rocksdb/db/compaction/compaction_picker_universal.cc

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/compaction/compaction_picker_universal.h"
#ifndef ROCKSDB_LITE
#include <cinttypes>
#include <limits>
#include <queue>
#include <string>
#include <utility>
#include "db/column_family.h"
#include "file/filename.h"
#include "logging/log_buffer.h"
#include "monitoring/statistics.h"
#include "test_util/sync_point.h"
#include "util/random.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
namespace {
// A helper class that form universal compactions. The class is used by
// UniversalCompactionPicker::PickCompaction().
// The usage is to create the class, and get the compaction object by calling
// PickCompaction().
class UniversalCompactionBuilder {
public:
UniversalCompactionBuilder(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp,
const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage,
UniversalCompactionPicker* picker,
LogBuffer* log_buffer)
: ioptions_(ioptions),
icmp_(icmp),
cf_name_(cf_name),
mutable_cf_options_(mutable_cf_options),
vstorage_(vstorage),
picker_(picker),
log_buffer_(log_buffer) {}
// Form and return the compaction object. The caller owns return object.
Compaction* PickCompaction();
private:
struct SortedRun {
SortedRun(int _level, FileMetaData* _file, uint64_t _size,
uint64_t _compensated_file_size, bool _being_compacted)
: level(_level),
file(_file),
size(_size),
compensated_file_size(_compensated_file_size),
being_compacted(_being_compacted) {
assert(compensated_file_size > 0);
assert(level != 0 || file != nullptr);
}
void Dump(char* out_buf, size_t out_buf_size,
bool print_path = false) const;
// sorted_run_count is added into the string to print
void DumpSizeInfo(char* out_buf, size_t out_buf_size,
size_t sorted_run_count) const;
int level;
// `file` Will be null for level > 0. For level = 0, the sorted run is
// for this file.
FileMetaData* file;
// For level > 0, `size` and `compensated_file_size` are sum of sizes all
// files in the level. `being_compacted` should be the same for all files
// in a non-zero level. Use the value here.
uint64_t size;
uint64_t compensated_file_size;
bool being_compacted;
};
// Pick Universal compaction to limit read amplification
Compaction* PickCompactionToReduceSortedRuns(
unsigned int ratio, unsigned int max_number_of_files_to_compact);
// Pick Universal compaction to limit space amplification.
Compaction* PickCompactionToReduceSizeAmp();
Compaction* PickDeleteTriggeredCompaction();
// Form a compaction from the sorted run indicated by start_index to the
// oldest sorted run.
// The caller is responsible for making sure that those files are not in
// compaction.
Compaction* PickCompactionToOldest(size_t start_index,
CompactionReason compaction_reason);
// Try to pick periodic compaction. The caller should only call it
// if there is at least one file marked for periodic compaction.
// null will be returned if no such a compaction can be formed
// because some files are being compacted.
Compaction* PickPeriodicCompaction();
// Used in universal compaction when the enabled_trivial_move
// option is set. Checks whether there are any overlapping files
// in the input. Returns true if the input files are non
// overlapping.
bool IsInputFilesNonOverlapping(Compaction* c);
const ImmutableCFOptions& ioptions_;
const InternalKeyComparator* icmp_;
double score_;
std::vector<SortedRun> sorted_runs_;
const std::string& cf_name_;
const MutableCFOptions& mutable_cf_options_;
VersionStorageInfo* vstorage_;
UniversalCompactionPicker* picker_;
LogBuffer* log_buffer_;
static std::vector<SortedRun> CalculateSortedRuns(
const VersionStorageInfo& vstorage, const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options);
// Pick a path ID to place a newly generated file, with its estimated file
// size.
static uint32_t GetPathId(const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options,
uint64_t file_size);
};
// Used in universal compaction when trivial move is enabled.
// This structure is used for the construction of min heap
// that contains the file meta data, the level of the file
// and the index of the file in that level
struct InputFileInfo {
InputFileInfo() : f(nullptr), level(0), index(0) {}
FileMetaData* f;
size_t level;
size_t index;
};
// Used in universal compaction when trivial move is enabled.
// This comparator is used for the construction of min heap
// based on the smallest key of the file.
struct SmallestKeyHeapComparator {
explicit SmallestKeyHeapComparator(const Comparator* ucmp) { ucmp_ = ucmp; }
bool operator()(InputFileInfo i1, InputFileInfo i2) const {
return (ucmp_->Compare(i1.f->smallest.user_key(),
i2.f->smallest.user_key()) > 0);
}
private:
const Comparator* ucmp_;
};
typedef std::priority_queue<InputFileInfo, std::vector<InputFileInfo>,
SmallestKeyHeapComparator>
SmallestKeyHeap;
// This function creates the heap that is used to find if the files are
// overlapping during universal compaction when the allow_trivial_move
// is set.
SmallestKeyHeap create_level_heap(Compaction* c, const Comparator* ucmp) {
SmallestKeyHeap smallest_key_priority_q =
SmallestKeyHeap(SmallestKeyHeapComparator(ucmp));
InputFileInfo input_file;
for (size_t l = 0; l < c->num_input_levels(); l++) {
if (c->num_input_files(l) != 0) {
if (l == 0 && c->start_level() == 0) {
for (size_t i = 0; i < c->num_input_files(0); i++) {
input_file.f = c->input(0, i);
input_file.level = 0;
input_file.index = i;
smallest_key_priority_q.push(std::move(input_file));
}
} else {
input_file.f = c->input(l, 0);
input_file.level = l;
input_file.index = 0;
smallest_key_priority_q.push(std::move(input_file));
}
}
}
return smallest_key_priority_q;
}
#ifndef NDEBUG
// smallest_seqno and largest_seqno are set iff. `files` is not empty.
void GetSmallestLargestSeqno(const std::vector<FileMetaData*>& files,
SequenceNumber* smallest_seqno,
SequenceNumber* largest_seqno) {
bool is_first = true;
for (FileMetaData* f : files) {
assert(f->fd.smallest_seqno <= f->fd.largest_seqno);
if (is_first) {
is_first = false;
*smallest_seqno = f->fd.smallest_seqno;
*largest_seqno = f->fd.largest_seqno;
} else {
if (f->fd.smallest_seqno < *smallest_seqno) {
*smallest_seqno = f->fd.smallest_seqno;
}
if (f->fd.largest_seqno > *largest_seqno) {
*largest_seqno = f->fd.largest_seqno;
}
}
}
}
#endif
} // namespace
// Algorithm that checks to see if there are any overlapping
// files in the input
bool UniversalCompactionBuilder::IsInputFilesNonOverlapping(Compaction* c) {
auto comparator = icmp_->user_comparator();
int first_iter = 1;
InputFileInfo prev, curr, next;
SmallestKeyHeap smallest_key_priority_q =
create_level_heap(c, icmp_->user_comparator());
while (!smallest_key_priority_q.empty()) {
curr = smallest_key_priority_q.top();
smallest_key_priority_q.pop();
if (first_iter) {
prev = curr;
first_iter = 0;
} else {
if (comparator->Compare(prev.f->largest.user_key(),
curr.f->smallest.user_key()) >= 0) {
// found overlapping files, return false
return false;
}
assert(comparator->Compare(curr.f->largest.user_key(),
prev.f->largest.user_key()) > 0);
prev = curr;
}
next.f = nullptr;
if (c->level(curr.level) != 0 &&
curr.index < c->num_input_files(curr.level) - 1) {
next.f = c->input(curr.level, curr.index + 1);
next.level = curr.level;
next.index = curr.index + 1;
}
if (next.f) {
smallest_key_priority_q.push(std::move(next));
}
}
return true;
}
bool UniversalCompactionPicker::NeedsCompaction(
const VersionStorageInfo* vstorage) const {
const int kLevel0 = 0;
if (vstorage->CompactionScore(kLevel0) >= 1) {
return true;
}
if (!vstorage->FilesMarkedForPeriodicCompaction().empty()) {
return true;
}
if (!vstorage->FilesMarkedForCompaction().empty()) {
return true;
}
return false;
}
Compaction* UniversalCompactionPicker::PickCompaction(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
Fix corruption with intra-L0 on ingested files (#5958) Summary: ## Problem Description Our process was abort when it call `CheckConsistency`. And the information in `stderr` show that "`L0 files seqno 3001491972 3004797440 vs. 3002875611 3004524421` ". Here are the causes of the accident I investigated. * RocksDB will call `CheckConsistency` whenever `MANIFEST` file is update. It will check sequence number interval of every file, except files which were ingested. * When one file is ingested into RocksDB, it will be assigned the value of global sequence number, and the minimum and maximum seqno of this file are equal, which are both equal to global sequence number. * `CheckConsistency` determines whether the file is ingested by whether the smallest and largest seqno of an sstable file are equal. * If IntraL0Compaction picks one sst which was ingested just now and compacted it into another sst, the `smallest_seqno` of this new file will be smaller than his `largest_seqno`. * If more than one ingested file was ingested before memtable schedule flush, and they all compact into one new sstable file by `IntraL0Compaction`. The sequence interval of this new file will be included in the interval of the memtable. So `CheckConsistency` will return a `Corruption`. * If a sstable was ingested after the memtable was schedule to flush, which would assign a larger seqno to it than memtable. Then the file was compacted with other files (these files were all flushed before the memtable) in L0 into one file. This compaction start before the flush job of memtable start, but completed after the flush job finish. So this new file produced by the compaction (we call it s1) would have a larger interval of sequence number than the file produced by flush (we call it s2). **But there was still some data in s1 written into RocksDB before the s2, so it's possible that some data in s2 was cover by old data in s1.** Of course, it would also make a `Corruption` because of overlap of seqno. There is the relationship of the files: > s1.smallest_seqno < s2.smallest_seqno < s2.largest_seqno < s1.largest_seqno So I skip pick sst file which was ingested in function `FindIntraL0Compaction ` ## Reason Here is my bug report: https://github.com/facebook/rocksdb/issues/5913 There are two situations that can cause the check to fail. ### First situation: - First we ingest five external sst into Rocksdb, and they happened to be ingested in L0. and there had been some data in memtable, which make the smallest sequence number of memtable is less than which of sst that we ingest. - If there had been one compaction job which compacted sst from L0 to L1, `LevelCompactionPicker` would trigger a `IntraL0Compaction` which would compact this five sst from L0 to L0. We call this sst A, which was merged from five ingested sst. - Then some data was put into memtable, and memtable was flushed to L0. We called this sst B. - RocksDB check consistency , and find the `smallest_seqno` of B is less than that of A and crash. Because A was merged from five sst, the smallest sequence number of it was less than the biggest sequece number of itself, so RocksDB could not tell if A was produce by ingested. ### Secondary situaion - First we have flushed many sst in L0, we call them [s1, s2, s3]. - There is an immutable memtable request to be flushed, but because flush thread is busy, so it has not been picked. we call it m1. And at the moment, one sst is ingested into L0. We call it s4. Because s4 is ingested after m1 became immutable memtable, so it has a larger log sequence number than m1. - m1 is flushed in L0. because it is small, this flush job finish quickly. we call it s5. - [s1, s2, s3, s4] are compacted into one sst to L0, by IntraL0Compaction. We call it s6. - compacted 4@0 files to L0 - When s6 is added into manifest, the corruption happened. because the largest sequence number of s6 is equal to s4, and they are both larger than that of s5. But because s1 is older than m1, so the smallest sequence number of s6 is smaller than that of s5. - s6.smallest_seqno < s5.smallest_seqno < s5.largest_seqno < s6.largest_seqno Pull Request resolved: https://github.com/facebook/rocksdb/pull/5958 Differential Revision: D18601316 fbshipit-source-id: 5fe54b3c9af52a2e1400728f565e895cde1c7267
2019-11-20 00:07:49 +01:00
VersionStorageInfo* vstorage, LogBuffer* log_buffer,
SequenceNumber /* earliest_memtable_seqno */) {
UniversalCompactionBuilder builder(ioptions_, icmp_, cf_name,
mutable_cf_options, vstorage, this,
log_buffer);
return builder.PickCompaction();
}
void UniversalCompactionBuilder::SortedRun::Dump(char* out_buf,
size_t out_buf_size,
bool print_path) const {
if (level == 0) {
assert(file != nullptr);
if (file->fd.GetPathId() == 0 || !print_path) {
snprintf(out_buf, out_buf_size, "file %" PRIu64, file->fd.GetNumber());
} else {
snprintf(out_buf, out_buf_size, "file %" PRIu64
"(path "
"%" PRIu32 ")",
file->fd.GetNumber(), file->fd.GetPathId());
}
} else {
snprintf(out_buf, out_buf_size, "level %d", level);
}
}
void UniversalCompactionBuilder::SortedRun::DumpSizeInfo(
char* out_buf, size_t out_buf_size, size_t sorted_run_count) const {
if (level == 0) {
assert(file != nullptr);
snprintf(out_buf, out_buf_size,
"file %" PRIu64 "[%" ROCKSDB_PRIszt
"] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")",
file->fd.GetNumber(), sorted_run_count, file->fd.GetFileSize(),
file->compensated_file_size);
} else {
snprintf(out_buf, out_buf_size,
"level %d[%" ROCKSDB_PRIszt
"] "
"with size %" PRIu64 " (compensated size %" PRIu64 ")",
level, sorted_run_count, size, compensated_file_size);
}
}
std::vector<UniversalCompactionBuilder::SortedRun>
UniversalCompactionBuilder::CalculateSortedRuns(
const VersionStorageInfo& vstorage, const ImmutableCFOptions& /*ioptions*/,
const MutableCFOptions& mutable_cf_options) {
std::vector<UniversalCompactionBuilder::SortedRun> ret;
for (FileMetaData* f : vstorage.LevelFiles(0)) {
ret.emplace_back(0, f, f->fd.GetFileSize(), f->compensated_file_size,
f->being_compacted);
}
for (int level = 1; level < vstorage.num_levels(); level++) {
uint64_t total_compensated_size = 0U;
uint64_t total_size = 0U;
bool being_compacted = false;
bool is_first = true;
for (FileMetaData* f : vstorage.LevelFiles(level)) {
total_compensated_size += f->compensated_file_size;
total_size += f->fd.GetFileSize();
if (mutable_cf_options.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
// mutable_cf_options.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;
}
// Universal style of compaction. Pick files that are contiguous in
// time-range to compact.
Compaction* UniversalCompactionBuilder::PickCompaction() {
const int kLevel0 = 0;
score_ = vstorage_->CompactionScore(kLevel0);
sorted_runs_ =
CalculateSortedRuns(*vstorage_, ioptions_, mutable_cf_options_);
if (sorted_runs_.size() == 0 ||
(vstorage_->FilesMarkedForPeriodicCompaction().empty() &&
vstorage_->FilesMarkedForCompaction().empty() &&
sorted_runs_.size() < (unsigned int)mutable_cf_options_
.level0_file_num_compaction_trigger)) {
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: nothing to do\n",
cf_name_.c_str());
TEST_SYNC_POINT_CALLBACK(
"UniversalCompactionBuilder::PickCompaction:Return", nullptr);
return nullptr;
}
VersionStorageInfo::LevelSummaryStorage tmp;
ROCKS_LOG_BUFFER_MAX_SZ(
log_buffer_, 3072,
"[%s] Universal: sorted runs files(%" ROCKSDB_PRIszt "): %s\n",
cf_name_.c_str(), sorted_runs_.size(), vstorage_->LevelSummary(&tmp));
Compaction* c = nullptr;
// Periodic compaction has higher priority than other type of compaction
// because it's a hard requirement.
if (!vstorage_->FilesMarkedForPeriodicCompaction().empty()) {
// Always need to do a full compaction for periodic compaction.
c = PickPeriodicCompaction();
}
// Check for size amplification.
if (c == nullptr &&
sorted_runs_.size() >=
static_cast<size_t>(
mutable_cf_options_.level0_file_num_compaction_trigger)) {
if ((c = PickCompactionToReduceSizeAmp()) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: compacting for size amp\n",
cf_name_.c_str());
} else {
// Size amplification is within limits. Try reducing read
// amplification while maintaining file size ratios.
unsigned int ratio =
mutable_cf_options_.compaction_options_universal.size_ratio;
if ((c = PickCompactionToReduceSortedRuns(ratio, UINT_MAX)) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: compacting for size ratio\n",
cf_name_.c_str());
} else {
// Size amplification and file size ratios are within configured limits.
// If max read amplification is exceeding configured limits, then force
// compaction without looking at filesize ratios and try to reduce
// the number of files to fewer than level0_file_num_compaction_trigger.
// This is guaranteed by NeedsCompaction()
assert(sorted_runs_.size() >=
static_cast<size_t>(
mutable_cf_options_.level0_file_num_compaction_trigger));
// Get the total number of sorted runs that are not being compacted
int num_sr_not_compacted = 0;
for (size_t i = 0; i < sorted_runs_.size(); i++) {
if (sorted_runs_[i].being_compacted == false) {
num_sr_not_compacted++;
}
}
// The number of sorted runs that are not being compacted is greater
// than the maximum allowed number of sorted runs
if (num_sr_not_compacted >
mutable_cf_options_.level0_file_num_compaction_trigger) {
unsigned int num_files =
num_sr_not_compacted -
mutable_cf_options_.level0_file_num_compaction_trigger + 1;
if ((c = PickCompactionToReduceSortedRuns(UINT_MAX, num_files)) !=
nullptr) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: compacting for file num -- %u\n",
cf_name_.c_str(), num_files);
}
}
}
}
}
if (c == nullptr) {
if ((c = PickDeleteTriggeredCompaction()) != nullptr) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: delete triggered compaction\n",
cf_name_.c_str());
}
}
if (c == nullptr) {
TEST_SYNC_POINT_CALLBACK(
"UniversalCompactionBuilder::PickCompaction:Return", nullptr);
return nullptr;
}
if (mutable_cf_options_.compaction_options_universal.allow_trivial_move ==
true &&
c->compaction_reason() != CompactionReason::kPeriodicCompaction) {
c->set_is_trivial_move(IsInputFilesNonOverlapping(c));
}
// validate that all the chosen files of L0 are non overlapping in time
#ifndef NDEBUG
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->fd.smallest_seqno <= f->fd.largest_seqno);
if (is_first) {
is_first = false;
}
prev_smallest_seqno = f->fd.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
RecordInHistogram(ioptions_.statistics, NUM_FILES_IN_SINGLE_COMPACTION,
c->inputs(0)->size());
picker_->RegisterCompaction(c);
vstorage_->ComputeCompactionScore(ioptions_, mutable_cf_options_);
TEST_SYNC_POINT_CALLBACK("UniversalCompactionBuilder::PickCompaction:Return",
c);
return c;
}
uint32_t UniversalCompactionBuilder::GetPathId(
const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options, uint64_t file_size) {
// Two conditions need to be satisfied:
// (1) the target path needs to be able to hold the file's size
// (2) Total size left in this and previous paths need to be not
// smaller than expected future file size before this new file is
// compacted, which is estimated based on size_ratio.
// For example, if now we are compacting files of size (1, 1, 2, 4, 8),
// we will make sure the target file, probably with size of 16, will be
// placed in a path so that eventually when new files are generated and
// compacted to (1, 1, 2, 4, 8, 16), all those files can be stored in or
// before the path we chose.
//
// TODO(sdong): now the case of multiple column families is not
// considered in this algorithm. So the target size can be violated in
// that case. We need to improve it.
uint64_t accumulated_size = 0;
uint64_t future_size =
file_size *
(100 - mutable_cf_options.compaction_options_universal.size_ratio) / 100;
uint32_t p = 0;
assert(!ioptions.cf_paths.empty());
for (; p < ioptions.cf_paths.size() - 1; p++) {
uint64_t target_size = ioptions.cf_paths[p].target_size;
if (target_size > file_size &&
accumulated_size + (target_size - file_size) > future_size) {
return p;
}
accumulated_size += target_size;
}
return p;
}
//
// Consider compaction files based on their size differences with
// the next file in time order.
//
Compaction* UniversalCompactionBuilder::PickCompactionToReduceSortedRuns(
unsigned int ratio, unsigned int max_number_of_files_to_compact) {
unsigned int min_merge_width =
mutable_cf_options_.compaction_options_universal.min_merge_width;
unsigned int max_merge_width =
mutable_cf_options_.compaction_options_universal.max_merge_width;
const SortedRun* sr = nullptr;
bool done = false;
size_t start_index = 0;
unsigned int candidate_count = 0;
unsigned int max_files_to_compact =
std::min(max_merge_width, max_number_of_files_to_compact);
min_merge_width = std::max(min_merge_width, 2U);
// Caller checks the size before executing this function. This invariant is
// important because otherwise we may have a possible integer underflow when
// dealing with unsigned types.
assert(sorted_runs_.size() > 0);
// Considers a candidate file only if it is smaller than the
// total size accumulated so far.
for (size_t loop = 0; loop < sorted_runs_.size(); loop++) {
candidate_count = 0;
// Skip files that are already being compacted
for (sr = nullptr; loop < sorted_runs_.size(); loop++) {
sr = &sorted_runs_[loop];
if (!sr->being_compacted) {
candidate_count = 1;
break;
}
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf));
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: %s"
"[%d] being compacted, skipping",
cf_name_.c_str(), file_num_buf, loop);
sr = nullptr;
}
// This file is not being compacted. Consider it as the
// first candidate to be compacted.
uint64_t candidate_size = sr != nullptr ? sr->compensated_file_size : 0;
if (sr != nullptr) {
char file_num_buf[kFormatFileNumberBufSize];
sr->Dump(file_num_buf, sizeof(file_num_buf), true);
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: Possible candidate %s[%d].",
cf_name_.c_str(), file_num_buf, loop);
}
// Check if the succeeding files need compaction.
for (size_t i = loop + 1;
candidate_count < max_files_to_compact && i < sorted_runs_.size();
i++) {
const SortedRun* succeeding_sr = &sorted_runs_[i];
if (succeeding_sr->being_compacted) {
break;
}
// Pick files if the total/last candidate file size (increased by the
// specified ratio) is still larger than the next candidate file.
// candidate_size is the total size of files picked so far with the
// default kCompactionStopStyleTotalSize; with
// kCompactionStopStyleSimilarSize, it's simply the size of the last
// picked file.
double sz = candidate_size * (100.0 + ratio) / 100.0;
if (sz < static_cast<double>(succeeding_sr->size)) {
break;
}
if (mutable_cf_options_.compaction_options_universal.stop_style ==
kCompactionStopStyleSimilarSize) {
// Similar-size stopping rule: also check the last picked file isn't
// far larger than the next candidate file.
sz = (succeeding_sr->size * (100.0 + ratio)) / 100.0;
if (sz < static_cast<double>(candidate_size)) {
// If the small file we've encountered begins a run of similar-size
// files, we'll pick them up on a future iteration of the outer
// loop. If it's some lonely straggler, it'll eventually get picked
// by the last-resort read amp strategy which disregards size ratios.
break;
}
candidate_size = succeeding_sr->compensated_file_size;
} else { // default kCompactionStopStyleTotalSize
candidate_size += succeeding_sr->compensated_file_size;
}
candidate_count++;
}
// Found a series of consecutive files that need compaction.
if (candidate_count >= (unsigned int)min_merge_width) {
start_index = loop;
done = true;
break;
} else {
for (size_t i = loop;
i < loop + candidate_count && i < sorted_runs_.size(); i++) {
const SortedRun* skipping_sr = &sorted_runs_[i];
char file_num_buf[256];
skipping_sr->DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: Skipping %s",
cf_name_.c_str(), file_num_buf);
}
}
}
if (!done || candidate_count <= 1) {
return nullptr;
}
size_t first_index_after = start_index + candidate_count;
// Compression is enabled if files compacted earlier already reached
// size ratio of compression.
bool enable_compression = true;
int ratio_to_compress =
mutable_cf_options_.compaction_options_universal.compression_size_percent;
if (ratio_to_compress >= 0) {
uint64_t total_size = 0;
for (auto& sorted_run : sorted_runs_) {
total_size += sorted_run.compensated_file_size;
}
uint64_t older_file_size = 0;
for (size_t i = sorted_runs_.size() - 1; i >= first_index_after; i--) {
older_file_size += sorted_runs_[i].size;
if (older_file_size * 100L >= total_size * (long)ratio_to_compress) {
enable_compression = false;
break;
}
}
}
uint64_t estimated_total_size = 0;
for (unsigned int i = 0; i < first_index_after; i++) {
estimated_total_size += sorted_runs_[i].size;
}
uint32_t path_id =
GetPathId(ioptions_, mutable_cf_options_, estimated_total_size);
int start_level = sorted_runs_[start_index].level;
int output_level;
if (first_index_after == sorted_runs_.size()) {
output_level = vstorage_->num_levels() - 1;
} else if (sorted_runs_[first_index_after].level == 0) {
output_level = 0;
} else {
output_level = sorted_runs_[first_index_after].level - 1;
}
// last level is reserved for the files ingested behind
if (ioptions_.allow_ingest_behind &&
(output_level == vstorage_->num_levels() - 1)) {
assert(output_level > 1);
output_level--;
}
std::vector<CompactionInputFiles> inputs(vstorage_->num_levels());
for (size_t i = 0; i < inputs.size(); ++i) {
inputs[i].level = start_level + static_cast<int>(i);
}
for (size_t i = start_index; i < first_index_after; i++) {
auto& picking_sr = sorted_runs_[i];
if (picking_sr.level == 0) {
FileMetaData* picking_file = picking_sr.file;
inputs[0].files.push_back(picking_file);
} else {
auto& files = inputs[picking_sr.level - start_level].files;
for (auto* f : vstorage_->LevelFiles(picking_sr.level)) {
files.push_back(f);
}
}
char file_num_buf[256];
picking_sr.DumpSizeInfo(file_num_buf, sizeof(file_num_buf), i);
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: Picking %s",
cf_name_.c_str(), file_num_buf);
}
CompactionReason compaction_reason;
if (max_number_of_files_to_compact == UINT_MAX) {
compaction_reason = CompactionReason::kUniversalSizeRatio;
} else {
compaction_reason = CompactionReason::kUniversalSortedRunNum;
}
return new Compaction(
vstorage_, ioptions_, mutable_cf_options_, std::move(inputs),
output_level,
MaxFileSizeForLevel(mutable_cf_options_, output_level,
kCompactionStyleUniversal),
LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage_, mutable_cf_options_, start_level,
1, enable_compression),
GetCompressionOptions(ioptions_, vstorage_, start_level,
enable_compression),
/* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
score_, false /* deletion_compaction */, compaction_reason);
}
// Look at overall size amplification. If size amplification
// 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* UniversalCompactionBuilder::PickCompactionToReduceSizeAmp() {
// percentage flexibility while reducing size amplification
uint64_t ratio = mutable_cf_options_.compaction_options_universal
.max_size_amplification_percent;
unsigned int candidate_count = 0;
uint64_t candidate_size = 0;
size_t start_index = 0;
const SortedRun* sr = nullptr;
assert(!sorted_runs_.empty());
if (sorted_runs_.back().being_compacted) {
return nullptr;
}
// Skip files that are already being compacted
for (size_t loop = 0; loop < 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);
}
return PickCompactionToOldest(start_index,
CompactionReason::kUniversalSizeAmplification);
}
// Pick files marked for compaction. Typically, files are marked by
// CompactOnDeleteCollector due to the presence of tombstones.
Compaction* UniversalCompactionBuilder::PickDeleteTriggeredCompaction() {
CompactionInputFiles start_level_inputs;
int output_level;
std::vector<CompactionInputFiles> inputs;
if (vstorage_->num_levels() == 1) {
// This is single level universal. Since we're basically trying to reclaim
// space by processing files marked for compaction due to high tombstone
// density, let's do the same thing as compaction to reduce size amp which
// has the same goals.
bool compact = false;
start_level_inputs.level = 0;
start_level_inputs.files.clear();
output_level = 0;
for (FileMetaData* f : vstorage_->LevelFiles(0)) {
if (f->marked_for_compaction) {
compact = true;
}
if (compact) {
start_level_inputs.files.push_back(f);
}
}
if (start_level_inputs.size() <= 1) {
// If only the last file in L0 is marked for compaction, ignore it
return nullptr;
}
inputs.push_back(start_level_inputs);
} else {
int start_level;
// For multi-level universal, the strategy is to make this look more like
// leveled. We pick one of the files marked for compaction and compact with
// overlapping files in the adjacent level.
picker_->PickFilesMarkedForCompaction(cf_name_, vstorage_, &start_level,
&output_level, &start_level_inputs);
if (start_level_inputs.empty()) {
return nullptr;
}
// Pick the first non-empty level after the start_level
for (output_level = start_level + 1; output_level < vstorage_->num_levels();
output_level++) {
if (vstorage_->NumLevelFiles(output_level) != 0) {
break;
}
}
// If all higher levels are empty, pick the highest level as output level
if (output_level == vstorage_->num_levels()) {
if (start_level == 0) {
output_level = vstorage_->num_levels() - 1;
} else {
// If start level is non-zero and all higher levels are empty, this
// compaction will translate into a trivial move. Since the idea is
// to reclaim space and trivial move doesn't help with that, we
// skip compaction in this case and return nullptr
return nullptr;
}
}
if (ioptions_.allow_ingest_behind &&
output_level == vstorage_->num_levels() - 1) {
assert(output_level > 1);
output_level--;
}
if (output_level != 0) {
if (start_level == 0) {
if (!picker_->GetOverlappingL0Files(vstorage_, &start_level_inputs,
output_level, nullptr)) {
return nullptr;
}
}
CompactionInputFiles output_level_inputs;
int parent_index = -1;
output_level_inputs.level = output_level;
if (!picker_->SetupOtherInputs(cf_name_, mutable_cf_options_, vstorage_,
&start_level_inputs, &output_level_inputs,
&parent_index, -1)) {
return nullptr;
}
inputs.push_back(start_level_inputs);
if (!output_level_inputs.empty()) {
inputs.push_back(output_level_inputs);
}
if (picker_->FilesRangeOverlapWithCompaction(inputs, output_level)) {
return nullptr;
}
} else {
inputs.push_back(start_level_inputs);
}
}
uint64_t estimated_total_size = 0;
// Use size of the output level as estimated file size
for (FileMetaData* f : vstorage_->LevelFiles(output_level)) {
estimated_total_size += f->fd.GetFileSize();
}
uint32_t path_id =
GetPathId(ioptions_, mutable_cf_options_, estimated_total_size);
return new Compaction(
vstorage_, ioptions_, mutable_cf_options_, std::move(inputs),
output_level,
MaxFileSizeForLevel(mutable_cf_options_, output_level,
kCompactionStyleUniversal),
/* max_grandparent_overlap_bytes */ LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
output_level, 1),
GetCompressionOptions(ioptions_, vstorage_, output_level),
/* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ true,
score_, false /* deletion_compaction */,
CompactionReason::kFilesMarkedForCompaction);
}
Compaction* UniversalCompactionBuilder::PickCompactionToOldest(
size_t start_index, CompactionReason compaction_reason) {
assert(start_index < sorted_runs_.size());
// Estimate total file size
uint64_t estimated_total_size = 0;
for (size_t loop = start_index; loop < sorted_runs_.size(); loop++) {
estimated_total_size += sorted_runs_[loop].size;
}
uint32_t path_id =
GetPathId(ioptions_, mutable_cf_options_, estimated_total_size);
int start_level = sorted_runs_[start_index].level;
std::vector<CompactionInputFiles> inputs(vstorage_->num_levels());
for (size_t i = 0; i < inputs.size(); ++i) {
inputs[i].level = start_level + static_cast<int>(i);
}
for (size_t loop = start_index; loop < sorted_runs_.size(); loop++) {
auto& picking_sr = sorted_runs_[loop];
if (picking_sr.level == 0) {
FileMetaData* f = picking_sr.file;
inputs[0].files.push_back(f);
} else {
auto& files = inputs[picking_sr.level - start_level].files;
for (auto* f : vstorage_->LevelFiles(picking_sr.level)) {
files.push_back(f);
}
}
std::string comp_reason_print_string;
if (compaction_reason == CompactionReason::kPeriodicCompaction) {
comp_reason_print_string = "periodic compaction";
} else if (compaction_reason ==
CompactionReason::kUniversalSizeAmplification) {
comp_reason_print_string = "size amp";
} else {
assert(false);
}
char file_num_buf[256];
picking_sr.DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: %s picking %s",
cf_name_.c_str(), comp_reason_print_string.c_str(),
file_num_buf);
}
// output files at the bottom most level, unless it's reserved
int output_level = vstorage_->num_levels() - 1;
// last level is reserved for the files ingested behind
if (ioptions_.allow_ingest_behind) {
assert(output_level > 1);
output_level--;
}
// We never check size for
// compaction_options_universal.compression_size_percent,
// because we always compact all the files, so always compress.
return new Compaction(
vstorage_, ioptions_, mutable_cf_options_, std::move(inputs),
output_level,
MaxFileSizeForLevel(mutable_cf_options_, output_level,
kCompactionStyleUniversal),
LLONG_MAX, path_id,
GetCompressionType(ioptions_, vstorage_, mutable_cf_options_, start_level,
1, true /* enable_compression */),
GetCompressionOptions(ioptions_, vstorage_, start_level,
true /* enable_compression */),
/* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
score_, false /* deletion_compaction */, compaction_reason);
}
Compaction* UniversalCompactionBuilder::PickPeriodicCompaction() {
ROCKS_LOG_BUFFER(log_buffer_, "[%s] Universal: Periodic Compaction",
cf_name_.c_str());
// In universal compaction, sorted runs contain older data are almost always
// generated earlier too. To simplify the problem, we just try to trigger
// a full compaction. We start from the oldest sorted run and include
// all sorted runs, until we hit a sorted already being compacted.
// Since usually the largest (which is usually the oldest) sorted run is
// included anyway, doing a full compaction won't increase write
// amplification much.
// Get some information from marked files to check whether a file is
// included in the compaction.
size_t start_index = sorted_runs_.size();
while (start_index > 0 && !sorted_runs_[start_index - 1].being_compacted) {
start_index--;
}
if (start_index == sorted_runs_.size()) {
return nullptr;
}
// There is a rare corner case where we can't pick up all the files
// because some files are being compacted and we end up with picking files
// but none of them need periodic compaction. Unless we simply recompact
// the last sorted run (either the last level or last L0 file), we would just
// execute the compaction, in order to simplify the logic.
if (start_index == sorted_runs_.size() - 1) {
bool included_file_marked = false;
int start_level = sorted_runs_[start_index].level;
FileMetaData* start_file = sorted_runs_[start_index].file;
for (const std::pair<int, FileMetaData*>& level_file_pair :
vstorage_->FilesMarkedForPeriodicCompaction()) {
if (start_level != 0) {
// Last sorted run is a level
if (start_level == level_file_pair.first) {
included_file_marked = true;
break;
}
} else {
// Last sorted run is a L0 file.
if (start_file == level_file_pair.second) {
included_file_marked = true;
break;
}
}
}
if (!included_file_marked) {
ROCKS_LOG_BUFFER(log_buffer_,
"[%s] Universal: Cannot form a compaction covering file "
"marked for periodic compaction",
cf_name_.c_str());
return nullptr;
}
}
Compaction* c = PickCompactionToOldest(start_index,
CompactionReason::kPeriodicCompaction);
TEST_SYNC_POINT_CALLBACK(
"UniversalCompactionPicker::PickPeriodicCompaction:Return", c);
return c;
}
} // namespace ROCKSDB_NAMESPACE
#endif // !ROCKSDB_LITE