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rocksdb/db/compaction_picker.cc

990 lines
38 KiB

// 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_picker.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <limits>
#include <string>
#include "db/filename.h"
#include "util/log_buffer.h"
#include "util/statistics.h"
namespace rocksdb {
uint64_t TotalCompensatedFileSize(const std::vector<FileMetaData*>& files) {
uint64_t sum = 0;
for (size_t i = 0; i < files.size() && files[i]; i++) {
sum += files[i]->compensated_file_size;
}
return sum;
}
namespace {
// Determine compression type, based on user options, level of the output
// file and whether compression is disabled.
// If enable_compression is false, then compression is always disabled no
// matter what the values of the other two parameters are.
// Otherwise, the compression type is determined based on options and level.
CompressionType GetCompressionType(
const ImmutableCFOptions& ioptions, int level,
const bool enable_compression = true) {
if (!enable_compression) {
// disable compression
return kNoCompression;
}
// If the use has specified a different compression level for each level,
// then pick the compression for that level.
if (!ioptions.compression_per_level.empty()) {
const int n = ioptions.compression_per_level.size() - 1;
// It is possible for level_ to be -1; in that case, we use level
// 0's compression. This occurs mostly in backwards compatibility
// situations when the builder doesn't know what level the file
// belongs to. Likewise, if level is beyond the end of the
// specified compression levels, use the last value.
return ioptions.compression_per_level[std::max(0, std::min(level, n))];
} else {
return ioptions.compression;
}
}
} // anonymous namespace
CompactionPicker::CompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp)
: ioptions_(ioptions),
compactions_in_progress_(ioptions_.num_levels),
icmp_(icmp) {
}
CompactionPicker::~CompactionPicker() {}
void CompactionPicker::SizeBeingCompacted(std::vector<uint64_t>& sizes) {
for (int level = 0; level < NumberLevels() - 1; level++) {
uint64_t total = 0;
for (auto c : compactions_in_progress_[level]) {
assert(c->level() == level);
for (int i = 0; i < c->num_input_files(0); i++) {
total += c->input(0, i)->compensated_file_size;
}
}
sizes[level] = total;
}
}
// Clear all files to indicate that they are not being compacted
// Delete this compaction from the list of running compactions.
void CompactionPicker::ReleaseCompactionFiles(Compaction* c, Status status) {
c->MarkFilesBeingCompacted(false);
compactions_in_progress_[c->level()].erase(c);
if (!status.ok()) {
c->ResetNextCompactionIndex();
}
}
void CompactionPicker::GetRange(const std::vector<FileMetaData*>& inputs,
InternalKey* smallest, InternalKey* largest) {
assert(!inputs.empty());
smallest->Clear();
largest->Clear();
for (size_t i = 0; i < inputs.size(); i++) {
FileMetaData* f = inputs[i];
if (i == 0) {
*smallest = f->smallest;
*largest = f->largest;
} else {
if (icmp_->Compare(f->smallest, *smallest) < 0) {
*smallest = f->smallest;
}
if (icmp_->Compare(f->largest, *largest) > 0) {
*largest = f->largest;
}
}
}
}
void CompactionPicker::GetRange(const std::vector<FileMetaData*>& inputs1,
const std::vector<FileMetaData*>& inputs2,
InternalKey* smallest, InternalKey* largest) {
std::vector<FileMetaData*> all = inputs1;
all.insert(all.end(), inputs2.begin(), inputs2.end());
GetRange(all, smallest, largest);
}
bool CompactionPicker::ExpandWhileOverlapping(const std::string& cf_name,
VersionStorageInfo* vstorage,
Compaction* c) {
assert(c != nullptr);
// If inputs are empty then there is nothing to expand.
if (c->inputs_[0].empty()) {
assert(c->inputs_[1].empty());
// This isn't good compaction
return false;
}
// GetOverlappingInputs will always do the right thing for level-0.
// So we don't need to do any expansion if level == 0.
if (c->level() == 0) {
return true;
}
const int level = c->level();
InternalKey smallest, largest;
// Keep expanding c->inputs_[0] until we are sure that there is a
// "clean cut" boundary between the files in input and the surrounding files.
// This will ensure that no parts of a key are lost during compaction.
int hint_index = -1;
size_t old_size;
do {
old_size = c->inputs_[0].size();
GetRange(c->inputs_[0].files, &smallest, &largest);
c->inputs_[0].clear();
vstorage->GetOverlappingInputs(level, &smallest, &largest,
&c->inputs_[0].files, hint_index,
&hint_index);
} while(c->inputs_[0].size() > old_size);
// Get the new range
GetRange(c->inputs_[0].files, &smallest, &largest);
// If, after the expansion, there are files that are already under
// compaction, then we must drop/cancel this compaction.
int parent_index = -1;
if (c->inputs_[0].empty()) {
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] ExpandWhileOverlapping() failure because zero input files",
cf_name.c_str());
}
if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0].files) ||
(c->level() != c->output_level() &&
ParentRangeInCompaction(vstorage, &smallest, &largest, level,
&parent_index))) {
c->inputs_[0].clear();
c->inputs_[1].clear();
if (!c->inputs_[0].empty()) {
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] ExpandWhileOverlapping() failure because some of the necessary"
" compaction input files are currently being compacted.",
c->column_family_data()->GetName().c_str());
}
return false;
}
return true;
}
// Returns true if any one of specified files are being compacted
bool CompactionPicker::FilesInCompaction(std::vector<FileMetaData*>& files) {
for (unsigned int i = 0; i < files.size(); i++) {
if (files[i]->being_compacted) {
return true;
}
}
return false;
}
// Returns true if any one of the parent files are being compacted
bool CompactionPicker::ParentRangeInCompaction(VersionStorageInfo* vstorage,
const InternalKey* smallest,
const InternalKey* largest,
int level, int* parent_index) {
std::vector<FileMetaData*> inputs;
assert(level + 1 < NumberLevels());
vstorage->GetOverlappingInputs(level + 1, smallest, largest, &inputs,
*parent_index, parent_index);
return FilesInCompaction(inputs);
}
// Populates the set of inputs from "level+1" that overlap with "level".
// Will also attempt to expand "level" if that doesn't expand "level+1"
// or cause "level" to include a file for compaction that has an overlapping
// user-key with another file.
void CompactionPicker::SetupOtherInputs(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, Compaction* c) {
// If inputs are empty, then there is nothing to expand.
// If both input and output levels are the same, no need to consider
// files at level "level+1"
if (c->inputs_[0].empty() || c->level() == c->output_level()) {
return;
}
const int level = c->level();
InternalKey smallest, largest;
// Get the range one last time.
GetRange(c->inputs_[0].files, &smallest, &largest);
// Populate the set of next-level files (inputs_[1]) to include in compaction
vstorage->GetOverlappingInputs(level + 1, &smallest, &largest,
&c->inputs_[1].files, c->parent_index_,
&c->parent_index_);
// Get entire range covered by compaction
InternalKey all_start, all_limit;
GetRange(c->inputs_[0].files, c->inputs_[1].files, &all_start, &all_limit);
// See if we can further grow the number of inputs in "level" without
// changing the number of "level+1" files we pick up. We also choose NOT
// to expand if this would cause "level" to include some entries for some
// user key, while excluding other entries for the same user key. This
// can happen when one user key spans multiple files.
if (!c->inputs_[1].empty()) {
std::vector<FileMetaData*> expanded0;
vstorage->GetOverlappingInputs(level, &all_start, &all_limit, &expanded0,
c->base_index_, nullptr);
const uint64_t inputs0_size = TotalCompensatedFileSize(c->inputs_[0].files);
const uint64_t inputs1_size = TotalCompensatedFileSize(c->inputs_[1].files);
const uint64_t expanded0_size = TotalCompensatedFileSize(expanded0);
uint64_t limit = mutable_cf_options.ExpandedCompactionByteSizeLimit(level);
if (expanded0.size() > c->inputs_[0].size() &&
inputs1_size + expanded0_size < limit &&
!FilesInCompaction(expanded0) &&
!vstorage->HasOverlappingUserKey(&expanded0, level)) {
InternalKey new_start, new_limit;
GetRange(expanded0, &new_start, &new_limit);
std::vector<FileMetaData*> expanded1;
vstorage->GetOverlappingInputs(level + 1, &new_start, &new_limit,
&expanded1, c->parent_index_,
&c->parent_index_);
if (expanded1.size() == c->inputs_[1].size() &&
!FilesInCompaction(expanded1)) {
Log(InfoLogLevel::INFO_LEVEL, ioptions_.info_log,
"[%s] Expanding@%d %zu+%zu (%" PRIu64 "+%" PRIu64
" bytes) to %zu+%zu (%" PRIu64 "+%" PRIu64 "bytes)\n",
cf_name.c_str(), level, c->inputs_[0].size(), c->inputs_[1].size(),
inputs0_size, inputs1_size, expanded0.size(), expanded1.size(),
expanded0_size, inputs1_size);
smallest = new_start;
largest = new_limit;
c->inputs_[0].files = expanded0;
c->inputs_[1].files = expanded1;
GetRange(c->inputs_[0].files, c->inputs_[1].files,
&all_start, &all_limit);
}
}
}
// Compute the set of grandparent files that overlap this compaction
// (parent == level+1; grandparent == level+2)
if (level + 2 < NumberLevels()) {
vstorage->GetOverlappingInputs(level + 2, &all_start, &all_limit,
&c->grandparents_);
}
}
Compaction* CompactionPicker::CompactRange(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, int input_level, int output_level,
uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
InternalKey** compaction_end) {
// CompactionPickerFIFO has its own implementation of compact range
assert(ioptions_.compaction_style != kCompactionStyleFIFO);
std::vector<FileMetaData*> inputs;
bool covering_the_whole_range = true;
// All files are 'overlapping' in universal style compaction.
// We have to compact the entire range in one shot.
if (ioptions_.compaction_style == kCompactionStyleUniversal) {
begin = nullptr;
end = nullptr;
}
vstorage->GetOverlappingInputs(input_level, begin, end, &inputs);
if (inputs.empty()) {
return nullptr;
}
// Avoid compacting too much in one shot in case the range is large.
// But we cannot do this for level-0 since level-0 files can overlap
// and we must not pick one file and drop another older file if the
// two files overlap.
if (input_level > 0) {
const uint64_t limit = mutable_cf_options.MaxFileSizeForLevel(input_level) *
mutable_cf_options.source_compaction_factor;
uint64_t total = 0;
for (size_t i = 0; i + 1 < inputs.size(); ++i) {
uint64_t s = inputs[i]->compensated_file_size;
total += s;
if (total >= limit) {
**compaction_end = inputs[i + 1]->smallest;
covering_the_whole_range = false;
inputs.resize(i + 1);
break;
}
}
}
assert(output_path_id < static_cast<uint32_t>(ioptions_.db_paths.size()));
Compaction* c = new Compaction(
vstorage->NumberLevels(), input_level, output_level,
mutable_cf_options.MaxFileSizeForLevel(output_level),
mutable_cf_options.MaxGrandParentOverlapBytes(input_level),
output_path_id, GetCompressionType(ioptions_, output_level));
c->inputs_[0].files = inputs;
if (ExpandWhileOverlapping(cf_name, vstorage, c) == false) {
delete c;
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] Could not compact due to expansion failure.\n", cf_name.c_str());
return nullptr;
}
SetupOtherInputs(cf_name, mutable_cf_options, vstorage, c);
if (covering_the_whole_range) {
*compaction_end = nullptr;
}
// These files that are to be manaully compacted do not trample
// upon other files because manual compactions are processed when
// the system has a max of 1 background compaction thread.
c->MarkFilesBeingCompacted(true);
// Is this compaction creating a file at the bottommost level
c->SetupBottomMostLevel(
vstorage, true, ioptions_.compaction_style == kCompactionStyleUniversal);
c->is_manual_compaction_ = true;
c->mutable_cf_options_ = mutable_cf_options;
return c;
}
Compaction* LevelCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, LogBuffer* log_buffer) {
Compaction* c = nullptr;
int level = -1;
// Compute the compactions needed. It is better to do it here
// and also in LogAndApply(), otherwise the values could be stale.
std::vector<uint64_t> size_being_compacted(NumberLevels() - 1);
SizeBeingCompacted(size_being_compacted);
CompactionOptionsFIFO dummy_compaction_options_fifo;
vstorage->ComputeCompactionScore(
mutable_cf_options, dummy_compaction_options_fifo, size_being_compacted);
// We prefer compactions triggered by too much data in a level over
// the compactions triggered by seeks.
//
// Find the compactions by size on all levels.
for (int i = 0; i < NumberLevels() - 1; i++) {
double score = vstorage->CompactionScore(i);
level = vstorage->CompactionScoreLevel(i);
assert(i == 0 || score <= vstorage->CompactionScore(i - 1));
if ((score >= 1)) {
c = PickCompactionBySize(mutable_cf_options, vstorage, level, score);
if (c == nullptr ||
ExpandWhileOverlapping(cf_name, vstorage, c) == false) {
delete c;
c = nullptr;
} else {
break;
}
}
}
if (c == nullptr) {
return nullptr;
}
// Two level 0 compaction won't run at the same time, so don't need to worry
// about files on level 0 being compacted.
if (level == 0) {
assert(compactions_in_progress_[0].empty());
InternalKey smallest, largest;
GetRange(c->inputs_[0].files, &smallest, &largest);
// Note that the next call will discard the file we placed in
// c->inputs_[0] earlier and replace it with an overlapping set
// which will include the picked file.
c->inputs_[0].clear();
vstorage->GetOverlappingInputs(0, &smallest, &largest,
&c->inputs_[0].files);
// If we include more L0 files in the same compaction run it can
// cause the 'smallest' and 'largest' key to get extended to a
// larger range. So, re-invoke GetRange to get the new key range
GetRange(c->inputs_[0].files, &smallest, &largest);
if (ParentRangeInCompaction(vstorage, &smallest, &largest, level,
&c->parent_index_)) {
delete c;
return nullptr;
}
assert(!c->inputs_[0].empty());
}
// Setup "level+1" files (inputs_[1])
SetupOtherInputs(cf_name, mutable_cf_options, vstorage, c);
// mark all the files that are being compacted
c->MarkFilesBeingCompacted(true);
// Is this compaction creating a file at the bottommost level
c->SetupBottomMostLevel(vstorage, false, false);
// remember this currently undergoing compaction
compactions_in_progress_[level].insert(c);
c->mutable_cf_options_ = mutable_cf_options;
return c;
}
Compaction* LevelCompactionPicker::PickCompactionBySize(
const MutableCFOptions& mutable_cf_options, VersionStorageInfo* vstorage,
int level, double score) {
Compaction* c = nullptr;
// level 0 files are overlapping. So we cannot pick more
// than one concurrent compactions at this level. This
// could be made better by looking at key-ranges that are
// being compacted at level 0.
if (level == 0 && compactions_in_progress_[level].size() == 1) {
return nullptr;
}
assert(level >= 0);
assert(level + 1 < NumberLevels());
c = new Compaction(vstorage->NumberLevels(), level, level + 1,
mutable_cf_options.MaxFileSizeForLevel(level + 1),
mutable_cf_options.MaxGrandParentOverlapBytes(level), 0,
GetCompressionType(ioptions_, level + 1));
c->score_ = score;
// Pick the largest file in this level that is not already
// being compacted
const std::vector<int>& file_size = vstorage->FilesBySize(level);
const std::vector<FileMetaData*>& level_files = vstorage->LevelFiles(level);
// record the first file that is not yet compacted
int nextIndex = -1;
for (unsigned int i = vstorage->NextCompactionIndex(level);
i < file_size.size(); i++) {
int index = file_size[i];
FileMetaData* f = level_files[index];
assert((i == file_size.size() - 1) ||
(i >= VersionStorageInfo::kNumberFilesToSort - 1) ||
(f->compensated_file_size >=
level_files[file_size[i + 1]]->compensated_file_size));
// do not pick a file to compact if it is being compacted
// from n-1 level.
if (f->being_compacted) {
continue;
}
// remember the startIndex for the next call to PickCompaction
if (nextIndex == -1) {
nextIndex = i;
}
// Do not pick this file if its parents at level+1 are being compacted.
// Maybe we can avoid redoing this work in SetupOtherInputs
int parent_index = -1;
if (ParentRangeInCompaction(vstorage, &f->smallest, &f->largest, level,
&parent_index)) {
continue;
}
c->inputs_[0].files.push_back(f);
c->base_index_ = index;
c->parent_index_ = parent_index;
break;
}
if (c->inputs_[0].empty()) {
delete c;
c = nullptr;
}
// store where to start the iteration in the next call to PickCompaction
vstorage->SetNextCompactionIndex(level, nextIndex);
return c;
}
// Universal style of compaction. Pick files that are contiguous in
// time-range to compact.
//
Compaction* UniversalCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, LogBuffer* log_buffer) {
const int kLevel0 = 0;
double score = vstorage->CompactionScore(kLevel0);
const std::vector<FileMetaData*>& level_files = vstorage->LevelFiles(kLevel0);
if ((level_files.size() <
(unsigned int)mutable_cf_options.level0_file_num_compaction_trigger)) {
LogToBuffer(log_buffer, "[%s] Universal: nothing to do\n", cf_name.c_str());
return nullptr;
}
VersionStorageInfo::FileSummaryStorage tmp;
LogToBuffer(log_buffer, 3072, "[%s] Universal: candidate files(%zu): %s\n",
cf_name.c_str(), level_files.size(),
vstorage->LevelFileSummary(&tmp, kLevel0));
// Check for size amplification first.
Compaction* c;
if ((c = PickCompactionUniversalSizeAmp(cf_name, mutable_cf_options, vstorage,
score, log_buffer)) != nullptr) {
LogToBuffer(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 = ioptions_.compaction_options_universal.size_ratio;
if ((c = PickCompactionUniversalReadAmp(cf_name, mutable_cf_options,
vstorage, score, ratio, UINT_MAX,
log_buffer)) != nullptr) {
LogToBuffer(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.
unsigned int num_files = level_files.size() -
mutable_cf_options.level0_file_num_compaction_trigger;
if ((c = PickCompactionUniversalReadAmp(
cf_name, mutable_cf_options, vstorage, score, UINT_MAX,
num_files, log_buffer)) != nullptr) {
LogToBuffer(log_buffer,
"[%s] Universal: compacting for file num -- %u\n",
cf_name.c_str(), num_files);
}
}
}
if (c == nullptr) {
return nullptr;
}
assert(c->inputs_[kLevel0].size() > 1);
// validate that all the chosen files are non overlapping in time
FileMetaData* newerfile __attribute__((unused)) = nullptr;
for (unsigned int i = 0; i < c->inputs_[kLevel0].size(); i++) {
FileMetaData* f = c->inputs_[kLevel0][i];
assert (f->smallest_seqno <= f->largest_seqno);
assert(newerfile == nullptr ||
newerfile->smallest_seqno > f->largest_seqno);
newerfile = f;
}
// Is the earliest file part of this compaction?
FileMetaData* last_file = level_files.back();
c->bottommost_level_ = c->inputs_[kLevel0].files.back() == last_file;
// update statistics
MeasureTime(ioptions_.statistics,
NUM_FILES_IN_SINGLE_COMPACTION, c->inputs_[kLevel0].size());
// mark all the files that are being compacted
c->MarkFilesBeingCompacted(true);
// remember this currently undergoing compaction
compactions_in_progress_[kLevel0].insert(c);
// Record whether this compaction includes all sst files.
// For now, it is only relevant in universal compaction mode.
c->is_full_compaction_ = (c->inputs_[kLevel0].size() == level_files.size());
c->mutable_cf_options_ = mutable_cf_options;
return c;
}
uint32_t UniversalCompactionPicker::GetPathId(
const ImmutableCFOptions& ioptions, 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 - ioptions.compaction_options_universal.size_ratio) / 100;
uint32_t p = 0;
for (; p < ioptions.db_paths.size() - 1; p++) {
uint64_t target_size = ioptions.db_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* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, double score, unsigned int ratio,
unsigned int max_number_of_files_to_compact, LogBuffer* log_buffer) {
const int kLevel0 = 0;
unsigned int min_merge_width =
ioptions_.compaction_options_universal.min_merge_width;
unsigned int max_merge_width =
ioptions_.compaction_options_universal.max_merge_width;
// The files are sorted from newest first to oldest last.
const auto& files = vstorage->LevelFiles(kLevel0);
FileMetaData* f = nullptr;
bool done = false;
int 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);
// Considers a candidate file only if it is smaller than the
// total size accumulated so far.
for (unsigned int loop = 0; loop < files.size(); loop++) {
candidate_count = 0;
// Skip files that are already being compacted
for (f = nullptr; loop < files.size(); loop++) {
f = files[loop];
if (!f->being_compacted) {
candidate_count = 1;
break;
}
LogToBuffer(log_buffer, "[%s] Universal: file %" PRIu64
"[%d] being compacted, skipping",
cf_name.c_str(), f->fd.GetNumber(), loop);
f = nullptr;
}
// This file is not being compacted. Consider it as the
// first candidate to be compacted.
uint64_t candidate_size = f != nullptr? f->compensated_file_size : 0;
if (f != nullptr) {
char file_num_buf[kFormatFileNumberBufSize];
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId(), file_num_buf,
sizeof(file_num_buf));
LogToBuffer(log_buffer, "[%s] Universal: Possible candidate file %s[%d].",
cf_name.c_str(), file_num_buf, loop);
}
// Check if the suceeding files need compaction.
for (unsigned int i = loop + 1;
candidate_count < max_files_to_compact && i < files.size(); i++) {
FileMetaData* suceeding_file = files[i];
if (suceeding_file->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>(suceeding_file->fd.GetFileSize())) {
break;
}
if (ioptions_.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 = (suceeding_file->fd.GetFileSize() * (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 = suceeding_file->compensated_file_size;
} else { // default kCompactionStopStyleTotalSize
candidate_size += suceeding_file->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 (unsigned int i = loop;
i < loop + candidate_count && i < files.size(); i++) {
FileMetaData* skipping_file = files[i];
LogToBuffer(log_buffer, "[%s] Universal: Skipping file %" PRIu64
"[%d] with size %" PRIu64
" (compensated size %" PRIu64 ") %d\n",
cf_name.c_str(), f->fd.GetNumber(), i,
skipping_file->fd.GetFileSize(),
skipping_file->compensated_file_size,
skipping_file->being_compacted);
}
}
}
if (!done || candidate_count <= 1) {
return nullptr;
}
unsigned int 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 =
ioptions_.compaction_options_universal.compression_size_percent;
if (ratio_to_compress >= 0) {
uint64_t total_size = vstorage->NumLevelBytes(kLevel0);
uint64_t older_file_size = 0;
for (unsigned int i = files.size() - 1;
i >= first_index_after; i--) {
older_file_size += files[i]->fd.GetFileSize();
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 += files[i]->fd.GetFileSize();
}
uint32_t path_id = GetPathId(ioptions_, estimated_total_size);
Compaction* c = new Compaction(
vstorage->NumberLevels(), kLevel0, kLevel0,
mutable_cf_options.MaxFileSizeForLevel(kLevel0), LLONG_MAX, path_id,
GetCompressionType(ioptions_, kLevel0, enable_compression));
c->score_ = score;
for (unsigned int i = start_index; i < first_index_after; i++) {
FileMetaData* picking_file = files[i];
c->inputs_[0].files.push_back(picking_file);
char file_num_buf[kFormatFileNumberBufSize];
FormatFileNumber(picking_file->fd.GetNumber(), picking_file->fd.GetPathId(),
file_num_buf, sizeof(file_num_buf));
LogToBuffer(log_buffer,
"[%s] Universal: Picking file %s[%d] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")\n",
cf_name.c_str(), file_num_buf, i,
picking_file->fd.GetFileSize(),
picking_file->compensated_file_size);
}
return c;
}
// Look at overall size amplification. If size amplification
// exceeeds 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* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, double score, LogBuffer* log_buffer) {
const int kLevel = 0;
// percentage flexibilty while reducing size amplification
uint64_t ratio = ioptions_.compaction_options_universal.
max_size_amplification_percent;
// The files are sorted from newest first to oldest last.
const auto& files = vstorage->LevelFiles(kLevel);
unsigned int candidate_count = 0;
uint64_t candidate_size = 0;
unsigned int start_index = 0;
FileMetaData* f = nullptr;
// Skip files that are already being compacted
for (unsigned int loop = 0; loop < files.size() - 1; loop++) {
f = files[loop];
if (!f->being_compacted) {
start_index = loop; // Consider this as the first candidate.
break;
}
char file_num_buf[kFormatFileNumberBufSize];
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId(), file_num_buf,
sizeof(file_num_buf));
LogToBuffer(log_buffer, "[%s] Universal: skipping file %s[%d] compacted %s",
cf_name.c_str(), file_num_buf, loop,
" cannot be a candidate to reduce size amp.\n");
f = nullptr;
}
if (f == nullptr) {
return nullptr; // no candidate files
}
char file_num_buf[kFormatFileNumberBufSize];
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId(), file_num_buf,
sizeof(file_num_buf));
LogToBuffer(log_buffer, "[%s] Universal: First candidate file %s[%d] %s",
cf_name.c_str(), file_num_buf, start_index,
" to reduce size amp.\n");
// keep adding up all the remaining files
for (unsigned int loop = start_index; loop < files.size() - 1; loop++) {
f = files[loop];
if (f->being_compacted) {
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId(), file_num_buf,
sizeof(file_num_buf));
LogToBuffer(
log_buffer, "[%s] Universal: Possible candidate file %s[%d] %s.",
cf_name.c_str(), file_num_buf, loop,
" is already being compacted. No size amp reduction possible.\n");
return nullptr;
}
candidate_size += f->compensated_file_size;
candidate_count++;
}
if (candidate_count == 0) {
return nullptr;
}
// size of earliest file
uint64_t earliest_file_size = files.back()->fd.GetFileSize();
// size amplification = percentage of additional size
if (candidate_size * 100 < ratio * earliest_file_size) {
LogToBuffer(
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 {
LogToBuffer(
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);
}
assert(start_index < files.size() - 1);
// Estimate total file size
uint64_t estimated_total_size = 0;
for (unsigned int loop = start_index; loop < files.size(); loop++) {
estimated_total_size += files[loop]->fd.GetFileSize();
}
uint32_t path_id = GetPathId(ioptions_, estimated_total_size);
// create a compaction request
// We always compact all the files, so always compress.
Compaction* c =
new Compaction(vstorage->NumberLevels(), kLevel, kLevel,
mutable_cf_options.MaxFileSizeForLevel(kLevel), LLONG_MAX,
path_id, GetCompressionType(ioptions_, kLevel));
c->score_ = score;
for (unsigned int loop = start_index; loop < files.size(); loop++) {
f = files[loop];
c->inputs_[0].files.push_back(f);
LogToBuffer(log_buffer,
"[%s] Universal: size amp picking file %" PRIu64
"[%d] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")",
cf_name.c_str(), f->fd.GetNumber(), loop, f->fd.GetFileSize(),
f->compensated_file_size);
}
return c;
}
Compaction* FIFOCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, LogBuffer* log_buffer) {
assert(vstorage->NumberLevels() == 1);
const int kLevel0 = 0;
const std::vector<FileMetaData*>& level_files = vstorage->LevelFiles(kLevel0);
uint64_t total_size = 0;
for (const auto& file : level_files) {
total_size += file->compensated_file_size;
}
if (total_size <= ioptions_.compaction_options_fifo.max_table_files_size ||
level_files.size() == 0) {
// total size not exceeded
LogToBuffer(log_buffer,
"[%s] FIFO compaction: nothing to do. Total size %" PRIu64
", max size %" PRIu64 "\n",
cf_name.c_str(), total_size,
ioptions_.compaction_options_fifo.max_table_files_size);
return nullptr;
}
if (compactions_in_progress_[0].size() > 0) {
LogToBuffer(log_buffer,
"[%s] FIFO compaction: Already executing compaction. No need "
"to run parallel compactions since compactions are very fast",
cf_name.c_str());
return nullptr;
}
Compaction* c = new Compaction(1, 0, 0, 0, 0, 0, kNoCompression, false,
true /* is deletion compaction */);
// delete old files (FIFO)
for (auto ritr = level_files.rbegin(); ritr != level_files.rend(); ++ritr) {
auto f = *ritr;
total_size -= f->compensated_file_size;
c->inputs_[0].files.push_back(f);
char tmp_fsize[16];
AppendHumanBytes(f->fd.GetFileSize(), tmp_fsize, sizeof(tmp_fsize));
LogToBuffer(log_buffer, "[%s] FIFO compaction: picking file %" PRIu64
" with size %s for deletion",
cf_name.c_str(), f->fd.GetNumber(), tmp_fsize);
if (total_size <= ioptions_.compaction_options_fifo.max_table_files_size) {
break;
}
}
c->MarkFilesBeingCompacted(true);
compactions_in_progress_[0].insert(c);
c->mutable_cf_options_ = mutable_cf_options;
return c;
}
Compaction* FIFOCompactionPicker::CompactRange(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, int input_level, int output_level,
uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
InternalKey** compaction_end) {
assert(input_level == 0);
assert(output_level == 0);
*compaction_end = nullptr;
LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, ioptions_.info_log);
Compaction* c =
PickCompaction(cf_name, mutable_cf_options, vstorage, &log_buffer);
if (c != nullptr) {
assert(output_path_id < static_cast<uint32_t>(ioptions_.db_paths.size()));
c->output_path_id_ = output_path_id;
}
log_buffer.FlushBufferToLog();
return c;
}
} // namespace rocksdb