rocksdb/db/compaction_picker.cc
Lei Jin 40fa8a4cd5 make statistics forward-able
Summary:
Make StatisticsImpl being able to forward stats to provided statistics
implementation. The main purpose is to allow us to collect internal
stats in the future even when user supplies custom statistics
implementation. It avoids intrumenting 2 sets of stats collection code.
One immediate use case is tuning advisor, which needs to collect some
internal stats, users may not be interested.

Test Plan:
ran db_bench and see stats show up at the end of run
Will run make all check since some tests rely on statistics

Reviewers: yhchiang, sdong, igor

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D20145
2014-07-28 12:05:36 -07:00

1005 lines
37 KiB
C++

// 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"
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <limits>
#include "db/filename.h"
#include "util/log_buffer.h"
#include "util/statistics.h"
namespace rocksdb {
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 Options& options, 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 compresison for that level.
if (!options.compression_per_level.empty()) {
const int n = options.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 options.compression_per_level[std::max(0, std::min(level, n))];
} else {
return options.compression;
}
}
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;
}
// Multiple two operands. If they overflow, return op1.
uint64_t MultiplyCheckOverflow(uint64_t op1, int op2) {
if (op1 == 0) {
return 0;
}
if (op2 <= 0) {
return op1;
}
uint64_t casted_op2 = (uint64_t) op2;
if (std::numeric_limits<uint64_t>::max() / op1 < casted_op2) {
return op1;
}
return op1 * casted_op2;
}
} // anonymous namespace
CompactionPicker::CompactionPicker(const Options* options,
const InternalKeyComparator* icmp)
: compactions_in_progress_(options->num_levels),
options_(options),
num_levels_(options->num_levels),
icmp_(icmp) {
max_file_size_.reset(new uint64_t[NumberLevels()]);
level_max_bytes_.reset(new uint64_t[NumberLevels()]);
int target_file_size_multiplier = options_->target_file_size_multiplier;
int max_bytes_multiplier = options_->max_bytes_for_level_multiplier;
for (int i = 0; i < NumberLevels(); i++) {
if (i == 0 && options_->compaction_style == kCompactionStyleUniversal) {
max_file_size_[i] = ULLONG_MAX;
level_max_bytes_[i] = options_->max_bytes_for_level_base;
} else if (i > 1) {
max_file_size_[i] = MultiplyCheckOverflow(max_file_size_[i - 1],
target_file_size_multiplier);
level_max_bytes_[i] = MultiplyCheckOverflow(
MultiplyCheckOverflow(level_max_bytes_[i - 1], max_bytes_multiplier),
options_->max_bytes_for_level_multiplier_additional[i - 1]);
} else {
max_file_size_[i] = options_->target_file_size_base;
level_max_bytes_[i] = options_->max_bytes_for_level_base;
}
}
}
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();
}
}
uint64_t CompactionPicker::MaxFileSizeForLevel(int level) const {
assert(level >= 0);
assert(level < NumberLevels());
return max_file_size_[level];
}
uint64_t CompactionPicker::MaxGrandParentOverlapBytes(int level) {
uint64_t result = MaxFileSizeForLevel(level);
result *= options_->max_grandparent_overlap_factor;
return result;
}
double CompactionPicker::MaxBytesForLevel(int level) {
// Note: the result for level zero is not really used since we set
// the level-0 compaction threshold based on number of files.
assert(level >= 0);
assert(level < NumberLevels());
return level_max_bytes_[level];
}
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(Compaction* c) {
// If inputs are empty then there is nothing to expand.
if (!c || c->inputs_[0].empty()) {
return true;
}
// 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();
c->input_version_->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(options_->info_log,
"[%s] ExpandWhileOverlapping() failure because zero input files",
c->column_family_data()->GetName().c_str());
}
if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0].files) ||
(c->level() != c->output_level() &&
ParentRangeInCompaction(c->input_version_, &smallest, &largest, level,
&parent_index))) {
c->inputs_[0].clear();
c->inputs_[1].clear();
return false;
}
return true;
}
uint64_t CompactionPicker::ExpandedCompactionByteSizeLimit(int level) {
uint64_t result = MaxFileSizeForLevel(level);
result *= options_->expanded_compaction_factor;
return result;
}
// 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(Version* version,
const InternalKey* smallest,
const InternalKey* largest,
int level, int* parent_index) {
std::vector<FileMetaData*> inputs;
assert(level + 1 < NumberLevels());
version->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(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
c->input_version_->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;
c->input_version_->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 = ExpandedCompactionByteSizeLimit(level);
if (expanded0.size() > c->inputs_[0].size() &&
inputs1_size + expanded0_size < limit &&
!FilesInCompaction(expanded0) &&
!c->input_version_->HasOverlappingUserKey(&expanded0, level)) {
InternalKey new_start, new_limit;
GetRange(expanded0, &new_start, &new_limit);
std::vector<FileMetaData*> expanded1;
c->input_version_->GetOverlappingInputs(level + 1, &new_start, &new_limit,
&expanded1, c->parent_index_,
&c->parent_index_);
if (expanded1.size() == c->inputs_[1].size() &&
!FilesInCompaction(expanded1)) {
Log(options_->info_log,
"[%s] Expanding@%d %zu+%zu (%" PRIu64 "+%" PRIu64
" bytes) to %zu+%zu (%" PRIu64 "+%" PRIu64 "bytes)\n",
c->column_family_data()->GetName().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()) {
c->input_version_->GetOverlappingInputs(level + 2, &all_start, &all_limit,
&c->grandparents_);
}
}
Compaction* CompactionPicker::CompactRange(Version* version, 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(options_->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 (options_->compaction_style == kCompactionStyleUniversal) {
begin = nullptr;
end = nullptr;
}
version->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 =
MaxFileSizeForLevel(input_level) * 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>(options_->db_paths.size()));
Compaction* c = new Compaction(
version, input_level, output_level, MaxFileSizeForLevel(output_level),
MaxGrandParentOverlapBytes(input_level), output_path_id,
GetCompressionType(*options_, output_level));
c->inputs_[0].files = inputs;
if (ExpandWhileOverlapping(c) == false) {
delete c;
Log(options_->info_log,
"[%s] Could not compact due to expansion failure.\n",
version->cfd_->GetName().c_str());
return nullptr;
}
SetupOtherInputs(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(true);
c->is_manual_compaction_ = true;
return c;
}
Compaction* LevelCompactionPicker::PickCompaction(Version* version,
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);
version->ComputeCompactionScore(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++) {
assert(i == 0 ||
version->compaction_score_[i] <= version->compaction_score_[i - 1]);
level = version->compaction_level_[i];
if ((version->compaction_score_[i] >= 1)) {
c = PickCompactionBySize(version, level, version->compaction_score_[i]);
if (ExpandWhileOverlapping(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();
c->input_version_->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(c->input_version_, &smallest, &largest, level,
&c->parent_index_)) {
delete c;
return nullptr;
}
assert(!c->inputs_[0].empty());
}
// Setup "level+1" files (inputs_[1])
SetupOtherInputs(c);
// mark all the files that are being compacted
c->MarkFilesBeingCompacted(true);
// Is this compaction creating a file at the bottommost level
c->SetupBottomMostLevel(false);
// remember this currently undergoing compaction
compactions_in_progress_[level].insert(c);
return c;
}
Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
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(version, level, level + 1, MaxFileSizeForLevel(level + 1),
MaxGrandParentOverlapBytes(level), 0,
GetCompressionType(*options_, level + 1));
c->score_ = score;
// Pick the largest file in this level that is not already
// being compacted
std::vector<int>& file_size = c->input_version_->files_by_size_[level];
// record the first file that is not yet compacted
int nextIndex = -1;
for (unsigned int i = c->input_version_->next_file_to_compact_by_size_[level];
i < file_size.size(); i++) {
int index = file_size[i];
FileMetaData* f = c->input_version_->files_[level][index];
// Check to verify files are arranged in descending compensated size.
assert((i == file_size.size() - 1) ||
(i >= Version::number_of_files_to_sort_ - 1) ||
(f->compensated_file_size >=
c->input_version_->files_[level][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(c->input_version_, &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
version->next_file_to_compact_by_size_[level] = nextIndex;
return c;
}
// Universal style of compaction. Pick files that are contiguous in
// time-range to compact.
//
Compaction* UniversalCompactionPicker::PickCompaction(Version* version,
LogBuffer* log_buffer) {
int level = 0;
double score = version->compaction_score_[0];
if ((version->files_[level].size() <
(unsigned int)options_->level0_file_num_compaction_trigger)) {
LogToBuffer(log_buffer, "[%s] Universal: nothing to do\n",
version->cfd_->GetName().c_str());
return nullptr;
}
Version::FileSummaryStorage tmp;
LogToBuffer(log_buffer, "[%s] Universal: candidate files(%zu): %s\n",
version->cfd_->GetName().c_str(), version->files_[level].size(),
version->LevelFileSummary(&tmp, 0));
// Check for size amplification first.
Compaction* c;
if ((c = PickCompactionUniversalSizeAmp(version, score, log_buffer)) !=
nullptr) {
LogToBuffer(log_buffer, "[%s] Universal: compacting for size amp\n",
version->cfd_->GetName().c_str());
} else {
// Size amplification is within limits. Try reducing read
// amplification while maintaining file size ratios.
unsigned int ratio = options_->compaction_options_universal.size_ratio;
if ((c = PickCompactionUniversalReadAmp(version, score, ratio, UINT_MAX,
log_buffer)) != nullptr) {
LogToBuffer(log_buffer, "[%s] Universal: compacting for size ratio\n",
version->cfd_->GetName().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 = version->files_[level].size() -
options_->level0_file_num_compaction_trigger;
if ((c = PickCompactionUniversalReadAmp(
version, score, UINT_MAX, num_files, log_buffer)) != nullptr) {
LogToBuffer(log_buffer, "[%s] Universal: compacting for file num\n",
version->cfd_->GetName().c_str());
}
}
}
if (c == nullptr) {
return nullptr;
}
assert(c->inputs_[0].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_[0].size(); i++) {
FileMetaData* f = c->inputs_[0][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 = c->input_version_->files_[level].back();
c->bottommost_level_ = c->inputs_[0].files.back() == last_file;
// update statistics
MeasureTime(options_->statistics.get(),
NUM_FILES_IN_SINGLE_COMPACTION, c->inputs_[0].size());
// mark all the files that are being compacted
c->MarkFilesBeingCompacted(true);
// remember this currently undergoing compaction
compactions_in_progress_[level].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_[0].size() == c->input_version_->files_[0].size());
return c;
}
uint32_t UniversalCompactionPicker::GetPathId(const Options& 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 - options.compaction_options_universal.size_ratio) / 100;
uint32_t p = 0;
for (; p < options.db_paths.size() - 1; p++) {
uint64_t target_size = options.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(
Version* version, double score, unsigned int ratio,
unsigned int max_number_of_files_to_compact, LogBuffer* log_buffer) {
int level = 0;
unsigned int min_merge_width =
options_->compaction_options_universal.min_merge_width;
unsigned int max_merge_width =
options_->compaction_options_universal.max_merge_width;
// The files are sorted from newest first to oldest last.
const auto& files = version->files_[level];
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",
version->cfd_->GetName().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) {
LogToBuffer(
log_buffer, "[%s] Universal: Possible candidate file %s[%d].",
version->cfd_->GetName().c_str(),
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(), 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* f = files[i];
if (f->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.
uint64_t sz = (candidate_size * (100L + ratio)) /100;
if (sz < f->fd.GetFileSize()) {
break;
}
if (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 = (f->fd.GetFileSize() * (100L + ratio)) / 100;
if (sz < 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 = f->compensated_file_size;
} else { // default kCompactionStopStyleTotalSize
candidate_size += f->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* f = files[i];
LogToBuffer(log_buffer, "[%s] Universal: Skipping file %" PRIu64
"[%d] with size %" PRIu64
" (compensated size %" PRIu64 ") %d\n",
version->cfd_->GetName().c_str(), f->fd.GetNumber(), i,
f->fd.GetFileSize(), f->compensated_file_size,
f->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 =
options_->compaction_options_universal.compression_size_percent;
if (ratio_to_compress >= 0) {
uint64_t total_size = version->NumLevelBytes(level);
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(*options_, estimated_total_size);
Compaction* c = new Compaction(
version, level, level, MaxFileSizeForLevel(level), LLONG_MAX, path_id,
GetCompressionType(*options_, level, enable_compression));
c->score_ = score;
for (unsigned int i = start_index; i < first_index_after; i++) {
FileMetaData* f = c->input_version_->files_[level][i];
c->inputs_[0].files.push_back(f);
LogToBuffer(log_buffer,
"[%s] Universal: Picking file %s[%d] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")\n",
version->cfd_->GetName().c_str(),
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
i, f->fd.GetFileSize(), f->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(
Version* version, double score, LogBuffer* log_buffer) {
int level = 0;
// percentage flexibilty while reducing size amplification
uint64_t ratio = options_->compaction_options_universal.
max_size_amplification_percent;
// The files are sorted from newest first to oldest last.
const auto& files = version->files_[level];
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;
}
LogToBuffer(log_buffer, "[%s] Universal: skipping file %s[%d] compacted %s",
version->cfd_->GetName().c_str(),
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
loop, " cannot be a candidate to reduce size amp.\n");
f = nullptr;
}
if (f == nullptr) {
return nullptr; // no candidate files
}
LogToBuffer(log_buffer, "[%s] Universal: First candidate file %s[%d] %s",
version->cfd_->GetName().c_str(),
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
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) {
LogToBuffer(
log_buffer, "[%s] Universal: Possible candidate file %s[%d] %s.",
version->cfd_->GetName().c_str(),
FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(), 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,
version->cfd_->GetName().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,
version->cfd_->GetName().c_str(), candidate_size, earliest_file_size);
}
assert(start_index >= 0 && 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(*options_, estimated_total_size);
// create a compaction request
// We always compact all the files, so always compress.
Compaction* c =
new Compaction(version, level, level, MaxFileSizeForLevel(level),
LLONG_MAX, path_id, GetCompressionType(*options_, level));
c->score_ = score;
for (unsigned int loop = start_index; loop < files.size(); loop++) {
f = c->input_version_->files_[level][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 ")",
version->cfd_->GetName().c_str(),
f->fd.GetNumber(), loop,
f->fd.GetFileSize(), f->compensated_file_size);
}
return c;
}
Compaction* FIFOCompactionPicker::PickCompaction(Version* version,
LogBuffer* log_buffer) {
assert(version->NumberLevels() == 1);
uint64_t total_size = 0;
for (const auto& file : version->files_[0]) {
total_size += file->compensated_file_size;
}
if (total_size <= options_->compaction_options_fifo.max_table_files_size ||
version->files_[0].size() == 0) {
// total size not exceeded
LogToBuffer(log_buffer,
"[%s] FIFO compaction: nothing to do. Total size %" PRIu64
", max size %" PRIu64 "\n",
version->cfd_->GetName().c_str(), total_size,
options_->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",
version->cfd_->GetName().c_str());
return nullptr;
}
Compaction* c = new Compaction(version, 0, 0, 0, 0, 0, kNoCompression, false,
true /* is deletion compaction */);
// delete old files (FIFO)
for (auto ritr = version->files_[0].rbegin();
ritr != version->files_[0].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",
version->cfd_->GetName().c_str(), f->fd.GetNumber(), tmp_fsize);
if (total_size <= options_->compaction_options_fifo.max_table_files_size) {
break;
}
}
c->MarkFilesBeingCompacted(true);
compactions_in_progress_[0].insert(c);
return c;
}
Compaction* FIFOCompactionPicker::CompactRange(
Version* version, 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, options_->info_log.get());
Compaction* c = PickCompaction(version, &log_buffer);
if (c != nullptr) {
assert(output_path_id < static_cast<uint32_t>(options_->db_paths.size()));
c->output_path_id_ = output_path_id;
}
log_buffer.FlushBufferToLog();
return c;
}
} // namespace rocksdb