ceph/src/rocksdb/java/src/main/java/org/rocksdb/CompactionPriority.java

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 package org.rocksdb;
   7
   8 /**
   9  * Compaction Priorities
  10  */
  11 public enum CompactionPriority {
  12
  13   /**
  14    * Slightly Prioritize larger files by size compensated by #deletes
  15    */
  16   ByCompensatedSize((byte)0x0),
  17
  18   /**
  19    * First compact files whose data's latest update time is oldest.
  20    * Try this if you only update some hot keys in small ranges.
  21    */
  22   OldestLargestSeqFirst((byte)0x1),
  23
  24   /**
  25    * First compact files whose range hasn't been compacted to the next level
  26    * for the longest. If your updates are random across the key space,
  27    * write amplification is slightly better with this option.
  28    */
  29   OldestSmallestSeqFirst((byte)0x2),
  30
  31   /**
  32    * First compact files whose ratio between overlapping size in next level
  33    * and its size is the smallest. It in many cases can optimize write
  34    * amplification.
  35    */
  36   MinOverlappingRatio((byte)0x3);
  37
  38
  39   private final byte value;
  40
  41   CompactionPriority(final byte value) {
  42     this.value = value;
  43   }
  44
  45   /**
  46    * Returns the byte value of the enumerations value
  47    *
  48    * @return byte representation
  49    */
  50   public byte getValue() {
  51     return value;
  52   }
  53
  54   /**
  55    * Get CompactionPriority by byte value.
  56    *
  57    * @param value byte representation of CompactionPriority.
  58    *
  59    * @return {@link org.rocksdb.CompactionPriority} instance or null.
  60    * @throws java.lang.IllegalArgumentException if an invalid
  61    *     value is provided.
  62    */
  63   public static CompactionPriority getCompactionPriority(final byte value) {
  64     for (final CompactionPriority compactionPriority :
  65         CompactionPriority.values()) {
  66       if (compactionPriority.getValue() == value){
  67         return compactionPriority;
  68       }
  69     }
  70     throw new IllegalArgumentException(
  71         "Illegal value provided for CompactionPriority.");
  72   }
  73 }