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rocksdb/db/compaction/compaction_outputs.cc

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12 KiB

// Copyright (c) Meta Platforms, Inc. and affiliates.
//
// 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).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/compaction/compaction_outputs.h"
#include "db/builder.h"
namespace ROCKSDB_NAMESPACE {
void CompactionOutputs::NewBuilder(const TableBuilderOptions& tboptions) {
builder_.reset(NewTableBuilder(tboptions, file_writer_.get()));
}
Status CompactionOutputs::Finish(const Status& intput_status,
const SeqnoToTimeMapping& seqno_time_mapping) {
FileMetaData* meta = GetMetaData();
assert(meta != nullptr);
Status s = intput_status;
if (s.ok()) {
std::string seqno_time_mapping_str;
seqno_time_mapping.Encode(seqno_time_mapping_str, meta->fd.smallest_seqno,
meta->fd.largest_seqno, meta->file_creation_time);
builder_->SetSeqnoTimeTableProperties(seqno_time_mapping_str,
meta->oldest_ancester_time);
s = builder_->Finish();
} else {
builder_->Abandon();
}
Status io_s = builder_->io_status();
if (s.ok()) {
s = io_s;
} else {
io_s.PermitUncheckedError();
}
const uint64_t current_bytes = builder_->FileSize();
if (s.ok()) {
meta->fd.file_size = current_bytes;
meta->marked_for_compaction = builder_->NeedCompact();
}
current_output().finished = true;
stats_.bytes_written += current_bytes;
stats_.num_output_files = outputs_.size();
return s;
}
IOStatus CompactionOutputs::WriterSyncClose(const Status& input_status,
SystemClock* clock,
Statistics* statistics,
bool use_fsync) {
IOStatus io_s;
if (input_status.ok()) {
StopWatch sw(clock, statistics, COMPACTION_OUTFILE_SYNC_MICROS);
io_s = file_writer_->Sync(use_fsync);
}
if (input_status.ok() && io_s.ok()) {
io_s = file_writer_->Close();
}
if (input_status.ok() && io_s.ok()) {
FileMetaData* meta = GetMetaData();
meta->file_checksum = file_writer_->GetFileChecksum();
meta->file_checksum_func_name = file_writer_->GetFileChecksumFuncName();
}
file_writer_.reset();
return io_s;
}
Status CompactionOutputs::AddToOutput(
const CompactionIterator& c_iter,
const CompactionFileOpenFunc& open_file_func,
const CompactionFileCloseFunc& close_file_func) {
Status s;
const Slice& key = c_iter.key();
if (!pending_close_ && c_iter.Valid() && partitioner_ && HasBuilder() &&
partitioner_->ShouldPartition(
PartitionerRequest(last_key_for_partitioner_, c_iter.user_key(),
current_output_file_size_)) == kRequired) {
pending_close_ = true;
}
if (pending_close_) {
s = close_file_func(*this, c_iter.InputStatus(), key);
pending_close_ = false;
}
if (!s.ok()) {
return s;
}
// Open output file if necessary
if (!HasBuilder()) {
s = open_file_func(*this);
}
if (!s.ok()) {
return s;
}
Output& curr = current_output();
assert(builder_ != nullptr);
const Slice& value = c_iter.value();
s = curr.validator.Add(key, value);
if (!s.ok()) {
return s;
}
builder_->Add(key, value);
stats_.num_output_records++;
current_output_file_size_ = builder_->EstimatedFileSize();
if (blob_garbage_meter_) {
s = blob_garbage_meter_->ProcessOutFlow(key, value);
}
if (!s.ok()) {
return s;
}
const ParsedInternalKey& ikey = c_iter.ikey();
s = current_output().meta.UpdateBoundaries(key, value, ikey.sequence,
ikey.type);
// Close output file if it is big enough. Two possibilities determine it's
// time to close it: (1) the current key should be this file's last key, (2)
// the next key should not be in this file.
//
// TODO(aekmekji): determine if file should be closed earlier than this
// during subcompactions (i.e. if output size, estimated by input size, is
// going to be 1.2MB and max_output_file_size = 1MB, prefer to have 0.6MB
// and 0.6MB instead of 1MB and 0.2MB)
if (compaction_->output_level() != 0 &&
current_output_file_size_ >= compaction_->max_output_file_size()) {
pending_close_ = true;
}
if (partitioner_) {
last_key_for_partitioner_.assign(c_iter.user_key().data_,
c_iter.user_key().size_);
}
return s;
}
Status CompactionOutputs::AddRangeDels(
const Slice* comp_start, const Slice* comp_end,
CompactionIterationStats& range_del_out_stats, bool bottommost_level,
const InternalKeyComparator& icmp, SequenceNumber earliest_snapshot,
const Slice& next_table_min_key) {
assert(HasRangeDel());
FileMetaData& meta = current_output().meta;
const Comparator* ucmp = icmp.user_comparator();
Slice lower_bound_guard, upper_bound_guard;
std::string smallest_user_key;
const Slice *lower_bound, *upper_bound;
bool lower_bound_from_sub_compact = false;
size_t output_size = outputs_.size();
if (output_size == 1) {
// For the first output table, include range tombstones before the min
// key but after the subcompaction boundary.
lower_bound = comp_start;
lower_bound_from_sub_compact = true;
} else if (meta.smallest.size() > 0) {
// For subsequent output tables, only include range tombstones from min
// key onwards since the previous file was extended to contain range
// tombstones falling before min key.
smallest_user_key = meta.smallest.user_key().ToString(false /*hex*/);
lower_bound_guard = Slice(smallest_user_key);
lower_bound = &lower_bound_guard;
} else {
lower_bound = nullptr;
}
if (!next_table_min_key.empty()) {
// This may be the last file in the subcompaction in some cases, so we
// need to compare the end key of subcompaction with the next file start
// key. When the end key is chosen by the subcompaction, we know that
// it must be the biggest key in output file. Therefore, it is safe to
// use the smaller key as the upper bound of the output file, to ensure
// that there is no overlapping between different output files.
upper_bound_guard = ExtractUserKey(next_table_min_key);
if (comp_end != nullptr &&
ucmp->Compare(upper_bound_guard, *comp_end) >= 0) {
upper_bound = comp_end;
} else {
upper_bound = &upper_bound_guard;
}
} else {
// This is the last file in the subcompaction, so extend until the
// subcompaction ends.
upper_bound = comp_end;
}
bool has_overlapping_endpoints;
if (upper_bound != nullptr && meta.largest.size() > 0) {
has_overlapping_endpoints =
ucmp->Compare(meta.largest.user_key(), *upper_bound) == 0;
} else {
has_overlapping_endpoints = false;
}
// The end key of the subcompaction must be bigger or equal to the upper
// bound. If the end of subcompaction is null or the upper bound is null,
// it means that this file is the last file in the compaction. So there
// will be no overlapping between this file and others.
assert(comp_end == nullptr || upper_bound == nullptr ||
ucmp->Compare(*upper_bound, *comp_end) <= 0);
auto it = range_del_agg_->NewIterator(lower_bound, upper_bound,
has_overlapping_endpoints);
// Position the range tombstone output iterator. There may be tombstone
// fragments that are entirely out of range, so make sure that we do not
// include those.
if (lower_bound != nullptr) {
it->Seek(*lower_bound);
} else {
it->SeekToFirst();
}
for (; it->Valid(); it->Next()) {
auto tombstone = it->Tombstone();
if (upper_bound != nullptr) {
int cmp = ucmp->Compare(*upper_bound, tombstone.start_key_);
if ((has_overlapping_endpoints && cmp < 0) ||
(!has_overlapping_endpoints && cmp <= 0)) {
// Tombstones starting after upper_bound only need to be included in
// the next table. If the current SST ends before upper_bound, i.e.,
// `has_overlapping_endpoints == false`, we can also skip over range
// tombstones that start exactly at upper_bound. Such range
// tombstones will be included in the next file and are not relevant
// to the point keys or endpoints of the current file.
break;
}
}
if (bottommost_level && tombstone.seq_ <= earliest_snapshot) {
// TODO(andrewkr): tombstones that span multiple output files are
// counted for each compaction output file, so lots of double
// counting.
range_del_out_stats.num_range_del_drop_obsolete++;
range_del_out_stats.num_record_drop_obsolete++;
continue;
}
auto kv = tombstone.Serialize();
assert(lower_bound == nullptr ||
ucmp->Compare(*lower_bound, kv.second) < 0);
// Range tombstone is not supported by output validator yet.
builder_->Add(kv.first.Encode(), kv.second);
InternalKey smallest_candidate = std::move(kv.first);
if (lower_bound != nullptr &&
ucmp->Compare(smallest_candidate.user_key(), *lower_bound) <= 0) {
// Pretend the smallest key has the same user key as lower_bound
// (the max key in the previous table or subcompaction) in order for
// files to appear key-space partitioned.
//
// When lower_bound is chosen by a subcompaction, we know that
// subcompactions over smaller keys cannot contain any keys at
// lower_bound. We also know that smaller subcompactions exist,
// because otherwise the subcompaction woud be unbounded on the left.
// As a result, we know that no other files on the output level will
// contain actual keys at lower_bound (an output file may have a
// largest key of lower_bound@kMaxSequenceNumber, but this only
// indicates a large range tombstone was truncated). Therefore, it is
// safe to use the tombstone's sequence number, to ensure that keys at
// lower_bound at lower levels are covered by truncated tombstones.
//
// If lower_bound was chosen by the smallest data key in the file,
// choose lowest seqnum so this file's smallest internal key comes
// after the previous file's largest. The fake seqnum is OK because
// the read path's file-picking code only considers user key.
smallest_candidate = InternalKey(
*lower_bound, lower_bound_from_sub_compact ? tombstone.seq_ : 0,
kTypeRangeDeletion);
}
InternalKey largest_candidate = tombstone.SerializeEndKey();
if (upper_bound != nullptr &&
ucmp->Compare(*upper_bound, largest_candidate.user_key()) <= 0) {
// Pretend the largest key has the same user key as upper_bound (the
// min key in the following table or subcompaction) in order for files
// to appear key-space partitioned.
//
// Choose highest seqnum so this file's largest internal key comes
// before the next file's/subcompaction's smallest. The fake seqnum is
// OK because the read path's file-picking code only considers the
// user key portion.
//
// Note Seek() also creates InternalKey with (user_key,
// kMaxSequenceNumber), but with kTypeDeletion (0x7) instead of
// kTypeRangeDeletion (0xF), so the range tombstone comes before the
// Seek() key in InternalKey's ordering. So Seek() will look in the
// next file for the user key.
largest_candidate =
InternalKey(*upper_bound, kMaxSequenceNumber, kTypeRangeDeletion);
}
#ifndef NDEBUG
SequenceNumber smallest_ikey_seqnum = kMaxSequenceNumber;
if (meta.smallest.size() > 0) {
smallest_ikey_seqnum = GetInternalKeySeqno(meta.smallest.Encode());
}
#endif
meta.UpdateBoundariesForRange(smallest_candidate, largest_candidate,
tombstone.seq_, icmp);
// The smallest key in a file is used for range tombstone truncation, so
// it cannot have a seqnum of 0 (unless the smallest data key in a file
// has a seqnum of 0). Otherwise, the truncated tombstone may expose
// deleted keys at lower levels.
assert(smallest_ikey_seqnum == 0 ||
ExtractInternalKeyFooter(meta.smallest.Encode()) !=
PackSequenceAndType(0, kTypeRangeDeletion));
}
return Status::OK();
}
} // namespace ROCKSDB_NAMESPACE