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rocksdb/db/compaction_picker.cc
Andrew Kryczka d659faad54 Level-based L0->L0 compaction 
Summary:
Level-based L0->L0 compaction operates on spans of files that aren't currently being compacted. It reduces the number of L0 files, thus making write stall conditions harder to reach.

- L0->L0 is triggered when base level is unavailable due to pending compactions
- L0->L0 always outputs one file of at most `max_level0_burst_file_size` bytes.
- Subcompactions are disabled for L0->L0 since we want to output one file.
- Input files are chosen as the longest span of available files that will fit within the size limit. This minimizes number of files in L0.
Closes https://github.com/facebook/rocksdb/pull/2027

Differential Revision: D4760318

Pulled By: ajkr

fbshipit-source-id: 9d07183
2017-04-04 18:09:11 -07:00

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// Copyright (c) 2011-present, 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 <queue>
#include <string>
#include <utility>
#include "db/column_family.h"
#include "util/filename.h"
#include "util/log_buffer.h"
#include "util/random.h"
#include "util/statistics.h"
#include "util/string_util.h"
#include "util/sync_point.h"
namespace rocksdb {
namespace {
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;
}
// Universal compaction is not supported in ROCKSDB_LITE
#ifndef ROCKSDB_LITE
// 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) {}
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 UserKeyComparator {
explicit UserKeyComparator(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>,
UserKeyComparator>
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(UserKeyComparator(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;
}
#endif // !ROCKSDB_LITE
} // anonymous 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,
const VersionStorageInfo* vstorage,
const MutableCFOptions& mutable_cf_options,
int level, int base_level,
const bool enable_compression) {
if (!enable_compression) {
// disable compression
return kNoCompression;
}
// If bottommost_compression is set and we are compacting to the
// bottommost level then we should use it.
if (ioptions.bottommost_compression != kDisableCompressionOption &&
level > base_level && level >= (vstorage->num_non_empty_levels() - 1)) {
return ioptions.bottommost_compression;
}
// If the user has specified a different compression level for each level,
// then pick the compression for that level.
if (!ioptions.compression_per_level.empty()) {
assert(level == 0 || level >= base_level);
int idx = (level == 0) ? 0 : level - base_level + 1;
const int n = static_cast<int>(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(idx, n))];
} else {
return mutable_cf_options.compression;
}
}
CompactionPicker::CompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp)
: ioptions_(ioptions), icmp_(icmp) {}
CompactionPicker::~CompactionPicker() {}
// Delete this compaction from the list of running compactions.
void CompactionPicker::ReleaseCompactionFiles(Compaction* c, Status status) {
UnregisterCompaction(c);
if (!status.ok()) {
c->ResetNextCompactionIndex();
}
}
void CompactionPicker::GetRange(const CompactionInputFiles& inputs,
InternalKey* smallest,
InternalKey* largest) const {
const int level = inputs.level;
assert(!inputs.empty());
smallest->Clear();
largest->Clear();
if (level == 0) {
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;
}
}
}
} else {
*smallest = inputs[0]->smallest;
*largest = inputs[inputs.size() - 1]->largest;
}
}
void CompactionPicker::GetRange(const CompactionInputFiles& inputs1,
const CompactionInputFiles& inputs2,
InternalKey* smallest,
InternalKey* largest) const {
assert(!inputs1.empty() || !inputs2.empty());
if (inputs1.empty()) {
GetRange(inputs2, smallest, largest);
} else if (inputs2.empty()) {
GetRange(inputs1, smallest, largest);
} else {
InternalKey smallest1, smallest2, largest1, largest2;
GetRange(inputs1, &smallest1, &largest1);
GetRange(inputs2, &smallest2, &largest2);
*smallest =
icmp_->Compare(smallest1, smallest2) < 0 ? smallest1 : smallest2;
*largest = icmp_->Compare(largest1, largest2) < 0 ? largest2 : largest1;
}
}
void CompactionPicker::GetRange(const std::vector<CompactionInputFiles>& inputs,
InternalKey* smallest,
InternalKey* largest) const {
InternalKey current_smallest;
InternalKey current_largest;
bool initialized = false;
for (const auto& in : inputs) {
if (in.empty()) {
continue;
}
GetRange(in, &current_smallest, &current_largest);
if (!initialized) {
*smallest = current_smallest;
*largest = current_largest;
initialized = true;
} else {
if (icmp_->Compare(current_smallest, *smallest) < 0) {
*smallest = current_smallest;
}
if (icmp_->Compare(current_largest, *largest) > 0) {
*largest = current_largest;
}
}
}
assert(initialized);
}
bool CompactionPicker::ExpandWhileOverlapping(const std::string& cf_name,
VersionStorageInfo* vstorage,
CompactionInputFiles* inputs) {
// This isn't good compaction
assert(!inputs->empty());
const int level = inputs->level;
// GetOverlappingInputs will always do the right thing for level-0.
// So we don't need to do any expansion if level == 0.
if (level == 0) {
return true;
}
InternalKey smallest, largest;
// Keep expanding inputs 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 = inputs->size();
GetRange(*inputs, &smallest, &largest);
inputs->clear();
vstorage->GetOverlappingInputs(level, &smallest, &largest, &inputs->files,
hint_index, &hint_index);
} while (inputs->size() > old_size);
// we started off with inputs non-empty and the previous loop only grew
// inputs. thus, inputs should be non-empty here
assert(!inputs->empty());
// If, after the expansion, there are files that are already under
// compaction, then we must drop/cancel this compaction.
if (FilesInCompaction(inputs->files)) {
ROCKS_LOG_WARN(
ioptions_.info_log,
"[%s] ExpandWhileOverlapping() failure because some of the necessary"
" compaction input files are currently being compacted.",
cf_name.c_str());
return false;
}
return true;
}
bool CompactionPicker::RangeOverlapWithCompaction(
const Slice& smallest_user_key, const Slice& largest_user_key,
int level) const {
const Comparator* ucmp = icmp_->user_comparator();
for (Compaction* c : compactions_in_progress_) {
if (c->output_level() == level &&
ucmp->Compare(smallest_user_key, c->GetLargestUserKey()) <= 0 &&
ucmp->Compare(largest_user_key, c->GetSmallestUserKey()) >= 0) {
// Overlap
return true;
}
}
// Did not overlap with any running compaction in level `level`
return false;
}
bool CompactionPicker::FilesRangeOverlapWithCompaction(
const std::vector<CompactionInputFiles>& inputs, int level) const {
bool is_empty = true;
for (auto& in : inputs) {
if (!in.empty()) {
is_empty = false;
break;
}
}
if (is_empty) {
// No files in inputs
return false;
}
InternalKey smallest, largest;
GetRange(inputs, &smallest, &largest);
return RangeOverlapWithCompaction(smallest.user_key(), largest.user_key(),
level);
}
// Returns true if any one of specified files are being compacted
bool CompactionPicker::FilesInCompaction(
const std::vector<FileMetaData*>& files) {
for (size_t i = 0; i < files.size(); i++) {
if (files[i]->being_compacted) {
return true;
}
}
return false;
}
Compaction* CompactionPicker::FormCompaction(
const CompactionOptions& compact_options,
const std::vector<CompactionInputFiles>& input_files, int output_level,
VersionStorageInfo* vstorage, const MutableCFOptions& mutable_cf_options,
uint32_t output_path_id) {
assert(input_files.size());
// TODO(rven ): we might be able to run concurrent level 0 compaction
// if the key ranges of the two compactions do not overlap, but for now
// we do not allow it.
if ((input_files[0].level == 0) && !level0_compactions_in_progress_.empty()) {
return nullptr;
}
// This compaction output could overlap with a running compaction
if (FilesRangeOverlapWithCompaction(input_files, output_level)) {
return nullptr;
}
auto c =
new Compaction(vstorage, ioptions_, mutable_cf_options, input_files,
output_level, compact_options.output_file_size_limit,
mutable_cf_options.max_compaction_bytes, output_path_id,
compact_options.compression, /* grandparents */ {}, true);
// If it's level 0 compaction, make sure we don't execute any other level 0
// compactions in parallel
RegisterCompaction(c);
return c;
}
Status CompactionPicker::GetCompactionInputsFromFileNumbers(
std::vector<CompactionInputFiles>* input_files,
std::unordered_set<uint64_t>* input_set, const VersionStorageInfo* vstorage,
const CompactionOptions& compact_options) const {
if (input_set->size() == 0U) {
return Status::InvalidArgument(
"Compaction must include at least one file.");
}
assert(input_files);
std::vector<CompactionInputFiles> matched_input_files;
matched_input_files.resize(vstorage->num_levels());
int first_non_empty_level = -1;
int last_non_empty_level = -1;
// TODO(yhchiang): use a lazy-initialized mapping from
// file_number to FileMetaData in Version.
for (int level = 0; level < vstorage->num_levels(); ++level) {
for (auto file : vstorage->LevelFiles(level)) {
auto iter = input_set->find(file->fd.GetNumber());
if (iter != input_set->end()) {
matched_input_files[level].files.push_back(file);
input_set->erase(iter);
last_non_empty_level = level;
if (first_non_empty_level == -1) {
first_non_empty_level = level;
}
}
}
}
if (!input_set->empty()) {
std::string message(
"Cannot find matched SST files for the following file numbers:");
for (auto fn : *input_set) {
message += " ";
message += ToString(fn);
}
return Status::InvalidArgument(message);
}
for (int level = first_non_empty_level; level <= last_non_empty_level;
++level) {
matched_input_files[level].level = level;
input_files->emplace_back(std::move(matched_input_files[level]));
}
return Status::OK();
}
// Returns true if any one of the parent files are being compacted
bool CompactionPicker::RangeInCompaction(VersionStorageInfo* vstorage,
const InternalKey* smallest,
const InternalKey* largest, int level,
int* level_index) {
std::vector<FileMetaData*> inputs;
assert(level < NumberLevels());
vstorage->GetOverlappingInputs(level, smallest, largest, &inputs,
*level_index, level_index);
return FilesInCompaction(inputs);
}
// Populates the set of inputs of all other levels that overlap with the
// start level.
// Now we assume all levels except start level and output level are empty.
// Will also attempt to expand "start level" if that doesn't expand
// "output level" or cause "level" to include a file for compaction that has an
// overlapping user-key with another file.
// REQUIRES: input_level and output_level are different
// REQUIRES: inputs->empty() == false
// Returns false if files on parent level are currently in compaction, which
// means that we can't compact them
bool CompactionPicker::SetupOtherInputs(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, CompactionInputFiles* inputs,
CompactionInputFiles* output_level_inputs, int* parent_index,
int base_index) {
assert(!inputs->empty());
assert(output_level_inputs->empty());
const int input_level = inputs->level;
const int output_level = output_level_inputs->level;
assert(input_level != output_level);
// For now, we only support merging two levels, start level and output level.
// We need to assert other levels are empty.
for (int l = input_level + 1; l < output_level; l++) {
assert(vstorage->NumLevelFiles(l) == 0);
}
InternalKey smallest, largest;
// Get the range one last time.
GetRange(*inputs, &smallest, &largest);
// Populate the set of next-level files (inputs_GetOutputLevelInputs()) to
// include in compaction
vstorage->GetOverlappingInputs(output_level, &smallest, &largest,
&output_level_inputs->files, *parent_index,
parent_index);
if (FilesInCompaction(output_level_inputs->files)) {
return false;
}
if (!output_level_inputs->empty()) {
if (!ExpandWhileOverlapping(cf_name, vstorage, output_level_inputs)) {
return false;
}
}
// 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 (!output_level_inputs->empty()) {
const uint64_t limit = mutable_cf_options.max_compaction_bytes;
const uint64_t output_level_inputs_size =
TotalCompensatedFileSize(output_level_inputs->files);
const uint64_t inputs_size = TotalCompensatedFileSize(inputs->files);
bool expand_inputs = false;
CompactionInputFiles expanded_inputs;
expanded_inputs.level = input_level;
// Get closed interval of output level
InternalKey all_start, all_limit;
GetRange(*inputs, *output_level_inputs, &all_start, &all_limit);
bool try_overlapping_inputs = true;
vstorage->GetOverlappingInputs(input_level, &all_start, &all_limit,
&expanded_inputs.files, base_index, nullptr);
uint64_t expanded_inputs_size =
TotalCompensatedFileSize(expanded_inputs.files);
if (!ExpandWhileOverlapping(cf_name, vstorage, &expanded_inputs)) {
try_overlapping_inputs = false;
}
if (try_overlapping_inputs && expanded_inputs.size() > inputs->size() &&
output_level_inputs_size + expanded_inputs_size < limit &&
!FilesInCompaction(expanded_inputs.files)) {
InternalKey new_start, new_limit;
GetRange(expanded_inputs, &new_start, &new_limit);
CompactionInputFiles expanded_output_level_inputs;
expanded_output_level_inputs.level = output_level;
vstorage->GetOverlappingInputs(output_level, &new_start, &new_limit,
&expanded_output_level_inputs.files,
*parent_index, parent_index);
assert(!expanded_output_level_inputs.empty());
if (!FilesInCompaction(expanded_output_level_inputs.files) &&
ExpandWhileOverlapping(cf_name, vstorage,
&expanded_output_level_inputs) &&
expanded_output_level_inputs.size() == output_level_inputs->size()) {
expand_inputs = true;
}
}
if (!expand_inputs) {
vstorage->GetCleanInputsWithinInterval(input_level, &all_start,
&all_limit, &expanded_inputs.files,
base_index, nullptr);
expanded_inputs_size = TotalCompensatedFileSize(expanded_inputs.files);
if (expanded_inputs.size() > inputs->size() &&
output_level_inputs_size + expanded_inputs_size < limit &&
!FilesInCompaction(expanded_inputs.files)) {
expand_inputs = true;
}
}
if (expand_inputs) {
ROCKS_LOG_INFO(ioptions_.info_log,
"[%s] Expanding@%d %" ROCKSDB_PRIszt "+%" ROCKSDB_PRIszt
"(%" PRIu64 "+%" PRIu64 " bytes) to %" ROCKSDB_PRIszt
"+%" ROCKSDB_PRIszt " (%" PRIu64 "+%" PRIu64 "bytes)\n",
cf_name.c_str(), input_level, inputs->size(),
output_level_inputs->size(), inputs_size,
output_level_inputs_size, expanded_inputs.size(),
output_level_inputs->size(), expanded_inputs_size,
output_level_inputs_size);
inputs->files = expanded_inputs.files;
}
}
return true;
}
void CompactionPicker::GetGrandparents(
VersionStorageInfo* vstorage, const CompactionInputFiles& inputs,
const CompactionInputFiles& output_level_inputs,
std::vector<FileMetaData*>* grandparents) {
InternalKey start, limit;
GetRange(inputs, output_level_inputs, &start, &limit);
// Compute the set of grandparent files that overlap this compaction
// (parent == level+1; grandparent == level+2)
if (output_level_inputs.level + 1 < NumberLevels()) {
vstorage->GetOverlappingInputs(output_level_inputs.level + 1, &start,
&limit, 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, bool* manual_conflict) {
// CompactionPickerFIFO has its own implementation of compact range
assert(ioptions_.compaction_style != kCompactionStyleFIFO);
if (input_level == ColumnFamilyData::kCompactAllLevels) {
assert(ioptions_.compaction_style == kCompactionStyleUniversal);
// Universal compaction with more than one level always compacts all the
// files together to the last level.
assert(vstorage->num_levels() > 1);
// DBImpl::CompactRange() set output level to be the last level
assert(output_level == vstorage->num_levels() - 1);
// DBImpl::RunManualCompaction will make full range for universal compaction
assert(begin == nullptr);
assert(end == nullptr);
*compaction_end = nullptr;
int start_level = 0;
for (; start_level < vstorage->num_levels() &&
vstorage->NumLevelFiles(start_level) == 0;
start_level++) {
}
if (start_level == vstorage->num_levels()) {
return nullptr;
}
if ((start_level == 0) && (!level0_compactions_in_progress_.empty())) {
*manual_conflict = true;
// Only one level 0 compaction allowed
return nullptr;
}
std::vector<CompactionInputFiles> inputs(vstorage->num_levels() -
start_level);
for (int level = start_level; level < vstorage->num_levels(); level++) {
inputs[level - start_level].level = level;
auto& files = inputs[level - start_level].files;
for (FileMetaData* f : vstorage->LevelFiles(level)) {
files.push_back(f);
}
if (FilesInCompaction(files)) {
*manual_conflict = true;
return nullptr;
}
}
// 2 non-exclusive manual compactions could run at the same time producing
// overlaping outputs in the same level.
if (FilesRangeOverlapWithCompaction(inputs, output_level)) {
// This compaction output could potentially conflict with the output
// of a currently running compaction, we cannot run it.
*manual_conflict = true;
return nullptr;
}
Compaction* c = new Compaction(
vstorage, ioptions_, mutable_cf_options, std::move(inputs),
output_level, mutable_cf_options.MaxFileSizeForLevel(output_level),
/* max_compaction_bytes */ LLONG_MAX, output_path_id,
GetCompressionType(ioptions_, vstorage, mutable_cf_options,
output_level, 1),
/* grandparents */ {}, /* is manual */ true);
RegisterCompaction(c);
return c;
}
CompactionInputFiles inputs;
inputs.level = input_level;
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.files);
if (inputs.empty()) {
return nullptr;
}
if ((input_level == 0) && (!level0_compactions_in_progress_.empty())) {
// Only one level 0 compaction allowed
TEST_SYNC_POINT("CompactionPicker::CompactRange:Conflict");
*manual_conflict = true;
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.max_compaction_bytes;
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.files.resize(i + 1);
break;
}
}
}
assert(output_path_id < static_cast<uint32_t>(ioptions_.db_paths.size()));
if (ExpandWhileOverlapping(cf_name, vstorage, &inputs) == false) {
// manual compaction is now multi-threaded, so it can
// happen that ExpandWhileOverlapping fails
// we handle it higher in RunManualCompaction
*manual_conflict = true;
return nullptr;
}
if (covering_the_whole_range) {
*compaction_end = nullptr;
}
CompactionInputFiles output_level_inputs;
if (output_level == ColumnFamilyData::kCompactToBaseLevel) {
assert(input_level == 0);
output_level = vstorage->base_level();
assert(output_level > 0);
}
output_level_inputs.level = output_level;
if (input_level != output_level) {
int parent_index = -1;
if (!SetupOtherInputs(cf_name, mutable_cf_options, vstorage, &inputs,
&output_level_inputs, &parent_index, -1)) {
// manual compaction is now multi-threaded, so it can
// happen that SetupOtherInputs fails
// we handle it higher in RunManualCompaction
*manual_conflict = true;
return nullptr;
}
}
std::vector<CompactionInputFiles> compaction_inputs({inputs});
if (!output_level_inputs.empty()) {
compaction_inputs.push_back(output_level_inputs);
}
for (size_t i = 0; i < compaction_inputs.size(); i++) {
if (FilesInCompaction(compaction_inputs[i].files)) {
*manual_conflict = true;
return nullptr;
}
}
// 2 non-exclusive manual compactions could run at the same time producing
// overlaping outputs in the same level.
if (FilesRangeOverlapWithCompaction(compaction_inputs, output_level)) {
// This compaction output could potentially conflict with the output
// of a currently running compaction, we cannot run it.
*manual_conflict = true;
return nullptr;
}
std::vector<FileMetaData*> grandparents;
GetGrandparents(vstorage, inputs, output_level_inputs, &grandparents);
Compaction* compaction = new Compaction(
vstorage, ioptions_, mutable_cf_options, std::move(compaction_inputs),
output_level, mutable_cf_options.MaxFileSizeForLevel(output_level),
mutable_cf_options.max_compaction_bytes, output_path_id,
GetCompressionType(ioptions_, vstorage, mutable_cf_options, output_level,
vstorage->base_level()),
std::move(grandparents), /* is manual compaction */ true);
TEST_SYNC_POINT_CALLBACK("CompactionPicker::CompactRange:Return", compaction);
RegisterCompaction(compaction);
// Creating a compaction influences the compaction score because the score
// takes running compactions into account (by skipping files that are already
// being compacted). Since we just changed compaction score, we recalculate it
// here
vstorage->ComputeCompactionScore(ioptions_, mutable_cf_options);
return compaction;
}
#ifndef ROCKSDB_LITE
namespace {
// Test whether two files have overlapping key-ranges.
bool HaveOverlappingKeyRanges(const Comparator* c, const SstFileMetaData& a,
const SstFileMetaData& b) {
if (c->Compare(a.smallestkey, b.smallestkey) >= 0) {
if (c->Compare(a.smallestkey, b.largestkey) <= 0) {
// b.smallestkey <= a.smallestkey <= b.largestkey
return true;
}
} else if (c->Compare(a.largestkey, b.smallestkey) >= 0) {
// a.smallestkey < b.smallestkey <= a.largestkey
return true;
}
if (c->Compare(a.largestkey, b.largestkey) <= 0) {
if (c->Compare(a.largestkey, b.smallestkey) >= 0) {
// b.smallestkey <= a.largestkey <= b.largestkey
return true;
}
} else if (c->Compare(a.smallestkey, b.largestkey) <= 0) {
// a.smallestkey <= b.largestkey < a.largestkey
return true;
}
return false;
}
} // namespace
Status CompactionPicker::SanitizeCompactionInputFilesForAllLevels(
std::unordered_set<uint64_t>* input_files,
const ColumnFamilyMetaData& cf_meta, const int output_level) const {
auto& levels = cf_meta.levels;
auto comparator = icmp_->user_comparator();
// TODO(yhchiang): If there is any input files of L1 or up and there
// is at least one L0 files. All L0 files older than the L0 file needs
// to be included. Otherwise, it is a false conditoin
// TODO(yhchiang): add is_adjustable to CompactionOptions
// the smallest and largest key of the current compaction input
std::string smallestkey;
std::string largestkey;
// a flag for initializing smallest and largest key
bool is_first = false;
const int kNotFound = -1;
// For each level, it does the following things:
// 1. Find the first and the last compaction input files
// in the current level.
// 2. Include all files between the first and the last
// compaction input files.
// 3. Update the compaction key-range.
// 4. For all remaining levels, include files that have
// overlapping key-range with the compaction key-range.
for (int l = 0; l <= output_level; ++l) {
auto& current_files = levels[l].files;
int first_included = static_cast<int>(current_files.size());
int last_included = kNotFound;
// identify the first and the last compaction input files
// in the current level.
for (size_t f = 0; f < current_files.size(); ++f) {
if (input_files->find(TableFileNameToNumber(current_files[f].name)) !=
input_files->end()) {
first_included = std::min(first_included, static_cast<int>(f));
last_included = std::max(last_included, static_cast<int>(f));
if (is_first == false) {
smallestkey = current_files[f].smallestkey;
largestkey = current_files[f].largestkey;
is_first = true;
}
}
}
if (last_included == kNotFound) {
continue;
}
if (l != 0) {
// expend the compaction input of the current level if it
// has overlapping key-range with other non-compaction input
// files in the same level.
while (first_included > 0) {
if (comparator->Compare(current_files[first_included - 1].largestkey,
current_files[first_included].smallestkey) <
0) {
break;
}
first_included--;
}
while (last_included < static_cast<int>(current_files.size()) - 1) {
if (comparator->Compare(current_files[last_included + 1].smallestkey,
current_files[last_included].largestkey) > 0) {
break;
}
last_included++;
}
}
// include all files between the first and the last compaction input files.
for (int f = first_included; f <= last_included; ++f) {
if (current_files[f].being_compacted) {
return Status::Aborted("Necessary compaction input file " +
current_files[f].name +
" is currently being compacted.");
}
input_files->insert(TableFileNameToNumber(current_files[f].name));
}
// update smallest and largest key
if (l == 0) {
for (int f = first_included; f <= last_included; ++f) {
if (comparator->Compare(smallestkey, current_files[f].smallestkey) >
0) {
smallestkey = current_files[f].smallestkey;
}
if (comparator->Compare(largestkey, current_files[f].largestkey) < 0) {
largestkey = current_files[f].largestkey;
}
}
} else {
if (comparator->Compare(smallestkey,
current_files[first_included].smallestkey) > 0) {
smallestkey = current_files[first_included].smallestkey;
}
if (comparator->Compare(largestkey,
current_files[last_included].largestkey) < 0) {
largestkey = current_files[last_included].largestkey;
}
}
SstFileMetaData aggregated_file_meta;
aggregated_file_meta.smallestkey = smallestkey;
aggregated_file_meta.largestkey = largestkey;
// For all lower levels, include all overlapping files.
// We need to add overlapping files from the current level too because even
// if there no input_files in level l, we would still need to add files
// which overlap with the range containing the input_files in levels 0 to l
// Level 0 doesn't need to be handled this way because files are sorted by
// time and not by key
for (int m = std::max(l, 1); m <= output_level; ++m) {
for (auto& next_lv_file : levels[m].files) {
if (HaveOverlappingKeyRanges(comparator, aggregated_file_meta,
next_lv_file)) {
if (next_lv_file.being_compacted) {
return Status::Aborted(
"File " + next_lv_file.name +
" that has overlapping key range with one of the compaction "
" input file is currently being compacted.");
}
input_files->insert(TableFileNameToNumber(next_lv_file.name));
}
}
}
}
return Status::OK();
}
Status CompactionPicker::SanitizeCompactionInputFiles(
std::unordered_set<uint64_t>* input_files,
const ColumnFamilyMetaData& cf_meta, const int output_level) const {
assert(static_cast<int>(cf_meta.levels.size()) - 1 ==
cf_meta.levels[cf_meta.levels.size() - 1].level);
if (output_level >= static_cast<int>(cf_meta.levels.size())) {
return Status::InvalidArgument(
"Output level for column family " + cf_meta.name +
" must between [0, " +
ToString(cf_meta.levels[cf_meta.levels.size() - 1].level) + "].");
}
if (output_level > MaxOutputLevel()) {
return Status::InvalidArgument(
"Exceed the maximum output level defined by "
"the current compaction algorithm --- " +
ToString(MaxOutputLevel()));
}
if (output_level < 0) {
return Status::InvalidArgument("Output level cannot be negative.");
}
if (input_files->size() == 0) {
return Status::InvalidArgument(
"A compaction must contain at least one file.");
}
Status s = SanitizeCompactionInputFilesForAllLevels(input_files, cf_meta,
output_level);
if (!s.ok()) {
return s;
}
// for all input files, check whether the file number matches
// any currently-existing files.
for (auto file_num : *input_files) {
bool found = false;
for (auto level_meta : cf_meta.levels) {
for (auto file_meta : level_meta.files) {
if (file_num == TableFileNameToNumber(file_meta.name)) {
if (file_meta.being_compacted) {
return Status::Aborted("Specified compaction input file " +
MakeTableFileName("", file_num) +
" is already being compacted.");
}
found = true;
break;
}
}
if (found) {
break;
}
}
if (!found) {
return Status::InvalidArgument(
"Specified compaction input file " + MakeTableFileName("", file_num) +
" does not exist in column family " + cf_meta.name + ".");
}
}
return Status::OK();
}
#endif // !ROCKSDB_LITE
void CompactionPicker::RegisterCompaction(Compaction* c) {
if (c == nullptr) {
return;
}
assert(ioptions_.compaction_style != kCompactionStyleLevel ||
c->output_level() == 0 ||
!FilesRangeOverlapWithCompaction(*c->inputs(), c->output_level()));
if (c->start_level() == 0 ||
ioptions_.compaction_style == kCompactionStyleUniversal) {
level0_compactions_in_progress_.insert(c);
}
compactions_in_progress_.insert(c);
}
void CompactionPicker::UnregisterCompaction(Compaction* c) {
if (c == nullptr) {
return;
}
if (c->start_level() == 0 ||
ioptions_.compaction_style == kCompactionStyleUniversal) {
level0_compactions_in_progress_.erase(c);
}
compactions_in_progress_.erase(c);
}
bool LevelCompactionPicker::NeedsCompaction(
const VersionStorageInfo* vstorage) const {
if (!vstorage->FilesMarkedForCompaction().empty()) {
return true;
}
for (int i = 0; i <= vstorage->MaxInputLevel(); i++) {
if (vstorage->CompactionScore(i) >= 1) {
return true;
}
}
return false;
}
void LevelCompactionPicker::PickFilesMarkedForCompactionExperimental(
const std::string& cf_name, VersionStorageInfo* vstorage,
CompactionInputFiles* inputs, int* level, int* output_level) {
if (vstorage->FilesMarkedForCompaction().empty()) {
return;
}
auto continuation = [&](std::pair<int, FileMetaData*> level_file) {
// If it's being compacted it has nothing to do here.
// If this assert() fails that means that some function marked some
// files as being_compacted, but didn't call ComputeCompactionScore()
assert(!level_file.second->being_compacted);
*level = level_file.first;
*output_level = (*level == 0) ? vstorage->base_level() : *level + 1;
if (*level == 0 && !level0_compactions_in_progress_.empty()) {
return false;
}
inputs->files = {level_file.second};
inputs->level = *level;
return ExpandWhileOverlapping(cf_name, vstorage, inputs);
};
// take a chance on a random file first
Random64 rnd(/* seed */ reinterpret_cast<uint64_t>(vstorage));
size_t random_file_index = static_cast<size_t>(rnd.Uniform(
static_cast<uint64_t>(vstorage->FilesMarkedForCompaction().size())));
if (continuation(vstorage->FilesMarkedForCompaction()[random_file_index])) {
// found the compaction!
return;
}
for (auto& level_file : vstorage->FilesMarkedForCompaction()) {
if (continuation(level_file)) {
// found the compaction!
return;
}
}
inputs->files.clear();
}
Compaction* LevelCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, LogBuffer* log_buffer) {
int level = -1;
int output_level = -1;
int parent_index = -1;
int base_index = -1;
CompactionInputFiles inputs;
double score = 0;
CompactionReason compaction_reason = CompactionReason::kUnknown;
// Find the compactions by size on all levels.
bool skipped_l0_to_base = false;
for (int i = 0; i < NumberLevels() - 1; i++) {
score = vstorage->CompactionScore(i);
level = vstorage->CompactionScoreLevel(i);
assert(i == 0 || score <= vstorage->CompactionScore(i - 1));
if (score >= 1) {
if (skipped_l0_to_base && level == vstorage->base_level()) {
// If L0->base_level compaction is pending, don't schedule further
// compaction from base level. Otherwise L0->base_level compaction
// may starve.
continue;
}
output_level = (level == 0) ? vstorage->base_level() : level + 1;
if (PickCompactionBySize(vstorage, level, output_level, &inputs,
&parent_index, &base_index) &&
ExpandWhileOverlapping(cf_name, vstorage, &inputs) &&
!FilesRangeOverlapWithCompaction({inputs}, output_level)) {
// found the compaction!
if (level == 0) {
// L0 score = `num L0 files` / `level0_file_num_compaction_trigger`
compaction_reason = CompactionReason::kLevelL0FilesNum;
} else {
// L1+ score = `Level files size` / `MaxBytesForLevel`
compaction_reason = CompactionReason::kLevelMaxLevelSize;
}
break;
} else {
// didn't find the compaction, clear the inputs
inputs.clear();
if (level == 0) {
skipped_l0_to_base = true;
// L0->base_level may be blocked due to ongoing L0->base_level
// compactions. It may also be blocked by an ongoing compaction from
// base_level downwards.
//
// In these cases, to reduce L0 file count and thus reduce likelihood
// of write stalls, we can attempt compacting a span of files within
// L0.
if (PickIntraL0Compaction(vstorage, mutable_cf_options, &inputs)) {
output_level = 0;
compaction_reason = CompactionReason::kLevelL0FilesNum;
break;
}
}
}
}
}
bool is_manual = false;
// if we didn't find a compaction, check if there are any files marked for
// compaction
if (inputs.empty()) {
is_manual = true;
parent_index = base_index = -1;
PickFilesMarkedForCompactionExperimental(cf_name, vstorage, &inputs, &level,
&output_level);
if (!inputs.empty()) {
compaction_reason = CompactionReason::kFilesMarkedForCompaction;
}
}
if (inputs.empty()) {
return nullptr;
}
assert(level >= 0 && output_level >= 0);
// 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 && output_level != 0) {
assert(level0_compactions_in_progress_.empty());
InternalKey smallest, largest;
GetRange(inputs, &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.
inputs.files.clear();
vstorage->GetOverlappingInputs(0, &smallest, &largest, &inputs.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(inputs, &smallest, &largest);
if (RangeInCompaction(vstorage, &smallest, &largest, output_level,
&parent_index)) {
return nullptr;
}
assert(!inputs.files.empty());
}
std::vector<CompactionInputFiles> compaction_inputs;
CompactionInputFiles output_level_inputs;
std::vector<FileMetaData*> grandparents;
// Setup input files from output level. For output to L0, we only compact
// spans of files that do not interact with any pending compactions, so don't
// need to consider other levels.
if (output_level != 0) {
output_level_inputs.level = output_level;
if (!SetupOtherInputs(cf_name, mutable_cf_options, vstorage, &inputs,
&output_level_inputs, &parent_index, base_index)) {
return nullptr;
}
compaction_inputs.push_back(inputs);
if (!output_level_inputs.empty()) {
compaction_inputs.push_back(output_level_inputs);
}
// In some edge cases we could pick a compaction that will be compacting
// a key range that overlap with another running compaction, and both
// of them have the same output level. This could happen if
// (1) we are running a non-exclusive manual compaction
// (2) AddFile ingest a new file into the LSM tree
// We need to disallow this from happening.
if (FilesRangeOverlapWithCompaction(compaction_inputs, output_level)) {
// This compaction output could potentially conflict with the output
// of a currently running compaction, we cannot run it.
return nullptr;
}
GetGrandparents(vstorage, inputs, output_level_inputs, &grandparents);
} else {
compaction_inputs.push_back(inputs);
}
auto c = new Compaction(
vstorage, ioptions_, mutable_cf_options, std::move(compaction_inputs),
output_level, mutable_cf_options.MaxFileSizeForLevel(output_level),
mutable_cf_options.max_compaction_bytes,
GetPathId(ioptions_, mutable_cf_options, output_level),
GetCompressionType(ioptions_, vstorage, mutable_cf_options, output_level,
vstorage->base_level()),
std::move(grandparents), is_manual, score,
false /* deletion_compaction */, compaction_reason);
// If it's level 0 compaction, make sure we don't execute any other level 0
// compactions in parallel
RegisterCompaction(c);
// Creating a compaction influences the compaction score because the score
// takes running compactions into account (by skipping files that are already
// being compacted). Since we just changed compaction score, we recalculate it
// here
vstorage->ComputeCompactionScore(ioptions_, mutable_cf_options);
TEST_SYNC_POINT_CALLBACK("LevelCompactionPicker::PickCompaction:Return", c);
return c;
}
/*
* Find the optimal path to place a file
* Given a level, finds the path where levels up to it will fit in levels
* up to and including this path
*/
uint32_t LevelCompactionPicker::GetPathId(
const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options, int level) {
uint32_t p = 0;
assert(!ioptions.db_paths.empty());
// size remaining in the most recent path
uint64_t current_path_size = ioptions.db_paths[0].target_size;
uint64_t level_size;
int cur_level = 0;
level_size = mutable_cf_options.max_bytes_for_level_base;
// Last path is the fallback
while (p < ioptions.db_paths.size() - 1) {
if (level_size <= current_path_size) {
if (cur_level == level) {
// Does desired level fit in this path?
return p;
} else {
current_path_size -= level_size;
level_size = static_cast<uint64_t>(
level_size * mutable_cf_options.max_bytes_for_level_multiplier);
cur_level++;
continue;
}
}
p++;
current_path_size = ioptions.db_paths[p].target_size;
}
return p;
}
bool LevelCompactionPicker::PickCompactionBySize(VersionStorageInfo* vstorage,
int level, int output_level,
CompactionInputFiles* inputs,
int* parent_index,
int* base_index) {
// 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 && !level0_compactions_in_progress_.empty()) {
TEST_SYNC_POINT("LevelCompactionPicker::PickCompactionBySize:0");
return false;
}
inputs->clear();
assert(level >= 0);
// Pick the largest file in this level that is not already
// being compacted
const std::vector<int>& file_size = vstorage->FilesByCompactionPri(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];
auto* f = level_files[index];
// 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
*parent_index = -1;
if (RangeInCompaction(vstorage, &f->smallest, &f->largest, output_level,
parent_index)) {
continue;
}
inputs->files.push_back(f);
inputs->level = level;
*base_index = index;
break;
}
// store where to start the iteration in the next call to PickCompaction
vstorage->SetNextCompactionIndex(level, nextIndex);
return inputs->size() > 0;
}
bool LevelCompactionPicker::PickIntraL0Compaction(
VersionStorageInfo* vstorage, const MutableCFOptions& mutable_cf_options,
CompactionInputFiles* inputs) {
inputs->clear();
const std::vector<FileMetaData*>& level_files =
vstorage->LevelFiles(0 /* level */);
if (level_files.size() <
static_cast<size_t>(
mutable_cf_options.level0_file_num_compaction_trigger + 2) ||
level_files[0]->being_compacted) {
// If L0 isn't accumulating much files beyond the regular trigger, don't
// resort to L0->L0 compaction yet.
return false;
}
size_t compact_bytes = level_files[0]->fd.file_size;
size_t compact_bytes_per_del_file = port::kMaxSizet;
// compaction range will be [0, span_len).
size_t span_len;
// pull in files until the amount of compaction work per deleted file begins
// increasing.
for (span_len = 1; span_len < level_files.size(); ++span_len) {
compact_bytes += level_files[span_len]->fd.file_size;
size_t new_compact_bytes_per_del_file = compact_bytes / span_len;
if (level_files[span_len]->being_compacted ||
new_compact_bytes_per_del_file > compact_bytes_per_del_file) {
break;
}
compact_bytes_per_del_file = new_compact_bytes_per_del_file;
}
if (span_len >= kMinFilesForIntraL0Compaction) {
inputs->level = 0;
for (size_t i = 0; i < span_len; ++i) {
inputs->files.push_back(level_files[i]);
}
return true;
}
return false;
}
#ifndef ROCKSDB_LITE
bool UniversalCompactionPicker::NeedsCompaction(
const VersionStorageInfo* vstorage) const {
const int kLevel0 = 0;
return vstorage->CompactionScore(kLevel0) >= 1;
}
void UniversalCompactionPicker::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 UniversalCompactionPicker::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<UniversalCompactionPicker::SortedRun>
UniversalCompactionPicker::CalculateSortedRuns(
const VersionStorageInfo& vstorage, const ImmutableCFOptions& ioptions) {
std::vector<UniversalCompactionPicker::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;
bool is_first = true;
for (FileMetaData* f : vstorage.LevelFiles(level)) {
total_compensated_size += f->compensated_file_size;
total_size += f->fd.GetFileSize();
if (ioptions.compaction_options_universal.allow_trivial_move == true) {
if (f->being_compacted) {
being_compacted = f->being_compacted;
}
} else {
// Compaction always includes all files for a non-zero level, so for a
// non-zero level, all the files should share the same being_compacted
// value.
// This assumption is only valid when
// ioptions.compaction_options_universal.allow_trivial_move is false
assert(is_first || f->being_compacted == being_compacted);
}
if (is_first) {
being_compacted = f->being_compacted;
is_first = false;
}
}
if (total_compensated_size > 0) {
ret.emplace_back(level, nullptr, total_size, total_compensated_size,
being_compacted);
}
}
return ret;
}
#ifndef NDEBUG
namespace {
// 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->smallest_seqno <= f->largest_seqno);
if (is_first) {
is_first = false;
*smallest_seqno = f->smallest_seqno;
*largest_seqno = f->largest_seqno;
} else {
if (f->smallest_seqno < *smallest_seqno) {
*smallest_seqno = f->smallest_seqno;
}
if (f->largest_seqno > *largest_seqno) {
*largest_seqno = f->largest_seqno;
}
}
}
}
} // namespace
#endif
// Algorithm that checks to see if there are any overlapping
// files in the input
bool CompactionPicker::IsInputNonOverlapping(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 (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;
}
// 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);
std::vector<SortedRun> sorted_runs =
CalculateSortedRuns(*vstorage, ioptions_);
if (sorted_runs.size() == 0 ||
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("UniversalCompactionPicker::PickCompaction:Return",
nullptr);
return nullptr;
}
VersionStorageInfo::LevelSummaryStorage tmp;
ROCKS_LOG_BUFFER_MAX_SZ(
log_buffer, 3072,
"[%s] Universal: sorted runs files(%" ROCKSDB_PRIszt "): %s\n",
cf_name.c_str(), sorted_runs.size(), vstorage->LevelSummary(&tmp));
// Check for size amplification first.
Compaction* c;
if ((c = PickCompactionUniversalSizeAmp(cf_name, mutable_cf_options, vstorage,
score, sorted_runs, log_buffer)) !=
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 = ioptions_.compaction_options_universal.size_ratio;
if ((c = PickCompactionUniversalReadAmp(
cf_name, mutable_cf_options, vstorage, score, ratio, UINT_MAX,
sorted_runs, log_buffer)) != 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 = PickCompactionUniversalReadAmp(
cf_name, mutable_cf_options, vstorage, score, UINT_MAX,
num_files, sorted_runs, log_buffer)) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer,
"[%s] Universal: compacting for file num -- %u\n",
cf_name.c_str(), num_files);
}
}
}
}
if (c == nullptr) {
TEST_SYNC_POINT_CALLBACK("UniversalCompactionPicker::PickCompaction:Return",
nullptr);
return nullptr;
}
if (ioptions_.compaction_options_universal.allow_trivial_move == true) {
c->set_is_trivial_move(IsInputNonOverlapping(c));
}
// validate that all the chosen files of L0 are non overlapping in time
#ifndef NDEBUG
SequenceNumber prev_smallest_seqno = 0U;
bool is_first = true;
size_t level_index = 0U;
if (c->start_level() == 0) {
for (auto f : *c->inputs(0)) {
assert(f->smallest_seqno <= f->largest_seqno);
if (is_first) {
is_first = false;
} else {
assert(prev_smallest_seqno > f->largest_seqno);
}
prev_smallest_seqno = f->smallest_seqno;
}
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;
} else if (prev_smallest_seqno > 0) {
// A level is considered as the bottommost level if there are
// no files in higher levels or if files in higher levels do
// not overlap with the files being compacted. Sequence numbers
// of files in bottommost level can be set to 0 to help
// compression. As a result, the following assert may not hold
// if the prev_smallest_seqno is 0.
assert(prev_smallest_seqno > largest_seqno);
}
prev_smallest_seqno = smallest_seqno;
}
}
#endif
// update statistics
MeasureTime(ioptions_.statistics, NUM_FILES_IN_SINGLE_COMPACTION,
c->inputs(0)->size());
RegisterCompaction(c);
TEST_SYNC_POINT_CALLBACK("UniversalCompactionPicker::PickCompaction:Return",
c);
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;
assert(!ioptions.db_paths.empty());
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,
const std::vector<SortedRun>& sorted_runs, LogBuffer* log_buffer) {
unsigned int min_merge_width =
ioptions_.compaction_options_universal.min_merge_width;
unsigned int max_merge_width =
ioptions_.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 (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 = (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 =
ioptions_.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_, 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;
}
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::kUniversalSortedRunNum;
} else {
compaction_reason = CompactionReason::kUniversalSizeRatio;
}
return new Compaction(
vstorage, ioptions_, mutable_cf_options, std::move(inputs), output_level,
mutable_cf_options.MaxFileSizeForLevel(output_level), LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage, mutable_cf_options, start_level,
1, enable_compression),
/* grandparents */ {}, /* is manual */ false, score,
false /* deletion_compaction */, compaction_reason);
}
// 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,
const std::vector<SortedRun>& sorted_runs, LogBuffer* log_buffer) {
// percentage flexibilty while reducing size amplification
uint64_t ratio =
ioptions_.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;
// Skip files that are already being compacted
for (size_t loop = 0; loop < sorted_runs.size() - 1; 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 < sorted_runs.size() - 1; 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);
}
assert(start_index < sorted_runs.size() - 1);
// 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_, 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);
}
// We always compact all the files, so always compress.
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);
}
}
char file_num_buf[256];
picking_sr.DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
ROCKS_LOG_BUFFER(log_buffer, "[%s] Universal: size amp picking %s",
cf_name.c_str(), file_num_buf);
}
return new Compaction(
vstorage, ioptions_, mutable_cf_options, std::move(inputs),
vstorage->num_levels() - 1,
mutable_cf_options.MaxFileSizeForLevel(vstorage->num_levels() - 1),
/* max_grandparent_overlap_bytes */ LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage, mutable_cf_options,
vstorage->num_levels() - 1, 1),
/* grandparents */ {}, /* is manual */ false, score,
false /* deletion_compaction */,
CompactionReason::kUniversalSizeAmplification);
}
bool FIFOCompactionPicker::NeedsCompaction(
const VersionStorageInfo* vstorage) const {
const int kLevel0 = 0;
return vstorage->CompactionScore(kLevel0) >= 1;
}
Compaction* FIFOCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, LogBuffer* log_buffer) {
assert(vstorage->num_levels() == 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->fd.file_size;
}
if (total_size <= ioptions_.compaction_options_fifo.max_table_files_size ||
level_files.size() == 0) {
// total size not exceeded
ROCKS_LOG_BUFFER(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 (!level0_compactions_in_progress_.empty()) {
ROCKS_LOG_BUFFER(
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;
}
std::vector<CompactionInputFiles> inputs;
inputs.emplace_back();
inputs[0].level = 0;
// delete old files (FIFO)
for (auto ritr = level_files.rbegin(); ritr != level_files.rend(); ++ritr) {
auto f = *ritr;
total_size -= f->compensated_file_size;
inputs[0].files.push_back(f);
char tmp_fsize[16];
AppendHumanBytes(f->fd.GetFileSize(), tmp_fsize, sizeof(tmp_fsize));
ROCKS_LOG_BUFFER(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;
}
}
Compaction* c = new Compaction(
vstorage, ioptions_, mutable_cf_options, std::move(inputs), 0, 0, 0, 0,
kNoCompression, {}, /* is manual */ false, vstorage->CompactionScore(0),
/* is deletion compaction */ true, CompactionReason::kFIFOMaxSize);
RegisterCompaction(c);
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, bool* manual_conflict) {
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);
log_buffer.FlushBufferToLog();
return c;
}
#endif // !ROCKSDB_LITE
} // namespace rocksdb
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