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rocksdb/db/compaction/compaction_picker_universal.cc

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// 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_picker_universal.h"
#ifndef ROCKSDB_LITE
#include <cinttypes>
#include <limits>
#include <queue>
#include <string>
#include <utility>
#include "db/column_family.h"
#include "file/filename.h"
#include "logging/log_buffer.h"
#include "monitoring/statistics.h"
#include "test_util/sync_point.h"
#include "util/random.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
namespace {
// A helper class that form universal compactions. The class is used by
// UniversalCompactionPicker::PickCompaction().
// The usage is to create the class, and get the compaction object by calling
// PickCompaction().
class UniversalCompactionBuilder {
public:
UniversalCompactionBuilder(
const ImmutableOptions& ioptions, const InternalKeyComparator* icmp,
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
const MutableDBOptions& mutable_db_options, VersionStorageInfo* vstorage,
UniversalCompactionPicker* picker, LogBuffer* log_buffer)
: ioptions_(ioptions),
icmp_(icmp),
cf_name_(cf_name),
mutable_cf_options_(mutable_cf_options),
mutable_db_options_(mutable_db_options),
vstorage_(vstorage),
picker_(picker),
log_buffer_(log_buffer) {}
// Form and return the compaction object. The caller owns return object.
Compaction* PickCompaction();
private:
struct SortedRun {
SortedRun(int _level, FileMetaData* _file, uint64_t _size,
uint64_t _compensated_file_size, bool _being_compacted)
: level(_level),
file(_file),
size(_size),
compensated_file_size(_compensated_file_size),
being_compacted(_being_compacted) {
assert(compensated_file_size > 0);
assert(level != 0 || file != nullptr);
}
void Dump(char* out_buf, size_t out_buf_size,
bool print_path = false) const;
// sorted_run_count is added into the string to print
void DumpSizeInfo(char* out_buf, size_t out_buf_size,
size_t sorted_run_count) const;
int level;
// `file` Will be null for level > 0. For level = 0, the sorted run is
// for this file.
FileMetaData* file;
// For level > 0, `size` and `compensated_file_size` are sum of sizes all
// files in the level. `being_compacted` should be the same for all files
// in a non-zero level. Use the value here.
uint64_t size;
uint64_t compensated_file_size;
bool being_compacted;
};
// Pick Universal compaction to limit read amplification
Compaction* PickCompactionToReduceSortedRuns(
unsigned int ratio, unsigned int max_number_of_files_to_compact);
// Pick Universal compaction to limit space amplification.
Compaction* PickCompactionToReduceSizeAmp();
Compaction* PickDeleteTriggeredCompaction();
// Form a compaction from the sorted run indicated by start_index to the
// oldest sorted run.
// The caller is responsible for making sure that those files are not in
// compaction.
Compaction* PickCompactionToOldest(size_t start_index,
CompactionReason compaction_reason);
// Try to pick periodic compaction. The caller should only call it
// if there is at least one file marked for periodic compaction.
// null will be returned if no such a compaction can be formed
// because some files are being compacted.
Compaction* PickPeriodicCompaction();
// Used in universal compaction when the enabled_trivial_move
// option is set. Checks whether there are any overlapping files
// in the input. Returns true if the input files are non
// overlapping.
bool IsInputFilesNonOverlapping(Compaction* c);
const ImmutableOptions& ioptions_;
const InternalKeyComparator* icmp_;
double score_;
std::vector<SortedRun> sorted_runs_;
const std::string& cf_name_;
const MutableCFOptions& mutable_cf_options_;
const MutableDBOptions& mutable_db_options_;
VersionStorageInfo* vstorage_;
UniversalCompactionPicker* picker_;
LogBuffer* log_buffer_;
static std::vector<SortedRun> CalculateSortedRuns(
const VersionStorageInfo& vstorage);
// Pick a path ID to place a newly generated file, with its estimated file
// size.
static uint32_t GetPathId(const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options,
uint64_t file_size);
};
// Used in universal compaction when trivial move is enabled.
// This structure is used for the construction of min heap
// that contains the file meta data, the level of the file
// and the index of the file in that level
struct InputFileInfo {
InputFileInfo() : f(nullptr), level(0), index(0) {}
FileMetaData* f;
size_t level;
size_t index;
};
// Used in universal compaction when trivial move is enabled.
// This comparator is used for the construction of min heap
// based on the smallest key of the file.
struct SmallestKeyHeapComparator {
explicit SmallestKeyHeapComparator(const Comparator* ucmp) { ucmp_ = ucmp; }
bool operator()(InputFileInfo i1, InputFileInfo i2) const {
return (ucmp_->Compare(i1.f->smallest.user_key(),
i2.f->smallest.user_key()) > 0);
}
private:
const Comparator* ucmp_;
};
typedef std::priority_queue<InputFileInfo, std::vector<InputFileInfo>,
SmallestKeyHeapComparator>
SmallestKeyHeap;
// This function creates the heap that is used to find if the files are
// overlapping during universal compaction when the allow_trivial_move
// is set.
SmallestKeyHeap create_level_heap(Compaction* c, const Comparator* ucmp) {
SmallestKeyHeap smallest_key_priority_q =
SmallestKeyHeap(SmallestKeyHeapComparator(ucmp));
InputFileInfo input_file;
for (size_t l = 0; l < c->num_input_levels(); l++) {
if (c->num_input_files(l) != 0) {
if (l == 0 && c->start_level() == 0) {
for (size_t i = 0; i < c->num_input_files(0); i++) {
input_file.f = c->input(0, i);
input_file.level = 0;
input_file.index = i;
smallest_key_priority_q.push(std::move(input_file));
}
} else {
input_file.f = c->input(l, 0);
input_file.level = l;
input_file.index = 0;
smallest_key_priority_q.push(std::move(input_file));
}
}
}
return smallest_key_priority_q;
}
#ifndef NDEBUG
// smallest_seqno and largest_seqno are set iff. `files` is not empty.
void GetSmallestLargestSeqno(const std::vector<FileMetaData*>& files,
SequenceNumber* smallest_seqno,
SequenceNumber* largest_seqno) {
bool is_first = true;
for (FileMetaData* f : files) {
assert(f->fd.smallest_seqno <= f->fd.largest_seqno);
if (is_first) {
is_first = false;
*smallest_seqno = f->fd.smallest_seqno;
*largest_seqno = f->fd.largest_seqno;
} else {
if (f->fd.smallest_seqno < *smallest_seqno) {
*smallest_seqno = f->fd.smallest_seqno;
}
if (f->fd.largest_seqno > *largest_seqno) {
*largest_seqno = f->fd.largest_seqno;
}
}
}
}
#endif
} // namespace
// Algorithm that checks to see if there are any overlapping
// files in the input
bool UniversalCompactionBuilder::IsInputFilesNonOverlapping(Compaction* c) {
auto comparator = icmp_->user_comparator();
int first_iter = 1;
InputFileInfo prev, curr, next;
SmallestKeyHeap smallest_key_priority_q =
create_level_heap(c, icmp_->user_comparator());
while (!smallest_key_priority_q.empty()) {
curr = smallest_key_priority_q.top();
smallest_key_priority_q.pop();
if (first_iter) {
prev = curr;
first_iter = 0;
} else {
if (comparator->Compare(prev.f->largest.user_key(),
curr.f->smallest.user_key()) >= 0) {
// found overlapping files, return false
return false;
}
assert(comparator->Compare(curr.f->largest.user_key(),
prev.f->largest.user_key()) > 0);
prev = curr;
}
next.f = nullptr;
if (c->level(curr.level) != 0 &&
curr.index < c->num_input_files(curr.level) - 1) {
next.f = c->input(curr.level, curr.index + 1);
next.level = curr.level;
next.index = curr.index + 1;
}
if (next.f) {
smallest_key_priority_q.push(std::move(next));
}
}
return true;
}
bool UniversalCompactionPicker::NeedsCompaction(
const VersionStorageInfo* vstorage) const {
const int kLevel0 = 0;
if (vstorage->CompactionScore(kLevel0) >= 1) {
return true;
}
if (!vstorage->FilesMarkedForPeriodicCompaction().empty()) {
return true;
}
if (!vstorage->FilesMarkedForCompaction().empty()) {
return true;
}
return false;
}
Compaction* UniversalCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
const MutableDBOptions& mutable_db_options, VersionStorageInfo* vstorage,
LogBuffer* log_buffer, SequenceNumber /* earliest_memtable_seqno */) {
UniversalCompactionBuilder builder(ioptions_, icmp_, cf_name,
mutable_cf_options, mutable_db_options,
vstorage, this, log_buffer);
return builder.PickCompaction();
}
void UniversalCompactionBuilder::SortedRun::Dump(char* out_buf,
size_t out_buf_size,
bool print_path) const {
if (level == 0) {
assert(file != nullptr);
if (file->fd.GetPathId() == 0 || !print_path) {
snprintf(out_buf, out_buf_size, "file %" PRIu64, file->fd.GetNumber());
} else {
snprintf(out_buf, out_buf_size, "file %" PRIu64
"(path "
"%" PRIu32 ")",
file->fd.GetNumber(), file->fd.GetPathId());
}
} else {
snprintf(out_buf, out_buf_size, "level %d", level);
}
}
void UniversalCompactionBuilder::SortedRun::DumpSizeInfo(
char* out_buf, size_t out_buf_size, size_t sorted_run_count) const {
if (level == 0) {
assert(file != nullptr);
snprintf(out_buf, out_buf_size,
"file %" PRIu64 "[%" ROCKSDB_PRIszt
"] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")",
file->fd.GetNumber(), sorted_run_count, file->fd.GetFileSize(),
file->compensated_file_size);
} else {
snprintf(out_buf, out_buf_size,
"level %d[%" ROCKSDB_PRIszt
"] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")",
level, sorted_run_count, size, compensated_file_size);
}
}
std::vector<UniversalCompactionBuilder::SortedRun>
UniversalCompactionBuilder::CalculateSortedRuns(
const VersionStorageInfo& vstorage) {
std::vector<UniversalCompactionBuilder::SortedRun> ret;
for (FileMetaData* f : vstorage.LevelFiles(0)) {
ret.emplace_back(0, f, f->fd.GetFileSize(), f->compensated_file_size,
f->being_compacted);
}
for (int level = 1; level < vstorage.num_levels(); level++) {
uint64_t total_compensated_size = 0U;
uint64_t total_size = 0U;
bool being_compacted = false;
for (FileMetaData* f : vstorage.LevelFiles(level)) {
total_compensated_size += f->compensated_file_size;
total_size += f->fd.GetFileSize();
// Size amp, read amp and periodic compactions always include all files
// for a non-zero level. However, a delete triggered compaction and
// a trivial move might pick a subset of files in a sorted run. So
// always check all files in a sorted run and mark the entire run as
// being compacted if one or more files are being compacted
if (f->being_compacted) {
being_compacted = f->being_compacted;
}
}
if (total_compensated_size > 0) {
ret.emplace_back(level, nullptr, total_size, total_compensated_size,
being_compacted);
}
}
return ret;
}
// Universal style of compaction. Pick files that are contiguous in
// time-range to compact.
Compaction* UniversalCompactionBuilder::PickCompaction() {
const int kLevel0 = 0;
score_ = vstorage_->CompactionScore(kLevel0);
sorted_runs_ = CalculateSortedRuns(*vstorage_);
if (sorted_runs_.size() == 0 ||
(vstorage_->FilesMarkedForPeriodicCompaction().empty() &&
vstorage_->FilesMarkedForCompaction().empty() &&
sorted_runs_.size() < (unsigned int)mutable_cf_options_
.level0_file_num_compaction_trigger)) {
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: nothing to do\n",
cf_name_.c_str());
TEST_SYNC_POINT_CALLBACK(
"UniversalCompactionBuilder::PickCompaction:Return", nullptr);
return nullptr;
}
VersionStorageInfo::LevelSummaryStorage tmp;
ROCKS_LOG_BUFFER_MAX_SZ(
log_buffer_, 3072,
"[%s] Universal: sorted runs: %" ROCKSDB_PRIszt " files: %s\n",
cf_name_.c_str(), sorted_runs_.size(), vstorage_->LevelSummary(&tmp));
Compaction* c = nullptr;
// Periodic compaction has higher priority than other type of compaction
// because it's a hard requirement.
if (!vstorage_->FilesMarkedForPeriodicCompaction().empty()) {
// Always need to do a full compaction for periodic compaction.
c = PickPeriodicCompaction();
}
// Check for size amplification.
if (c == nullptr &&
sorted_runs_.size() >=
static_cast<size_t>(
mutable_cf_options_.level0_file_num_compaction_trigger)) {
if ((c = PickCompactionToReduceSizeAmp()) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: compacting for size amp\n",
cf_name_.c_str());
} else {
// Size amplification is within limits. Try reducing read
// amplification while maintaining file size ratios.
unsigned int ratio =
mutable_cf_options_.compaction_options_universal.size_ratio;
if ((c = PickCompactionToReduceSortedRuns(ratio, UINT_MAX)) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: compacting for size ratio\n",
cf_name_.c_str());
} else {
// Size amplification and file size ratios are within configured limits.
// If max read amplification is exceeding configured limits, then force
// compaction without looking at filesize ratios and try to reduce
// the number of files to fewer than level0_file_num_compaction_trigger.
// This is guaranteed by NeedsCompaction()
assert(sorted_runs_.size() >=
static_cast<size_t>(
mutable_cf_options_.level0_file_num_compaction_trigger));
// Get the total number of sorted runs that are not being compacted
int num_sr_not_compacted = 0;
for (size_t i = 0; i < sorted_runs_.size(); i++) {
if (sorted_runs_[i].being_compacted == false) {
num_sr_not_compacted++;
}
}
// The number of sorted runs that are not being compacted is greater
// than the maximum allowed number of sorted runs
if (num_sr_not_compacted >
mutable_cf_options_.level0_file_num_compaction_trigger) {
unsigned int num_files =
num_sr_not_compacted -
mutable_cf_options_.level0_file_num_compaction_trigger + 1;
if ((c = PickCompactionToReduceSortedRuns(UINT_MAX, num_files)) !=
nullptr) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: compacting for file num -- %u\n",
cf_name_.c_str(), num_files);
}
}
}
}
}
if (c == nullptr) {
if ((c = PickDeleteTriggeredCompaction()) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: delete triggered compaction\n",
cf_name_.c_str());
}
}
if (c == nullptr) {
TEST_SYNC_POINT_CALLBACK(
"UniversalCompactionBuilder::PickCompaction:Return", nullptr);
return nullptr;
}
if (mutable_cf_options_.compaction_options_universal.allow_trivial_move ==
true &&
c->compaction_reason() != CompactionReason::kPeriodicCompaction) {
c->set_is_trivial_move(IsInputFilesNonOverlapping(c));
}
// validate that all the chosen files of L0 are non overlapping in time
#ifndef NDEBUG
bool is_first = true;
size_t level_index = 0U;
if (c->start_level() == 0) {
for (auto f : *c->inputs(0)) {
assert(f->fd.smallest_seqno <= f->fd.largest_seqno);
if (is_first) {
is_first = false;
}
}
level_index = 1U;
}
for (; level_index < c->num_input_levels(); level_index++) {
if (c->num_input_files(level_index) != 0) {
SequenceNumber smallest_seqno = 0U;
SequenceNumber largest_seqno = 0U;
GetSmallestLargestSeqno(*(c->inputs(level_index)), &smallest_seqno,
&largest_seqno);
if (is_first) {
is_first = false;
}
}
}
#endif
// update statistics
RecordInHistogram(ioptions_.stats, NUM_FILES_IN_SINGLE_COMPACTION,
c->inputs(0)->size());
picker_->RegisterCompaction(c);
vstorage_->ComputeCompactionScore(ioptions_, mutable_cf_options_);
TEST_SYNC_POINT_CALLBACK("UniversalCompactionBuilder::PickCompaction:Return",
c);
return c;
}
uint32_t UniversalCompactionBuilder::GetPathId(
const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options, uint64_t file_size) {
// Two conditions need to be satisfied:
// (1) the target path needs to be able to hold the file's size
// (2) Total size left in this and previous paths need to be not
// smaller than expected future file size before this new file is
// compacted, which is estimated based on size_ratio.
// For example, if now we are compacting files of size (1, 1, 2, 4, 8),
// we will make sure the target file, probably with size of 16, will be
// placed in a path so that eventually when new files are generated and
// compacted to (1, 1, 2, 4, 8, 16), all those files can be stored in or
// before the path we chose.
//
// TODO(sdong): now the case of multiple column families is not
// considered in this algorithm. So the target size can be violated in
// that case. We need to improve it.
uint64_t accumulated_size = 0;
uint64_t future_size =
file_size *
(100 - mutable_cf_options.compaction_options_universal.size_ratio) / 100;
uint32_t p = 0;
assert(!ioptions.cf_paths.empty());
for (; p < ioptions.cf_paths.size() - 1; p++) {
uint64_t target_size = ioptions.cf_paths[p].target_size;
if (target_size > file_size &&
accumulated_size + (target_size - file_size) > future_size) {
return p;
}
accumulated_size += target_size;
}
return p;
}
//
// Consider compaction files based on their size differences with
// the next file in time order.
//
Compaction* UniversalCompactionBuilder::PickCompactionToReduceSortedRuns(
unsigned int ratio, unsigned int max_number_of_files_to_compact) {
unsigned int min_merge_width =
mutable_cf_options_.compaction_options_universal.min_merge_width;
unsigned int max_merge_width =
mutable_cf_options_.compaction_options_universal.max_merge_width;
const SortedRun* sr = nullptr;
bool done = false;
size_t start_index = 0;
unsigned int candidate_count = 0;
unsigned int max_files_to_compact =
std::min(max_merge_width, max_number_of_files_to_compact);
min_merge_width = std::max(min_merge_width, 2U);
// Caller checks the size before executing this function. This invariant is
// important because otherwise we may have a possible integer underflow when
// dealing with unsigned types.
assert(sorted_runs_.size() > 0);
// Considers a candidate file only if it is smaller than the
// total size accumulated so far.
for (size_t loop = 0; loop < sorted_runs_.size(); loop++) {
candidate_count = 0;
// Skip files that are already being compacted
for (sr = nullptr; loop < sorted_runs_.size(); loop++) {
sr = &sorted_runs_[loop];
if (!sr->being_compacted) {
candidate_count = 1;
break;
}
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf));
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: %s"
"[%d] being compacted, skipping",
cf_name_.c_str(), file_num_buf, loop);
sr = nullptr;
}
// This file is not being compacted. Consider it as the
// first candidate to be compacted.
uint64_t candidate_size = sr != nullptr ? sr->compensated_file_size : 0;
if (sr != nullptr) {
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf), true);
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: Possible candidate %s[%d].",
cf_name_.c_str(), file_num_buf, loop);
}
// Check if the succeeding files need compaction.
for (size_t i = loop + 1;
candidate_count < max_files_to_compact && i < sorted_runs_.size();
i++) {
const SortedRun* succeeding_sr = &sorted_runs_[i];
if (succeeding_sr->being_compacted) {
break;
}
// Pick files if the total/last candidate file size (increased by the
// specified ratio) is still larger than the next candidate file.
// candidate_size is the total size of files picked so far with the
// default kCompactionStopStyleTotalSize; with
// kCompactionStopStyleSimilarSize, it's simply the size of the last
// picked file.
double sz = candidate_size * (100.0 + ratio) / 100.0;
if (sz < static_cast<double>(succeeding_sr->size)) {
break;
}
if (mutable_cf_options_.compaction_options_universal.stop_style ==
kCompactionStopStyleSimilarSize) {
// Similar-size stopping rule: also check the last picked file isn't
// far larger than the next candidate file.
sz = (succeeding_sr->size * (100.0 + ratio)) / 100.0;
if (sz < static_cast<double>(candidate_size)) {
// If the small file we've encountered begins a run of similar-size
// files, we'll pick them up on a future iteration of the outer
// loop. If it's some lonely straggler, it'll eventually get picked
// by the last-resort read amp strategy which disregards size ratios.
break;
}
candidate_size = succeeding_sr->compensated_file_size;
} else { // default kCompactionStopStyleTotalSize
candidate_size += succeeding_sr->compensated_file_size;
}
candidate_count++;
}
// Found a series of consecutive files that need compaction.
if (candidate_count >= (unsigned int)min_merge_width) {
start_index = loop;
done = true;
break;
} else {
for (size_t i = loop;
i < loop + candidate_count && i < sorted_runs_.size(); i++) {
const SortedRun* skipping_sr = &sorted_runs_[i];
char file_num_buf[256];
skipping_sr->DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: Skipping %s",
cf_name_.c_str(), file_num_buf);
}
}
}
if (!done || candidate_count <= 1) {
return nullptr;
}
size_t first_index_after = start_index + candidate_count;
// Compression is enabled if files compacted earlier already reached
// size ratio of compression.
bool enable_compression = true;
int ratio_to_compress =
mutable_cf_options_.compaction_options_universal.compression_size_percent;
if (ratio_to_compress >= 0) {
uint64_t total_size = 0;
for (auto& sorted_run : sorted_runs_) {
total_size += sorted_run.compensated_file_size;
}
uint64_t older_file_size = 0;
for (size_t i = sorted_runs_.size() - 1; i >= first_index_after; i--) {
older_file_size += sorted_runs_[i].size;
if (older_file_size * 100L >= total_size * (long)ratio_to_compress) {
enable_compression = false;
break;
}
}
}
uint64_t estimated_total_size = 0;
for (unsigned int i = 0; i < first_index_after; i++) {
estimated_total_size += sorted_runs_[i].size;
}
uint32_t path_id =
GetPathId(ioptions_, mutable_cf_options_, estimated_total_size);
int start_level = sorted_runs_[start_index].level;
int output_level;
if (first_index_after == sorted_runs_.size()) {
output_level = vstorage_->num_levels() - 1;
} else if (sorted_runs_[first_index_after].level == 0) {
output_level = 0;
} else {
output_level = sorted_runs_[first_index_after].level - 1;
}
// last level is reserved for the files ingested behind
if (ioptions_.allow_ingest_behind &&
(output_level == vstorage_->num_levels() - 1)) {
assert(output_level > 1);
output_level--;
}
std::vector<CompactionInputFiles> inputs(vstorage_->num_levels());
for (size_t i = 0; i < inputs.size(); ++i) {
inputs[i].level = start_level + static_cast<int>(i);
}
for (size_t i = start_index; i < first_index_after; i++) {
auto& picking_sr = sorted_runs_[i];
if (picking_sr.level == 0) {
FileMetaData* picking_file = picking_sr.file;
inputs[0].files.push_back(picking_file);
} else {
auto& files = inputs[picking_sr.level - start_level].files;
for (auto* f : vstorage_->LevelFiles(picking_sr.level)) {
files.push_back(f);
}
}
char file_num_buf[256];
picking_sr.DumpSizeInfo(file_num_buf, sizeof(file_num_buf), i);
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: Picking %s",
cf_name_.c_str(), file_num_buf);
}
CompactionReason compaction_reason;
if (max_number_of_files_to_compact == UINT_MAX) {
compaction_reason = CompactionReason::kUniversalSizeRatio;
} else {
compaction_reason = CompactionReason::kUniversalSortedRunNum;
}
return new Compaction(
vstorage_, ioptions_, mutable_cf_options_, mutable_db_options_,
std::move(inputs), output_level,
MaxFileSizeForLevel(mutable_cf_options_, output_level,
kCompactionStyleUniversal),
LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage_, mutable_cf_options_, start_level,
1, enable_compression),
GetCompressionOptions(mutable_cf_options_, vstorage_, start_level,
enable_compression),
/* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
score_, false /* deletion_compaction */, compaction_reason);
}
// Look at overall size amplification. If size amplification
// exceeds the configured value, then do a compaction
// of the candidate files all the way upto the earliest
// base file (overrides configured values of file-size ratios,
// min_merge_width and max_merge_width).
//
Compaction* UniversalCompactionBuilder::PickCompactionToReduceSizeAmp() {
// percentage flexibility while reducing size amplification
uint64_t ratio = mutable_cf_options_.compaction_options_universal
.max_size_amplification_percent;
unsigned int candidate_count = 0;
uint64_t candidate_size = 0;
size_t start_index = 0;
const SortedRun* sr = nullptr;
assert(!sorted_runs_.empty());
if (sorted_runs_.back().being_compacted) {
return nullptr;
}
// Skip files that are already being compacted
for (size_t loop = 0; loop + 1 < sorted_runs_.size(); loop++) {
sr = &sorted_runs_[loop];
if (!sr->being_compacted) {
start_index = loop; // Consider this as the first candidate.
break;
}
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf), true);
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: skipping %s[%d] compacted %s",
cf_name_.c_str(), file_num_buf, loop,
" cannot be a candidate to reduce size amp.\n");
sr = nullptr;
}
if (sr == nullptr) {
return nullptr; // no candidate files
}
{
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf), true);
ROCKS_LOG_BUFFER(
log_buffer_,
"[%s] Universal: First candidate %s[%" ROCKSDB_PRIszt "] %s",
cf_name_.c_str(), file_num_buf, start_index, " to reduce size amp.\n");
}
// keep adding up all the remaining files
for (size_t loop = start_index; loop + 1 < sorted_runs_.size(); loop++) {
sr = &sorted_runs_[loop];
if (sr->being_compacted) {
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf), true);
ROCKS_LOG_BUFFER(
log_buffer_, "[%s] Universal: Possible candidate %s[%d] %s",
cf_name_.c_str(), file_num_buf, start_index,
" is already being compacted. No size amp reduction possible.\n");
return nullptr;
}
candidate_size += sr->compensated_file_size;
candidate_count++;
}
if (candidate_count == 0) {
return nullptr;
}
// size of earliest file
uint64_t earliest_file_size = sorted_runs_.back().size;
// size amplification = percentage of additional size
if (candidate_size * 100 < ratio * earliest_file_size) {
ROCKS_LOG_BUFFER(
log_buffer_,
"[%s] Universal: size amp not needed. newer-files-total-size %" PRIu64
" earliest-file-size %" PRIu64,
cf_name_.c_str(), candidate_size, earliest_file_size);
return nullptr;
} else {
ROCKS_LOG_BUFFER(
log_buffer_,
"[%s] Universal: size amp needed. newer-files-total-size %" PRIu64
" earliest-file-size %" PRIu64,
cf_name_.c_str(), candidate_size, earliest_file_size);
}
return PickCompactionToOldest(start_index,
CompactionReason::kUniversalSizeAmplification);
}
// Pick files marked for compaction. Typically, files are marked by
// CompactOnDeleteCollector due to the presence of tombstones.
Compaction* UniversalCompactionBuilder::PickDeleteTriggeredCompaction() {
CompactionInputFiles start_level_inputs;
int output_level;
std::vector<CompactionInputFiles> inputs;
if (vstorage_->num_levels() == 1) {
// This is single level universal. Since we're basically trying to reclaim
// space by processing files marked for compaction due to high tombstone
// density, let's do the same thing as compaction to reduce size amp which
// has the same goals.
int start_index = -1;
start_level_inputs.level = 0;
start_level_inputs.files.clear();
output_level = 0;
// Find the first file marked for compaction. Ignore the last file
for (size_t loop = 0; loop + 1 < sorted_runs_.size(); loop++) {
SortedRun* sr = &sorted_runs_[loop];
if (sr->being_compacted) {
continue;
}
FileMetaData* f = vstorage_->LevelFiles(0)[loop];
if (f->marked_for_compaction) {
start_level_inputs.files.push_back(f);
start_index =
static_cast<int>(loop); // Consider this as the first candidate.
break;
}
}
if (start_index < 0) {
// Either no file marked, or they're already being compacted
return nullptr;
}
for (size_t loop = start_index + 1; loop < sorted_runs_.size(); loop++) {
SortedRun* sr = &sorted_runs_[loop];
if (sr->being_compacted) {
break;
}
FileMetaData* f = vstorage_->LevelFiles(0)[loop];
start_level_inputs.files.push_back(f);
}
if (start_level_inputs.size() <= 1) {
// If only the last file in L0 is marked for compaction, ignore it
return nullptr;
}
inputs.push_back(start_level_inputs);
} else {
int start_level;
// For multi-level universal, the strategy is to make this look more like
// leveled. We pick one of the files marked for compaction and compact with
// overlapping files in the adjacent level.
picker_->PickFilesMarkedForCompaction(cf_name_, vstorage_, &start_level,
&output_level, &start_level_inputs);
if (start_level_inputs.empty()) {
return nullptr;
}
// Pick the first non-empty level after the start_level
for (output_level = start_level + 1; output_level < vstorage_->num_levels();
output_level++) {
if (vstorage_->NumLevelFiles(output_level) != 0) {
break;
}
}
// If all higher levels are empty, pick the highest level as output level
if (output_level == vstorage_->num_levels()) {
if (start_level == 0) {
output_level = vstorage_->num_levels() - 1;
} else {
// If start level is non-zero and all higher levels are empty, this
// compaction will translate into a trivial move. Since the idea is
// to reclaim space and trivial move doesn't help with that, we
// skip compaction in this case and return nullptr
return nullptr;
}
}
if (ioptions_.allow_ingest_behind &&
output_level == vstorage_->num_levels() - 1) {
assert(output_level > 1);
output_level--;
}
if (output_level != 0) {
if (start_level == 0) {
if (!picker_->GetOverlappingL0Files(vstorage_, &start_level_inputs,
output_level, nullptr)) {
return nullptr;
}
}
CompactionInputFiles output_level_inputs;
int parent_index = -1;
output_level_inputs.level = output_level;
if (!picker_->SetupOtherInputs(cf_name_, mutable_cf_options_, vstorage_,
&start_level_inputs, &output_level_inputs,
&parent_index, -1)) {
return nullptr;
}
inputs.push_back(start_level_inputs);
if (!output_level_inputs.empty()) {
inputs.push_back(output_level_inputs);
}
if (picker_->FilesRangeOverlapWithCompaction(inputs, output_level)) {
return nullptr;
}
} else {
inputs.push_back(start_level_inputs);
}
}
uint64_t estimated_total_size = 0;
// Use size of the output level as estimated file size
for (FileMetaData* f : vstorage_->LevelFiles(output_level)) {
estimated_total_size += f->fd.GetFileSize();
}
uint32_t path_id =
GetPathId(ioptions_, mutable_cf_options_, estimated_total_size);
return new Compaction(
vstorage_, ioptions_, mutable_cf_options_, mutable_db_options_,
std::move(inputs), output_level,
MaxFileSizeForLevel(mutable_cf_options_, output_level,
kCompactionStyleUniversal),
/* max_grandparent_overlap_bytes */ LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
output_level, 1),
GetCompressionOptions(mutable_cf_options_, vstorage_, output_level),
/* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
score_, false /* deletion_compaction */,
CompactionReason::kFilesMarkedForCompaction);
}
Compaction* UniversalCompactionBuilder::PickCompactionToOldest(
size_t start_index, CompactionReason compaction_reason) {
assert(start_index < sorted_runs_.size());
// Estimate total file size
uint64_t estimated_total_size = 0;
for (size_t loop = start_index; loop < sorted_runs_.size(); loop++) {
estimated_total_size += sorted_runs_[loop].size;
}
uint32_t path_id =
GetPathId(ioptions_, mutable_cf_options_, estimated_total_size);
int start_level = sorted_runs_[start_index].level;
std::vector<CompactionInputFiles> inputs(vstorage_->num_levels());
for (size_t i = 0; i < inputs.size(); ++i) {
inputs[i].level = start_level + static_cast<int>(i);
}
for (size_t loop = start_index; loop < sorted_runs_.size(); loop++) {
auto& picking_sr = sorted_runs_[loop];
if (picking_sr.level == 0) {
FileMetaData* f = picking_sr.file;
inputs[0].files.push_back(f);
} else {
auto& files = inputs[picking_sr.level - start_level].files;
for (auto* f : vstorage_->LevelFiles(picking_sr.level)) {
files.push_back(f);
}
}
std::string comp_reason_print_string;
if (compaction_reason == CompactionReason::kPeriodicCompaction) {
comp_reason_print_string = "periodic compaction";
} else if (compaction_reason ==
CompactionReason::kUniversalSizeAmplification) {
comp_reason_print_string = "size amp";
} else {
assert(false);
comp_reason_print_string = "unknown: ";
comp_reason_print_string.append(
std::to_string(static_cast<int>(compaction_reason)));
}
char file_num_buf[256];
picking_sr.DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: %s picking %s",
cf_name_.c_str(), comp_reason_print_string.c_str(),
file_num_buf);
}
// output files at the bottom most level, unless it's reserved
int output_level = vstorage_->num_levels() - 1;
// last level is reserved for the files ingested behind
if (ioptions_.allow_ingest_behind) {
assert(output_level > 1);
output_level--;
}
// We never check size for
// compaction_options_universal.compression_size_percent,
// because we always compact all the files, so always compress.
return new Compaction(
vstorage_, ioptions_, mutable_cf_options_, mutable_db_options_,
std::move(inputs), output_level,
MaxFileSizeForLevel(mutable_cf_options_, output_level,
kCompactionStyleUniversal),
LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
output_level, 1, true /* enable_compression */),
GetCompressionOptions(mutable_cf_options_, vstorage_, output_level,
true /* enable_compression */),
/* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
score_, false /* deletion_compaction */, compaction_reason);
}
Compaction* UniversalCompactionBuilder::PickPeriodicCompaction() {
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: Periodic Compaction",
cf_name_.c_str());
// In universal compaction, sorted runs contain older data are almost always
// generated earlier too. To simplify the problem, we just try to trigger
// a full compaction. We start from the oldest sorted run and include
// all sorted runs, until we hit a sorted already being compacted.
// Since usually the largest (which is usually the oldest) sorted run is
// included anyway, doing a full compaction won't increase write
// amplification much.
// Get some information from marked files to check whether a file is
// included in the compaction.
size_t start_index = sorted_runs_.size();
while (start_index > 0 && !sorted_runs_[start_index - 1].being_compacted) {
start_index--;
}
if (start_index == sorted_runs_.size()) {
return nullptr;
}
// There is a rare corner case where we can't pick up all the files
// because some files are being compacted and we end up with picking files
// but none of them need periodic compaction. Unless we simply recompact
// the last sorted run (either the last level or last L0 file), we would just
// execute the compaction, in order to simplify the logic.
if (start_index == sorted_runs_.size() - 1) {
bool included_file_marked = false;
int start_level = sorted_runs_[start_index].level;
FileMetaData* start_file = sorted_runs_[start_index].file;
for (const std::pair<int, FileMetaData*>& level_file_pair :
vstorage_->FilesMarkedForPeriodicCompaction()) {
if (start_level != 0) {
// Last sorted run is a level
if (start_level == level_file_pair.first) {
included_file_marked = true;
break;
}
} else {
// Last sorted run is a L0 file.
if (start_file == level_file_pair.second) {
included_file_marked = true;
break;
}
}
}
if (!included_file_marked) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: Cannot form a compaction covering file "
"marked for periodic compaction",
cf_name_.c_str());
return nullptr;
}
}
Compaction* c = PickCompactionToOldest(start_index,
CompactionReason::kPeriodicCompaction);
TEST_SYNC_POINT_CALLBACK(
"UniversalCompactionPicker::PickPeriodicCompaction:Return", c);
return c;
}
} // namespace ROCKSDB_NAMESPACE
#endif // !ROCKSDB_LITE
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