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rocksdb/db/compaction_job.cc
Anurag Indu 3d1a924ff3 Adding stats for the merge and filter operation 
Summary:
We have addded new stats and perf_context for measuring the merge and filter operation time consumption.
We have bounded all the merge operations within the GUARD statment and collected the total time for these operations in the DB.

Test Plan: WIP

Reviewers: rven, yhchiang, kradhakrishnan, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D34377
2015-03-24 14:42:04 -07:00

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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/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/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/sync_point.h"
#include "util/thread_status_util.h"
namespace rocksdb {
struct CompactionJob::CompactionState {
Compaction* const compaction;
// If there were two snapshots with seq numbers s1 and
// s2 and s1 < s2, and if we find two instances of a key k1 then lies
// entirely within s1 and s2, then the earlier version of k1 can be safely
// deleted because that version is not visible in any snapshot.
std::vector<SequenceNumber> existing_snapshots;
// 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;
};
std::vector<Output> outputs;
// State kept for output being generated
std::unique_ptr<WritableFile> outfile;
std::unique_ptr<TableBuilder> builder;
uint64_t total_bytes;
Output* current_output() { return &outputs[outputs.size() - 1]; }
explicit CompactionState(Compaction* c)
: compaction(c),
total_bytes(0),
num_input_records(0),
num_output_records(0) {}
// Create a client visible context of this compaction
CompactionFilter::Context GetFilterContextV1() {
CompactionFilter::Context context;
context.is_full_compaction = compaction->IsFullCompaction();
context.is_manual_compaction = compaction->IsManualCompaction();
return context;
}
// Create a client visible context of this compaction
CompactionFilterContext GetFilterContext() {
CompactionFilterContext context;
context.is_full_compaction = compaction->IsFullCompaction();
context.is_manual_compaction = compaction->IsManualCompaction();
return context;
}
std::vector<std::string> key_str_buf_;
std::vector<std::string> existing_value_str_buf_;
// new_value_buf_ will only be appended if a value changes
std::vector<std::string> new_value_buf_;
// if values_changed_buf_[i] is true
// new_value_buf_ will add a new entry with the changed value
std::vector<bool> value_changed_buf_;
// to_delete_buf_[i] is true iff key_buf_[i] is deleted
std::vector<bool> to_delete_buf_;
std::vector<std::string> other_key_str_buf_;
std::vector<std::string> other_value_str_buf_;
std::vector<Slice> combined_key_buf_;
std::vector<Slice> combined_value_buf_;
std::string cur_prefix_;
uint64_t num_input_records;
uint64_t num_output_records;
// Buffers the kv-pair that will be run through compaction filter V2
// in the future.
void BufferKeyValueSlices(const Slice& key, const Slice& value) {
key_str_buf_.emplace_back(key.ToString());
existing_value_str_buf_.emplace_back(value.ToString());
}
// Buffers the kv-pair that will not be run through compaction filter V2
// in the future.
void BufferOtherKeyValueSlices(const Slice& key, const Slice& value) {
other_key_str_buf_.emplace_back(key.ToString());
other_value_str_buf_.emplace_back(value.ToString());
}
// Add a kv-pair to the combined buffer
void AddToCombinedKeyValueSlices(const Slice& key, const Slice& value) {
// The real strings are stored in the batch buffers
combined_key_buf_.emplace_back(key);
combined_value_buf_.emplace_back(value);
}
// Merging the two buffers
void MergeKeyValueSliceBuffer(const InternalKeyComparator* comparator) {
size_t i = 0;
size_t j = 0;
size_t total_size = key_str_buf_.size() + other_key_str_buf_.size();
combined_key_buf_.reserve(total_size);
combined_value_buf_.reserve(total_size);
while (i + j < total_size) {
int comp_res = 0;
if (i < key_str_buf_.size() && j < other_key_str_buf_.size()) {
comp_res = comparator->Compare(key_str_buf_[i], other_key_str_buf_[j]);
} else if (i >= key_str_buf_.size() && j < other_key_str_buf_.size()) {
comp_res = 1;
} else if (j >= other_key_str_buf_.size() && i < key_str_buf_.size()) {
comp_res = -1;
}
if (comp_res > 0) {
AddToCombinedKeyValueSlices(other_key_str_buf_[j],
other_value_str_buf_[j]);
j++;
} else if (comp_res < 0) {
AddToCombinedKeyValueSlices(key_str_buf_[i],
existing_value_str_buf_[i]);
i++;
}
}
}
void CleanupBatchBuffer() {
to_delete_buf_.clear();
key_str_buf_.clear();
existing_value_str_buf_.clear();
new_value_buf_.clear();
value_changed_buf_.clear();
to_delete_buf_.shrink_to_fit();
key_str_buf_.shrink_to_fit();
existing_value_str_buf_.shrink_to_fit();
new_value_buf_.shrink_to_fit();
value_changed_buf_.shrink_to_fit();
other_key_str_buf_.clear();
other_value_str_buf_.clear();
other_key_str_buf_.shrink_to_fit();
other_value_str_buf_.shrink_to_fit();
}
void CleanupMergedBuffer() {
combined_key_buf_.clear();
combined_value_buf_.clear();
combined_key_buf_.shrink_to_fit();
combined_value_buf_.shrink_to_fit();
}
};
CompactionJob::CompactionJob(
int job_id, Compaction* compaction, const DBOptions& db_options,
const MutableCFOptions& mutable_cf_options, const EnvOptions& env_options,
VersionSet* versions, std::atomic<bool>* shutting_down,
LogBuffer* log_buffer, Directory* db_directory, Directory* output_directory,
Statistics* stats, SnapshotList* snapshots, bool is_snapshot_supported,
std::shared_ptr<Cache> table_cache,
std::function<uint64_t()> yield_callback)
: job_id_(job_id),
compact_(new CompactionState(compaction)),
compaction_stats_(1),
db_options_(db_options),
mutable_cf_options_(mutable_cf_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),
snapshots_(snapshots),
is_snapshot_supported_(is_snapshot_supported),
table_cache_(std::move(table_cache)),
yield_callback_(std::move(yield_callback)) {
ThreadStatusUtil::SetColumnFamily(
compact_->compaction->column_family_data());
ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION);
}
CompactionJob::~CompactionJob() {
assert(compact_ == nullptr);
ThreadStatusUtil::ResetThreadStatus();
}
void CompactionJob::Prepare() {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_PREPARE);
compact_->CleanupBatchBuffer();
compact_->CleanupMergedBuffer();
auto* compaction = compact_->compaction;
// Generate file_levels_ for compaction berfore making Iterator
compaction->GenerateFileLevels();
ColumnFamilyData* cfd = compact_->compaction->column_family_data();
assert(cfd != nullptr);
{
Compaction::InputLevelSummaryBuffer inputs_summary;
LogToBuffer(log_buffer_, "[%s] [JOB %d] Compacting %s, score %.2f",
cfd->GetName().c_str(), job_id_,
compaction->InputLevelSummary(&inputs_summary),
compaction->score());
}
char scratch[2345];
compact_->compaction->Summary(scratch, sizeof(scratch));
LogToBuffer(log_buffer_, "[%s] Compaction start summary: %s\n",
cfd->GetName().c_str(), scratch);
assert(cfd->current()->storage_info()->NumLevelFiles(
compact_->compaction->level()) > 0);
assert(compact_->builder == nullptr);
assert(!compact_->outfile);
visible_at_tip_ = 0;
latest_snapshot_ = 0;
// TODO(icanadi) move snapshots_ out of CompactionJob
snapshots_->getAll(compact_->existing_snapshots);
if (compact_->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_ = compact_->existing_snapshots.back();
// Add the current seqno as the 'latest' virtual
// snapshot to the end of this list.
compact_->existing_snapshots.push_back(versions_->LastSequence());
earliest_snapshot_ = compact_->existing_snapshots[0];
}
// Is this compaction producing files at the bottommost level?
bottommost_level_ = compact_->compaction->BottomMostLevel();
}
Status CompactionJob::Run() {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_RUN);
TEST_SYNC_POINT("CompactionJob::Run():Start");
log_buffer_->FlushBufferToLog();
ColumnFamilyData* cfd = compact_->compaction->column_family_data();
const uint64_t start_micros = env_->NowMicros();
std::unique_ptr<Iterator> input(
versions_->MakeInputIterator(compact_->compaction));
input->SeekToFirst();
Status status;
ParsedInternalKey ikey;
std::unique_ptr<CompactionFilterV2> compaction_filter_from_factory_v2 =
nullptr;
auto context = compact_->GetFilterContext();
compaction_filter_from_factory_v2 =
cfd->ioptions()->compaction_filter_factory_v2->CreateCompactionFilterV2(
context);
auto compaction_filter_v2 = compaction_filter_from_factory_v2.get();
int64_t imm_micros = 0; // Micros spent doing imm_ compactions
if (!compaction_filter_v2) {
status = ProcessKeyValueCompaction(&imm_micros, input.get(), false);
} else {
// temp_backup_input always point to the start of the current buffer
// temp_backup_input = backup_input;
// iterate through input,
// 1) buffer ineligible keys and value keys into 2 separate buffers;
// 2) send value_buffer to compaction filter and alternate the values;
// 3) merge value_buffer with ineligible_value_buffer;
// 4) run the modified "compaction" using the old for loop.
bool prefix_initialized = false;
shared_ptr<Iterator> backup_input(
versions_->MakeInputIterator(compact_->compaction));
backup_input->SeekToFirst();
uint64_t total_filter_time = 0;
while (backup_input->Valid() &&
!shutting_down_->load(std::memory_order_acquire) &&
!cfd->IsDropped()) {
// FLUSH preempts compaction
// TODO(icanadi) this currently only checks if flush is necessary on
// compacting column family. we should also check if flush is necessary on
// other column families, too
imm_micros += yield_callback_();
Slice key = backup_input->key();
Slice value = backup_input->value();
if (!ParseInternalKey(key, &ikey)) {
// log error
Log(InfoLogLevel::WARN_LEVEL, db_options_.info_log,
"[%s] [JOB %d] Failed to parse key: %s", cfd->GetName().c_str(),
job_id_, key.ToString().c_str());
continue;
} else {
const SliceTransform* transformer =
cfd->ioptions()->compaction_filter_factory_v2->GetPrefixExtractor();
const auto key_prefix = transformer->Transform(ikey.user_key);
if (!prefix_initialized) {
compact_->cur_prefix_ = key_prefix.ToString();
prefix_initialized = true;
}
// If the prefix remains the same, keep buffering
if (key_prefix.compare(Slice(compact_->cur_prefix_)) == 0) {
// Apply the compaction filter V2 to all the kv pairs sharing
// the same prefix
if (ikey.type == kTypeValue &&
(visible_at_tip_ || ikey.sequence > latest_snapshot_)) {
// Buffer all keys sharing the same prefix for CompactionFilterV2
// Iterate through keys to check prefix
compact_->BufferKeyValueSlices(key, value);
} else {
// buffer ineligible keys
compact_->BufferOtherKeyValueSlices(key, value);
}
backup_input->Next();
continue;
// finish changing values for eligible keys
} else {
// Now prefix changes, this batch is done.
// Call compaction filter on the buffered values to change the value
if (compact_->key_str_buf_.size() > 0) {
uint64_t time = 0;
CallCompactionFilterV2(compaction_filter_v2, &time);
total_filter_time += time;
}
compact_->cur_prefix_ = key_prefix.ToString();
}
}
// Merge this batch of data (values + ineligible keys)
compact_->MergeKeyValueSliceBuffer(&cfd->internal_comparator());
// Done buffering for the current prefix. Spit it out to disk
// Now just iterate through all the kv-pairs
status = ProcessKeyValueCompaction(&imm_micros, input.get(), true);
if (!status.ok()) {
break;
}
// After writing the kv-pairs, we can safely remove the reference
// to the string buffer and clean them up
compact_->CleanupBatchBuffer();
compact_->CleanupMergedBuffer();
// Buffer the key that triggers the mismatch in prefix
if (ikey.type == kTypeValue &&
(visible_at_tip_ || ikey.sequence > latest_snapshot_)) {
compact_->BufferKeyValueSlices(key, value);
} else {
compact_->BufferOtherKeyValueSlices(key, value);
}
backup_input->Next();
if (!backup_input->Valid()) {
// If this is the single last value, we need to merge it.
if (compact_->key_str_buf_.size() > 0) {
uint64_t time = 0;
CallCompactionFilterV2(compaction_filter_v2, &time);
total_filter_time += time;
}
compact_->MergeKeyValueSliceBuffer(&cfd->internal_comparator());
status = ProcessKeyValueCompaction(&imm_micros, input.get(), true);
if (!status.ok()) {
break;
}
compact_->CleanupBatchBuffer();
compact_->CleanupMergedBuffer();
}
} // done processing all prefix batches
// finish the last batch
if (status.ok()) {
if (compact_->key_str_buf_.size() > 0) {
uint64_t time = 0;
CallCompactionFilterV2(compaction_filter_v2, &time);
total_filter_time += time;
}
compact_->MergeKeyValueSliceBuffer(&cfd->internal_comparator());
status = ProcessKeyValueCompaction(&imm_micros, input.get(), true);
}
RecordTick(stats_, FILTER_OPERATION_TOTAL_TIME, total_filter_time);
} // checking for compaction filter v2
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() && compact_->builder != nullptr) {
status = FinishCompactionOutputFile(input.get());
}
if (status.ok()) {
status = input->status();
}
input.reset();
if (output_directory_ && !db_options_.disableDataSync) {
output_directory_->Fsync();
}
compaction_stats_.micros = env_->NowMicros() - start_micros - imm_micros;
compaction_stats_.files_in_leveln =
static_cast<int>(compact_->compaction->num_input_files(0));
compaction_stats_.files_in_levelnp1 =
static_cast<int>(compact_->compaction->num_input_files(1));
MeasureTime(stats_, COMPACTION_TIME, compaction_stats_.micros);
size_t num_output_files = compact_->outputs.size();
if (compact_->builder != nullptr) {
// An error occurred so ignore the last output.
assert(num_output_files > 0);
--num_output_files;
}
compaction_stats_.files_out_levelnp1 = static_cast<int>(num_output_files);
for (size_t i = 0; i < compact_->compaction->num_input_files(0); i++) {
compaction_stats_.bytes_readn +=
compact_->compaction->input(0, i)->fd.GetFileSize();
compaction_stats_.num_input_records +=
static_cast<uint64_t>(compact_->compaction->input(0, i)->num_entries);
}
for (size_t i = 0; i < compact_->compaction->num_input_files(1); i++) {
compaction_stats_.bytes_readnp1 +=
compact_->compaction->input(1, i)->fd.GetFileSize();
}
for (size_t i = 0; i < num_output_files; i++) {
compaction_stats_.bytes_written += compact_->outputs[i].file_size;
}
if (compact_->num_input_records > compact_->num_output_records) {
compaction_stats_.num_dropped_records +=
compact_->num_input_records - compact_->num_output_records;
compact_->num_input_records = compact_->num_output_records = 0;
}
RecordCompactionIOStats();
LogFlush(db_options_.info_log);
TEST_SYNC_POINT("CompactionJob::Run():End");
return status;
}
void CompactionJob::Install(Status* status, InstrumentedMutex* db_mutex) {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_INSTALL);
db_mutex->AssertHeld();
ColumnFamilyData* cfd = compact_->compaction->column_family_data();
cfd->internal_stats()->AddCompactionStats(
compact_->compaction->output_level(), compaction_stats_);
if (status->ok()) {
*status = InstallCompactionResults(db_mutex);
}
VersionStorageInfo::LevelSummaryStorage tmp;
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(),
cfd->current()->storage_info()->LevelSummary(&tmp),
(stats.bytes_readn + stats.bytes_readnp1) /
static_cast<double>(stats.micros),
stats.bytes_written / static_cast<double>(stats.micros),
compact_->compaction->output_level(), stats.files_in_leveln,
stats.files_in_levelnp1, stats.files_out_levelnp1,
stats.bytes_readn / 1048576.0, stats.bytes_readnp1 / 1048576.0,
stats.bytes_written / 1048576.0,
(stats.bytes_written + stats.bytes_readnp1 + stats.bytes_readn) /
static_cast<double>(stats.bytes_readn),
stats.bytes_written / static_cast<double>(stats.bytes_readn),
status->ToString().c_str(), stats.num_input_records,
stats.num_dropped_records);
CleanupCompaction(*status);
}
Status CompactionJob::ProcessKeyValueCompaction(int64_t* imm_micros,
Iterator* input,
bool is_compaction_v2) {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_PROCESS_KV);
size_t combined_idx = 0;
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 = 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) {
auto context = compact_->GetFilterContextV1();
compaction_filter_from_factory =
cfd->ioptions()->compaction_filter_factory->CreateCompactionFilter(
context);
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;
while (input->Valid() && !shutting_down_->load(std::memory_order_acquire) &&
!cfd->IsDropped() && status.ok()) {
compact_->num_input_records++;
if (++loop_cnt > 1000) {
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);
key_drop_newer_entry = 0;
}
if (key_drop_obsolete > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_OBSOLETE, key_drop_obsolete);
key_drop_obsolete = 0;
}
RecordCompactionIOStats();
loop_cnt = 0;
}
// FLUSH preempts compaction
// TODO(icanadi) this currently only checks if flush is necessary on
// compacting column family. we should also check if flush is necessary on
// other column families, too
(*imm_micros) += yield_callback_();
Slice key;
Slice value;
// If is_compaction_v2 is on, kv-pairs are reset to the prefix batch.
// This prefix batch should contain results after calling
// compaction_filter_v2.
//
// If is_compaction_v2 is off, this function will go through all the
// kv-pairs in input.
if (!is_compaction_v2) {
key = input->key();
value = input->value();
} else {
if (combined_idx >= compact_->combined_key_buf_.size()) {
break;
}
assert(combined_idx < compact_->combined_key_buf_.size());
key = compact_->combined_key_buf_[combined_idx];
value = compact_->combined_value_buf_[combined_idx];
++combined_idx;
}
if (compact_->compaction->ShouldStopBefore(key) &&
compact_->builder != nullptr) {
status = FinishCompactionOutputFile(input);
if (!status.ok()) {
break;
}
}
// Handle key/value, add to state, etc.
bool drop = false;
bool current_entry_is_merging = false;
if (!ParseInternalKey(key, &ikey)) {
// Do not hide error keys
// TODO: error key stays in db forever? Figure out the intention/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;
} else {
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 && !is_compaction_v2 && ikey.type == kTypeValue &&
(visible_at_tip_ || ikey.sequence > 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 delete marker.
bool value_changed = false;
compaction_filter_value.clear();
if (stats_ != nullptr) {
timer.Start();
}
bool to_delete = compaction_filter->Filter(
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 =
visible_at_tip_
? visible_at_tip_
: is_snapshot_supported_
? findEarliestVisibleSnapshot(ikey.sequence,
compact_->existing_snapshots,
&prev_snapshot)
: 0;
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);
drop = true; // (A)
++key_drop_newer_entry;
} else if (ikey.type == kTypeDeletion &&
ikey.sequence <= earliest_snapshot_ &&
compact_->compaction->KeyNotExistsBeyondOutputLevel(
ikey.user_key)) {
// 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.
drop = true;
++key_drop_obsolete;
} 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.
int steps = 0;
merge.MergeUntil(input, prev_snapshot, bottommost_level_,
db_options_.statistics.get(), &steps, env_);
// Skip the Merge ops
combined_idx = combined_idx - 1 + steps;
current_entry_is_merging = true;
if (merge.IsSuccess()) {
// Successfully found Put/Delete/(end-of-key-range) while merging
// Get the merge result
key = merge.key();
ParseInternalKey(key, &ikey);
value = merge.value();
} else {
// Did not find a Put/Delete/(end-of-key-range) while merging
// We now have some stack of merge operands to write out.
// NOTE: key,value, and ikey are now referring to old entries.
// These will be correctly set below.
assert(!merge.keys().empty());
assert(merge.keys().size() == merge.values().size());
// Hack to make sure last_sequence_for_key is correct
ParseInternalKey(merge.keys().front(), &ikey);
}
}
last_sequence_for_key = ikey.sequence;
visible_in_snapshot = visible;
}
if (!drop) {
// We may write a single key (e.g.: for Put/Delete or successful merge).
// Or we may instead have to write a sequence/list of keys.
// We have to write a sequence iff we have an unsuccessful merge
bool has_merge_list = current_entry_is_merging && !merge.IsSuccess();
const std::deque<std::string>* keys = nullptr;
const std::deque<std::string>* values = nullptr;
std::deque<std::string>::const_reverse_iterator key_iter;
std::deque<std::string>::const_reverse_iterator value_iter;
if (has_merge_list) {
keys = &merge.keys();
values = &merge.values();
key_iter = keys->rbegin(); // The back (*rbegin()) is the first key
value_iter = values->rbegin();
key = Slice(*key_iter);
value = Slice(*value_iter);
}
// If we have a list of keys to write, traverse the list.
// If we have a single key to write, simply write that key.
while (true) {
// Invariant: key,value,ikey will always be the next entry to write
char* kptr = (char*)key.data();
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 < 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());
kptr = (char*)kstr.c_str();
UpdateInternalKey(kptr, key.size(), (uint64_t)0, ikey.type);
}
Slice newkey(kptr, key.size());
assert((key.clear(), 1)); // we do not need 'key' anymore
// Open output file if necessary
if (compact_->builder == nullptr) {
status = OpenCompactionOutputFile();
if (!status.ok()) {
break;
}
}
SequenceNumber seqno = GetInternalKeySeqno(newkey);
if (compact_->builder->NumEntries() == 0) {
compact_->current_output()->smallest.DecodeFrom(newkey);
compact_->current_output()->smallest_seqno = seqno;
} else {
compact_->current_output()->smallest_seqno =
std::min(compact_->current_output()->smallest_seqno, seqno);
}
compact_->current_output()->largest.DecodeFrom(newkey);
compact_->builder->Add(newkey, value);
compact_->num_output_records++,
compact_->current_output()->largest_seqno =
std::max(compact_->current_output()->largest_seqno, seqno);
// Close output file if it is big enough
if (compact_->builder->FileSize() >=
compact_->compaction->MaxOutputFileSize()) {
status = FinishCompactionOutputFile(input);
if (!status.ok()) {
break;
}
}
// If we have a list of entries, move to next element
// If we only had one entry, then break the loop.
if (has_merge_list) {
++key_iter;
++value_iter;
// If at end of list
if (key_iter == keys->rend() || value_iter == values->rend()) {
// Sanity Check: if one ends, then both end
assert(key_iter == keys->rend() && value_iter == values->rend());
break;
}
// Otherwise not at end of list. Update key, value, and ikey.
key = Slice(*key_iter);
value = Slice(*value_iter);
ParseInternalKey(key, &ikey);
} else {
// Only had one item to begin with (Put/Delete)
break;
}
} // while (true)
} // if (!drop)
// MergeUntil has moved input to the next entry
if (!current_entry_is_merging) {
input->Next();
}
}
RecordTick(stats_, FILTER_OPERATION_TOTAL_TIME, total_filter_time);
if (key_drop_user > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_USER, key_drop_user);
}
if (key_drop_newer_entry > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_NEWER_ENTRY, key_drop_newer_entry);
}
if (key_drop_obsolete > 0) {
RecordTick(stats_, COMPACTION_KEY_DROP_OBSOLETE, key_drop_obsolete);
}
RecordCompactionIOStats();
return status;
}
void CompactionJob::CallCompactionFilterV2(
CompactionFilterV2* compaction_filter_v2, uint64_t* time) {
if (compact_ == nullptr || compaction_filter_v2 == nullptr) {
return;
}
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_FILTER_V2);
// Assemble slice vectors for user keys and existing values.
// We also keep track of our parsed internal key structs because
// we may need to access the sequence number in the event that
// keys are garbage collected during the filter process.
std::vector<ParsedInternalKey> ikey_buf;
std::vector<Slice> user_key_buf;
std::vector<Slice> existing_value_buf;
for (const auto& key : compact_->key_str_buf_) {
ParsedInternalKey ikey;
ParseInternalKey(Slice(key), &ikey);
ikey_buf.emplace_back(ikey);
user_key_buf.emplace_back(ikey.user_key);
}
for (const auto& value : compact_->existing_value_str_buf_) {
existing_value_buf.emplace_back(Slice(value));
}
// 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 delete marker.
StopWatchNano timer(env_, stats_ != nullptr);
compact_->to_delete_buf_ = compaction_filter_v2->Filter(
compact_->compaction->level(), user_key_buf, existing_value_buf,
&compact_->new_value_buf_, &compact_->value_changed_buf_);
*time = timer.ElapsedNanos();
// new_value_buf_.size() <= to_delete__buf_.size(). "=" iff all
// kv-pairs in this compaction run needs to be deleted.
assert(compact_->to_delete_buf_.size() == compact_->key_str_buf_.size());
assert(compact_->to_delete_buf_.size() ==
compact_->existing_value_str_buf_.size());
assert(compact_->value_changed_buf_.empty() ||
compact_->to_delete_buf_.size() ==
compact_->value_changed_buf_.size());
int new_value_idx = 0;
for (unsigned int i = 0; i < compact_->to_delete_buf_.size(); ++i) {
if (compact_->to_delete_buf_[i]) {
// update the string buffer directly
// the Slice buffer points to the updated buffer
UpdateInternalKey(&compact_->key_str_buf_[i][0],
compact_->key_str_buf_[i].size(), ikey_buf[i].sequence,
kTypeDeletion);
// no value associated with delete
compact_->existing_value_str_buf_[i].clear();
RecordTick(stats_, COMPACTION_KEY_DROP_USER);
} else if (!compact_->value_changed_buf_.empty() &&
compact_->value_changed_buf_[i]) {
compact_->existing_value_str_buf_[i] =
compact_->new_value_buf_[new_value_idx++];
}
} // for
}
Status CompactionJob::FinishCompactionOutputFile(Iterator* input) {
AutoThreadOperationStageUpdater stage_updater(
ThreadStatus::STAGE_COMPACTION_SYNC_FILE);
assert(compact_ != nullptr);
assert(compact_->outfile);
assert(compact_->builder != nullptr);
const uint64_t output_number = compact_->current_output()->number;
const uint32_t output_path_id = compact_->current_output()->path_id;
assert(output_number != 0);
// Check for iterator errors
Status s = input->status();
const uint64_t current_entries = compact_->builder->NumEntries();
if (s.ok()) {
s = compact_->builder->Finish();
} else {
compact_->builder->Abandon();
}
const uint64_t current_bytes = compact_->builder->FileSize();
compact_->current_output()->file_size = current_bytes;
compact_->total_bytes += current_bytes;
compact_->builder.reset();
// Finish and check for file errors
if (s.ok() && !db_options_.disableDataSync) {
if (db_options_.use_fsync) {
StopWatch sw(env_, stats_, COMPACTION_OUTFILE_SYNC_MICROS);
s = compact_->outfile->Fsync();
} else {
StopWatch sw(env_, stats_, COMPACTION_OUTFILE_SYNC_MICROS);
s = compact_->outfile->Sync();
}
}
if (s.ok()) {
s = compact_->outfile->Close();
}
compact_->outfile.reset();
if (s.ok() && current_entries > 0) {
// Verify that the table is usable
ColumnFamilyData* cfd = 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);
s = iter->status();
delete iter;
if (s.ok()) {
Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
"[%s] [JOB %d] Generated table #%" PRIu64 ": %" PRIu64
" keys, %" PRIu64 " bytes",
cfd->GetName().c_str(), job_id_, output_number, current_entries,
current_bytes);
}
}
return s;
}
Status CompactionJob::InstallCompactionResults(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 (size_t i = 0; i < compact_->outputs.size(); i++) {
const CompactionState::Output& out = 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);
}
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, const std::vector<SequenceNumber>& snapshots,
SequenceNumber* prev_snapshot) {
assert(snapshots.size());
SequenceNumber prev __attribute__((unused)) = 0;
for (const auto cur : 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, snapshots[snapshots.size() - 1]);
assert(0);
return 0;
}
void CompactionJob::RecordCompactionIOStats() {
RecordTick(stats_, COMPACT_READ_BYTES, IOSTATS(bytes_read));
IOSTATS_RESET(bytes_read);
RecordTick(stats_, COMPACT_WRITE_BYTES, IOSTATS(bytes_written));
IOSTATS_RESET(bytes_written);
}
Status CompactionJob::OpenCompactionOutputFile() {
assert(compact_ != nullptr);
assert(compact_->builder == nullptr);
// no need to lock because VersionSet::next_file_number_ is atomic
uint64_t file_number = versions_->NewFileNumber();
// Make the output file
std::string fname = TableFileName(db_options_.db_paths, file_number,
compact_->compaction->GetOutputPathId());
Status s = env_->NewWritableFile(fname, &compact_->outfile, 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",
compact_->compaction->column_family_data()->GetName().c_str(), job_id_,
file_number, s.ToString().c_str());
LogFlush(db_options_.info_log);
return s;
}
CompactionState::Output out;
out.number = file_number;
out.path_id = compact_->compaction->GetOutputPathId();
out.smallest.Clear();
out.largest.Clear();
out.smallest_seqno = out.largest_seqno = 0;
compact_->outputs.push_back(out);
compact_->outfile->SetIOPriority(Env::IO_LOW);
compact_->outfile->SetPreallocationBlockSize(static_cast<size_t>(
compact_->compaction->OutputFilePreallocationSize(mutable_cf_options_)));
ColumnFamilyData* cfd = 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;
}
compact_->builder.reset(NewTableBuilder(
*cfd->ioptions(), cfd->internal_comparator(), compact_->outfile.get(),
compact_->compaction->OutputCompressionType(),
cfd->ioptions()->compression_opts, skip_filters));
LogFlush(db_options_.info_log);
return s;
}
void CompactionJob::CleanupCompaction(const Status& status) {
if (compact_->builder != nullptr) {
// May happen if we get a shutdown call in the middle of compaction
compact_->builder->Abandon();
compact_->builder.reset();
} else {
assert(!status.ok() || compact_->outfile == nullptr);
}
for (size_t i = 0; i < compact_->outputs.size(); i++) {
const CompactionState::Output& out = compact_->outputs[i];
// If this file was inserted into the table cache then remove
// them here because this compaction was not committed.
if (!status.ok()) {
TableCache::Evict(table_cache_.get(), out.number);
}
}
delete compact_;
compact_ = nullptr;
}
} // namespace rocksdb
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