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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.
#pragma once
#include "db/version_set.h"
#include "options/cf_options.h"
#include "util/arena.h"
#include "util/autovector.h"
namespace rocksdb {
// The structure that manages compaction input files associated
// with the same physical level.
struct CompactionInputFiles {
int level;
std::vector<FileMetaData*> files;
inline bool empty() const { return files.empty(); }
inline size_t size() const { return files.size(); }
inline void clear() { files.clear(); }
inline FileMetaData* operator[](size_t i) const { return files[i]; }
class Version;
class ColumnFamilyData;
class VersionStorageInfo;
class CompactionFilter;
// A Compaction encapsulates information about a compaction.
class Compaction {
Compaction(VersionStorageInfo* input_version,
const ImmutableCFOptions& immutable_cf_options,
const MutableCFOptions& mutable_cf_options,
std::vector<CompactionInputFiles> inputs, int output_level,
uint64_t target_file_size, uint64_t max_compaction_bytes,
uint32_t output_path_id, CompressionType compression,
std::vector<FileMetaData*> grandparents,
bool manual_compaction = false, double score = -1,
bool deletion_compaction = false,
CompactionReason compaction_reason = CompactionReason::kUnknown);
// No copying allowed
Compaction(const Compaction&) = delete;
void operator=(const Compaction&) = delete;
// Returns the level associated to the specified compaction input level.
// If compaction_input_level is not specified, then input_level is set to 0.
int level(size_t compaction_input_level = 0) const {
return inputs_[compaction_input_level].level;
int start_level() const { return start_level_; }
// Outputs will go to this level
int output_level() const { return output_level_; }
// Returns the number of input levels in this compaction.
size_t num_input_levels() const { return inputs_.size(); }
// Return the object that holds the edits to the descriptor done
// by this compaction.
VersionEdit* edit() { return &edit_; }
// Returns the number of input files associated to the specified
// compaction input level.
// The function will return 0 if when "compaction_input_level" < 0
// or "compaction_input_level" >= "num_input_levels()".
size_t num_input_files(size_t compaction_input_level) const {
if (compaction_input_level < inputs_.size()) {
return inputs_[compaction_input_level].size();
return 0;
// Returns input version of the compaction
Version* input_version() const { return input_version_; }
// Returns the ColumnFamilyData associated with the compaction.
ColumnFamilyData* column_family_data() const { return cfd_; }
// Returns the file meta data of the 'i'th input file at the
// specified compaction input level.
// REQUIREMENT: "compaction_input_level" must be >= 0 and
// < "input_levels()"
FileMetaData* input(size_t compaction_input_level, size_t i) const {
assert(compaction_input_level < inputs_.size());
return inputs_[compaction_input_level][i];
// Returns the list of file meta data of the specified compaction
// input level.
// REQUIREMENT: "compaction_input_level" must be >= 0 and
// < "input_levels()"
const std::vector<FileMetaData*>* inputs(
size_t compaction_input_level) const {
assert(compaction_input_level < inputs_.size());
return &inputs_[compaction_input_level].files;
const std::vector<CompactionInputFiles>* inputs() { return &inputs_; }
// Returns the LevelFilesBrief of the specified compaction input level.
const LevelFilesBrief* input_levels(size_t compaction_input_level) const {
return &input_levels_[compaction_input_level];
// Maximum size of files to build during this compaction.
uint64_t max_output_file_size() const { return max_output_file_size_; }
// What compression for output
CompressionType output_compression() const { return output_compression_; }
// Whether need to write output file to second DB path.
uint32_t output_path_id() const { return output_path_id_; }
// Is this a trivial compaction that can be implemented by just
// moving a single input file to the next level (no merging or splitting)
bool IsTrivialMove() const;
// If true, then the compaction can be done by simply deleting input files.
bool deletion_compaction() const { return deletion_compaction_; }
// Add all inputs to this compaction as delete operations to *edit.
void AddInputDeletions(VersionEdit* edit);
// Returns true if the available information we have guarantees that
// the input "user_key" does not exist in any level beyond "output_level()".
bool KeyNotExistsBeyondOutputLevel(const Slice& user_key,
std::vector<size_t>* level_ptrs) const;
// Clear all files to indicate that they are not being compacted
// Delete this compaction from the list of running compactions.
// Requirement: DB mutex held
void ReleaseCompactionFiles(Status status);
// Returns the summary of the compaction in "output" with maximum "len"
// in bytes. The caller is responsible for the memory management of
// "output".
void Summary(char* output, int len);
// Return the score that was used to pick this compaction run.
double score() const { return score_; }
// Is this compaction creating a file in the bottom most level?
bool bottommost_level() const { return bottommost_level_; }
// Does this compaction include all sst files?
bool is_full_compaction() const { return is_full_compaction_; }
// Was this compaction triggered manually by the client?
bool is_manual_compaction() const { return is_manual_compaction_; }
// Used when allow_trivial_move option is set in
// Universal compaction. If all the input files are
// non overlapping, then is_trivial_move_ variable
// will be set true, else false
void set_is_trivial_move(bool trivial_move) {
is_trivial_move_ = trivial_move;
// Used when allow_trivial_move option is set in
// Universal compaction. Returns true, if the input files
// are non-overlapping and can be trivially moved.
bool is_trivial_move() const { return is_trivial_move_; }
// How many total levels are there?
int number_levels() const { return number_levels_; }
// Return the ImmutableCFOptions that should be used throughout the compaction
// procedure
const ImmutableCFOptions* immutable_cf_options() const {
return &immutable_cf_options_;
// Return the MutableCFOptions that should be used throughout the compaction
// procedure
const MutableCFOptions* mutable_cf_options() const {
return &mutable_cf_options_;
// Returns the size in bytes that the output file should be preallocated to.
// In level compaction, that is max_file_size_. In universal compaction, that
// is the sum of all input file sizes.
uint64_t OutputFilePreallocationSize() const;
void SetInputVersion(Version* input_version);
struct InputLevelSummaryBuffer {
char buffer[128];
const char* InputLevelSummary(InputLevelSummaryBuffer* scratch) const;
uint64_t CalculateTotalInputSize() const;
// In case of compaction error, reset the nextIndex that is used
// to pick up the next file to be compacted from files_by_size_
void ResetNextCompactionIndex();
// Create a CompactionFilter from compaction_filter_factory
std::unique_ptr<CompactionFilter> CreateCompactionFilter() const;
// Is the input level corresponding to output_level_ empty?
bool IsOutputLevelEmpty() const;
// Should this compaction be broken up into smaller ones run in parallel?
bool ShouldFormSubcompactions() const;
// test function to validate the functionality of IsBottommostLevel()
// function -- determines if compaction with inputs and storage is bottommost
static bool TEST_IsBottommostLevel(
int output_level, VersionStorageInfo* vstorage,
const std::vector<CompactionInputFiles>& inputs);
TablePropertiesCollection GetOutputTableProperties() const {
return output_table_properties_;
void SetOutputTableProperties(TablePropertiesCollection tp) {
output_table_properties_ = std::move(tp);
Slice GetSmallestUserKey() const { return smallest_user_key_; }
Slice GetLargestUserKey() const { return largest_user_key_; }
CompactionReason compaction_reason() { return compaction_reason_; }
const std::vector<FileMetaData*>& grandparents() const {
return grandparents_;
uint64_t max_compaction_bytes() const { return max_compaction_bytes_; }
uint64_t MaxInputFileCreationTime() const;
// mark (or clear) all files that are being compacted
void MarkFilesBeingCompacted(bool mark_as_compacted);
// get the smallest and largest key present in files to be compacted
static void GetBoundaryKeys(VersionStorageInfo* vstorage,
const std::vector<CompactionInputFiles>& inputs,
Slice* smallest_key, Slice* largest_key);
// helper function to determine if compaction with inputs and storage is
// bottommost
static bool IsBottommostLevel(
int output_level, VersionStorageInfo* vstorage,
const std::vector<CompactionInputFiles>& inputs);
static bool IsFullCompaction(VersionStorageInfo* vstorage,
const std::vector<CompactionInputFiles>& inputs);
VersionStorageInfo* input_vstorage_;
const int start_level_; // the lowest level to be compacted
const int output_level_; // levels to which output files are stored
uint64_t max_output_file_size_;
uint64_t max_compaction_bytes_;
const ImmutableCFOptions immutable_cf_options_;
const MutableCFOptions mutable_cf_options_;
Version* input_version_;
VersionEdit edit_;
const int number_levels_;
ColumnFamilyData* cfd_;
Arena arena_; // Arena used to allocate space for file_levels_
const uint32_t output_path_id_;
CompressionType output_compression_;
// If true, then the comaction can be done by simply deleting input files.
const bool deletion_compaction_;
// Compaction input files organized by level. Constant after construction
const std::vector<CompactionInputFiles> inputs_;
// A copy of inputs_, organized more closely in memory
autovector<LevelFilesBrief, 2> input_levels_;
// State used to check for number of overlapping grandparent files
// (grandparent == "output_level_ + 1")
std::vector<FileMetaData*> grandparents_;
const double score_; // score that was used to pick this compaction.
// Is this compaction creating a file in the bottom most level?
const bool bottommost_level_;
// Does this compaction include all sst files?
const bool is_full_compaction_;
// Is this compaction requested by the client?
const bool is_manual_compaction_;
// True if we can do trivial move in Universal multi level
// compaction
bool is_trivial_move_;
// Does input compression match the output compression?
bool InputCompressionMatchesOutput() const;
// table properties of output files
TablePropertiesCollection output_table_properties_;
// smallest user keys in compaction
Slice smallest_user_key_;
// largest user keys in compaction
Slice largest_user_key_;
// Reason for compaction
CompactionReason compaction_reason_;
// Utility function
extern uint64_t TotalFileSize(const std::vector<FileMetaData*>& files);
} // namespace rocksdb