rocksdb/db/compaction_picker.h
Yueh-Hsuan Chiang 28c82ff1b3 CompactFiles, EventListener and GetDatabaseMetaData
Summary:
This diff adds three sets of APIs to RocksDB.

= GetColumnFamilyMetaData =
* This APIs allow users to obtain the current state of a RocksDB instance on one column family.
* See GetColumnFamilyMetaData in include/rocksdb/db.h

= EventListener =
* A virtual class that allows users to implement a set of
  call-back functions which will be called when specific
  events of a RocksDB instance happens.
* To register EventListener, simply insert an EventListener to ColumnFamilyOptions::listeners

= CompactFiles =
* CompactFiles API inputs a set of file numbers and an output level, and RocksDB
  will try to compact those files into the specified level.

= Example =
* Example code can be found in example/compact_files_example.cc, which implements
  a simple external compactor using EventListener, GetColumnFamilyMetaData, and
  CompactFiles API.

Test Plan:
listener_test
compactor_test
example/compact_files_example
export ROCKSDB_TESTS=CompactFiles
db_test
export ROCKSDB_TESTS=MetaData
db_test

Reviewers: ljin, igor, rven, sdong

Reviewed By: sdong

Subscribers: MarkCallaghan, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D24705
2014-11-07 14:45:18 -08:00

294 lines
12 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <vector>
#include <memory>
#include <set>
#include <unordered_set>
#include "db/version_set.h"
#include "db/compaction.h"
#include "rocksdb/status.h"
#include "rocksdb/options.h"
#include "rocksdb/env.h"
#include "util/mutable_cf_options.h"
#include <vector>
#include <memory>
#include <set>
#include <string>
namespace rocksdb {
class LogBuffer;
class Compaction;
class VersionStorageInfo;
struct CompactionInputFiles;
class CompactionPicker {
public:
CompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp);
virtual ~CompactionPicker();
// Pick level and inputs for a new compaction.
// Returns nullptr if there is no compaction to be done.
// Otherwise returns a pointer to a heap-allocated object that
// describes the compaction. Caller should delete the result.
virtual Compaction* PickCompaction(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage,
LogBuffer* log_buffer) = 0;
// Return a compaction object for compacting the range [begin,end] in
// the specified level. Returns nullptr if there is nothing in that
// level that overlaps the specified range. Caller should delete
// the result.
//
// The returned Compaction might not include the whole requested range.
// In that case, compaction_end will be set to the next key that needs
// compacting. In case the compaction will compact the whole range,
// compaction_end will be set to nullptr.
// Client is responsible for compaction_end storage -- when called,
// *compaction_end should point to valid InternalKey!
virtual Compaction* 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);
// Given the current number of levels, returns the lowest allowed level
// for compaction input.
virtual int MaxInputLevel(int current_num_levels) const = 0;
// The maximum allowed output level. Default value is NumberLevels() - 1.
virtual int MaxOutputLevel() const {
return NumberLevels() - 1;
}
// Sanitize the input set of compaction input files.
// When the input parameters do not describe a valid compaction, the
// function will try to fix the input_files by adding necessary
// files. If it's not possible to conver an invalid input_files
// into a valid one by adding more files, the function will return a
// non-ok status with specific reason.
Status SanitizeCompactionInputFiles(
std::unordered_set<uint64_t>* input_files,
const ColumnFamilyMetaData& cf_meta,
const int output_level) const;
// Free up the files that participated in a compaction
void ReleaseCompactionFiles(Compaction* c, Status status);
// Return the total amount of data that is undergoing
// compactions per level
void SizeBeingCompacted(std::vector<uint64_t>& sizes);
// Returns true if any one of the specified files are being compacted
bool FilesInCompaction(const std::vector<FileMetaData*>& files);
// Takes a list of CompactionInputFiles and returns a Compaction object.
Compaction* FormCompaction(
const CompactionOptions& compact_options,
const autovector<CompactionInputFiles>& input_files,
int output_level, VersionStorageInfo* vstorage,
const MutableCFOptions& mutable_cf_options) const;
// Converts a set of compaction input file numbers into
// a list of CompactionInputFiles.
Status GetCompactionInputsFromFileNumbers(
autovector<CompactionInputFiles>* input_files,
std::unordered_set<uint64_t>* input_set,
const VersionStorageInfo* vstorage,
const CompactionOptions& compact_options) const;
protected:
int NumberLevels() const { return ioptions_.num_levels; }
// Stores the minimal range that covers all entries in inputs in
// *smallest, *largest.
// REQUIRES: inputs is not empty
void GetRange(const std::vector<FileMetaData*>& inputs, InternalKey* smallest,
InternalKey* largest);
// Stores the minimal range that covers all entries in inputs1 and inputs2
// in *smallest, *largest.
// REQUIRES: inputs is not empty
void GetRange(const std::vector<FileMetaData*>& inputs1,
const std::vector<FileMetaData*>& inputs2,
InternalKey* smallest, InternalKey* largest);
// Add more files to the inputs on "level" to make sure that
// no newer version of a key is compacted to "level+1" while leaving an older
// version in a "level". Otherwise, any Get() will search "level" first,
// and will likely return an old/stale value for the key, since it always
// searches in increasing order of level to find the value. This could
// also scramble the order of merge operands. This function should be
// called any time a new Compaction is created, and its inputs_[0] are
// populated.
//
// Will return false if it is impossible to apply this compaction.
bool ExpandWhileOverlapping(const std::string& cf_name,
VersionStorageInfo* vstorage, Compaction* c);
// Returns true if any one of the parent files are being compacted
bool ParentRangeInCompaction(VersionStorageInfo* vstorage,
const InternalKey* smallest,
const InternalKey* largest, int level,
int* index);
void SetupOtherInputs(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, Compaction* c);
const ImmutableCFOptions& ioptions_;
// A helper function to SanitizeCompactionInputFiles() that
// sanitizes "input_files" by adding necessary files.
virtual Status SanitizeCompactionInputFilesForAllLevels(
std::unordered_set<uint64_t>* input_files,
const ColumnFamilyMetaData& cf_meta,
const int output_level) const;
// record all the ongoing compactions for all levels
std::vector<std::set<Compaction*>> compactions_in_progress_;
const InternalKeyComparator* const icmp_;
};
class UniversalCompactionPicker : public CompactionPicker {
public:
UniversalCompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp)
: CompactionPicker(ioptions, icmp) {}
virtual Compaction* PickCompaction(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage,
LogBuffer* log_buffer) override;
// The maxinum allowed input level. Always returns 0.
virtual int MaxInputLevel(int current_num_levels) const override {
return 0;
}
// The maximum allowed output level. Always returns 0.
virtual int MaxOutputLevel() const override {
return 0;
}
private:
// Pick Universal compaction to limit read amplification
Compaction* PickCompactionUniversalReadAmp(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, double score, unsigned int ratio,
unsigned int num_files, LogBuffer* log_buffer);
// Pick Universal compaction to limit space amplification.
Compaction* PickCompactionUniversalSizeAmp(
const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, double score, LogBuffer* log_buffer);
// Pick a path ID to place a newly generated file, with its estimated file
// size.
static uint32_t GetPathId(const ImmutableCFOptions& ioptions,
uint64_t file_size);
};
class LevelCompactionPicker : public CompactionPicker {
public:
LevelCompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp)
: CompactionPicker(ioptions, icmp) {}
virtual Compaction* PickCompaction(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage,
LogBuffer* log_buffer) override;
// Returns current_num_levels - 2, meaning the last level cannot be
// compaction input level.
virtual int MaxInputLevel(int current_num_levels) const override {
return current_num_levels - 2;
}
private:
// For the specfied level, pick a compaction.
// Returns nullptr if there is no compaction to be done.
// If level is 0 and there is already a compaction on that level, this
// function will return nullptr.
Compaction* PickCompactionBySize(const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage, int level,
double score);
};
class FIFOCompactionPicker : public CompactionPicker {
public:
FIFOCompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp)
: CompactionPicker(ioptions, icmp) {}
virtual Compaction* PickCompaction(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* version,
LogBuffer* log_buffer) override;
virtual Compaction* 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) override;
// The maxinum allowed input level. Always returns 0.
virtual int MaxInputLevel(int current_num_levels) const override {
return 0;
}
// The maximum allowed output level. Always returns 0.
virtual int MaxOutputLevel() const override {
return 0;
}
};
class NullCompactionPicker : public CompactionPicker {
public:
NullCompactionPicker(const ImmutableCFOptions& ioptions,
const InternalKeyComparator* icmp) :
CompactionPicker(ioptions, icmp) {}
virtual ~NullCompactionPicker() {}
// Always return "nullptr"
Compaction* PickCompaction(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
VersionStorageInfo* vstorage,
LogBuffer* log_buffer) override {
return nullptr;
}
// Always return "nullptr"
Compaction* 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) override {
return nullptr;
}
// Given the current number of levels, returns the highest allowed level
// for compaction input.
virtual int MaxInputLevel(int current_num_levels) const {
return current_num_levels - 2;
}
};
// Utility function
extern uint64_t TotalCompensatedFileSize(const std::vector<FileMetaData*>& files);
} // namespace rocksdb