| /* |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| package org.apache.hadoop.hbase.master.normalizer; |
| |
| import java.util.List; |
| import org.apache.hadoop.conf.Configurable; |
| import org.apache.hadoop.hbase.client.TableDescriptor; |
| import org.apache.hadoop.hbase.master.MasterServices; |
| import org.apache.yetus.audience.InterfaceAudience; |
| |
| /** |
| * Performs "normalization" of regions of a table, making sure that suboptimal |
| * choice of split keys doesn't leave cluster in a situation when some regions are |
| * substantially larger than others for considerable amount of time. |
| * |
| * Users who want to use this feature could either use default {@link SimpleRegionNormalizer} |
| * or plug in their own implementation. Please note that overly aggressive normalization rules |
| * (attempting to make all regions perfectly equal in size) could potentially lead to |
| * "split/merge storms". |
| */ |
| @InterfaceAudience.Private |
| interface RegionNormalizer extends Configurable { |
| /** |
| * Set the master service. Must be called before first call to |
| * {@link #computePlansForTable(TableDescriptor)}. |
| * @param masterServices master services to use |
| */ |
| void setMasterServices(MasterServices masterServices); |
| |
| /** |
| * Computes a list of normalizer actions to perform on the target table. This is the primary |
| * entry-point from the Master driving a normalization activity. |
| * @param tableDescriptor table descriptor for table which needs normalize |
| * @return A list of the normalization actions to perform, or an empty list |
| * if there's nothing to do. |
| */ |
| List<NormalizationPlan> computePlansForTable(TableDescriptor tableDescriptor); |
| } |