001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.master.balancer;
019
020import org.apache.hadoop.conf.Configuration;
021import org.apache.yetus.audience.InterfaceAudience;
022
023/**
024 * Compute the cost of total number of write requests. The more unbalanced the higher the computed
025 * cost will be. This uses a rolling average of regionload.
026 */
027@InterfaceAudience.Private
028class WriteRequestCostFunction extends CostFromRegionLoadAsRateFunction {
029
030  private static final String WRITE_REQUEST_COST_KEY =
031    "hbase.master.balancer.stochastic.writeRequestCost";
032  private static final float DEFAULT_WRITE_REQUEST_COST = 5;
033
034  WriteRequestCostFunction(Configuration conf) {
035    this.setMultiplier(conf.getFloat(WRITE_REQUEST_COST_KEY, DEFAULT_WRITE_REQUEST_COST));
036  }
037
038  @Override
039  protected double getCostFromRl(BalancerRegionLoad rl) {
040    return rl.getWriteRequestsCount();
041  }
042}