hbase-client/src/main/java/org/apache/hadoop/hbase/MemoryCompactionPolicy.java

   1 /**
   2  *
   3  * Licensed to the Apache Software Foundation (ASF) under one
   4  * or more contributor license agreements.  See the NOTICE file
   5  * distributed with this work for additional information
   6  * regarding copyright ownership.  The ASF licenses this file
   7  * to you under the Apache License, Version 2.0 (the
   8  * "License"); you may not use this file except in compliance
   9  * with the License.  You may obtain a copy of the License at
  10  *
  11  *     http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  */
  19 package org.apache.hadoop.hbase;
  20
  21 import org.apache.yetus.audience.InterfaceAudience;
  22
  23 /**
  24  * Enum describing all possible memory compaction policies
  25  */
  26 @InterfaceAudience.Public
  27 public enum MemoryCompactionPolicy {
  28   /**
  29    * No memory compaction, when size threshold is exceeded data is flushed to disk
  30    */
  31   NONE,
  32   /**
  33    * Basic policy applies optimizations which modify the index to a more compacted representation.
  34    * This is beneficial in all access patterns. The smaller the cells are the greater the
  35    * benefit of this policy.
  36    * This is the default policy.
  37    */
  38   BASIC,
  39   /**
  40    * In addition to compacting the index representation as the basic policy, eager policy
  41    * eliminates duplication while the data is still in memory (much like the
  42    * on-disk compaction does after the data is flushed to disk). This policy is most useful for
  43    * applications with high data churn or small working sets.
  44    */
  45   EAGER,
  46   /**
  47    * Adaptive compaction adapts to the workload. It applies either index compaction or data
  48    * compaction based on the ratio of duplicate cells in the data.
  49    */
  50   ADAPTIVE
  51
  52 }