YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

// Copyright (c) 2011-present, 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.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#ifndef YB_ROCKSDB_UNIVERSAL_COMPACTION_H

#define YB_ROCKSDB_UNIVERSAL_COMPACTION_H

#include <climits>

#include "yb/util/size_literals.h"

using yb::operator"" _MB;

namespace rocksdb {

//

// Algorithm used to make a compaction request stop picking new files

// into a single compaction run

//

enum CompactionStopStyle {

  kCompactionStopStyleSimilarSize, // pick files of similar size

  kCompactionStopStyleTotalSize    // total size of picked files > next file

};

class CompactionOptionsUniversal {

 public:

  // Percentage flexibilty while comparing file size. If the candidate file(s)

  // size is 1% smaller than the next file's size, then include next file into

  // this candidate set. // Default: 1

  unsigned int size_ratio;

  // Always include files with size less or equal to always_include_threshold into candidate set.

  size_t always_include_size_threshold = 0;

  // The minimum number of files in a single compaction run. Default: 2

  unsigned int min_merge_width;

  // The maximum number of files in a single compaction run. Default: UINT_MAX

  unsigned int max_merge_width;

  // The size amplification is defined as the amount (in percentage) of

  // additional storage needed to store a single byte of data in the database.

  // For example, a size amplification of 2% means that a database that

  // contains 100 bytes of user-data may occupy upto 102 bytes of

  // physical storage. By this definition, a fully compacted database has

  // a size amplification of 0%. Rocksdb uses the following heuristic

  // to calculate size amplification: it assumes that all files excluding

  // the earliest file contribute to the size amplification.

  // Default: 200, which means that a 100 byte database could require upto

  // 300 bytes of storage.

  unsigned int max_size_amplification_percent;

  // If this option is set to be -1 (the default value), all the output files

  // will follow compression type specified.

  //

  // If this option is not negative, we will try to make sure compressed

  // size is just above this value. In normal cases, at least this percentage

  // of data will be compressed.

  // When we are compacting to a new file, here is the criteria whether

  // it needs to be compressed: assuming here are the list of files sorted

  // by generation time:

  //    A1...An B1...Bm C1...Ct

  // where A1 is the newest and Ct is the oldest, and we are going to compact

  // B1...Bm, we calculate the total size of all the files as total_size, as

  // well as  the total size of C1...Ct as total_C, the compaction output file

  // will be compressed iff

  //   total_C / total_size < this percentage

  // Default: -1

  int compression_size_percent;

  // The algorithm used to stop picking files into a single compaction run

  // Default: kCompactionStopStyleTotalSize

  CompactionStopStyle stop_style;

  // Option to optimize the universal multi level compaction by enabling

  // trivial move for non overlapping files.

  // Default: false

  bool allow_trivial_move;

  // Default set of parameters

  CompactionOptionsUniversal()

      : size_ratio(1),

        min_merge_width(2),

        max_merge_width(UINT_MAX),

        max_size_amplification_percent(200),

        compression_size_percent(-1),

        stop_style(kCompactionStopStyleTotalSize),

        allow_trivial_move(false) {}

};

}  // namespace rocksdb

#endif  // YB_ROCKSDB_UNIVERSAL_COMPACTION_H