| /** |
| * 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.regionserver; |
| |
| import java.util.Arrays; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| |
| /** |
| * A custom RegionSplitPolicy implementing a SplitPolicy that groups |
| * rows by a prefix of the row-key |
| * |
| * This ensures that a region is not split "inside" a prefix of a row key. |
| * I.e. rows can be co-located in a region by their prefix. |
| */ |
| @InterfaceAudience.Private |
| public class KeyPrefixRegionSplitPolicy extends IncreasingToUpperBoundRegionSplitPolicy { |
| private static final Log LOG = LogFactory |
| .getLog(KeyPrefixRegionSplitPolicy.class); |
| @Deprecated |
| public static final String PREFIX_LENGTH_KEY_DEPRECATED = "prefix_split_key_policy.prefix_length"; |
| public static final String PREFIX_LENGTH_KEY = "KeyPrefixRegionSplitPolicy.prefix_length"; |
| |
| private int prefixLength = 0; |
| |
| @Override |
| protected void configureForRegion(HRegion region) { |
| super.configureForRegion(region); |
| prefixLength = 0; |
| |
| // read the prefix length from the table descriptor |
| String prefixLengthString = region.getTableDesc().getValue( |
| PREFIX_LENGTH_KEY); |
| if (prefixLengthString == null) { |
| //read the deprecated value |
| prefixLengthString = region.getTableDesc().getValue(PREFIX_LENGTH_KEY_DEPRECATED); |
| if (prefixLengthString == null) { |
| LOG.error(PREFIX_LENGTH_KEY + " not specified for table " |
| + region.getTableDesc().getTableName() |
| + ". Using default RegionSplitPolicy"); |
| return; |
| } |
| } |
| try { |
| prefixLength = Integer.parseInt(prefixLengthString); |
| } catch (NumberFormatException nfe) { |
| /* Differentiate NumberFormatException from an invalid value range reported below. */ |
| LOG.error("Number format exception when parsing " + PREFIX_LENGTH_KEY + " for table " |
| + region.getTableDesc().getTableName() + ":" |
| + prefixLengthString + ". " + nfe); |
| return; |
| } |
| if (prefixLength <= 0) { |
| LOG.error("Invalid value for " + PREFIX_LENGTH_KEY + " for table " |
| + region.getTableDesc().getTableName() + ":" |
| + prefixLengthString + ". Using default RegionSplitPolicy"); |
| } |
| } |
| |
| @Override |
| protected byte[] getSplitPoint() { |
| byte[] splitPoint = super.getSplitPoint(); |
| if (prefixLength > 0 && splitPoint != null && splitPoint.length > 0) { |
| // group split keys by a prefix |
| return Arrays.copyOf(splitPoint, |
| Math.min(prefixLength, splitPoint.length)); |
| } else { |
| return splitPoint; |
| } |
| } |
| } |