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rocksdb/db/compaction_job.cc

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// Copyright (c) 2013, 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.
//
// 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_job.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <algorithm>
#include <vector>
#include <memory>
#include <list>
#include "db/builder.h"
#include "db/db_iter.h"
#include "db/dbformat.h"
#include "db/event_helpers.h"
#include "db/filename.h"
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/memtable.h"
#include "db/merge_helper.h"
#include "db/memtable_list.h"
#include "db/merge_context.h"
#include "db/version_set.h"
#include "port/port.h"
#include "port/likely.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/statistics.h"
#include "rocksdb/status.h"
#include "rocksdb/table.h"
#include "table/block.h"
#include "table/block_based_table_factory.h"
#include "table/merger.h"
#include "table/table_builder.h"
#include "table/two_level_iterator.h"
#include "util/coding.h"
#include "util/file_reader_writer.h"
#include "util/logging.h"
#include "util/log_buffer.h"
#include "util/mutexlock.h"
#include "util/perf_context_imp.h"
#include "util/iostats_context_imp.h"
#include "util/stop_watch.h"
#include "util/string_util.h"
#include "util/sync_point.h"
#include "util/thread_status_util.h"
namespace rocksdb {
// Maintains state for each sub-compaction
struct CompactionJob::SubCompactionState {
Compaction* compaction;
// The boundaries of the key-range this compaction is interested in. No two
// subcompactions may have overlapping key-ranges.
// 'start' is inclusive, 'end' is exclusive, and nullptr means unbounded
Slice *start, *end;
// The return status of this compaction
Status status;
// Files produced by compaction
struct Output {
uint64_t number;
uint32_t path_id;
uint64_t file_size;
InternalKey smallest, largest;
SequenceNumber smallest_seqno, largest_seqno;
bool need_compaction;
};
// State kept for output being generated
std::vector<Output> outputs;
std::unique_ptr<WritableFileWriter> outfile;
std::unique_ptr<TableBuilder> builder;
Output* current_output() {
if (outputs.empty()) {
// This subcompaction's ouptut could be empty if compaction was aborted
// before this subcompaction had a chance to generate any output files.
// When subcompactions are executed sequentially this is more likely and
// will be particulalry likely for the last subcompaction to be empty.
// Once they are run in parallel however it should be much rarer.
return nullptr;
} else {
return &outputs.back();
}
}
// State during the sub-compaction
uint64_t total_bytes;
uint64_t num_input_records;
uint64_t num_output_records;
SequenceNumber earliest_snapshot;
SequenceNumber visible_at_tip;
SequenceNumber latest_snapshot;
CompactionJobStats compaction_job_stats;
// "level_ptrs" holds indices that remember which file of an associated
// level we were last checking during the last call to compaction->
// KeyNotExistsBeyondOutputLevel(). This allows future calls to the function
// to pick off where it left off since each subcompaction's key range is
// increasing so a later call to the function must be looking for a key that
// is in or beyond the last file checked during the previous call
std::vector<size_t> level_ptrs;
SubCompactionState(Compaction* c, Slice* _start, Slice* _end,
SequenceNumber earliest, SequenceNumber visible,
SequenceNumber latest)
: compaction(c),
start(_start),
end(_end),
outfile(nullptr),
builder(nullptr),
total_bytes(0),
num_input_records(0),
num_output_records(0),
earliest_snapshot(earliest),
visible_at_tip(visible),
latest_snapshot(latest) {
assert(compaction != nullptr);
level_ptrs = std::vector<size_t>(compaction->number_levels(), 0);
}
SubCompactionState(SubCompactionState&& o) {
*this = std::move(o);
}
SubCompactionState& operator=(SubCompactionState&& o) {
compaction = std::move(o.compaction);
start = std::move(o.start);
end = std::move(o.end);
status = std::move(o.status);
outputs = std::move(o.outputs);
outfile = std::move(o.outfile);
builder = std::move(o.builder);
total_bytes = std::move(o.total_bytes);
num_input_records = std::move(o.num_input_records);
num_output_records = std::move(o.num_output_records);
earliest_snapshot = std::move(o.earliest_snapshot);
visible_at_tip = std::move(o.visible_at_tip);
latest_snapshot = std::move(o.latest_snapshot);
level_ptrs = std::move(o.level_ptrs);
return *this;
}
// Because member unique_ptrs do not have these.
SubCompactionState(const SubCompactionState&) = delete;
SubCompactionState& operator=(const SubCompactionState&) = delete;
};
// Maintains state for the entire compaction
struct CompactionJob::CompactionState {
Compaction* const compaction;
// REQUIRED: subcompaction states are stored in order of increasing
// key-range
std::vector<CompactionJob::SubCompactionState> sub_compact_states;
Status status;
uint64_t total_bytes;
uint64_t num_input_records;
uint64_t num_output_records;
explicit CompactionState(Compaction* c)
: compaction(c),
total_bytes(0),
num_input_records(0),
num_output_records(0) {}
size_t NumOutputFiles() {
size_t total = 0;
for (auto& s : sub_compact_states) {
total += s.outputs.size();
}
return total;
}
Slice SmallestUserKey() {
for (size_t i = 0; i < sub_compact_states.size(); i++) {
if (!sub_compact_states[i].outputs.empty()) {
return sub_compact_states[i].outputs[0].smallest.user_key();
}
}
// TODO(aekmekji): should we exit with an error if it reaches here?
assert(0);
return Slice(nullptr, 0);
}
Slice LargestUserKey() {
for (int i = static_cast<int>(sub_compact_states.size() - 1); i >= 0; i--) {
if (!sub_compact_states[i].outputs.empty()) {
assert(sub_compact_states[i].current_output() != nullptr);
return sub_compact_states[i].current_output()->largest.user_key();
}
}
// TODO(aekmekji): should we exit with an error if it reaches here?
assert(0);
return Slice(nullptr, 0);
}
};
void CompactionJob::AggregateStatistics() {
for (SubCompactionState& sc : compact_->sub_compact_states) {
compact_->total_bytes += sc.total_bytes;
compact_->num_input_records += sc.num_input_records;
compact_->num_output_records += sc.num_output_records;
if (compaction_job_stats_) {
compaction_job_stats_->Add(sc.compaction_job_stats);
}
}
}
CompactionJob::CompactionJob(
int job_id, Compaction* compaction, const DBOptions& db_options,
const EnvOptions& env_options, VersionSet* versions,
std::atomic<bool>* shutting_down, LogBuffer* log_buffer,
Directory* db_directory, Directory* output_directory, Statistics* stats,
std::vector<SequenceNumber> existing_snapshots,
std::shared_ptr<Cache> table_cache, EventLogger* event_logger,
bool paranoid_file_checks, bool measure_io_stats, const std::string& dbname,
CompactionJobStats* compaction_job_stats)
: job_id_(job_id),
compact_(new CompactionState(compaction)),
compaction_job_stats_(compaction_job_stats),
compaction_stats_(1),
dbname_(dbname),
db_options_(db_options),
env_options_(env_options),
env_(db_options.env),
versions_(versions),
shutting_down_(shutting_down),
log_buffer_(log_buffer),
db_directory_(db_directory),
output_directory_(output_directory),
stats_(stats),
existing_snapshots_(std::move(existing_snapshots)),
table_cache_(std::move(table_cache)),
event_logger_(event_logger),
paranoid_file_checks_(paranoid_file_checks),
measure_io_stats_(measure_io_stats) {
assert(log_buffer_ != nullptr);
ThreadStatusUtil::SetColumnFamily(compact_->compaction->column_family_data());
ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION);
ReportStartedCompaction(compaction);
}
CompactionJob::~CompactionJob() {
assert(compact_ == nullptr);
ThreadStatusUtil::ResetThreadStatus();
}
void CompactionJob::ReportStartedCompaction(
Compaction* compaction) {
ThreadStatusUtil::SetColumnFamily(
compact_->compaction->column_family_data());
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::COMPACTION_JOB_ID,
job_id_);
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::COMPACTION_INPUT_OUTPUT_LEVEL,
(static_cast<uint64_t>(compact_->compaction->start_level()) << 32) +
compact_->compaction->output_level());
// In the current design, a CompactionJob is always created
// for non-trivial compaction.
assert(compaction->IsTrivialMove() == false ||
compaction->is_manual_compaction() == true);
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::COMPACTION_PROP_FLAGS,
compaction->is_manual_compaction() +
(compaction->deletion_compaction() << 1));
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::COMPACTION_TOTAL_INPUT_BYTES,
compaction->CalculateTotalInputSize());
IOSTATS_RESET(bytes_written);
IOSTATS_RESET(bytes_read);
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::COMPACTION_BYTES_WRITTEN, 0);
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::COMPACTION_BYTES_READ, 0);
// Set the thread operation after operation properties
// to ensure GetThreadList() can always show them all together.
ThreadStatusUtil::SetThreadOperation(
ThreadStatus::OP_COMPACTION);
if (compaction_job_stats_) {
compaction_job_stats_->is_manual_compaction =
compaction->is_manual_compaction();
}
}
void CompactionJob::Prepare() {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_PREPARE);
// Generate file_levels_ for compaction berfore making Iterator
auto* c = compact_->compaction;
assert(c->column_family_data() != nullptr);
assert(c->column_family_data()->current()->storage_info()
->NumLevelFiles(compact_->compaction->level()) > 0);
// Is this compaction producing files at the bottommost level?
bottommost_level_ = c->bottommost_level();
// Initialize subcompaction states
SequenceNumber earliest_snapshot;
SequenceNumber latest_snapshot = 0;
SequenceNumber visible_at_tip = 0;
if (existing_snapshots_.size() == 0) {
// optimize for fast path if there are no snapshots
visible_at_tip = versions_->LastSequence();
earliest_snapshot = visible_at_tip;
} else {
latest_snapshot = existing_snapshots_.back();
// Add the current seqno as the 'latest' virtual
// snapshot to the end of this list.
existing_snapshots_.push_back(versions_->LastSequence());
earliest_snapshot = existing_snapshots_[0];
}
InitializeSubCompactions(earliest_snapshot, visible_at_tip, latest_snapshot);
}
// For L0-L1 compaction, iterators work in parallel by processing
// different subsets of the full key range. This function sets up
// the local states used by each of these subcompactions during
// their execution
void CompactionJob::InitializeSubCompactions(const SequenceNumber& earliest,
const SequenceNumber& visible,
const SequenceNumber& latest) {
Compaction* c = compact_->compaction;
auto& bounds = sub_compaction_boundaries_;
if (c->IsSubCompaction()) {
auto* cmp = c->column_family_data()->user_comparator();
for (size_t which = 0; which < c->num_input_levels(); which++) {
if (c->level(which) == 1) {
const LevelFilesBrief* flevel = c->input_levels(which);
size_t num_files = flevel->num_files;
if (num_files > 1) {
std::vector<Slice> candidates;
auto& files = flevel->files;
Slice global_min = ExtractUserKey(files[0].smallest_key);
Slice global_max = ExtractUserKey(files[num_files - 1].largest_key);
for (size_t i = 1; i < num_files; i++) {
// Make sure the smallest key in two consecutive L1 files are
// unique before adding the smallest key as a boundary. Also ensure
// that the boundary won't lead to an empty subcompaction (happens
// if the boundary == the smallest or largest key)
Slice s1 = ExtractUserKey(files[i].smallest_key);
Slice s2 = i == num_files - 1
? Slice()
: ExtractUserKey(files[i + 1].smallest_key);
if ( (i == num_files - 1 && cmp->Compare(s1, global_max) < 0)
|| (i < num_files - 1 && cmp->Compare(s1, s2) < 0 &&
cmp->Compare(s1, global_min) > 0)) {
candidates.emplace_back(s1);
}
}
// Divide the potential L1 file boundaries (those that passed the
// checks above) into 'num_subcompactions' groups such that each have
// as close to an equal number of files in it as possible
// TODO(aekmekji): refine this later to depend on file size
size_t files_left = candidates.size();
size_t subcompactions_left =
static_cast<size_t>(db_options_.num_subcompactions) < files_left
? db_options_.num_subcompactions
: files_left;
size_t num_to_include;
size_t index = 0;
while (files_left > 1 && subcompactions_left > 1) {
num_to_include = files_left / subcompactions_left;
index += num_to_include;
sub_compaction_boundaries_.emplace_back(candidates[index]);
files_left -= num_to_include;
subcompactions_left--;
}
}
break;
}
}
}
// Note: it's necessary for the first iterator sub-range to have
// start == nullptr and for the last to have end == nullptr
for (size_t i = 0; i <= bounds.size(); i++) {
Slice *start = i == 0 ? nullptr : &bounds[i - 1];
Slice *end = i == bounds.size() ? nullptr : &bounds[i];
compact_->sub_compact_states.emplace_back(compact_->compaction, start,
end, earliest, visible, latest);
}
}
Status CompactionJob::Run() {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_RUN);
TEST_SYNC_POINT("CompactionJob::Run():Start");
log_buffer_->FlushBufferToLog();
LogCompaction();
// Run each subcompaction sequentially
const uint64_t start_micros = env_->NowMicros();
for (size_t i = 0; i < compact_->sub_compact_states.size(); i++) {
ProcessKeyValueCompaction(&compact_->sub_compact_states[i]);
}
compaction_stats_.micros = env_->NowMicros() - start_micros;
MeasureTime(stats_, COMPACTION_TIME, compaction_stats_.micros);
// Determine if any of the subcompactions failed
Status status;
for (const auto& state : compact_->sub_compact_states) {
if (!state.status.ok()) {
status = state.status;
break;
}
}
// Finish up all book-keeping to unify the subcompaction results
AggregateStatistics();
UpdateCompactionStats();
RecordCompactionIOStats();
LogFlush(db_options_.info_log);
TEST_SYNC_POINT("CompactionJob::Run():End");
compact_->status = status;
return status;
}
Status CompactionJob::Install(const MutableCFOptions& mutable_cf_options,
InstrumentedMutex* db_mutex) {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_INSTALL);
db_mutex->AssertHeld();
Status status = compact_->status;
ColumnFamilyData* cfd = compact_->compaction->column_family_data();
cfd->internal_stats()->AddCompactionStats(
compact_->compaction->output_level(), compaction_stats_);
if (status.ok()) {
status = InstallCompactionResults(mutable_cf_options, db_mutex);
}
VersionStorageInfo::LevelSummaryStorage tmp;
auto vstorage = cfd->current()->storage_info();
const auto& stats = compaction_stats_;
LogToBuffer(
log_buffer_,
"[%s] compacted to: %s, MB/sec: %.1f rd, %.1f wr, level %d, "
"files in(%d, %d) out(%d) "
"MB in(%.1f, %.1f) out(%.1f), read-write-amplify(%.1f) "
"write-amplify(%.1f) %s, records in: %d, records dropped: %d\n",
cfd->GetName().c_str(), vstorage->LevelSummary(&tmp),
(stats.bytes_read_non_output_levels + stats.bytes_read_output_level) /
static_cast<double>(stats.micros),
stats.bytes_written / static_cast<double>(stats.micros),
compact_->compaction->output_level(),
stats.num_input_files_in_non_output_levels,
stats.num_input_files_in_output_level,
stats.num_output_files,
stats.bytes_read_non_output_levels / 1048576.0,
stats.bytes_read_output_level / 1048576.0,
stats.bytes_written / 1048576.0,
(stats.bytes_written + stats.bytes_read_output_level +
stats.bytes_read_non_output_levels) /
static_cast<double>(stats.bytes_read_non_output_levels),
stats.bytes_written /
static_cast<double>(stats.bytes_read_non_output_levels),
status.ToString().c_str(), stats.num_input_records,
stats.num_dropped_records);
UpdateCompactionJobStats(stats);
auto stream = event_logger_->LogToBuffer(log_buffer_);
stream << "job" << job_id_ << "event"
<< "compaction_finished"
<< "output_level" << compact_->compaction->output_level()
<< "num_output_files" << compact_->NumOutputFiles()
<< "total_output_size" << compact_->total_bytes
<< "num_input_records" << compact_->num_input_records
<< "num_output_records" << compact_->num_output_records;
if (measure_io_stats_ && compaction_job_stats_ != nullptr) {
stream << "file_write_nanos" << compaction_job_stats_->file_write_nanos;
stream << "file_range_sync_nanos"
<< compaction_job_stats_->file_range_sync_nanos;
stream << "file_fsync_nanos" << compaction_job_stats_->file_fsync_nanos;
stream << "file_prepare_write_nanos"
<< compaction_job_stats_->file_prepare_write_nanos;
}
stream << "lsm_state";
stream.StartArray();
for (int level = 0; level < vstorage->num_levels(); ++level) {
stream << vstorage->NumLevelFiles(level);
}
stream.EndArray();
CleanupCompaction();
return status;
}
void CompactionJob::ProcessKeyValueCompaction(SubCompactionState* sub_compact) {
assert(sub_compact != nullptr);
std::unique_ptr<Iterator> input_ptr(
versions_->MakeInputIterator(sub_compact->compaction));
Iterator* input = input_ptr.get();
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_PROCESS_KV);
// I/O measurement variables
PerfLevel prev_perf_level = PerfLevel::kEnableTime;
uint64_t prev_write_nanos = 0;
uint64_t prev_fsync_nanos = 0;
uint64_t prev_range_sync_nanos = 0;
uint64_t prev_prepare_write_nanos = 0;
if (measure_io_stats_) {
prev_perf_level = GetPerfLevel();
SetPerfLevel(PerfLevel::kEnableTime);
prev_write_nanos = iostats_context.write_nanos;
prev_fsync_nanos = iostats_context.fsync_nanos;
prev_range_sync_nanos = iostats_context.range_sync_nanos;
prev_prepare_write_nanos = iostats_context.prepare_write_nanos;
}
// Variables used inside the loop
Status status;
std::string compaction_filter_value;
ParsedInternalKey ikey;
IterKey current_user_key;
bool has_current_user_key = false;
IterKey delete_key;
SequenceNumber last_sequence_for_key __attribute__((unused)) =
kMaxSequenceNumber;
SequenceNumber visible_in_snapshot = kMaxSequenceNumber;
ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();
MergeHelper merge(cfd->user_comparator(), cfd->ioptions()->merge_operator,
db_options_.info_log.get(),
cfd->ioptions()->min_partial_merge_operands,
false /* internal key corruption is expected */);
auto compaction_filter = cfd->ioptions()->compaction_filter;
std::unique_ptr<CompactionFilter> compaction_filter_from_factory = nullptr;
if (compaction_filter == nullptr) {
compaction_filter_from_factory =
sub_compact->compaction->CreateCompactionFilter();
compaction_filter = compaction_filter_from_factory.get();
}
TEST_SYNC_POINT("CompactionJob::Run():Inprogress");
int64_t key_drop_user = 0;
int64_t key_drop_newer_entry = 0;
int64_t key_drop_obsolete = 0;
int64_t loop_cnt = 0;
StopWatchNano timer(env_, stats_ != nullptr);
uint64_t total_filter_time = 0;
Slice* start = sub_compact->start;
Slice* end = sub_compact->end;
if (start != nullptr) {
IterKey start_iter;
start_iter.SetInternalKey(*start, kMaxSequenceNumber, kValueTypeForSeek);
Slice start_key = start_iter.GetKey();
input->Seek(start_key);
} else {
input->SeekToFirst();
}
// TODO(noetzli): check whether we could check !shutting_down_->... only
// only occasionally (see diff D42687)
while (input->Valid() && !shutting_down_->load(std::memory_order_acquire) &&
!cfd->IsDropped() && status.ok()) {
Slice key = input->key();
Slice value = input->value();
// First check that the key is parseable before performing the comparison
// to determine if it's within the range we want. Parsing may fail if the
// key being passed in is a user key without any internal key component
if (!ParseInternalKey(key, &ikey)) {
// Do not hide error keys
// TODO: error key stays in db forever? Figure out the rationale
// v10 error v8 : we cannot hide v8 even though it's pretty obvious.
current_user_key.Clear();
has_current_user_key = false;
last_sequence_for_key = kMaxSequenceNumber;
visible_in_snapshot = kMaxSequenceNumber;
sub_compact->compaction_job_stats.num_corrupt_keys++;
status = WriteKeyValue(key, value, ikey, input->status(), sub_compact);
input->Next();
continue;
}
// If an end key (exclusive) is specified, check if the current key is
// >= than it and exit if it is because the iterator is out of its range
if (end != nullptr &&
cfd->user_comparator()->Compare(ikey.user_key, *end) >= 0) {
break;
}
sub_compact->num_input_records++;
if (++loop_cnt > 1000) {
RecordDroppedKeys(&key_drop_user, &key_drop_newer_entry,
&key_drop_obsolete,
&sub_compact->compaction_job_stats);
RecordCompactionIOStats();
loop_cnt = 0;
}
sub_compact->compaction_job_stats.total_input_raw_key_bytes += key.size();
sub_compact->compaction_job_stats.total_input_raw_value_bytes +=
value.size();
if (sub_compact->compaction->ShouldStopBefore(key) &&
sub_compact->builder != nullptr) {
status = FinishCompactionOutputFile(input->status(), sub_compact);
if (!status.ok()) {
break;
}
}
if (ikey.type == kTypeDeletion) {
sub_compact->compaction_job_stats.num_input_deletion_records++;
}
if (!has_current_user_key ||
cfd->user_comparator()->Compare(ikey.user_key,
current_user_key.GetKey()) != 0) {
// First occurrence of this user key
current_user_key.SetKey(ikey.user_key);
has_current_user_key = true;
last_sequence_for_key = kMaxSequenceNumber;
visible_in_snapshot = kMaxSequenceNumber;
// apply the compaction filter to the first occurrence of the user key
if (compaction_filter && ikey.type == kTypeValue &&
(sub_compact->visible_at_tip ||
ikey.sequence > sub_compact->latest_snapshot)) {
// 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.
bool value_changed = false;
compaction_filter_value.clear();
if (stats_ != nullptr) {
timer.Start();
}
bool to_delete = compaction_filter->Filter(
sub_compact->compaction->level(), ikey.user_key, value,
&compaction_filter_value, &value_changed);
total_filter_time += timer.ElapsedNanos();
if (to_delete) {
// make a copy of the original key and convert it to a delete
delete_key.SetInternalKey(ExtractUserKey(key), ikey.sequence,
kTypeDeletion);
// anchor the key again
key = delete_key.GetKey();
// needed because ikey is backed by key
ParseInternalKey(key, &ikey);
// no value associated with delete
value.clear();
++key_drop_user;
} else if (value_changed) {
value = compaction_filter_value;
}
}
}
// If there are no snapshots, then this kv affect visibility at tip.
// Otherwise, search though all existing snapshots to find
// the earlist snapshot that is affected by this kv.
SequenceNumber prev_snapshot = 0; // 0 means no previous snapshot
SequenceNumber visible =
sub_compact->visible_at_tip
? sub_compact->visible_at_tip
: findEarliestVisibleSnapshot(ikey.sequence, &prev_snapshot);
if (visible_in_snapshot == visible) {
// If the earliest snapshot is which this key is visible in
// is the same as the visibily 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
// TODO: why not > ?
assert(last_sequence_for_key >= ikey.sequence);
++key_drop_newer_entry;
input->Next(); // (A)
} else if (ikey.type == kTypeDeletion &&
ikey.sequence <= sub_compact->earliest_snapshot &&
sub_compact->compaction->KeyNotExistsBeyondOutputLevel(
ikey.user_key, &sub_compact->level_ptrs)) {
// 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.
++key_drop_obsolete;
input->Next();
} else if (ikey.type == kTypeMerge) {
if (!merge.HasOperator()) {
LogToBuffer(log_buffer_, "Options::merge_operator is null.");
status = Status::InvalidArgument(
"merge_operator is not properly initialized.");
break;
}
// 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. Turn out this
// logic could also be nicely re-used for memtable flush purge
// optimization in BuildTable.
merge.MergeUntil(input, prev_snapshot, bottommost_level_,
db_options_.statistics.get(), env_);
// NOTE: key, value, and ikey refer to old entries.
// These will be correctly set below.
const auto& keys = merge.keys();
const auto& values = merge.values();
assert(!keys.empty());
assert(keys.size() == values.size());
// We have a list of keys to write, write all keys in the list.
for (auto key_iter = keys.rbegin(), value_iter = values.rbegin();
!status.ok() || key_iter != keys.rend(); key_iter++, value_iter++) {
key = Slice(*key_iter);
value = Slice(*value_iter);
bool valid_key __attribute__((__unused__)) =
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);
status = WriteKeyValue(key, value, ikey, input->status(), sub_compact);
}
} else {
status = WriteKeyValue(key, value, ikey, input->status(), sub_compact);
input->Next();
}
last_sequence_for_key = ikey.sequence;
visible_in_snapshot = visible;
}
RecordTick(stats_, FILTER_OPERATION_TOTAL_TIME, total_filter_time);
RecordDroppedKeys(&key_drop_user, &key_drop_newer_entry, &key_drop_obsolete,
&sub_compact->compaction_job_stats);
RecordCompactionIOStats();
if (status.ok() &&
(shutting_down_->load(std::memory_order_acquire) || cfd->IsDropped())) {
status = Status::ShutdownInProgress(
"Database shutdown or Column family drop during compaction");
}
if (status.ok() && sub_compact->builder != nullptr) {
status = FinishCompactionOutputFile(input->status(), sub_compact);
}
if (status.ok()) {
status = input->status();
}
if (output_directory_ && !db_options_.disableDataSync) {
// TODO(aekmekji): Maybe only call once after all subcompactions complete?
output_directory_->Fsync();
}
if (measure_io_stats_) {
sub_compact->compaction_job_stats.file_write_nanos +=
iostats_context.write_nanos - prev_write_nanos;
sub_compact->compaction_job_stats.file_fsync_nanos +=
iostats_context.fsync_nanos - prev_fsync_nanos;
sub_compact->compaction_job_stats.file_range_sync_nanos +=
iostats_context.range_sync_nanos - prev_range_sync_nanos;
sub_compact->compaction_job_stats.file_prepare_write_nanos +=
iostats_context.prepare_write_nanos - prev_prepare_write_nanos;
if (prev_perf_level != PerfLevel::kEnableTime) {
SetPerfLevel(prev_perf_level);
}
}
input_ptr.reset();
sub_compact->status = status;
}
Status CompactionJob::WriteKeyValue(const Slice& key, const Slice& value,
const ParsedInternalKey& ikey, const Status& input_status,
SubCompactionState* sub_compact) {
Slice newkey(key.data(), key.size());
std::string kstr;
// 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
// then we can squash the seqno to zero.
if (bottommost_level_ && ikey.sequence < sub_compact->earliest_snapshot &&
ikey.type != kTypeMerge) {
assert(ikey.type != kTypeDeletion);
// make a copy because updating in place would cause problems
// with the priority queue that is managing the input key iterator
kstr.assign(key.data(), key.size());
UpdateInternalKey(&kstr, (uint64_t)0, ikey.type);
newkey = Slice(kstr);
}
// Open output file if necessary
if (sub_compact->builder == nullptr) {
Status status = OpenCompactionOutputFile(sub_compact);
if (!status.ok()) {
return status;
}
}
assert(sub_compact->builder != nullptr);
assert(sub_compact->current_output() != nullptr);
SequenceNumber seqno = GetInternalKeySeqno(newkey);
if (sub_compact->builder->NumEntries() == 0) {
sub_compact->current_output()->smallest.DecodeFrom(newkey);
sub_compact->current_output()->smallest_seqno = seqno;
} else {
sub_compact->current_output()->smallest_seqno =
std::min(sub_compact->current_output()->smallest_seqno, seqno);
}
sub_compact->current_output()->largest.DecodeFrom(newkey);
sub_compact->builder->Add(newkey, value);
sub_compact->num_output_records++;
sub_compact->current_output()->largest_seqno =
std::max(sub_compact->current_output()->largest_seqno, seqno);
// Close output file if it is big enough
Status status;
if (sub_compact->builder->FileSize() >=
sub_compact->compaction->max_output_file_size()) {
status = FinishCompactionOutputFile(input_status, sub_compact);
}
return status;
}
void CompactionJob::RecordDroppedKeys(
int64_t* key_drop_user,
int64_t* key_drop_newer_entry,
int64_t* key_drop_obsolete,
CompactionJobStats* compaction_job_stats) {
if (*key_drop_user > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_USER, *key_drop_user);
*key_drop_user = 0;
}
if (*key_drop_newer_entry > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_NEWER_ENTRY, *key_drop_newer_entry);
if (compaction_job_stats) {
compaction_job_stats->num_records_replaced += *key_drop_newer_entry;
}
*key_drop_newer_entry = 0;
}
if (*key_drop_obsolete > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_OBSOLETE, *key_drop_obsolete);
if (compaction_job_stats) {
compaction_job_stats->num_expired_deletion_records += *key_drop_obsolete;
}
*key_drop_obsolete = 0;
}
}
Status CompactionJob::FinishCompactionOutputFile(const Status& input_status,
SubCompactionState* sub_compact) {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_SYNC_FILE);
assert(sub_compact != nullptr);
assert(sub_compact->outfile);
assert(sub_compact->builder != nullptr);
assert(sub_compact->current_output() != nullptr);
const uint64_t output_number = sub_compact->current_output()->number;
const uint32_t output_path_id = sub_compact->current_output()->path_id;
assert(output_number != 0);
TableProperties table_properties;
// Check for iterator errors
Status s = input_status;
const uint64_t current_entries = sub_compact->builder->NumEntries();
sub_compact->current_output()->need_compaction =
sub_compact->builder->NeedCompact();
if (s.ok()) {
s = sub_compact->builder->Finish();
} else {
sub_compact->builder->Abandon();
}
const uint64_t current_bytes = sub_compact->builder->FileSize();
sub_compact->current_output()->file_size = current_bytes;
sub_compact->total_bytes += current_bytes;
// Finish and check for file errors
if (s.ok() && !db_options_.disableDataSync) {
StopWatch sw(env_, stats_, COMPACTION_OUTFILE_SYNC_MICROS);
s = sub_compact->outfile->Sync(db_options_.use_fsync);
}
if (s.ok()) {
s = sub_compact->outfile->Close();
}
sub_compact->outfile.reset();
if (s.ok() && current_entries > 0) {
// Verify that the table is usable
ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();
FileDescriptor fd(output_number, output_path_id, current_bytes);
Iterator* iter = cfd->table_cache()->NewIterator(
ReadOptions(), env_options_, cfd->internal_comparator(), fd, nullptr,
cfd->internal_stats()->GetFileReadHist(
compact_->compaction->output_level()),
false);
s = iter->status();
if (s.ok() && paranoid_file_checks_) {
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {}
s = iter->status();
}
delete iter;
if (s.ok()) {
TableFileCreationInfo info(sub_compact->builder->GetTableProperties());
info.db_name = dbname_;
info.cf_name = cfd->GetName();
info.file_path = TableFileName(cfd->ioptions()->db_paths,
fd.GetNumber(), fd.GetPathId());
info.file_size = fd.GetFileSize();
info.job_id = job_id_;
Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
"[%s] [JOB %d] Generated table #%" PRIu64 ": %" PRIu64
" keys, %" PRIu64 " bytes%s",
cfd->GetName().c_str(), job_id_, output_number, current_entries,
current_bytes,
sub_compact->current_output()->need_compaction ? " (need compaction)"
: "");
EventHelpers::LogAndNotifyTableFileCreation(
event_logger_, cfd->ioptions()->listeners, fd, info);
}
}
sub_compact->builder.reset();
return s;
}
Status CompactionJob::InstallCompactionResults(
const MutableCFOptions& mutable_cf_options, InstrumentedMutex* db_mutex) {
db_mutex->AssertHeld();
auto* compaction = compact_->compaction;
// paranoia: verify that the files that we started with
// still exist in the current version and in the same original level.
// This ensures that a concurrent compaction did not erroneously
// pick the same files to compact_.
if (!versions_->VerifyCompactionFileConsistency(compaction)) {
Compaction::InputLevelSummaryBuffer inputs_summary;
Log(InfoLogLevel::ERROR_LEVEL, db_options_.info_log,
"[%s] [JOB %d] Compaction %s aborted",
compaction->column_family_data()->GetName().c_str(), job_id_,
compaction->InputLevelSummary(&inputs_summary));
return Status::Corruption("Compaction input files inconsistent");
}
{
Compaction::InputLevelSummaryBuffer inputs_summary;
Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
"[%s] [JOB %d] Compacted %s => %" PRIu64 " bytes",
compaction->column_family_data()->GetName().c_str(), job_id_,
compaction->InputLevelSummary(&inputs_summary), compact_->total_bytes);
}
// Add compaction outputs
compaction->AddInputDeletions(compact_->compaction->edit());
for (SubCompactionState& sub_compact : compact_->sub_compact_states) {
for (size_t i = 0; i < sub_compact.outputs.size(); i++) {
const SubCompactionState::Output& out = sub_compact.outputs[i];
compaction->edit()->AddFile(compaction->output_level(), out.number,
out.path_id, out.file_size, out.smallest,
out.largest, out.smallest_seqno,
out.largest_seqno, out.need_compaction);
}
}
return versions_->LogAndApply(compaction->column_family_data(),
mutable_cf_options, compaction->edit(),
db_mutex, db_directory_);
}
// Given a sequence number, return the sequence number of the
// earliest snapshot that this sequence number is visible in.
// The snapshots themselves are arranged in ascending order of
// sequence numbers.
// Employ a sequential search because the total number of
// snapshots are typically small.
inline SequenceNumber CompactionJob::findEarliestVisibleSnapshot(
SequenceNumber in, SequenceNumber* prev_snapshot) {
assert(existing_snapshots_.size());
SequenceNumber prev __attribute__((unused)) = 0;
for (const auto cur : existing_snapshots_) {
assert(prev <= cur);
if (cur >= in) {
*prev_snapshot = prev;
return cur;
}
prev = cur; // assignment
assert(prev);
}
Log(InfoLogLevel::WARN_LEVEL, db_options_.info_log,
"CompactionJob is not able to find snapshot"
" with SeqId later than %" PRIu64
": current MaxSeqId is %" PRIu64 "",
in, existing_snapshots_[existing_snapshots_.size() - 1]);
assert(0);
return 0;
}
void CompactionJob::RecordCompactionIOStats() {
RecordTick(stats_, COMPACT_READ_BYTES, IOSTATS(bytes_read));
ThreadStatusUtil::IncreaseThreadOperationProperty(
ThreadStatus::COMPACTION_BYTES_READ, IOSTATS(bytes_read));
IOSTATS_RESET(bytes_read);
RecordTick(stats_, COMPACT_WRITE_BYTES, IOSTATS(bytes_written));
ThreadStatusUtil::IncreaseThreadOperationProperty(
ThreadStatus::COMPACTION_BYTES_WRITTEN, IOSTATS(bytes_written));
IOSTATS_RESET(bytes_written);
}
Status CompactionJob::OpenCompactionOutputFile(SubCompactionState*
sub_compact) {
assert(sub_compact != nullptr);
assert(sub_compact->builder == nullptr);
// no need to lock because VersionSet::next_file_number_ is atomic
uint64_t file_number = versions_->NewFileNumber();
// Make the output file
unique_ptr<WritableFile> writable_file;
std::string fname = TableFileName(db_options_.db_paths, file_number,
sub_compact->compaction->output_path_id());
Status s = env_->NewWritableFile(fname, &writable_file, env_options_);
if (!s.ok()) {
Log(InfoLogLevel::ERROR_LEVEL, db_options_.info_log,
"[%s] [JOB %d] OpenCompactionOutputFiles for table #%" PRIu64
" fails at NewWritableFile with status %s",
sub_compact->compaction->column_family_data()->GetName().c_str(),
job_id_, file_number, s.ToString().c_str());
LogFlush(db_options_.info_log);
return s;
}
SubCompactionState::Output out;
out.number = file_number;
out.path_id = sub_compact->compaction->output_path_id();
out.smallest.Clear();
out.largest.Clear();
out.smallest_seqno = out.largest_seqno = 0;
sub_compact->outputs.push_back(out);
writable_file->SetIOPriority(Env::IO_LOW);
writable_file->SetPreallocationBlockSize(static_cast<size_t>(
sub_compact->compaction->OutputFilePreallocationSize()));
sub_compact->outfile.reset(
new WritableFileWriter(std::move(writable_file), env_options_));
ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();
bool skip_filters = false;
// If the Column family flag is to only optimize filters for hits,
// we can skip creating filters if this is the bottommost_level where
// data is going to be found
//
if (cfd->ioptions()->optimize_filters_for_hits && bottommost_level_) {
skip_filters = true;
}
sub_compact->builder.reset(NewTableBuilder(
*cfd->ioptions(), cfd->internal_comparator(),
cfd->int_tbl_prop_collector_factories(), sub_compact->outfile.get(),
sub_compact->compaction->output_compression(),
cfd->ioptions()->compression_opts, skip_filters));
LogFlush(db_options_.info_log);
return s;
}
void CompactionJob::CleanupCompaction() {
for (SubCompactionState& sub_compact : compact_->sub_compact_states) {
const auto& sub_status = sub_compact.status;
if (sub_compact.builder != nullptr) {
// May happen if we get a shutdown call in the middle of compaction
sub_compact.builder->Abandon();
sub_compact.builder.reset();
} else {
assert(!sub_status.ok() || sub_compact.outfile == nullptr);
}
for (size_t i = 0; i < sub_compact.outputs.size(); i++) {
const SubCompactionState::Output& out = sub_compact.outputs[i];
// If this file was inserted into the table cache then remove
// them here because this compaction was not committed.
if (!sub_status.ok()) {
TableCache::Evict(table_cache_.get(), out.number);
}
}
}
delete compact_;
compact_ = nullptr;
}
#ifndef ROCKSDB_LITE
namespace {
void CopyPrefix(
const Slice& src, size_t prefix_length, std::string* dst) {
assert(prefix_length > 0);
size_t length = src.size() > prefix_length ? prefix_length : src.size();
dst->assign(src.data(), length);
}
} // namespace
#endif // !ROCKSDB_LITE
void CompactionJob::UpdateCompactionStats() {
Compaction* compaction = compact_->compaction;
compaction_stats_.num_input_files_in_non_output_levels = 0;
compaction_stats_.num_input_files_in_output_level = 0;
for (int input_level = 0;
input_level < static_cast<int>(compaction->num_input_levels());
++input_level) {
if (compaction->start_level() + input_level
!= compaction->output_level()) {
UpdateCompactionInputStatsHelper(
&compaction_stats_.num_input_files_in_non_output_levels,
&compaction_stats_.bytes_read_non_output_levels,
input_level);
} else {
UpdateCompactionInputStatsHelper(
&compaction_stats_.num_input_files_in_output_level,
&compaction_stats_.bytes_read_output_level,
input_level);
}
}
for (const auto& sub_compact : compact_->sub_compact_states) {
size_t num_output_files = sub_compact.outputs.size();
if (sub_compact.builder != nullptr) {
// An error occurred so ignore the last output.
assert(num_output_files > 0);
--num_output_files;
}
compaction_stats_.num_output_files += static_cast<int>(num_output_files);
for (size_t i = 0; i < num_output_files; i++) {
compaction_stats_.bytes_written += sub_compact.outputs[i].file_size;
}
if (sub_compact.num_input_records > sub_compact.num_output_records) {
compaction_stats_.num_dropped_records +=
sub_compact.num_input_records - sub_compact.num_output_records;
}
}
}
void CompactionJob::UpdateCompactionInputStatsHelper(
int* num_files, uint64_t* bytes_read, int input_level) {
const Compaction* compaction = compact_->compaction;
auto num_input_files = compaction->num_input_files(input_level);
*num_files += static_cast<int>(num_input_files);
for (size_t i = 0; i < num_input_files; ++i) {
const auto* file_meta = compaction->input(input_level, i);
*bytes_read += file_meta->fd.GetFileSize();
compaction_stats_.num_input_records +=
static_cast<uint64_t>(file_meta->num_entries);
}
}
void CompactionJob::UpdateCompactionJobStats(
const InternalStats::CompactionStats& stats) const {
#ifndef ROCKSDB_LITE
if (compaction_job_stats_) {
compaction_job_stats_->elapsed_micros = stats.micros;
// input information
compaction_job_stats_->total_input_bytes =
stats.bytes_read_non_output_levels +
stats.bytes_read_output_level;
compaction_job_stats_->num_input_records =
compact_->num_input_records;
compaction_job_stats_->num_input_files =
stats.num_input_files_in_non_output_levels +
stats.num_input_files_in_output_level;
compaction_job_stats_->num_input_files_at_output_level =
stats.num_input_files_in_output_level;
// output information
compaction_job_stats_->total_output_bytes = stats.bytes_written;
compaction_job_stats_->num_output_records =
compact_->num_output_records;
compaction_job_stats_->num_output_files = stats.num_output_files;
if (compact_->NumOutputFiles() > 0U) {
CopyPrefix(
compact_->SmallestUserKey(),
CompactionJobStats::kMaxPrefixLength,
&compaction_job_stats_->smallest_output_key_prefix);
CopyPrefix(
compact_->LargestUserKey(),
CompactionJobStats::kMaxPrefixLength,
&compaction_job_stats_->largest_output_key_prefix);
}
}
#endif // !ROCKSDB_LITE
}
void CompactionJob::LogCompaction() {
Compaction* compaction = compact_->compaction;
ColumnFamilyData* cfd = compaction->column_family_data();
// Let's check if anything will get logged. Don't prepare all the info if
// we're not logging
if (db_options_.info_log_level <= InfoLogLevel::INFO_LEVEL) {
Compaction::InputLevelSummaryBuffer inputs_summary;
Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
"[%s] [JOB %d] Compacting %s, score %.2f", cfd->GetName().c_str(),
job_id_, compaction->InputLevelSummary(&inputs_summary),
compaction->score());
char scratch[2345];
compaction->Summary(scratch, sizeof(scratch));
Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
"[%s] Compaction start summary: %s\n", cfd->GetName().c_str(), scratch);
// build event logger report
auto stream = event_logger_->Log();
stream << "job" << job_id_ << "event"
<< "compaction_started";
for (size_t i = 0; i < compaction->num_input_levels(); ++i) {
stream << ("files_L" + ToString(compaction->level(i)));
stream.StartArray();
for (auto f : *compaction->inputs(i)) {
stream << f->fd.GetNumber();
}
stream.EndArray();
}
stream << "score" << compaction->score() << "input_data_size"
<< compaction->CalculateTotalInputSize();
}
}
} // namespace rocksdb
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