| import{_ as d,r as s,o as l,c as o,a as r,d as e,e as t,b as i,f as n}from"./app-6140e563.js";const c={},u=n('<h2 id="hadoop-tsfile" tabindex="-1"><a class="header-anchor" href="#hadoop-tsfile" aria-hidden="true">#</a> Hadoop-TsFile</h2><h3 id="about-hadoop-tsfile-connector" tabindex="-1"><a class="header-anchor" href="#about-hadoop-tsfile-connector" aria-hidden="true">#</a> About Hadoop-TsFile-Connector</h3><p>TsFile-Hadoop-Connector implements the support of Hadoop for external data sources of Tsfile type. This enables users to read, write and query Tsfile by Hadoop.</p><p>With this connector, you can</p><ul><li>load a single TsFile, from either the local file system or hdfs, into Hadoop</li><li>load all files in a specific directory, from either the local file system or hdfs, into hadoop</li><li>write data from Hadoop into TsFile</li></ul><h3 id="system-requirements" tabindex="-1"><a class="header-anchor" href="#system-requirements" aria-hidden="true">#</a> System Requirements</h3><table><thead><tr><th style="text-align:center;">Hadoop Version</th><th style="text-align:center;">Java Version</th><th style="text-align:center;">TsFile Version</th></tr></thead><tbody><tr><td style="text-align:center;"><code>2.7.3</code></td><td style="text-align:center;"><code>1.8</code></td><td style="text-align:center;"><code>1.0.0</code></td></tr></tbody></table>',7),v={href:"https://github.com/apache/iotdb/tree/master/tsfile",target:"_blank",rel:"noopener noreferrer"},b=n(`<h3 id="data-type-correspondence" tabindex="-1"><a class="header-anchor" href="#data-type-correspondence" aria-hidden="true">#</a> Data Type Correspondence</h3><table><thead><tr><th>TsFile data type</th><th>Hadoop writable</th></tr></thead><tbody><tr><td>BOOLEAN</td><td>BooleanWritable</td></tr><tr><td>INT32</td><td>IntWritable</td></tr><tr><td>INT64</td><td>LongWritable</td></tr><tr><td>FLOAT</td><td>FloatWritable</td></tr><tr><td>DOUBLE</td><td>DoubleWritable</td></tr><tr><td>TEXT</td><td>Text</td></tr></tbody></table><h3 id="tsfinputformat-explanation" tabindex="-1"><a class="header-anchor" href="#tsfinputformat-explanation" aria-hidden="true">#</a> TSFInputFormat Explanation</h3><p>TSFInputFormat extract data from tsfile and format them into records of <code>MapWritable</code>.</p><p>Suppose that we want to extract data of the device named <code>d1</code> which has three sensors named <code>s1</code>, <code>s2</code>, <code>s3</code>.</p><p><code>s1</code>'s type is <code>BOOLEAN</code>, <code>s2</code>'s type is <code>DOUBLE</code>, <code>s3</code>'s type is <code>TEXT</code>.</p><p>The <code>MapWritable</code> struct will be like:</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>{ |
| "time_stamp": 10000000, |
| "device_id": d1, |
| "s1": true, |
| "s2": 3.14, |
| "s3": "middle" |
| } |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>In the Map job of Hadoop, you can get any value you want by key as following:</p><p><code>mapwritable.get(new Text("s1"))</code></p><blockquote><p>Note: All keys in <code>MapWritable</code> are <code>Text</code> type.</p></blockquote><h3 id="examples" tabindex="-1"><a class="header-anchor" href="#examples" aria-hidden="true">#</a> Examples</h3><h4 id="read-example-calculate-the-sum" tabindex="-1"><a class="header-anchor" href="#read-example-calculate-the-sum" aria-hidden="true">#</a> Read Example: calculate the sum</h4><p>First of all, we should tell InputFormat what kind of data we want from tsfile.</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code> // configure reading time enable |
| TSFInputFormat.setReadTime(job, true); |
| // configure reading deviceId enable |
| TSFInputFormat.setReadDeviceId(job, true); |
| // configure reading which deltaObjectIds |
| String[] deviceIds = {"device_1"}; |
| TSFInputFormat.setReadDeviceIds(job, deltaObjectIds); |
| // configure reading which measurementIds |
| String[] measurementIds = {"sensor_1", "sensor_2", "sensor_3"}; |
| TSFInputFormat.setReadMeasurementIds(job, measurementIds); |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>And then,the output key and value of mapper and reducer should be specified</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code> // set inputformat and outputformat |
| job.setInputFormatClass(TSFInputFormat.class); |
| // set mapper output key and value |
| job.setMapOutputKeyClass(Text.class); |
| job.setMapOutputValueClass(DoubleWritable.class); |
| // set reducer output key and value |
| job.setOutputKeyClass(Text.class); |
| job.setOutputValueClass(DoubleWritable.class); |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Then, the <code>mapper</code> and <code>reducer</code> class is how you deal with the <code>MapWritable</code> produced by <code>TSFInputFormat</code> class.</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code> public static class TSMapper extends Mapper<NullWritable, MapWritable, Text, DoubleWritable> { |
| |
| @Override |
| protected void map(NullWritable key, MapWritable value, |
| Mapper<NullWritable, MapWritable, Text, DoubleWritable>.Context context) |
| throws IOException, InterruptedException { |
| |
| Text deltaObjectId = (Text) value.get(new Text("device_id")); |
| context.write(deltaObjectId, (DoubleWritable) value.get(new Text("sensor_3"))); |
| } |
| } |
| |
| public static class TSReducer extends Reducer<Text, DoubleWritable, Text, DoubleWritable> { |
| |
| @Override |
| protected void reduce(Text key, Iterable<DoubleWritable> values, |
| Reducer<Text, DoubleWritable, Text, DoubleWritable>.Context context) |
| throws IOException, InterruptedException { |
| |
| double sum = 0; |
| for (DoubleWritable value : values) { |
| sum = sum + value.get(); |
| } |
| context.write(key, new DoubleWritable(sum)); |
| } |
| } |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div>`,19),m={href:"https://github.com/apache/iotdb/blob/master/example/hadoop/src/main/java/org/apache/iotdb//hadoop/tsfile/TSFMRReadExample.java",target:"_blank",rel:"noopener noreferrer"},p=n(`<h4 id="write-example-write-the-average-into-tsfile" tabindex="-1"><a class="header-anchor" href="#write-example-write-the-average-into-tsfile" aria-hidden="true">#</a> Write Example: write the average into Tsfile</h4><p>Except for the <code>OutputFormatClass</code>, the rest of configuration code for hadoop map-reduce job is almost same as above.</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code> job.setOutputFormatClass(TSFOutputFormat.class); |
| // set reducer output key and value |
| job.setOutputKeyClass(NullWritable.class); |
| job.setOutputValueClass(HDFSTSRecord.class); |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Then, the <code>mapper</code> and <code>reducer</code> class is how you deal with the <code>MapWritable</code> produced by <code>TSFInputFormat</code> class.</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code> public static class TSMapper extends Mapper<NullWritable, MapWritable, Text, MapWritable> { |
| @Override |
| protected void map(NullWritable key, MapWritable value, |
| Mapper<NullWritable, MapWritable, Text, MapWritable>.Context context) |
| throws IOException, InterruptedException { |
| |
| Text deltaObjectId = (Text) value.get(new Text("device_id")); |
| long timestamp = ((LongWritable)value.get(new Text("timestamp"))).get(); |
| if (timestamp % 100000 == 0) { |
| context.write(deltaObjectId, new MapWritable(value)); |
| } |
| } |
| } |
| |
| /** |
| * This reducer calculate the average value. |
| */ |
| public static class TSReducer extends Reducer<Text, MapWritable, NullWritable, HDFSTSRecord> { |
| |
| @Override |
| protected void reduce(Text key, Iterable<MapWritable> values, |
| Reducer<Text, MapWritable, NullWritable, HDFSTSRecord>.Context context) throws IOException, InterruptedException { |
| long sensor1_value_sum = 0; |
| long sensor2_value_sum = 0; |
| double sensor3_value_sum = 0; |
| long num = 0; |
| for (MapWritable value : values) { |
| num++; |
| sensor1_value_sum += ((LongWritable)value.get(new Text("sensor_1"))).get(); |
| sensor2_value_sum += ((LongWritable)value.get(new Text("sensor_2"))).get(); |
| sensor3_value_sum += ((DoubleWritable)value.get(new Text("sensor_3"))).get(); |
| } |
| HDFSTSRecord tsRecord = new HDFSTSRecord(1L, key.toString()); |
| DataPoint dPoint1 = new LongDataPoint("sensor_1", sensor1_value_sum / num); |
| DataPoint dPoint2 = new LongDataPoint("sensor_2", sensor2_value_sum / num); |
| DataPoint dPoint3 = new DoubleDataPoint("sensor_3", sensor3_value_sum / num); |
| tsRecord.addTuple(dPoint1); |
| tsRecord.addTuple(dPoint2); |
| tsRecord.addTuple(dPoint3); |
| context.write(NullWritable.get(), tsRecord); |
| } |
| } |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div>`,5),h={href:"https://github.com/apache/iotdb/blob/master/example/hadoop/src/main/java/org/apache/iotdb//hadoop/tsfile/TSMRWriteExample.java",target:"_blank",rel:"noopener noreferrer"};function x(g,f){const a=s("ExternalLinkIcon");return l(),o("div",null,[r(` |
| |
| 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. |
| |
| `),u,e("blockquote",null,[e("p",null,[t("Note: For more information about how to download and use TsFile, please see the following link: "),e("a",v,[t("https://github.com/apache/iotdb/tree/master/tsfile"),i(a)]),t(".")])]),b,e("blockquote",null,[e("p",null,[t("Note: For the complete code, please see the following link: "),e("a",m,[t("https://github.com/apache/iotdb/blob/master/example/hadoop/src/main/java/org/apache/iotdb//hadoop/tsfile/TSFMRReadExample.java"),i(a)])])]),p,e("blockquote",null,[e("p",null,[t("Note: For the complete code, please see the following link: "),e("a",h,[t("https://github.com/apache/iotdb/blob/master/example/hadoop/src/main/java/org/apache/iotdb//hadoop/tsfile/TSMRWriteExample.java"),i(a)])])])])}const w=d(c,[["render",x],["__file","MapReduce-TsFile.html.vue"]]);export{w as default}; |
