wrappers::LessOfComparator>
|
|
TombstoneMap;
|
|
// Maps snapshot seqnum -> map of tombstones that fall in that stripe, i.e.,
|
|
// their seqnums are greater than the next smaller snapshot's seqnum.
|
|
typedef std::map<SequenceNumber, TombstoneMap> StripeMap;
|
|
|
|
Status AddTombstones(InternalIterator* input, bool arena);
|
|
StripeMap::iterator GetStripeMapIter(SequenceNumber seq);
|
|
|
|
PinnedIteratorsManager pinned_iters_mgr_;
|
|
StripeMap stripe_map_;
|
|
const InternalKeyComparator icmp_;
|
|
};
|
|
} // namespace rocksdb
|