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rocksdb/db/compaction.cc

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/compaction.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <vector>
#include "db/column_family.h"
#include "util/logging.h"
#include "util/sync_point.h"
namespace rocksdb {
uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
uint64_t sum = 0;
for (size_t i = 0; i < files.size() && files[i]; i++) {
sum += files[i]->fd.GetFileSize();
}
return sum;
}
void Compaction::SetInputVersion(Version* _input_version) {
input_version_ = _input_version;
cfd_ = input_version_->cfd();
cfd_->Ref();
input_version_->Ref();
edit_.SetColumnFamily(cfd_->GetID());
}
// helper function to determine if compaction is creating files at the
// bottommost level
bool Compaction::IsBottommostLevel(
int output_level, VersionStorageInfo* vstorage,
const std::vector<CompactionInputFiles>& inputs) {
if (inputs[0].level == 0 &&
inputs[0].files.back() != vstorage->LevelFiles(0).back()) {
return false;
}
// checks whether there are files living beyond the output_level.
for (int i = output_level + 1; i < vstorage->num_levels(); i++) {
if (vstorage->NumLevelFiles(i) > 0) {
return false;
}
}
return true;
}
bool Compaction::IsFullCompaction(
VersionStorageInfo* vstorage,
const std::vector<CompactionInputFiles>& inputs) {
int num_files_in_compaction = 0;
int total_num_files = 0;
for (int l = 0; l < vstorage->num_levels(); l++) {
total_num_files += vstorage->NumLevelFiles(l);
}
for (size_t i = 0; i < inputs.size(); i++) {
num_files_in_compaction += inputs[i].size();
}
return num_files_in_compaction == total_num_files;
}
Compaction::Compaction(VersionStorageInfo* vstorage,
const MutableCFOptions& _mutable_cf_options,
std::vector<CompactionInputFiles> _inputs,
int _output_level, uint64_t _target_file_size,
uint64_t _max_grandparent_overlap_bytes,
uint32_t _output_path_id, CompressionType _compression,
std::vector<FileMetaData*> _grandparents,
bool _manual_compaction, double _score,
bool _deletion_compaction)
: start_level_(_inputs[0].level),
output_level_(_output_level),
max_output_file_size_(_target_file_size),
max_grandparent_overlap_bytes_(_max_grandparent_overlap_bytes),
mutable_cf_options_(_mutable_cf_options),
input_version_(nullptr),
number_levels_(vstorage->num_levels()),
cfd_(nullptr),
output_path_id_(_output_path_id),
output_compression_(_compression),
deletion_compaction_(_deletion_compaction),
inputs_(std::move(_inputs)),
grandparents_(std::move(_grandparents)),
grandparent_index_(0),
seen_key_(false),
overlapped_bytes_(0),
score_(_score),
bottommost_level_(IsBottommostLevel(output_level_, vstorage, inputs_)),
is_full_compaction_(IsFullCompaction(vstorage, inputs_)),
is_manual_compaction_(_manual_compaction),
level_ptrs_(std::vector<size_t>(number_levels_, 0)) {
MarkFilesBeingCompacted(true);
#ifndef NDEBUG
for (size_t i = 1; i < inputs_.size(); ++i) {
assert(inputs_[i].level > inputs_[i - 1].level);
}
#endif
// setup input_levels_
{
input_levels_.resize(num_input_levels());
for (size_t which = 0; which < num_input_levels(); which++) {
DoGenerateLevelFilesBrief(&input_levels_[which], inputs_[which].files,
&arena_);
}
}
}
Compaction::~Compaction() {
if (input_version_ != nullptr) {
input_version_->Unref();
}
if (cfd_ != nullptr) {
if (cfd_->Unref()) {
delete cfd_;
}
}
}
bool Compaction::InputCompressionMatchesOutput() const {
int base_level = input_version_->storage_info()->base_level();
bool matches = (GetCompressionType(*cfd_->ioptions(), start_level_,
base_level) == output_compression_);
if (matches) {
TEST_SYNC_POINT("Compaction::InputCompressionMatchesOutput:Matches");
return true;
}
TEST_SYNC_POINT("Compaction::InputCompressionMatchesOutput:DidntMatch");
return false;
}
bool Compaction::IsTrivialMove() const {
// Avoid a move if there is lots of overlapping grandparent data.
// Otherwise, the move could create a parent file that will require
// a very expensive merge later on.
// If start_level_== output_level_, the purpose is to force compaction
// filter to be applied to that level, and thus cannot be a trivia move.
return (start_level_ != output_level_ && num_input_levels() == 1 &&
num_input_files(0) == 1 &&
input(0, 0)->fd.GetPathId() == GetOutputPathId() &&
InputCompressionMatchesOutput() &&
TotalFileSize(grandparents_) <= max_grandparent_overlap_bytes_);
}
void Compaction::AddInputDeletions(VersionEdit* out_edit) {
for (size_t which = 0; which < num_input_levels(); which++) {
for (size_t i = 0; i < inputs_[which].size(); i++) {
out_edit->DeleteFile(level(which), inputs_[which][i]->fd.GetNumber());
}
}
}
bool Compaction::KeyNotExistsBeyondOutputLevel(const Slice& user_key) {
assert(input_version_ != nullptr);
assert(cfd_->ioptions()->compaction_style != kCompactionStyleFIFO);
if (cfd_->ioptions()->compaction_style == kCompactionStyleUniversal) {
return bottommost_level_;
}
// Maybe use binary search to find right entry instead of linear search?
const Comparator* user_cmp = cfd_->user_comparator();
for (int lvl = output_level_ + 1; lvl < number_levels_; lvl++) {
const std::vector<FileMetaData*>& files =
input_version_->storage_info()->LevelFiles(lvl);
for (; level_ptrs_[lvl] < files.size(); ) {
FileMetaData* f = files[level_ptrs_[lvl]];
if (user_cmp->Compare(user_key, f->largest.user_key()) <= 0) {
// We've advanced far enough
if (user_cmp->Compare(user_key, f->smallest.user_key()) >= 0) {
// Key falls in this file's range, so definitely
// exists beyond output level
return false;
}
break;
}
level_ptrs_[lvl]++;
}
}
return true;
}
bool Compaction::ShouldStopBefore(const Slice& internal_key) {
// Scan to find earliest grandparent file that contains key.
const InternalKeyComparator* icmp = &cfd_->internal_comparator();
while (grandparent_index_ < grandparents_.size() &&
icmp->Compare(internal_key,
grandparents_[grandparent_index_]->largest.Encode()) > 0) {
if (seen_key_) {
overlapped_bytes_ += grandparents_[grandparent_index_]->fd.GetFileSize();
}
assert(grandparent_index_ + 1 >= grandparents_.size() ||
icmp->Compare(grandparents_[grandparent_index_]->largest.Encode(),
grandparents_[grandparent_index_+1]->smallest.Encode())
< 0);
grandparent_index_++;
}
seen_key_ = true;
if (overlapped_bytes_ > max_grandparent_overlap_bytes_) {
// Too much overlap for current output; start new output
overlapped_bytes_ = 0;
return true;
} else {
return false;
}
}
// Mark (or clear) each file that is being compacted
void Compaction::MarkFilesBeingCompacted(bool mark_as_compacted) {
for (size_t i = 0; i < num_input_levels(); i++) {
for (unsigned int j = 0; j < inputs_[i].size(); j++) {
assert(mark_as_compacted ? !inputs_[i][j]->being_compacted :
inputs_[i][j]->being_compacted);
inputs_[i][j]->being_compacted = mark_as_compacted;
}
}
}
// Sample output:
// If compacting 3 L0 files, 2 L3 files and 1 L4 file, and outputting to L5,
// print: "3@0 + 2@3 + 1@4 files to L5"
const char* Compaction::InputLevelSummary(
InputLevelSummaryBuffer* scratch) const {
int len = 0;
bool is_first = true;
for (auto& input_level : inputs_) {
if (input_level.empty()) {
continue;
}
if (!is_first) {
len +=
snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len, " + ");
} else {
is_first = false;
}
len += snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len,
"%zu@%d", input_level.size(), input_level.level);
}
snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len,
" files to L%d", output_level());
return scratch->buffer;
}
uint64_t Compaction::CalculateTotalInputSize() const {
uint64_t size = 0;
for (auto& input_level : inputs_) {
for (auto f : input_level.files) {
size += f->fd.GetFileSize();
}
}
return size;
}
void Compaction::ReleaseCompactionFiles(Status status) {
MarkFilesBeingCompacted(false);
cfd_->compaction_picker()->ReleaseCompactionFiles(this, status);
}
void Compaction::ResetNextCompactionIndex() {
assert(input_version_ != nullptr);
input_version_->storage_info()->ResetNextCompactionIndex(start_level_);
}
namespace {
int InputSummary(const std::vector<FileMetaData*>& files, char* output,
int len) {
*output = '\0';
int write = 0;
for (unsigned int i = 0; i < files.size(); i++) {
int sz = len - write;
int ret;
char sztxt[16];
AppendHumanBytes(files.at(i)->fd.GetFileSize(), sztxt, 16);
ret = snprintf(output + write, sz, "%" PRIu64 "(%s) ",
files.at(i)->fd.GetNumber(), sztxt);
if (ret < 0 || ret >= sz) break;
write += ret;
}
// if files.size() is non-zero, overwrite the last space
return write - !!files.size();
}
} // namespace
void Compaction::Summary(char* output, int len) {
int write =
snprintf(output, len, "Base version %" PRIu64
" Base level %d, inputs: [",
input_version_->GetVersionNumber(),
start_level_);
if (write < 0 || write >= len) {
return;
}
for (size_t level_iter = 0; level_iter < num_input_levels(); ++level_iter) {
if (level_iter > 0) {
write += snprintf(output + write, len - write, "], [");
if (write < 0 || write >= len) {
return;
}
}
write +=
InputSummary(inputs_[level_iter].files, output + write, len - write);
if (write < 0 || write >= len) {
return;
}
}
snprintf(output + write, len - write, "]");
}
uint64_t Compaction::OutputFilePreallocationSize(
const MutableCFOptions& mutable_options) {
uint64_t preallocation_size = 0;
if (cfd_->ioptions()->compaction_style == kCompactionStyleLevel) {
preallocation_size = mutable_options.MaxFileSizeForLevel(output_level());
} else {
for (size_t level_iter = 0; level_iter < num_input_levels(); ++level_iter) {
for (const auto& f : inputs_[level_iter].files) {
preallocation_size += f->fd.GetFileSize();
}
}
}
// Over-estimate slightly so we don't end up just barely crossing
// the threshold
return preallocation_size * 1.1;
}
} // namespace rocksdb