| Title: Apache Accumulo Combiner Example |
| Notice: 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. |
| |
| This tutorial uses the following Java class, which can be found in org.apache.accumulo.examples.simple.combiner in the examples-simple module: |
| |
| * StatsCombiner.java - a combiner that calculates max, min, sum, and count |
| |
| This is a simple combiner example. To build this example run maven and then |
| copy the produced jar into the accumulo lib dir. This is already done in the |
| tar distribution. |
| |
| $ bin/accumulo shell -u username |
| Enter current password for 'username'@'instance': *** |
| |
| Shell - Apache Accumulo Interactive Shell |
| - |
| - version: 1.5.0 |
| - instance name: instance |
| - instance id: 00000000-0000-0000-0000-000000000000 |
| - |
| - type 'help' for a list of available commands |
| - |
| username@instance> createtable runners |
| username@instance runners> setiter -t runners -p 10 -scan -minc -majc -n decStats -class org.apache.accumulo.examples.simple.combiner.StatsCombiner |
| Combiner that keeps track of min, max, sum, and count |
| ----------> set StatsCombiner parameter all, set to true to apply Combiner to every column, otherwise leave blank. if true, columns option will be ignored.: |
| ----------> set StatsCombiner parameter columns, <col fam>[:<col qual>]{,<col fam>[:<col qual>]} escape non aplhanum chars using %<hex>.: stat |
| ----------> set StatsCombiner parameter radix, radix/base of the numbers: 10 |
| username@instance runners> setiter -t runners -p 11 -scan -minc -majc -n hexStats -class org.apache.accumulo.examples.simple.combiner.StatsCombiner |
| Combiner that keeps track of min, max, sum, and count |
| ----------> set StatsCombiner parameter all, set to true to apply Combiner to every column, otherwise leave blank. if true, columns option will be ignored.: |
| ----------> set StatsCombiner parameter columns, <col fam>[:<col qual>]{,<col fam>[:<col qual>]} escape non aplhanum chars using %<hex>.: hstat |
| ----------> set StatsCombiner parameter radix, radix/base of the numbers: 16 |
| username@instance runners> insert 123456 name first Joe |
| username@instance runners> insert 123456 stat marathon 240 |
| username@instance runners> scan |
| 123456 name:first [] Joe |
| 123456 stat:marathon [] 240,240,240,1 |
| username@instance runners> insert 123456 stat marathon 230 |
| username@instance runners> insert 123456 stat marathon 220 |
| username@instance runners> scan |
| 123456 name:first [] Joe |
| 123456 stat:marathon [] 220,240,690,3 |
| username@instance runners> insert 123456 hstat virtualMarathon 6a |
| username@instance runners> insert 123456 hstat virtualMarathon 6b |
| username@instance runners> scan |
| 123456 hstat:virtualMarathon [] 6a,6b,d5,2 |
| 123456 name:first [] Joe |
| 123456 stat:marathon [] 220,240,690,3 |
| |
| In this example a table is created and the example stats combiner is applied to |
| the column family stat and hstat. The stats combiner computes min,max,sum, and |
| count. It can be configured to use a different base or radix. In the example |
| above the column family stat is configured for base 10 and the column family |
| hstat is configured for base 16. |