rocksdb/db/compaction_picker.h

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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 <memory>
#include <set>
#include <string>
#include <unordered_set>
#include <vector>
#include "db/compaction.h"
#include "db/version_set.h"
#include "options/cf_options.h"
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/status.h"
namespace rocksdb {
// The file contains an abstract class CompactionPicker, and its two
// sub-classes LevelCompactionPicker and NullCompactionPicker, as
// well as some helper functions used by them.
class LogBuffer;
class Compaction;
class VersionStorageInfo;
struct CompactionInputFiles;
// An abstract class to pick compactions from an existing LSM-tree.
//
// Each compaction style inherits the class and implement the
// interface to form automatic compactions. If NeedCompaction() is true,
// then call PickCompaction() to find what files need to be compacted
// and where to put the output files.
//
// Non-virtual functions CompactRange() and CompactFiles() are used to
// pick files to compact based on users' DB::CompactRange() and
// DB::CompactFiles() requests, respectively. There is little
// compaction style specific logic for them.
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,
const CompactRangeOptions& compact_range_options,
const InternalKey* begin, const InternalKey* end,
InternalKey** compaction_end, bool* manual_conflict,
uint64_t max_file_num_to_ignore);
// The maximum allowed output level. Default value is NumberLevels() - 1.
virtual int MaxOutputLevel() const { return NumberLevels() - 1; }
virtual bool NeedsCompaction(const VersionStorageInfo* vstorage) const = 0;
// 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.
#ifndef ROCKSDB_LITE
Status SanitizeCompactionInputFiles(std::unordered_set<uint64_t>* input_files,
const ColumnFamilyMetaData& cf_meta,
const int output_level) const;
#endif // ROCKSDB_LITE
// Free up the files that participated in a compaction
//
// Requirement: DB mutex held
void ReleaseCompactionFiles(Compaction* c, Status status);
// Returns true if any one of the specified files are being compacted
bool AreFilesInCompaction(const std::vector<FileMetaData*>& files);
// Takes a list of CompactionInputFiles and returns a (manual) Compaction
// object.
//
// Caller must provide a set of input files that has been passed through
// `SanitizeCompactionInputFiles` earlier. The lock should not be released
// between that call and this one.
Compaction* CompactFiles(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);
// Converts a set of compaction input file numbers into
// a list of CompactionInputFiles.
Status GetCompactionInputsFromFileNumbers(
Make Compaction class easier to use Summary: The goal of this diff is to make Compaction class easier to use. This should also make new compaction algorithms easier to write (like CompactFiles from @yhchiang and dynamic leveled and multi-leveled universal from @sdong). Here are couple of things demonstrating that Compaction class is hard to use: 1. we have two constructors of Compaction class 2. there's this thing called grandparents_, but it appears to only be setup for leveled compaction and not compactfiles 3. it's easy to introduce a subtle and dangerous bug like this: D36225 4. SetupBottomMostLevel() is hard to understand and it shouldn't be. See this comment: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction.cc#L236-L241. It also made it harder for @yhchiang to write CompactFiles, as evidenced by this: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction_picker.cc#L204-L210 The problem is that we create Compaction object, which holds a lot of state, and then pass it around to some functions. After those functions are done mutating, then we call couple of functions on Compaction object, like SetupBottommostLevel() and MarkFilesBeingCompacted(). It is very hard to see what's happening with all that Compaction's state while it's travelling across different functions. If you're writing a new PickCompaction() function you need to try really hard to understand what are all the functions you need to run on Compaction object and what state you need to setup. My proposed solution is to make important parts of Compaction immutable after construction. PickCompaction() should calculate compaction inputs and then pass them onto Compaction object once they are finalized. That makes it easy to create a new compaction -- just provide all the parameters to the constructor and you're done. No need to call confusing functions after you created your object. This diff doesn't fully achieve that goal, but it comes pretty close. Here are some of the changes: * have one Compaction constructor instead of two. * inputs_ is constant after construction * MarkFilesBeingCompacted() is now private to Compaction class and automatically called on construction/destruction. * SetupBottommostLevel() is gone. Compaction figures it out on its own based on the input. * CompactionPicker's functions are not passing around Compaction object anymore. They are only passing around the state that they need. Test Plan: make check make asan_check make valgrind_check Reviewers: rven, anthony, sdong, yhchiang Reviewed By: yhchiang Subscribers: sdong, yhchiang, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D36687
2015-04-11 00:01:54 +02:00
std::vector<CompactionInputFiles>* input_files,
std::unordered_set<uint64_t>* input_set,
const VersionStorageInfo* vstorage,
const CompactionOptions& compact_options) const;
// Is there currently a compaction involving level 0 taking place
bool IsLevel0CompactionInProgress() const {
return !level0_compactions_in_progress_.empty();
}
// Return true if the passed key range overlap with a compaction output
// that is currently running.
bool RangeOverlapWithCompaction(const Slice& smallest_user_key,
const Slice& largest_user_key,
int level) const;
// Stores the minimal range that covers all entries in inputs in
// *smallest, *largest.
// REQUIRES: inputs is not empty
void GetRange(const CompactionInputFiles& inputs, InternalKey* smallest,
InternalKey* largest) const;
// Stores the minimal range that covers all entries in inputs1 and inputs2
// in *smallest, *largest.
// REQUIRES: inputs is not empty
void GetRange(const CompactionInputFiles& inputs1,
const CompactionInputFiles& inputs2, InternalKey* smallest,
InternalKey* largest) const;
// Stores the minimal range that covers all entries in inputs
// in *smallest, *largest.
// REQUIRES: inputs is not empty (at least on entry have one file)
void GetRange(const std::vector<CompactionInputFiles>& inputs,
InternalKey* smallest, InternalKey* largest) const;
int NumberLevels() const { return ioptions_.num_levels; }
// 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 ExpandInputsToCleanCut(const std::string& cf_name,
Make Compaction class easier to use Summary: The goal of this diff is to make Compaction class easier to use. This should also make new compaction algorithms easier to write (like CompactFiles from @yhchiang and dynamic leveled and multi-leveled universal from @sdong). Here are couple of things demonstrating that Compaction class is hard to use: 1. we have two constructors of Compaction class 2. there's this thing called grandparents_, but it appears to only be setup for leveled compaction and not compactfiles 3. it's easy to introduce a subtle and dangerous bug like this: D36225 4. SetupBottomMostLevel() is hard to understand and it shouldn't be. See this comment: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction.cc#L236-L241. It also made it harder for @yhchiang to write CompactFiles, as evidenced by this: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction_picker.cc#L204-L210 The problem is that we create Compaction object, which holds a lot of state, and then pass it around to some functions. After those functions are done mutating, then we call couple of functions on Compaction object, like SetupBottommostLevel() and MarkFilesBeingCompacted(). It is very hard to see what's happening with all that Compaction's state while it's travelling across different functions. If you're writing a new PickCompaction() function you need to try really hard to understand what are all the functions you need to run on Compaction object and what state you need to setup. My proposed solution is to make important parts of Compaction immutable after construction. PickCompaction() should calculate compaction inputs and then pass them onto Compaction object once they are finalized. That makes it easy to create a new compaction -- just provide all the parameters to the constructor and you're done. No need to call confusing functions after you created your object. This diff doesn't fully achieve that goal, but it comes pretty close. Here are some of the changes: * have one Compaction constructor instead of two. * inputs_ is constant after construction * MarkFilesBeingCompacted() is now private to Compaction class and automatically called on construction/destruction. * SetupBottommostLevel() is gone. Compaction figures it out on its own based on the input. * CompactionPicker's functions are not passing around Compaction object anymore. They are only passing around the state that they need. Test Plan: make check make asan_check make valgrind_check Reviewers: rven, anthony, sdong, yhchiang Reviewed By: yhchiang Subscribers: sdong, yhchiang, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D36687
2015-04-11 00:01:54 +02:00
VersionStorageInfo* vstorage,
CompactionInputFiles* inputs,
InternalKey** next_smallest = nullptr);
// Returns true if any one of the parent files are being compacted
bool IsRangeInCompaction(VersionStorageInfo* vstorage,
const InternalKey* smallest,
const InternalKey* largest, int level, int* index);
// Returns true if the key range that `inputs` files cover overlap with the
// key range of a currently running compaction.
bool FilesRangeOverlapWithCompaction(
const std::vector<CompactionInputFiles>& inputs, int level) const;
Make Compaction class easier to use Summary: The goal of this diff is to make Compaction class easier to use. This should also make new compaction algorithms easier to write (like CompactFiles from @yhchiang and dynamic leveled and multi-leveled universal from @sdong). Here are couple of things demonstrating that Compaction class is hard to use: 1. we have two constructors of Compaction class 2. there's this thing called grandparents_, but it appears to only be setup for leveled compaction and not compactfiles 3. it's easy to introduce a subtle and dangerous bug like this: D36225 4. SetupBottomMostLevel() is hard to understand and it shouldn't be. See this comment: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction.cc#L236-L241. It also made it harder for @yhchiang to write CompactFiles, as evidenced by this: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction_picker.cc#L204-L210 The problem is that we create Compaction object, which holds a lot of state, and then pass it around to some functions. After those functions are done mutating, then we call couple of functions on Compaction object, like SetupBottommostLevel() and MarkFilesBeingCompacted(). It is very hard to see what's happening with all that Compaction's state while it's travelling across different functions. If you're writing a new PickCompaction() function you need to try really hard to understand what are all the functions you need to run on Compaction object and what state you need to setup. My proposed solution is to make important parts of Compaction immutable after construction. PickCompaction() should calculate compaction inputs and then pass them onto Compaction object once they are finalized. That makes it easy to create a new compaction -- just provide all the parameters to the constructor and you're done. No need to call confusing functions after you created your object. This diff doesn't fully achieve that goal, but it comes pretty close. Here are some of the changes: * have one Compaction constructor instead of two. * inputs_ is constant after construction * MarkFilesBeingCompacted() is now private to Compaction class and automatically called on construction/destruction. * SetupBottommostLevel() is gone. Compaction figures it out on its own based on the input. * CompactionPicker's functions are not passing around Compaction object anymore. They are only passing around the state that they need. Test Plan: make check make asan_check make valgrind_check Reviewers: rven, anthony, sdong, yhchiang Reviewed By: yhchiang Subscribers: sdong, yhchiang, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D36687
2015-04-11 00:01:54 +02:00
bool SetupOtherInputs(const std::string& cf_name,
const MutableCFOptions& mutable_cf_options,
Make Compaction class easier to use Summary: The goal of this diff is to make Compaction class easier to use. This should also make new compaction algorithms easier to write (like CompactFiles from @yhchiang and dynamic leveled and multi-leveled universal from @sdong). Here are couple of things demonstrating that Compaction class is hard to use: 1. we have two constructors of Compaction class 2. there's this thing called grandparents_, but it appears to only be setup for leveled compaction and not compactfiles 3. it's easy to introduce a subtle and dangerous bug like this: D36225 4. SetupBottomMostLevel() is hard to understand and it shouldn't be. See this comment: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction.cc#L236-L241. It also made it harder for @yhchiang to write CompactFiles, as evidenced by this: https://github.com/facebook/rocksdb/blob/afbafeaeaebfd27a0f3e992fee8e0c57d07658fa/db/compaction_picker.cc#L204-L210 The problem is that we create Compaction object, which holds a lot of state, and then pass it around to some functions. After those functions are done mutating, then we call couple of functions on Compaction object, like SetupBottommostLevel() and MarkFilesBeingCompacted(). It is very hard to see what's happening with all that Compaction's state while it's travelling across different functions. If you're writing a new PickCompaction() function you need to try really hard to understand what are all the functions you need to run on Compaction object and what state you need to setup. My proposed solution is to make important parts of Compaction immutable after construction. PickCompaction() should calculate compaction inputs and then pass them onto Compaction object once they are finalized. That makes it easy to create a new compaction -- just provide all the parameters to the constructor and you're done. No need to call confusing functions after you created your object. This diff doesn't fully achieve that goal, but it comes pretty close. Here are some of the changes: * have one Compaction constructor instead of two. * inputs_ is constant after construction * MarkFilesBeingCompacted() is now private to Compaction class and automatically called on construction/destruction. * SetupBottommostLevel() is gone. Compaction figures it out on its own based on the input. * CompactionPicker's functions are not passing around Compaction object anymore. They are only passing around the state that they need. Test Plan: make check make asan_check make valgrind_check Reviewers: rven, anthony, sdong, yhchiang Reviewed By: yhchiang Subscribers: sdong, yhchiang, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D36687
2015-04-11 00:01:54 +02:00
VersionStorageInfo* vstorage,
CompactionInputFiles* inputs,
CompactionInputFiles* output_level_inputs,
int* parent_index, int base_index);
void GetGrandparents(VersionStorageInfo* vstorage,
const CompactionInputFiles& inputs,
const CompactionInputFiles& output_level_inputs,
std::vector<FileMetaData*>* grandparents);
void PickFilesMarkedForCompaction(const std::string& cf_name,
VersionStorageInfo* vstorage,
int* start_level, int* output_level,
CompactionInputFiles* start_level_inputs);
bool GetOverlappingL0Files(VersionStorageInfo* vstorage,
CompactionInputFiles* start_level_inputs,
int output_level, int* parent_index);
// Register this compaction in the set of running compactions
void RegisterCompaction(Compaction* c);
// Remove this compaction from the set of running compactions
void UnregisterCompaction(Compaction* c);
std::set<Compaction*>* level0_compactions_in_progress() {
return &level0_compactions_in_progress_;
}
std::unordered_set<Compaction*>* compactions_in_progress() {
return &compactions_in_progress_;
}
protected:
const ImmutableCFOptions& ioptions_;
// A helper function to SanitizeCompactionInputFiles() that
// sanitizes "input_files" by adding necessary files.
#ifndef ROCKSDB_LITE
virtual Status SanitizeCompactionInputFilesForAllLevels(
std::unordered_set<uint64_t>* input_files,
const ColumnFamilyMetaData& cf_meta, const int output_level) const;
#endif // ROCKSDB_LITE
// Keeps track of all compactions that are running on Level0.
// Protected by DB mutex
std::set<Compaction*> level0_compactions_in_progress_;
// Keeps track of all compactions that are running.
// Protected by DB mutex
std::unordered_set<Compaction*> compactions_in_progress_;
const InternalKeyComparator* const icmp_;
};
// Picking compactions for leveled compaction. See wiki page
// https://github.com/facebook/rocksdb/wiki/Leveled-Compaction
// for description of Leveled compaction.
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;
virtual bool NeedsCompaction(
const VersionStorageInfo* vstorage) const override;
};
#ifndef ROCKSDB_LITE
// A dummy compaction that never triggers any automatic
// compaction.
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*/,
const CompactRangeOptions& /*compact_range_options*/,
const InternalKey* /*begin*/,
const InternalKey* /*end*/,
InternalKey** /*compaction_end*/,
bool* /*manual_conflict*/,
uint64_t /*max_file_num_to_ignore*/) override {
return nullptr;
}
// Always returns false.
virtual bool NeedsCompaction(
const VersionStorageInfo* /*vstorage*/) const override {
return false;
}
};
#endif // !ROCKSDB_LITE
// Attempts to find an intra L0 compaction conforming to the given parameters.
//
// @param level_files Metadata for L0 files.
// @param min_files_to_compact Minimum number of files required to
// do the compaction.
// @param max_compact_bytes_per_del_file Maximum average size in bytes per
// file that is going to get deleted by
// the compaction.
// @param max_compaction_bytes Maximum total size in bytes (in terms
// of compensated file size) for files
// to be compacted.
// @param [out] comp_inputs If a compaction was found, will be
// initialized with corresponding input
// files. Cannot be nullptr.
//
// @return true iff compaction was found.
bool FindIntraL0Compaction(const std::vector<FileMetaData*>& level_files,
size_t min_files_to_compact,
uint64_t max_compact_bytes_per_del_file,
uint64_t max_compaction_bytes,
CompactionInputFiles* comp_inputs);
CompressionType GetCompressionType(const ImmutableCFOptions& ioptions,
const VersionStorageInfo* vstorage,
const MutableCFOptions& mutable_cf_options,
int level, int base_level,
const bool enable_compression = true);
CompressionOptions GetCompressionOptions(const ImmutableCFOptions& ioptions,
const VersionStorageInfo* vstorage,
int level,
const bool enable_compression = true);
} // namespace rocksdb