001/**
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019package org.apache.hadoop.hbase;
020
021import org.apache.yetus.audience.InterfaceAudience;
022
023/**
024 * Enum describing all possible memory compaction policies
025 */
026@InterfaceAudience.Public
027public enum MemoryCompactionPolicy {
028  /**
029   * No memory compaction, when size threshold is exceeded data is flushed to disk
030   */
031  NONE,
032  /**
033   * Basic policy applies optimizations which modify the index to a more compacted representation.
034   * This is beneficial in all access patterns. The smaller the cells are the greater the
035   * benefit of this policy.
036   * This is the default policy.
037   */
038  BASIC,
039  /**
040   * In addition to compacting the index representation as the basic policy, eager policy
041   * eliminates duplication while the data is still in memory (much like the
042   * on-disk compaction does after the data is flushed to disk). This policy is most useful for
043   * applications with high data churn or small working sets.
044   */
045  EAGER,
046  /**
047   * Adaptive compaction adapts to the workload. It applies either index compaction or data
048   * compaction based on the ratio of duplicate cells in the data.
049   */
050  ADAPTIVE
051
052}