import{_ as p,r as o,o as i,c as l,a as c,d as s,e as n,b as t,f as a}from"./app-d2093efc.js";const u={},r=a(`<h2 id="tsfile-api" tabindex="-1"><a class="header-anchor" href="#tsfile-api" aria-hidden="true">#</a> TsFile API</h2><p>TsFile is a file format of Time Series used in IoTDB. This session introduces the usage of this file format.</p><h3 id="tsfile-library-installation" tabindex="-1"><a class="header-anchor" href="#tsfile-library-installation" aria-hidden="true">#</a> TsFile library Installation</h3><p>There are two ways to use TsFile in your own project.</p><ul><li>Use as jars: Compile the source codes and build to jars</li></ul><div class="language-bash line-numbers-mode" data-ext="sh"><pre class="language-bash"><code><span class="token function">git</span> clone https://github.com/apache/iotdb.git
<span class="token builtin class-name">cd</span> tsfile/
mvn clean package <span class="token parameter variable">-Dmaven.test.skip</span><span class="token operator">=</span>true
</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></div><p>Then, all the jars are in folder named <code>target/</code>. Import <code>target/tsfile-0.12.0-jar-with-dependencies.jar</code> to your project.</p><ul><li><p>Use as a maven dependency:</p><p>Compile source codes and deploy to your local repository in three steps:</p><ul><li><p>Get the source codes</p><div class="language-bash line-numbers-mode" data-ext="sh"><pre class="language-bash"><code><span class="token function">git</span> clone https://github.com/apache/iotdb.git
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div></li><li><p>Compile the source codes and deploy</p><div class="language-bash line-numbers-mode" data-ext="sh"><pre class="language-bash"><code><span class="token builtin class-name">cd</span> tsfile/
mvn clean <span class="token function">install</span> <span class="token parameter variable">-Dmaven.test.skip</span><span class="token operator">=</span>true
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div></li><li><p>add dependencies into your project:</p><div class="language-xml line-numbers-mode" data-ext="xml"><pre class="language-xml"><code> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.apache.iotdb<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>tsfile<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>1.0.0<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>
</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></div></li></ul><p>Or, you can download the dependencies from official Maven repository:</p><ul><li><p>First, find your maven <code>settings.xml</code> on path: <code>\${username}\\.m2\\settings.xml</code><br> , add this <code>&lt;profile&gt;</code> to <code>&lt;profiles&gt;</code>:</p><div class="language-xml line-numbers-mode" data-ext="xml"><pre class="language-xml"><code>  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>profile</span><span class="token punctuation">&gt;</span></span>
       <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>id</span><span class="token punctuation">&gt;</span></span>allow-snapshots<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>id</span><span class="token punctuation">&gt;</span></span>
          <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>activation</span><span class="token punctuation">&gt;</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>activeByDefault</span><span class="token punctuation">&gt;</span></span>true<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>activeByDefault</span><span class="token punctuation">&gt;</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>activation</span><span class="token punctuation">&gt;</span></span>
       <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>repositories</span><span class="token punctuation">&gt;</span></span>
         <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>repository</span><span class="token punctuation">&gt;</span></span>  
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>id</span><span class="token punctuation">&gt;</span></span>apache.snapshots<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>id</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>name</span><span class="token punctuation">&gt;</span></span>Apache Development Snapshot Repository<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>name</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>url</span><span class="token punctuation">&gt;</span></span>https://repository.apache.org/content/repositories/snapshots/<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>url</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>releases</span><span class="token punctuation">&gt;</span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>enabled</span><span class="token punctuation">&gt;</span></span>false<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>enabled</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>releases</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>snapshots</span><span class="token punctuation">&gt;</span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>enabled</span><span class="token punctuation">&gt;</span></span>true<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>enabled</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>snapshots</span><span class="token punctuation">&gt;</span></span>
          <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>repository</span><span class="token punctuation">&gt;</span></span>
       <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>repositories</span><span class="token punctuation">&gt;</span></span>
     <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>profile</span><span class="token punctuation">&gt;</span></span>
</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></div></li><li><p>Then add dependencies into your project:</p><div class="language-xml line-numbers-mode" data-ext="xml"><pre class="language-xml"><code> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.apache.iotdb<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>tsfile<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>1.0.0<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>
</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></div></li></ul></li></ul><h3 id="tsfile-usage" tabindex="-1"><a class="header-anchor" href="#tsfile-usage" aria-hidden="true">#</a> TsFile Usage</h3><p>This section demonstrates the detailed usages of TsFile.</p><p>Time-series Data<br> Time-series data is considered as a sequence of quadruples. A quadruple is defined as (device, measurement, time, value).</p><ul><li><p><strong>measurement</strong>: A physical or formal measurement that a time-series data takes, e.g., the temperature of a city, the<br> sales number of some goods or the speed of a train at different times. As a traditional sensor (like a thermometer) also<br> takes a single measurement and produce a time-series, we will use measurement and sensor interchangeably below.</p></li><li><p><strong>device</strong>: A device refers to an entity that takes several measurements (producing multiple time-series), e.g.,<br> a running train monitors its speed, oil meter, miles it has run, current passengers each is conveyed to a time-series dataset.</p></li></ul><p><strong>One Line of Data</strong>: In many industrial applications, a device normally contains more than one sensor and these sensors<br> may have values at the same timestamp, which is called one line of data.</p><p>Formally, one line of data consists of a <code>device_id</code>, a timestamp which indicates the milliseconds since January 1,<br> 1970, 00:00:00, and several data pairs composed of <code>measurement_id</code> and corresponding <code>value</code>. All data pairs in one<br> line belong to this <code>device_id</code> and have the same timestamp. If one of the <code>measurements</code> does not have a <code>value</code><br> in the <code>timestamp</code>, use a space instead(Actually, TsFile does not store null values). Its format is shown as follow:</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>device_id, timestamp, &lt;measurement_id, value&gt;...
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>An example is illustrated as follow. In this example, the data type of two measurements are <code>INT32</code>, <code>FLOAT</code> respectively.</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>device_1, 1490860659000, m1, 10, m2, 12.12
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h4 id="write-tsfile" tabindex="-1"><a class="header-anchor" href="#write-tsfile" aria-hidden="true">#</a> Write TsFile</h4><p>A TsFile is generated by the following three steps and the complete code is given in the section &quot;Example for writing TsFile&quot;.</p><ol><li><p>construct a <code>TsFileWriter</code> instance.</p><p>Here are the available constructors:</p><ul><li>Without pre-defined schema</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token class-name">TsFileWriter</span><span class="token punctuation">(</span><span class="token class-name">File</span> file<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>With pre-defined schema</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token class-name">TsFileWriter</span><span class="token punctuation">(</span><span class="token class-name">File</span> file<span class="token punctuation">,</span> <span class="token class-name">Schema</span> schema<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>This one is for using the HDFS file system. <code>TsFileOutput</code> can be an instance of class <code>HDFSOutput</code>.</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token class-name">TsFileWriter</span><span class="token punctuation">(</span><span class="token class-name">TsFileOutput</span> output<span class="token punctuation">,</span> <span class="token class-name">Schema</span> schema<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> 
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>If you want to set some TSFile configuration on your own, you could use param <code>config</code>. For example:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">TSFileConfig</span> conf <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TSFileConfig</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conf<span class="token punctuation">.</span><span class="token function">setTSFileStorageFs</span><span class="token punctuation">(</span><span class="token string">&quot;HDFS&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">TsFileWriter</span> tsFileWriter <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TsFileWriter</span><span class="token punctuation">(</span>file<span class="token punctuation">,</span> schema<span class="token punctuation">,</span> conf<span class="token punctuation">)</span><span class="token punctuation">;</span>
</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></div><p>In this example, data files will be stored in HDFS, instead of local file system. If you&#39;d like to store data files in local file system, you can use <code>conf.setTSFileStorageFs(&quot;LOCAL&quot;)</code>, which is also the default config.</p><p>You can also config the ip and rpc port of your HDFS by <code>config.setHdfsIp(...)</code> and <code>config.setHdfsPort(...)</code>. The default ip is <code>localhost</code> and default rpc port is <code>9000</code>.</p><p><strong>Parameters:</strong></p><ul><li><p>file : The TsFile to write</p></li><li><p>schema : The file schemas, will be introduced in next part.</p></li><li><p>config : The config of TsFile.</p></li></ul></li><li><p>add measurements</p><p>Or you can make an instance of class <code>Schema</code> first and pass this to the constructor of class <code>TsFileWriter</code></p><p>The class <code>Schema</code> contains a map whose key is the name of one measurement schema, and the value is the schema itself.</p><p>Here are the interfaces:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token comment">// Create an empty Schema or from an existing map</span>
<span class="token keyword">public</span> <span class="token class-name">Schema</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token class-name">Schema</span><span class="token punctuation">(</span><span class="token class-name">Map</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">&gt;</span></span> measurements<span class="token punctuation">)</span>
<span class="token comment">// Use this two interfaces to add measurements</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">registerMeasurement</span><span class="token punctuation">(</span><span class="token class-name">MeasurementSchema</span> descriptor<span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">registerMeasurements</span><span class="token punctuation">(</span><span class="token class-name">Map</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">&gt;</span></span> measurements<span class="token punctuation">)</span>
<span class="token comment">// Some useful getter and checker</span>
<span class="token keyword">public</span> <span class="token class-name">TSDataType</span> <span class="token function">getMeasurementDataType</span><span class="token punctuation">(</span><span class="token class-name">String</span> measurementId<span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token class-name">MeasurementSchema</span> <span class="token function">getMeasurementSchema</span><span class="token punctuation">(</span><span class="token class-name">String</span> measurementId<span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">&gt;</span></span> <span class="token function">getAllMeasurementSchema</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token keyword">boolean</span> <span class="token function">hasMeasurement</span><span class="token punctuation">(</span><span class="token class-name">String</span> measurementId<span class="token punctuation">)</span>
</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></div><p>You can always use the following interface in <code>TsFileWriter</code> class to add additional measurements:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">addMeasurement</span><span class="token punctuation">(</span><span class="token class-name">MeasurementSchema</span> measurementSchema<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">WriteProcessException</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The class <code>MeasurementSchema</code> contains the information of one measurement, there are several constructors:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">(</span><span class="token class-name">String</span> measurementId<span class="token punctuation">,</span> <span class="token class-name">TSDataType</span> type<span class="token punctuation">,</span> <span class="token class-name">TSEncoding</span> encoding<span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">(</span><span class="token class-name">String</span> measurementId<span class="token punctuation">,</span> <span class="token class-name">TSDataType</span> type<span class="token punctuation">,</span> <span class="token class-name">TSEncoding</span> encoding<span class="token punctuation">,</span> <span class="token class-name">CompressionType</span> compressionType<span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">(</span><span class="token class-name">String</span> measurementId<span class="token punctuation">,</span> <span class="token class-name">TSDataType</span> type<span class="token punctuation">,</span> <span class="token class-name">TSEncoding</span> encoding<span class="token punctuation">,</span> <span class="token class-name">CompressionType</span> compressionType<span class="token punctuation">,</span> 
<span class="token class-name">Map</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> props<span class="token punctuation">)</span>
</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><strong>Parameters:</strong><br> ​</p><ul><li><p>measurementID: The name of this measurement, typically the name of the sensor.</p></li><li><p>type: The data type, now support six types: <code>BOOLEAN</code>, <code>INT32</code>, <code>INT64</code>, <code>FLOAT</code>, <code>DOUBLE</code>, <code>TEXT</code>;</p></li><li><p>encoding: The data encoding.</p></li><li><p>compression: The data compression.</p></li><li><p>props: Properties for special data types.Such as <code>max_point_number</code> for <code>FLOAT</code> and <code>DOUBLE</code>, <code>max_string_length</code> for<br><code>TEXT</code>. Use as string pairs into a map such as (&quot;max_point_number&quot;, &quot;3&quot;).</p></li></ul><blockquote><p><strong>Notice:</strong> Although one measurement name can be used in multiple deltaObjects, the properties cannot be changed. I.e.<br> it&#39;s not allowed to add one measurement name for multiple times with different type or encoding.<br> Here is a bad example:</p></blockquote><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token comment">// The measurement &quot;sensor_1&quot; is float type</span>
<span class="token function">addMeasurement</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">MeasurementSchema</span><span class="token punctuation">(</span><span class="token string">&quot;sensor_1&quot;</span><span class="token punctuation">,</span> <span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">FLOAT</span><span class="token punctuation">,</span> <span class="token class-name">TSEncoding</span><span class="token punctuation">.</span><span class="token constant">RLE</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// This call will throw a WriteProcessException exception</span>
</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></li></ol><p>addMeasurement(new MeasurementSchema(&quot;sensor_1&quot;, TSDataType.INT32, TSEncoding.RLE));</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code></code></pre><div class="line-numbers" aria-hidden="true"></div></div><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>
3. insert and write data continually.

  Use this interface to create a new \`TSRecord\`(a timestamp and device pair).
  
  \`\`\`java
  public TSRecord(long timestamp, String deviceId)
  \`\`\`
</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><pre><code>Then create a \`DataPoint\`(a measurement and value pair), and use the addTuple method to add the DataPoint to the correct
TsRecord.

Use this method to write

\`\`\`java
public void write(TSRecord record) throws IOException, WriteProcessException
</code></pre><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>
4. call \`close\` to finish this writing process. 

  \`\`\`java
  public void close() throws IOException
  \`\`\`

We are also able to write data into a closed TsFile.

1. Use \`ForceAppendTsFileWriter\` to open a closed file.

  \`\`\`java
  public ForceAppendTsFileWriter(File file) throws IOException
  \`\`\`

2. call \`doTruncate\` truncate the part of Metadata

3. Then use \`ForceAppendTsFileWriter\` to construct a new \`TsFileWriter\`

\`\`\`java
public TsFileWriter(TsFileIOWriter fileWriter) throws IOException
</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></div><p>Please note, we should redo the step of adding measurements before writing new data to the TsFile.</p><h4 id="example-for-writing-a-tsfile" tabindex="-1"><a class="header-anchor" href="#example-for-writing-a-tsfile" aria-hidden="true">#</a> Example for writing a TsFile</h4><p>You should install TsFile to your local maven repository.</p><div class="language-bash line-numbers-mode" data-ext="sh"><pre class="language-bash"><code>mvn clean <span class="token function">install</span> <span class="token parameter variable">-pl</span> tsfile <span class="token parameter variable">-am</span> <span class="token parameter variable">-DskipTests</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>You could write a TsFile by constructing <strong>TSRecord</strong> if you have the <strong>non-aligned</strong> (e.g. not all sensors contain values) time series data.</p><p>A more thorough example can be found at <code>/example/tsfile/src/main/java/org/apache/iotdb/tsfile/TsFileWriteWithTSRecord.java</code></p><p>You could write a TsFile by constructing <strong>Tablet</strong> if you have the <strong>aligned</strong> time series data.</p><p>A more thorough example can be found at <code>/example/tsfile/src/main/java/org/apache/iotdb/tsfile/TsFileWriteWithTablet.java</code></p><p>You could write data into a closed TsFile by using <strong>ForceAppendTsFileWriter</strong>.</p><p>A more thorough example can be found at <code>/example/tsfile/src/main/java/org/apache/iotdb/tsfile/TsFileForceAppendWrite.java</code></p><h4 id="interface-for-reading-tsfile" tabindex="-1"><a class="header-anchor" href="#interface-for-reading-tsfile" aria-hidden="true">#</a> Interface for Reading TsFile</h4><ul><li>Definition of Path</li></ul><p>A path is a dot-separated string which uniquely identifies a time-series in TsFile, e.g., &quot;root.area_1.device_1.sensor_1&quot;.<br> The last section &quot;sensor_1&quot; is called &quot;measurementId&quot; while the remaining parts &quot;root.area_1.device_1&quot; is called deviceId.<br> As mentioned above, the same measurement in different devices has the same data type and encoding, and devices are also unique.</p><p>In read interfaces, The parameter <code>paths</code> indicates the measurements to be selected.</p><p>Path instance can be easily constructed through the class <code>Path</code>. For example:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">Path</span> p <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Path</span><span class="token punctuation">(</span><span class="token string">&quot;device_1.sensor_1&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>We will pass an ArrayList of paths for final query call to support multiple paths.</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Path</span><span class="token punctuation">&gt;</span></span> paths <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Path</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
paths<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Path</span><span class="token punctuation">(</span><span class="token string">&quot;device_1.sensor_1&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
paths<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Path</span><span class="token punctuation">(</span><span class="token string">&quot;device_1.sensor_3&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</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></div><blockquote><p><strong>Notice:</strong> When constructing a Path, the format of the parameter should be a dot-separated string, the last part will<br> be recognized as measurementId while the remaining parts will be recognized as deviceId.</p></blockquote>`,44),d=s("li",null,[s("p",null,"Definition of Filter")],-1),k=s("li",null,[s("p",null,[n("Usage Scenario"),s("br"),n(" Filter is used in TsFile reading process to select data satisfying one or more given condition(s).")])],-1),m=s("li",null,[s("p",null,[n("IExpression"),s("br"),n(" The "),s("code",null,"IExpression"),n(" is a filter expression interface and it will be passed to our final query call."),s("br"),n(" We create one or more filter expressions and may use binary filter operators to link them to our final expression.")])],-1),v=s("p",null,[s("strong",null,"Create a Filter Expression")],-1),g=s("p",null,"There are two types of filters.",-1),h=s("p",null,[n("TimeFilter: A filter for "),s("code",null,"time"),n(" in time-series data.")],-1),b=s("div",{class:"language-text line-numbers-mode","data-ext":"text"},[s("pre",{class:"language-text"},[s("code",null,`IExpression timeFilterExpr = new GlobalTimeExpression(TimeFilter);
`)]),s("div",{class:"line-numbers","aria-hidden":"true"},[s("div",{class:"line-number"})])],-1),f=s("p",null,[n("Use the following relationships to get a "),s("code",null,"TimeFilter"),n(" object (value is a long int variable).")],-1),y=s("thead",null,[s("tr",null,[s("th",null,"Relationship"),s("th",null,"Description")])],-1),T=s("tr",null,[s("td",null,"TimeFilter.eq(value)"),s("td",null,"Choose the time equal to the value")],-1),x={href:"http://TimeFilter.lt",target:"_blank",rel:"noopener noreferrer"},w=s("td",null,"Choose the time less than the value",-1),F={href:"http://TimeFilter.gt",target:"_blank",rel:"noopener noreferrer"},E=s("td",null,"Choose the time greater than the value",-1),S=s("tr",null,[s("td",null,"TimeFilter.ltEq(value)"),s("td",null,"Choose the time less than or equal to the value")],-1),q=s("tr",null,[s("td",null,"TimeFilter.gtEq(value)"),s("td",null,"Choose the time greater than or equal to the value")],-1),_=s("tr",null,[s("td",null,"TimeFilter.notEq(value)"),s("td",null,"Choose the time not equal to the value")],-1),j=s("tr",null,[s("td",null,"TimeFilter.not(TimeFilter)"),s("td",null,"Choose the time not satisfy another TimeFilter")],-1),I=a(`<li><p>ValueFilter: A filter for <code>value</code> in time-series data.</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>IExpression valueFilterExpr = new SingleSeriesExpression(Path, ValueFilter);
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The usage of <code>ValueFilter</code> is the same as using <code>TimeFilter</code>, just to make sure that the type of the value<br> equal to the measurement&#39;s(defined in the path).</p></li>`,1),O=s("li",null,[s("p",null,[s("strong",null,"Binary Filter Operators")]),s("p",null,"Binary filter operators can be used to link two single expressions."),s("ul",null,[s("li",null,"BinaryExpression.and(Expression, Expression): Choose the value satisfy for both expressions."),s("li",null,"BinaryExpression.or(Expression, Expression): Choose the value satisfy for at least one expression.")])],-1),A=a(`<p>Filter Expression Examples</p><ul><li><p><strong>TimeFilterExpression Examples</strong></p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">IExpression</span> timeFilterExpr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">GlobalTimeExpression</span><span class="token punctuation">(</span><span class="token class-name">TimeFilter</span><span class="token punctuation">.</span><span class="token function">eq</span><span class="token punctuation">(</span><span class="token number">15</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// series time = 15</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div></li></ul><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>    \`\`\`java
    IExpression timeFilterExpr = new GlobalTimeExpression(TimeFilter.ltEq(15)); // series time &lt;= 15
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code>    <span class="token class-name">IExpression</span> timeFilterExpr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">GlobalTimeExpression</span><span class="token punctuation">(</span><span class="token class-name">TimeFilter</span><span class="token punctuation">.</span><span class="token function">lt</span><span class="token punctuation">(</span><span class="token number">15</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// series time &lt; 15</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><pre><code>\`\`\`java
</code></pre><p>IExpression timeFilterExpr = new GlobalTimeExpression(TimeFilter.gtEq(15)); // series time &gt;= 15<br><code></code>java<br> IExpression timeFilterExpr = new GlobalTimeExpression(TimeFilter.notEq(15)); // series time != 15</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>    \`\`\`java
    IExpression timeFilterExpr = BinaryExpression.and(
        new GlobalTimeExpression(TimeFilter.gtEq(15L)),
    new GlobalTimeExpression(TimeFilter.lt(25L))); // 15 &lt;= series time &lt; 25
</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><pre><code>\`\`\`java
IExpression timeFilterExpr = BinaryExpression.or(
    new GlobalTimeExpression(TimeFilter.gtEq(15L)),
    new GlobalTimeExpression(TimeFilter.lt(25L))); // series time &gt;= 15 or series time &lt; 25
\`\`\`
</code></pre><ul><li>Read Interface</li></ul><p>First, we open the TsFile and get a <code>ReadOnlyTsFile</code> instance from a file path string <code>path</code>.</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">TsFileSequenceReader</span> reader <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TsFileSequenceReader</span><span class="token punctuation">(</span>path<span class="token punctuation">)</span><span class="token punctuation">;</span>
   
<span class="token class-name">ReadOnlyTsFile</span> readTsFile <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ReadOnlyTsFile</span><span class="token punctuation">(</span>reader<span class="token punctuation">)</span><span class="token punctuation">;</span>
</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></div><p>Next, we prepare the path array and query expression, then get final <code>QueryExpression</code> object by this interface:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">QueryExpression</span> queryExpression <span class="token operator">=</span> <span class="token class-name">QueryExpression</span><span class="token punctuation">.</span><span class="token function">create</span><span class="token punctuation">(</span>paths<span class="token punctuation">,</span> statement<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The ReadOnlyTsFile class has two <code>query</code> method to perform a query.</p><ul><li><p><strong>Method 1</strong></p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token class-name">QueryDataSet</span> <span class="token function">query</span><span class="token punctuation">(</span><span class="token class-name">QueryExpression</span> queryExpression<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div></li><li><p><strong>Method 2</strong></p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">public</span> <span class="token class-name">QueryDataSet</span> <span class="token function">query</span><span class="token punctuation">(</span><span class="token class-name">QueryExpression</span> queryExpression<span class="token punctuation">,</span> <span class="token keyword">long</span> partitionStartOffset<span class="token punctuation">,</span> <span class="token keyword">long</span> partitionEndOffset<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>This method is designed for advanced applications such as the TsFile-Spark Connector.</p><ul><li><p><strong>params</strong> : For method 2, two additional parameters are added to support partial query:</p><ul><li><code>partitionStartOffset</code>: start offset for a TsFile</li><li><code>partitionEndOffset</code>: end offset for a TsFile</li></ul><blockquote><p><strong>What is Partial Query ?</strong></p><p>In some distributed file systems(e.g. HDFS), a file is split into severval parts which are called &quot;Blocks&quot; and stored in different nodes. Executing a query paralleled in each nodes involved makes better efficiency. Thus Partial Query is needed. Paritial Query only selects the results stored in the part split by <code>QueryConstant.PARTITION_START_OFFSET</code> and <code>QueryConstant.PARTITION_END_OFFSET</code> for a TsFile.</p></blockquote></li></ul></li><li><p>QueryDataset Interface</p></li></ul><p>The query performed above will return a <code>QueryDataset</code> object.</p><p>Here&#39;s the useful interfaces for user.</p><ul><li><p><code>bool hasNext();</code></p><p>Return true if this dataset still has elements.</p></li><li><p><code>List&lt;Path&gt; getPaths()</code></p><p>Get the paths in this data set.</p></li><li><p><code>List&lt;TSDataType&gt; getDataTypes();</code></p></li></ul><p>Get the data types. The class TSDataType is an enum class, the value will be one of the following:</p><pre><code>   BOOLEAN,
   INT32,
   INT64,
   FLOAT,
   DOUBLE,
   TEXT;
</code></pre><ul><li><p><code>RowRecord next() throws IOException;</code></p><p>Get the next record.</p><p>The class <code>RowRecord</code> consists of a <code>long</code> timestamp and a <code>List&lt;Field&gt;</code> for data in different sensors,<br> we can use two getter methods to get them.</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">long</span> <span class="token function">getTimestamp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Field</span><span class="token punctuation">&gt;</span></span> <span class="token function">getFields</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div><p>To get data from one Field, use these methods:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">TSDataType</span> <span class="token function">getDataType</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Object</span> <span class="token function">getObjectValue</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div></li></ul><h4 id="example-for-reading-an-existing-tsfile" tabindex="-1"><a class="header-anchor" href="#example-for-reading-an-existing-tsfile" aria-hidden="true">#</a> Example for reading an existing TsFile</h4><p>You should install TsFile to your local maven repository.</p><p>A more thorough example with query statement can be found at<br><code>/tsfile/example/src/main/java/org/apache/iotdb/tsfile/TsFileRead.java</code></p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile</span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">ArrayList</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span></span><span class="token class-name">ReadOnlyTsFile</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span></span><span class="token class-name">TsFileSequenceReader</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>common<span class="token punctuation">.</span></span><span class="token class-name">Path</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>expression<span class="token punctuation">.</span></span><span class="token class-name">IExpression</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>expression<span class="token punctuation">.</span></span><span class="token class-name">QueryExpression</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>expression<span class="token punctuation">.</span>impl<span class="token punctuation">.</span></span><span class="token class-name">BinaryExpression</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>expression<span class="token punctuation">.</span>impl<span class="token punctuation">.</span></span><span class="token class-name">GlobalTimeExpression</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>expression<span class="token punctuation">.</span>impl<span class="token punctuation">.</span></span><span class="token class-name">SingleSeriesExpression</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>filter<span class="token punctuation">.</span></span><span class="token class-name">TimeFilter</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>filter<span class="token punctuation">.</span></span><span class="token class-name">ValueFilter</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>read<span class="token punctuation">.</span>query<span class="token punctuation">.</span>dataset<span class="token punctuation">.</span></span><span class="token class-name">QueryDataSet</span></span><span class="token punctuation">;</span>

<span class="token doc-comment comment">/**
 * The class is to show how to read TsFile file named &quot;test.tsfile&quot;.
 * The TsFile file &quot;test.tsfile&quot; is generated from class TsFileWrite.
 * Run TsFileWrite to generate the test.tsfile first
 */</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">TsFileRead</span> <span class="token punctuation">{</span>
  <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">queryAndPrint</span><span class="token punctuation">(</span><span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Path</span><span class="token punctuation">&gt;</span></span> paths<span class="token punctuation">,</span> <span class="token class-name">ReadOnlyTsFile</span> readTsFile<span class="token punctuation">,</span> <span class="token class-name">IExpression</span> statement<span class="token punctuation">)</span>
          <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
    <span class="token class-name">QueryExpression</span> queryExpression <span class="token operator">=</span> <span class="token class-name">QueryExpression</span><span class="token punctuation">.</span><span class="token function">create</span><span class="token punctuation">(</span>paths<span class="token punctuation">,</span> statement<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">QueryDataSet</span> queryDataSet <span class="token operator">=</span> readTsFile<span class="token punctuation">.</span><span class="token function">query</span><span class="token punctuation">(</span>queryExpression<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">while</span> <span class="token punctuation">(</span>queryDataSet<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>queryDataSet<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">&quot;------------&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>

  <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>

    <span class="token comment">// file path</span>
    <span class="token class-name">String</span> path <span class="token operator">=</span> <span class="token string">&quot;test.tsfile&quot;</span><span class="token punctuation">;</span>

    <span class="token comment">// create reader and get the readTsFile interface</span>
    <span class="token class-name">TsFileSequenceReader</span> reader <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TsFileSequenceReader</span><span class="token punctuation">(</span>path<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">ReadOnlyTsFile</span> readTsFile <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ReadOnlyTsFile</span><span class="token punctuation">(</span>reader<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">// use these paths(all sensors) for all the queries</span>
    <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Path</span><span class="token punctuation">&gt;</span></span> paths <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    paths<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Path</span><span class="token punctuation">(</span><span class="token string">&quot;device_1.sensor_1&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    paths<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Path</span><span class="token punctuation">(</span><span class="token string">&quot;device_1.sensor_2&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    paths<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Path</span><span class="token punctuation">(</span><span class="token string">&quot;device_1.sensor_3&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// no query statement</span>
    <span class="token function">queryAndPrint</span><span class="token punctuation">(</span>paths<span class="token punctuation">,</span> readTsFile<span class="token punctuation">,</span> <span class="token keyword">null</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">//close the reader when you left</span>
    reader<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</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 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><h3 id="change-tsfile-configuration" tabindex="-1"><a class="header-anchor" href="#change-tsfile-configuration" aria-hidden="true">#</a> Change TsFile Configuration</h3><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">TSFileConfig</span> config <span class="token operator">=</span> <span class="token class-name">TSFileDescriptor</span><span class="token punctuation">.</span><span class="token function">getInstance</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getConfig</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
config<span class="token punctuation">.</span><span class="token function">setXXX</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div>`,27);function D(L,P){const e=o("ExternalLinkIcon");return i(),l("div",null,[c(`

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    regarding copyright ownership.  The ASF licenses this file
    to you under the Apache License, Version 2.0 (the
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