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Diffstat (limited to 'src/rocksdb/db/compaction/compaction_iterator.cc')
| -rw-r--r-- | src/rocksdb/db/compaction/compaction_iterator.cc | 774 |
1 files changed, 774 insertions, 0 deletions
diff --git a/src/rocksdb/db/compaction/compaction_iterator.cc b/src/rocksdb/db/compaction/compaction_iterator.cc new file mode 100644 index 000000000..1bebfc717 --- /dev/null +++ b/src/rocksdb/db/compaction/compaction_iterator.cc @@ -0,0 +1,774 @@ +// Copyright (c) 2011-present, Facebook, Inc. All rights reserved. +// This source code is licensed under both the GPLv2 (found in the +// COPYING file in the root directory) and Apache 2.0 License +// (found in the LICENSE.Apache file in the root directory). + +#include <cinttypes> + +#include "db/compaction/compaction_iterator.h" +#include "db/snapshot_checker.h" +#include "port/likely.h" +#include "rocksdb/listener.h" +#include "table/internal_iterator.h" +#include "test_util/sync_point.h" + +#define DEFINITELY_IN_SNAPSHOT(seq, snapshot) \ + ((seq) <= (snapshot) && \ + (snapshot_checker_ == nullptr || \ + LIKELY(snapshot_checker_->CheckInSnapshot((seq), (snapshot)) == \ + SnapshotCheckerResult::kInSnapshot))) + +#define DEFINITELY_NOT_IN_SNAPSHOT(seq, snapshot) \ + ((seq) > (snapshot) || \ + (snapshot_checker_ != nullptr && \ + UNLIKELY(snapshot_checker_->CheckInSnapshot((seq), (snapshot)) == \ + SnapshotCheckerResult::kNotInSnapshot))) + +#define IN_EARLIEST_SNAPSHOT(seq) \ + ((seq) <= earliest_snapshot_ && \ + (snapshot_checker_ == nullptr || LIKELY(IsInEarliestSnapshot(seq)))) + +namespace ROCKSDB_NAMESPACE { + +CompactionIterator::CompactionIterator( + InternalIterator* input, const Comparator* cmp, MergeHelper* merge_helper, + SequenceNumber last_sequence, std::vector<SequenceNumber>* snapshots, + SequenceNumber earliest_write_conflict_snapshot, + const SnapshotChecker* snapshot_checker, Env* env, + bool report_detailed_time, bool expect_valid_internal_key, + CompactionRangeDelAggregator* range_del_agg, const Compaction* compaction, + const CompactionFilter* compaction_filter, + const std::atomic<bool>* shutting_down, + const SequenceNumber preserve_deletes_seqnum, + const std::atomic<bool>* manual_compaction_paused, + const std::shared_ptr<Logger> info_log) + : CompactionIterator( + input, cmp, merge_helper, last_sequence, snapshots, + earliest_write_conflict_snapshot, snapshot_checker, env, + report_detailed_time, expect_valid_internal_key, range_del_agg, + std::unique_ptr<CompactionProxy>( + compaction ? new CompactionProxy(compaction) : nullptr), + compaction_filter, shutting_down, preserve_deletes_seqnum, + manual_compaction_paused, info_log) {} + +CompactionIterator::CompactionIterator( + InternalIterator* input, const Comparator* cmp, MergeHelper* merge_helper, + SequenceNumber /*last_sequence*/, std::vector<SequenceNumber>* snapshots, + SequenceNumber earliest_write_conflict_snapshot, + const SnapshotChecker* snapshot_checker, Env* env, + bool report_detailed_time, bool expect_valid_internal_key, + CompactionRangeDelAggregator* range_del_agg, + std::unique_ptr<CompactionProxy> compaction, + const CompactionFilter* compaction_filter, + const std::atomic<bool>* shutting_down, + const SequenceNumber preserve_deletes_seqnum, + const std::atomic<bool>* manual_compaction_paused, + const std::shared_ptr<Logger> info_log) + : input_(input), + cmp_(cmp), + merge_helper_(merge_helper), + snapshots_(snapshots), + earliest_write_conflict_snapshot_(earliest_write_conflict_snapshot), + snapshot_checker_(snapshot_checker), + env_(env), + report_detailed_time_(report_detailed_time), + expect_valid_internal_key_(expect_valid_internal_key), + range_del_agg_(range_del_agg), + compaction_(std::move(compaction)), + compaction_filter_(compaction_filter), + shutting_down_(shutting_down), + manual_compaction_paused_(manual_compaction_paused), + preserve_deletes_seqnum_(preserve_deletes_seqnum), + current_user_key_sequence_(0), + current_user_key_snapshot_(0), + merge_out_iter_(merge_helper_), + current_key_committed_(false), + info_log_(info_log) { + assert(compaction_filter_ == nullptr || compaction_ != nullptr); + assert(snapshots_ != nullptr); + bottommost_level_ = + compaction_ == nullptr ? false : compaction_->bottommost_level(); + if (compaction_ != nullptr) { + level_ptrs_ = std::vector<size_t>(compaction_->number_levels(), 0); + } + if (snapshots_->size() == 0) { + // optimize for fast path if there are no snapshots + visible_at_tip_ = true; + earliest_snapshot_iter_ = snapshots_->end(); + earliest_snapshot_ = kMaxSequenceNumber; + latest_snapshot_ = 0; + } else { + visible_at_tip_ = false; + earliest_snapshot_iter_ = snapshots_->begin(); + earliest_snapshot_ = snapshots_->at(0); + latest_snapshot_ = snapshots_->back(); + } +#ifndef NDEBUG + // findEarliestVisibleSnapshot assumes this ordering. + for (size_t i = 1; i < snapshots_->size(); ++i) { + assert(snapshots_->at(i - 1) < snapshots_->at(i)); + } +#endif + input_->SetPinnedItersMgr(&pinned_iters_mgr_); + TEST_SYNC_POINT_CALLBACK("CompactionIterator:AfterInit", compaction_.get()); +} + +CompactionIterator::~CompactionIterator() { + // input_ Iteartor lifetime is longer than pinned_iters_mgr_ lifetime + input_->SetPinnedItersMgr(nullptr); +} + +void CompactionIterator::ResetRecordCounts() { + iter_stats_.num_record_drop_user = 0; + iter_stats_.num_record_drop_hidden = 0; + iter_stats_.num_record_drop_obsolete = 0; + iter_stats_.num_record_drop_range_del = 0; + iter_stats_.num_range_del_drop_obsolete = 0; + iter_stats_.num_optimized_del_drop_obsolete = 0; +} + +void CompactionIterator::SeekToFirst() { + NextFromInput(); + PrepareOutput(); +} + +void CompactionIterator::Next() { + // If there is a merge output, return it before continuing to process the + // input. + if (merge_out_iter_.Valid()) { + merge_out_iter_.Next(); + + // Check if we returned all records of the merge output. + if (merge_out_iter_.Valid()) { + key_ = merge_out_iter_.key(); + value_ = merge_out_iter_.value(); + bool valid_key __attribute__((__unused__)); + valid_key = ParseInternalKey(key_, &ikey_); + // MergeUntil stops when it encounters a corrupt key and does not + // include them in the result, so we expect the keys here to be valid. + assert(valid_key); + if (!valid_key) { + ROCKS_LOG_FATAL(info_log_, "Invalid key (%s) in compaction", + key_.ToString(true).c_str()); + } + + // Keep current_key_ in sync. + current_key_.UpdateInternalKey(ikey_.sequence, ikey_.type); + key_ = current_key_.GetInternalKey(); + ikey_.user_key = current_key_.GetUserKey(); + valid_ = true; + } else { + // We consumed all pinned merge operands, release pinned iterators + pinned_iters_mgr_.ReleasePinnedData(); + // MergeHelper moves the iterator to the first record after the merged + // records, so even though we reached the end of the merge output, we do + // not want to advance the iterator. + NextFromInput(); + } + } else { + // Only advance the input iterator if there is no merge output and the + // iterator is not already at the next record. + if (!at_next_) { + input_->Next(); + } + NextFromInput(); + } + + if (valid_) { + // Record that we've outputted a record for the current key. + has_outputted_key_ = true; + } + + PrepareOutput(); +} + +void CompactionIterator::InvokeFilterIfNeeded(bool* need_skip, + Slice* skip_until) { + if (compaction_filter_ != nullptr && + (ikey_.type == kTypeValue || ikey_.type == kTypeBlobIndex)) { + // If the user has specified a compaction filter and the sequence + // number is greater than any external snapshot, then invoke the + // filter. If the return value of the compaction filter is true, + // replace the entry with a deletion marker. + CompactionFilter::Decision filter; + compaction_filter_value_.clear(); + compaction_filter_skip_until_.Clear(); + CompactionFilter::ValueType value_type = + ikey_.type == kTypeValue ? CompactionFilter::ValueType::kValue + : CompactionFilter::ValueType::kBlobIndex; + // Hack: pass internal key to BlobIndexCompactionFilter since it needs + // to get sequence number. + Slice& filter_key = ikey_.type == kTypeValue ? ikey_.user_key : key_; + { + StopWatchNano timer(env_, report_detailed_time_); + filter = compaction_filter_->FilterV2( + compaction_->level(), filter_key, value_type, value_, + &compaction_filter_value_, compaction_filter_skip_until_.rep()); + iter_stats_.total_filter_time += + env_ != nullptr && report_detailed_time_ ? timer.ElapsedNanos() : 0; + } + + if (filter == CompactionFilter::Decision::kRemoveAndSkipUntil && + cmp_->Compare(*compaction_filter_skip_until_.rep(), ikey_.user_key) <= + 0) { + // Can't skip to a key smaller than the current one. + // Keep the key as per FilterV2 documentation. + filter = CompactionFilter::Decision::kKeep; + } + + if (filter == CompactionFilter::Decision::kRemove) { + // convert the current key to a delete; key_ is pointing into + // current_key_ at this point, so updating current_key_ updates key() + ikey_.type = kTypeDeletion; + current_key_.UpdateInternalKey(ikey_.sequence, kTypeDeletion); + // no value associated with delete + value_.clear(); + iter_stats_.num_record_drop_user++; + } else if (filter == CompactionFilter::Decision::kChangeValue) { + value_ = compaction_filter_value_; + } else if (filter == CompactionFilter::Decision::kRemoveAndSkipUntil) { + *need_skip = true; + compaction_filter_skip_until_.ConvertFromUserKey(kMaxSequenceNumber, + kValueTypeForSeek); + *skip_until = compaction_filter_skip_until_.Encode(); + } + } +} + +void CompactionIterator::NextFromInput() { + at_next_ = false; + valid_ = false; + + while (!valid_ && input_->Valid() && !IsPausingManualCompaction() && + !IsShuttingDown()) { + key_ = input_->key(); + value_ = input_->value(); + iter_stats_.num_input_records++; + + if (!ParseInternalKey(key_, &ikey_)) { + // If `expect_valid_internal_key_` is false, return the corrupted key + // and let the caller decide what to do with it. + // TODO(noetzli): We should have a more elegant solution for this. + if (expect_valid_internal_key_) { + assert(!"Corrupted internal key not expected."); + status_ = Status::Corruption("Corrupted internal key not expected."); + break; + } + key_ = current_key_.SetInternalKey(key_); + has_current_user_key_ = false; + current_user_key_sequence_ = kMaxSequenceNumber; + current_user_key_snapshot_ = 0; + iter_stats_.num_input_corrupt_records++; + valid_ = true; + break; + } + TEST_SYNC_POINT_CALLBACK("CompactionIterator:ProcessKV", &ikey_); + + // Update input statistics + if (ikey_.type == kTypeDeletion || ikey_.type == kTypeSingleDeletion) { + iter_stats_.num_input_deletion_records++; + } + iter_stats_.total_input_raw_key_bytes += key_.size(); + iter_stats_.total_input_raw_value_bytes += value_.size(); + + // If need_skip is true, we should seek the input iterator + // to internal key skip_until and continue from there. + bool need_skip = false; + // Points either into compaction_filter_skip_until_ or into + // merge_helper_->compaction_filter_skip_until_. + Slice skip_until; + + // Check whether the user key changed. After this if statement current_key_ + // is a copy of the current input key (maybe converted to a delete by the + // compaction filter). ikey_.user_key is pointing to the copy. + if (!has_current_user_key_ || + !cmp_->Equal(ikey_.user_key, current_user_key_)) { + // First occurrence of this user key + // Copy key for output + key_ = current_key_.SetInternalKey(key_, &ikey_); + current_user_key_ = ikey_.user_key; + has_current_user_key_ = true; + has_outputted_key_ = false; + current_user_key_sequence_ = kMaxSequenceNumber; + current_user_key_snapshot_ = 0; + current_key_committed_ = KeyCommitted(ikey_.sequence); + + // Apply the compaction filter to the first committed version of the user + // key. + if (current_key_committed_) { + InvokeFilterIfNeeded(&need_skip, &skip_until); + } + } else { + // Update the current key to reflect the new sequence number/type without + // copying the user key. + // TODO(rven): Compaction filter does not process keys in this path + // Need to have the compaction filter process multiple versions + // if we have versions on both sides of a snapshot + current_key_.UpdateInternalKey(ikey_.sequence, ikey_.type); + key_ = current_key_.GetInternalKey(); + ikey_.user_key = current_key_.GetUserKey(); + + // Note that newer version of a key is ordered before older versions. If a + // newer version of a key is committed, so as the older version. No need + // to query snapshot_checker_ in that case. + if (UNLIKELY(!current_key_committed_)) { + assert(snapshot_checker_ != nullptr); + current_key_committed_ = KeyCommitted(ikey_.sequence); + // Apply the compaction filter to the first committed version of the + // user key. + if (current_key_committed_) { + InvokeFilterIfNeeded(&need_skip, &skip_until); + } + } + } + + if (UNLIKELY(!current_key_committed_)) { + assert(snapshot_checker_ != nullptr); + valid_ = true; + break; + } + + // If there are no snapshots, then this kv affect visibility at tip. + // Otherwise, search though all existing snapshots to find the earliest + // snapshot that is affected by this kv. + SequenceNumber last_sequence __attribute__((__unused__)); + last_sequence = current_user_key_sequence_; + current_user_key_sequence_ = ikey_.sequence; + SequenceNumber last_snapshot = current_user_key_snapshot_; + SequenceNumber prev_snapshot = 0; // 0 means no previous snapshot + current_user_key_snapshot_ = + visible_at_tip_ + ? earliest_snapshot_ + : findEarliestVisibleSnapshot(ikey_.sequence, &prev_snapshot); + + if (need_skip) { + // This case is handled below. + } else if (clear_and_output_next_key_) { + // In the previous iteration we encountered a single delete that we could + // not compact out. We will keep this Put, but can drop it's data. + // (See Optimization 3, below.) + assert(ikey_.type == kTypeValue); + if (ikey_.type != kTypeValue) { + ROCKS_LOG_FATAL(info_log_, + "Unexpected key type %d for compaction output", + ikey_.type); + } + assert(current_user_key_snapshot_ == last_snapshot); + if (current_user_key_snapshot_ != last_snapshot) { + ROCKS_LOG_FATAL(info_log_, + "current_user_key_snapshot_ (%" PRIu64 + ") != last_snapshot (%" PRIu64 ")", + current_user_key_snapshot_, last_snapshot); + } + + value_.clear(); + valid_ = true; + clear_and_output_next_key_ = false; + } else if (ikey_.type == kTypeSingleDeletion) { + // We can compact out a SingleDelete if: + // 1) We encounter the corresponding PUT -OR- we know that this key + // doesn't appear past this output level + // =AND= + // 2) We've already returned a record in this snapshot -OR- + // there are no earlier earliest_write_conflict_snapshot. + // + // Rule 1 is needed for SingleDelete correctness. Rule 2 is needed to + // allow Transactions to do write-conflict checking (if we compacted away + // all keys, then we wouldn't know that a write happened in this + // snapshot). If there is no earlier snapshot, then we know that there + // are no active transactions that need to know about any writes. + // + // Optimization 3: + // If we encounter a SingleDelete followed by a PUT and Rule 2 is NOT + // true, then we must output a SingleDelete. In this case, we will decide + // to also output the PUT. While we are compacting less by outputting the + // PUT now, hopefully this will lead to better compaction in the future + // when Rule 2 is later true (Ie, We are hoping we can later compact out + // both the SingleDelete and the Put, while we couldn't if we only + // outputted the SingleDelete now). + // In this case, we can save space by removing the PUT's value as it will + // never be read. + // + // Deletes and Merges are not supported on the same key that has a + // SingleDelete as it is not possible to correctly do any partial + // compaction of such a combination of operations. The result of mixing + // those operations for a given key is documented as being undefined. So + // we can choose how to handle such a combinations of operations. We will + // try to compact out as much as we can in these cases. + // We will report counts on these anomalous cases. + + // The easiest way to process a SingleDelete during iteration is to peek + // ahead at the next key. + ParsedInternalKey next_ikey; + input_->Next(); + + // Check whether the next key exists, is not corrupt, and is the same key + // as the single delete. + if (input_->Valid() && ParseInternalKey(input_->key(), &next_ikey) && + cmp_->Equal(ikey_.user_key, next_ikey.user_key)) { + // Check whether the next key belongs to the same snapshot as the + // SingleDelete. + if (prev_snapshot == 0 || + DEFINITELY_NOT_IN_SNAPSHOT(next_ikey.sequence, prev_snapshot)) { + if (next_ikey.type == kTypeSingleDeletion) { + // We encountered two SingleDeletes in a row. This could be due to + // unexpected user input. + // Skip the first SingleDelete and let the next iteration decide how + // to handle the second SingleDelete + + // First SingleDelete has been skipped since we already called + // input_->Next(). + ++iter_stats_.num_record_drop_obsolete; + ++iter_stats_.num_single_del_mismatch; + } else if (has_outputted_key_ || + DEFINITELY_IN_SNAPSHOT( + ikey_.sequence, earliest_write_conflict_snapshot_)) { + // Found a matching value, we can drop the single delete and the + // value. It is safe to drop both records since we've already + // outputted a key in this snapshot, or there is no earlier + // snapshot (Rule 2 above). + + // Note: it doesn't matter whether the second key is a Put or if it + // is an unexpected Merge or Delete. We will compact it out + // either way. We will maintain counts of how many mismatches + // happened + if (next_ikey.type != kTypeValue && + next_ikey.type != kTypeBlobIndex) { + ++iter_stats_.num_single_del_mismatch; + } + + ++iter_stats_.num_record_drop_hidden; + ++iter_stats_.num_record_drop_obsolete; + // Already called input_->Next() once. Call it a second time to + // skip past the second key. + input_->Next(); + } else { + // Found a matching value, but we cannot drop both keys since + // there is an earlier snapshot and we need to leave behind a record + // to know that a write happened in this snapshot (Rule 2 above). + // Clear the value and output the SingleDelete. (The value will be + // outputted on the next iteration.) + + // Setting valid_ to true will output the current SingleDelete + valid_ = true; + + // Set up the Put to be outputted in the next iteration. + // (Optimization 3). + clear_and_output_next_key_ = true; + } + } else { + // We hit the next snapshot without hitting a put, so the iterator + // returns the single delete. + valid_ = true; + } + } else { + // We are at the end of the input, could not parse the next key, or hit + // a different key. The iterator returns the single delete if the key + // possibly exists beyond the current output level. We set + // has_current_user_key to false so that if the iterator is at the next + // key, we do not compare it again against the previous key at the next + // iteration. If the next key is corrupt, we return before the + // comparison, so the value of has_current_user_key does not matter. + has_current_user_key_ = false; + if (compaction_ != nullptr && IN_EARLIEST_SNAPSHOT(ikey_.sequence) && + compaction_->KeyNotExistsBeyondOutputLevel(ikey_.user_key, + &level_ptrs_)) { + // Key doesn't exist outside of this range. + // Can compact out this SingleDelete. + ++iter_stats_.num_record_drop_obsolete; + ++iter_stats_.num_single_del_fallthru; + if (!bottommost_level_) { + ++iter_stats_.num_optimized_del_drop_obsolete; + } + } else { + // Output SingleDelete + valid_ = true; + } + } + + if (valid_) { + at_next_ = true; + } + } else if (last_snapshot == current_user_key_snapshot_ || + (last_snapshot > 0 && + last_snapshot < current_user_key_snapshot_)) { + // If the earliest snapshot is which this key is visible in + // is the same as the visibility of a previous instance of the + // same key, then this kv is not visible in any snapshot. + // Hidden by an newer entry for same user key + // + // Note: Dropping this key will not affect TransactionDB write-conflict + // checking since there has already been a record returned for this key + // in this snapshot. + assert(last_sequence >= current_user_key_sequence_); + if (last_sequence < current_user_key_sequence_) { + ROCKS_LOG_FATAL(info_log_, + "last_sequence (%" PRIu64 + ") < current_user_key_sequence_ (%" PRIu64 ")", + last_sequence, current_user_key_sequence_); + } + + ++iter_stats_.num_record_drop_hidden; // (A) + input_->Next(); + } else if (compaction_ != nullptr && ikey_.type == kTypeDeletion && + IN_EARLIEST_SNAPSHOT(ikey_.sequence) && + ikeyNotNeededForIncrementalSnapshot() && + compaction_->KeyNotExistsBeyondOutputLevel(ikey_.user_key, + &level_ptrs_)) { + // TODO(noetzli): This is the only place where we use compaction_ + // (besides the constructor). We should probably get rid of this + // dependency and find a way to do similar filtering during flushes. + // + // For this user key: + // (1) there is no data in higher levels + // (2) data in lower levels will have larger sequence numbers + // (3) data in layers that are being compacted here and have + // smaller sequence numbers will be dropped in the next + // few iterations of this loop (by rule (A) above). + // Therefore this deletion marker is obsolete and can be dropped. + // + // Note: Dropping this Delete will not affect TransactionDB + // write-conflict checking since it is earlier than any snapshot. + // + // It seems that we can also drop deletion later than earliest snapshot + // given that: + // (1) The deletion is earlier than earliest_write_conflict_snapshot, and + // (2) No value exist earlier than the deletion. + ++iter_stats_.num_record_drop_obsolete; + if (!bottommost_level_) { + ++iter_stats_.num_optimized_del_drop_obsolete; + } + input_->Next(); + } else if ((ikey_.type == kTypeDeletion) && bottommost_level_ && + ikeyNotNeededForIncrementalSnapshot()) { + // Handle the case where we have a delete key at the bottom most level + // We can skip outputting the key iff there are no subsequent puts for this + // key + ParsedInternalKey next_ikey; + input_->Next(); + // Skip over all versions of this key that happen to occur in the same snapshot + // range as the delete + while (input_->Valid() && ParseInternalKey(input_->key(), &next_ikey) && + cmp_->Equal(ikey_.user_key, next_ikey.user_key) && + (prev_snapshot == 0 || + DEFINITELY_NOT_IN_SNAPSHOT(next_ikey.sequence, prev_snapshot))) { + input_->Next(); + } + // If you find you still need to output a row with this key, we need to output the + // delete too + if (input_->Valid() && ParseInternalKey(input_->key(), &next_ikey) && + cmp_->Equal(ikey_.user_key, next_ikey.user_key)) { + valid_ = true; + at_next_ = true; + } + } else if (ikey_.type == kTypeMerge) { + if (!merge_helper_->HasOperator()) { + status_ = Status::InvalidArgument( + "merge_operator is not properly initialized."); + return; + } + + pinned_iters_mgr_.StartPinning(); + // We know the merge type entry is not hidden, otherwise we would + // have hit (A) + // We encapsulate the merge related state machine in a different + // object to minimize change to the existing flow. + Status s = merge_helper_->MergeUntil(input_, range_del_agg_, + prev_snapshot, bottommost_level_); + merge_out_iter_.SeekToFirst(); + + if (!s.ok() && !s.IsMergeInProgress()) { + status_ = s; + return; + } else if (merge_out_iter_.Valid()) { + // NOTE: key, value, and ikey_ refer to old entries. + // These will be correctly set below. + key_ = merge_out_iter_.key(); + value_ = merge_out_iter_.value(); + bool valid_key __attribute__((__unused__)); + valid_key = ParseInternalKey(key_, &ikey_); + // MergeUntil stops when it encounters a corrupt key and does not + // include them in the result, so we expect the keys here to valid. + assert(valid_key); + if (!valid_key) { + ROCKS_LOG_FATAL(info_log_, "Invalid key (%s) in compaction", + key_.ToString(true).c_str()); + } + // Keep current_key_ in sync. + current_key_.UpdateInternalKey(ikey_.sequence, ikey_.type); + key_ = current_key_.GetInternalKey(); + ikey_.user_key = current_key_.GetUserKey(); + valid_ = true; + } else { + // all merge operands were filtered out. reset the user key, since the + // batch consumed by the merge operator should not shadow any keys + // coming after the merges + has_current_user_key_ = false; + pinned_iters_mgr_.ReleasePinnedData(); + + if (merge_helper_->FilteredUntil(&skip_until)) { + need_skip = true; + } + } + } else { + // 1. new user key -OR- + // 2. different snapshot stripe + bool should_delete = range_del_agg_->ShouldDelete( + key_, RangeDelPositioningMode::kForwardTraversal); + if (should_delete) { + ++iter_stats_.num_record_drop_hidden; + ++iter_stats_.num_record_drop_range_del; + input_->Next(); + } else { + valid_ = true; + } + } + + if (need_skip) { + input_->Seek(skip_until); + } + } + + if (!valid_ && IsShuttingDown()) { + status_ = Status::ShutdownInProgress(); + } + + if (IsPausingManualCompaction()) { + status_ = Status::Incomplete(Status::SubCode::kManualCompactionPaused); + } +} + +void CompactionIterator::PrepareOutput() { + if (valid_) { + if (compaction_filter_ && ikey_.type == kTypeBlobIndex) { + const auto blob_decision = compaction_filter_->PrepareBlobOutput( + user_key(), value_, &compaction_filter_value_); + + if (blob_decision == CompactionFilter::BlobDecision::kCorruption) { + status_ = Status::Corruption( + "Corrupted blob reference encountered during GC"); + valid_ = false; + } else if (blob_decision == CompactionFilter::BlobDecision::kIOError) { + status_ = Status::IOError("Could not relocate blob during GC"); + valid_ = false; + } else if (blob_decision == + CompactionFilter::BlobDecision::kChangeValue) { + value_ = compaction_filter_value_; + } + } + + // Zeroing out the sequence number leads to better compression. + // If this is the bottommost level (no files in lower levels) + // and the earliest snapshot is larger than this seqno + // and the userkey differs from the last userkey in compaction + // then we can squash the seqno to zero. + // + // This is safe for TransactionDB write-conflict checking since transactions + // only care about sequence number larger than any active snapshots. + // + // Can we do the same for levels above bottom level as long as + // KeyNotExistsBeyondOutputLevel() return true? + if (valid_ && compaction_ != nullptr && + !compaction_->allow_ingest_behind() && + ikeyNotNeededForIncrementalSnapshot() && bottommost_level_ && + IN_EARLIEST_SNAPSHOT(ikey_.sequence) && ikey_.type != kTypeMerge) { + assert(ikey_.type != kTypeDeletion && ikey_.type != kTypeSingleDeletion); + if (ikey_.type == kTypeDeletion || ikey_.type == kTypeSingleDeletion) { + ROCKS_LOG_FATAL(info_log_, + "Unexpected key type %d for seq-zero optimization", + ikey_.type); + } + ikey_.sequence = 0; + current_key_.UpdateInternalKey(0, ikey_.type); + } + } +} + +inline SequenceNumber CompactionIterator::findEarliestVisibleSnapshot( + SequenceNumber in, SequenceNumber* prev_snapshot) { + assert(snapshots_->size()); + if (snapshots_->size() == 0) { + ROCKS_LOG_FATAL(info_log_, + "No snapshot left in findEarliestVisibleSnapshot"); + } + auto snapshots_iter = std::lower_bound( + snapshots_->begin(), snapshots_->end(), in); + if (snapshots_iter == snapshots_->begin()) { + *prev_snapshot = 0; + } else { + *prev_snapshot = *std::prev(snapshots_iter); + assert(*prev_snapshot < in); + if (*prev_snapshot >= in) { + ROCKS_LOG_FATAL(info_log_, + "*prev_snapshot >= in in findEarliestVisibleSnapshot"); + } + } + if (snapshot_checker_ == nullptr) { + return snapshots_iter != snapshots_->end() + ? *snapshots_iter : kMaxSequenceNumber; + } + bool has_released_snapshot = !released_snapshots_.empty(); + for (; snapshots_iter != snapshots_->end(); ++snapshots_iter) { + auto cur = *snapshots_iter; + assert(in <= cur); + if (in > cur) { + ROCKS_LOG_FATAL(info_log_, "in > cur in findEarliestVisibleSnapshot"); + } + // Skip if cur is in released_snapshots. + if (has_released_snapshot && released_snapshots_.count(cur) > 0) { + continue; + } + auto res = snapshot_checker_->CheckInSnapshot(in, cur); + if (res == SnapshotCheckerResult::kInSnapshot) { + return cur; + } else if (res == SnapshotCheckerResult::kSnapshotReleased) { + released_snapshots_.insert(cur); + } + *prev_snapshot = cur; + } + return kMaxSequenceNumber; +} + +// used in 2 places - prevents deletion markers to be dropped if they may be +// needed and disables seqnum zero-out in PrepareOutput for recent keys. +inline bool CompactionIterator::ikeyNotNeededForIncrementalSnapshot() { + return (!compaction_->preserve_deletes()) || + (ikey_.sequence < preserve_deletes_seqnum_); +} + +bool CompactionIterator::IsInEarliestSnapshot(SequenceNumber sequence) { + assert(snapshot_checker_ != nullptr); + bool pre_condition = (earliest_snapshot_ == kMaxSequenceNumber || + (earliest_snapshot_iter_ != snapshots_->end() && + *earliest_snapshot_iter_ == earliest_snapshot_)); + assert(pre_condition); + if (!pre_condition) { + ROCKS_LOG_FATAL(info_log_, + "Pre-Condition is not hold in IsInEarliestSnapshot"); + } + auto in_snapshot = + snapshot_checker_->CheckInSnapshot(sequence, earliest_snapshot_); + while (UNLIKELY(in_snapshot == SnapshotCheckerResult::kSnapshotReleased)) { + // Avoid the the current earliest_snapshot_ being return as + // earliest visible snapshot for the next value. So if a value's sequence + // is zero-ed out by PrepareOutput(), the next value will be compact out. + released_snapshots_.insert(earliest_snapshot_); + earliest_snapshot_iter_++; + + if (earliest_snapshot_iter_ == snapshots_->end()) { + earliest_snapshot_ = kMaxSequenceNumber; + } else { + earliest_snapshot_ = *earliest_snapshot_iter_; + } + in_snapshot = + snapshot_checker_->CheckInSnapshot(sequence, earliest_snapshot_); + } + assert(in_snapshot != SnapshotCheckerResult::kSnapshotReleased); + if (in_snapshot == SnapshotCheckerResult::kSnapshotReleased) { + ROCKS_LOG_FATAL(info_log_, + "Unexpected released snapshot in IsInEarliestSnapshot"); + } + return in_snapshot == SnapshotCheckerResult::kInSnapshot; +} + +} // namespace ROCKSDB_NAMESPACE |