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fill="currentColor" aria-label="print icon"><path d="M819.2 364.8h-44.8V128c0-17.067-14.933-32-32-32H281.6c-17.067 0-32 14.933-32 32v236.8h-44.8C145.067 364.8 96 413.867 96 473.6v192c0 59.733 49.067 108.8 108.8 108.8h44.8V896c0 17.067 14.933 32 32 32h460.8c17.067 0 32-14.933 32-32V774.4h44.8c59.733 0 108.8-49.067 108.8-108.8v-192c0-59.733-49.067-108.8-108.8-108.8zM313.6 160h396.8v204.8H313.6V160zm396.8 704H313.6V620.8h396.8V864zM864 665.6c0 25.6-19.2 44.8-44.8 44.8h-44.8V588.8c0-17.067-14.933-32-32-32H281.6c-17.067 0-32 14.933-32 32v121.6h-44.8c-25.6 0-44.8-19.2-44.8-44.8v-192c0-25.6 19.2-44.8 44.8-44.8h614.4c25.6 0 44.8 19.2 44.8 44.8v192z"></path></svg></button></div><div class="toc-wrapper"><ul class="toc-list"><!--[--><li class="toc-item"><a class="vp-link toc-link level2 toc-link level2" href="#installation">Installation</a></li><li><ul class="toc-list"><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#dependencies">Dependencies</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#how-to-install">How to install</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#using-iotdb-java-native-api-with-maven">Using IoTDB Java Native API with Maven</a></li><!----><!--]--></ul></li><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level2 toc-link level2" href="#syntax-convention">Syntax Convention</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level2 toc-link level2" href="#native-apis">Native APIs</a></li><li><ul class="toc-list"><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#initialization">Initialization</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#data-definition-interface-ddi">Data Definition Interface (DDI)</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#data-manipulation-interface-dmi">Data Manipulation Interface (DMI)</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#iotdb-sql-interface">IoTDB-SQL Interface</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#write-test-interface-to-profile-network-cost">Write Test Interface (to profile network cost)</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level3 toc-link level3" href="#coding-examples">Coding Examples</a></li><!----><!--]--></ul></li><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level2 toc-link level2" href="#session-pool-for-native-api">Session Pool for Native API</a></li><!----><!--]--><!--[--><li class="toc-item"><a class="vp-link toc-link level2 toc-link level2" href="#cluster-information-related-apis-only-works-in-the-cluster-mode">Cluster information related APIs (only works in the cluster mode)</a></li><!----><!--]--></ul><div class="toc-marker" style="top:-1.7rem;"></div></div><!--[--><!----><!--]--></aside></div><!--[--><!----><!--]--><div class="theme-hope-content"><!--

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 --><h1 id="java-native-api" tabindex="-1"><a class="header-anchor" href="#java-native-api" aria-hidden="true">#</a> Java Native API</h1><h2 id="installation" tabindex="-1"><a class="header-anchor" href="#installation" aria-hidden="true">#</a> Installation</h2><h3 id="dependencies" tabindex="-1"><a class="header-anchor" href="#dependencies" aria-hidden="true">#</a> Dependencies</h3><ul><li>JDK &gt;= 1.8+</li><li>Maven &gt;= 3.9+</li></ul><h3 id="how-to-install" tabindex="-1"><a class="header-anchor" href="#how-to-install" aria-hidden="true">#</a> How to install</h3><p>In root directory:</p><blockquote><p>mvn clean install -pl iotdb-client/session -am -DskipTests</p></blockquote><h3 id="using-iotdb-java-native-api-with-maven" tabindex="-1"><a class="header-anchor" href="#using-iotdb-java-native-api-with-maven" aria-hidden="true">#</a> Using IoTDB Java Native API with Maven</h3><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>dependencies</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>
       <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>iotdb-session<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>
 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependencies</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></div><h2 id="syntax-convention" tabindex="-1"><a class="header-anchor" href="#syntax-convention" aria-hidden="true">#</a> Syntax Convention</h2><ul><li><strong>IoTDB-SQL interface:</strong> The input SQL parameter needs to conform to the <a href="/UserGuide/Master/stage/Syntax-Conventions/Literal-Values.html" class="">syntax conventions</a> and be escaped for JAVA strings. For example, you need to add a backslash before the double-quotes. (That is: after JAVA escaping, it is consistent with the SQL statement executed on the command line.)</li><li><strong>Other interfaces:</strong><ul><li>The node names in path or path prefix: The node names are required to be escaped by backticks (`) in the SQL statement.</li><li>Identifiers (such as template names): The identifiers are required to be escaped by backticks (`) in the SQL statement.</li></ul></li><li><strong>Code example for syntax convention could be found at:</strong> <code>example/session/src/main/java/org/apache/iotdb/SyntaxConventionRelatedExample.java</code></li></ul><h2 id="native-apis" tabindex="-1"><a class="header-anchor" href="#native-apis" aria-hidden="true">#</a> Native APIs</h2><p>In this section we will demonstrate the commonly used interfaces and their parameters in the Native API:</p><h3 id="initialization" tabindex="-1"><a class="header-anchor" href="#initialization" aria-hidden="true">#</a> Initialization</h3><ul><li>Initialize a Session</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token comment">// use default configuration </span>
 session <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Session<span class="token punctuation">.</span>Builder</span><span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// initialize with a single node</span>
 session <span class="token operator">=</span>
     <span class="token keyword">new</span> <span class="token class-name">Session<span class="token punctuation">.</span>Builder</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">host</span><span class="token punctuation">(</span><span class="token class-name">String</span> host<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">port</span><span class="token punctuation">(</span><span class="token keyword">int</span> port<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// initialize with multiple nodes</span>
 session <span class="token operator">=</span>
     <span class="token keyword">new</span> <span class="token class-name">Session<span class="token punctuation">.</span>Builder</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">nodeUrls</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">String</span><span class="token punctuation">&gt;</span></span> nodeUrls<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// other configurations</span>
 session <span class="token operator">=</span>
     <span class="token keyword">new</span> <span class="token class-name">Session<span class="token punctuation">.</span>Builder</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">fetchSize</span><span class="token punctuation">(</span><span class="token keyword">int</span> fetchSize<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">username</span><span class="token punctuation">(</span><span class="token class-name">String</span> username<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">password</span><span class="token punctuation">(</span><span class="token class-name">String</span> password<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">thriftDefaultBufferSize</span><span class="token punctuation">(</span><span class="token keyword">int</span> thriftDefaultBufferSize<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">thriftMaxFrameSize</span><span class="token punctuation">(</span><span class="token keyword">int</span> thriftMaxFrameSize<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">enableRedirection</span><span class="token punctuation">(</span><span class="token keyword">boolean</span> enableRedirection<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">version</span><span class="token punctuation">(</span><span class="token class-name">Version</span> version<span class="token punctuation">)</span>
         <span class="token punctuation">.</span><span class="token function">build</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></div><p><code>Version</code> represents the SQL semantic version used by the client, which is used to be compatible with the SQL semantics of <code>0.12</code> when upgrading <code>0.13</code>. The possible values are: <code>V_0_12</code>, <code>V_0_13</code>, <code>V_1_0</code>.</p><ul><li>Open a Session</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token keyword">open</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><ul><li>Open a session, with a parameter specifying whether to enable RPC compression</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token keyword">open</span><span class="token punctuation">(</span><span class="token keyword">boolean</span> enableRPCCompression<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Notice: The RPC compression setting of the client is required to match that of the IoTDB server</p><ul><li>Close a Session</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">close</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><h3 id="data-definition-interface-ddi" tabindex="-1"><a class="header-anchor" href="#data-definition-interface-ddi" aria-hidden="true">#</a> Data Definition Interface (DDI)</h3><h4 id="database-management" tabindex="-1"><a class="header-anchor" href="#database-management" aria-hidden="true">#</a> Database Management</h4><ul><li>Create database</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">setStorageGroup</span><span class="token punctuation">(</span><span class="token class-name">String</span> storageGroupId<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>Delete one or several databases</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">deleteStorageGroup</span><span class="token punctuation">(</span><span class="token class-name">String</span> storageGroup<span class="token punctuation">)</span>
 <span class="token keyword">void</span> <span class="token function">deleteStorageGroups</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">String</span><span class="token punctuation">&gt;</span></span> storageGroups<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><h4 id="timeseries-management" tabindex="-1"><a class="header-anchor" href="#timeseries-management" aria-hidden="true">#</a> Timeseries Management</h4><ul><li>Create one or multiple timeseries</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">createTimeseries</span><span class="token punctuation">(</span><span class="token class-name">String</span> path<span class="token punctuation">,</span> <span class="token class-name">TSDataType</span> dataType<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> compressor<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>
       <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> tags<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> attributes<span class="token punctuation">,</span> <span class="token class-name">String</span> measurementAlias<span class="token punctuation">)</span>

 <span class="token keyword">void</span> <span class="token function">createMultiTimeseries</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">String</span><span class="token punctuation">&gt;</span></span> paths<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">TSDataType</span><span class="token punctuation">&gt;</span></span> dataTypes<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">TSEncoding</span><span class="token punctuation">&gt;</span></span> encodings<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">CompressionType</span><span class="token punctuation">&gt;</span></span> compressors<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">Map</span><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 class="token punctuation">&gt;</span></span> propsList<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">Map</span><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 class="token punctuation">&gt;</span></span> tagsList<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">Map</span><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 class="token punctuation">&gt;</span></span> attributesList<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">String</span><span class="token punctuation">&gt;</span></span> measurementAliasList<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></div><ul><li>Create aligned timeseries</li></ul><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>void createAlignedTimeseries(String prefixPath, List&lt;String&gt; measurements,
       List&lt;TSDataType&gt; dataTypes, List&lt;TSEncoding&gt; encodings,
       List &lt;CompressionType&gt; compressors, List&lt;String&gt; measurementAliasList);
 </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>Attention: Alias of measurements are <strong>not supported</strong> currently.</p><ul><li>Delete one or several timeseries</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">deleteTimeseries</span><span class="token punctuation">(</span><span class="token class-name">String</span> path<span class="token punctuation">)</span>
 <span class="token keyword">void</span> <span class="token function">deleteTimeseries</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">String</span><span class="token punctuation">&gt;</span></span> paths<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><ul><li>Check whether the specific timeseries exists.</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">boolean</span> <span class="token function">checkTimeseriesExists</span><span class="token punctuation">(</span><span class="token class-name">String</span> path<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h4 id="schema-template" tabindex="-1"><a class="header-anchor" href="#schema-template" aria-hidden="true">#</a> Schema Template</h4><p>Creation of a schema-templates will help to improve performance when ingesting data of a large number of identical devices.<br> You can use Template, InternalNode and MeasurementNode types to describe the structure of the template, and use <code>createSchemaTemplate</code> to create it inside the current session.</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">createSchemaTemplate</span><span class="token punctuation">(</span><span class="token class-name">Template</span> template<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token class-name">Class</span> <span class="token class-name">Template</span> <span class="token punctuation">{</span>
     <span class="token keyword">private</span> <span class="token class-name">String</span> name<span class="token punctuation">;</span>
     <span class="token keyword">private</span> <span class="token keyword">boolean</span> directShareTime<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">Node</span><span class="token punctuation">&gt;</span></span> children<span class="token punctuation">;</span>
     <span class="token keyword">public</span> <span class="token class-name">Template</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">,</span> <span class="token keyword">boolean</span> isShareTime<span class="token punctuation">)</span><span class="token punctuation">;</span>

     <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">addToTemplate</span><span class="token punctuation">(</span><span class="token class-name">Node</span> node<span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">deleteFromTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setShareTime</span><span class="token punctuation">(</span><span class="token keyword">boolean</span> shareTime<span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">}</span>

 <span class="token class-name">Abstract</span> <span class="token class-name">Class</span> <span class="token class-name">Node</span> <span class="token punctuation">{</span>
     <span class="token keyword">private</span> <span class="token class-name">String</span> name<span class="token punctuation">;</span>
     <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">addChild</span><span class="token punctuation">(</span><span class="token class-name">Node</span> node<span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">deleteChild</span><span class="token punctuation">(</span><span class="token class-name">Node</span> node<span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">}</span>

 <span class="token class-name">Class</span> <span class="token class-name">MeasurementNode</span> <span class="token keyword">extends</span> <span class="token class-name">Node</span> <span class="token punctuation">{</span>
     <span class="token class-name">TSDataType</span> dataType<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> compressor<span class="token punctuation">;</span>
     <span class="token keyword">public</span> <span class="token class-name">MeasurementNode</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">,</span>
                            <span class="token class-name">TSDataType</span> dataType<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> compressor<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></div><blockquote><p>We strongly recommend you create only flat templates and don&#39;t make use of the ability to create hierarchical structures as tree-structured templates may not be supported in further version of IoTDB.</p></blockquote><p>A snippet of using above Method and Class：</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">MeasurementNode</span> nodeX <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">MeasurementNode</span><span class="token punctuation">(</span><span class="token string">&quot;x&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 class-name">CompressionType</span><span class="token punctuation">.</span><span class="token constant">SNAPPY</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token class-name">MeasurementNode</span> nodeY <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">MeasurementNode</span><span class="token punctuation">(</span><span class="token string">&quot;y&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 class-name">CompressionType</span><span class="token punctuation">.</span><span class="token constant">SNAPPY</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token class-name">MeasurementNode</span> nodeSpeed <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">MeasurementNode</span><span class="token punctuation">(</span><span class="token string">&quot;speed&quot;</span><span class="token punctuation">,</span> <span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">DOUBLE</span><span class="token punctuation">,</span> <span class="token class-name">TSEncoding</span><span class="token punctuation">.</span><span class="token constant">GORILLA</span><span class="token punctuation">,</span> <span class="token class-name">CompressionType</span><span class="token punctuation">.</span><span class="token constant">SNAPPY</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// This is the template we suggest to implement</span>
 <span class="token class-name">Template</span> flatTemplate <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Template</span><span class="token punctuation">(</span><span class="token string">&quot;flatTemplate&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 template<span class="token punctuation">.</span><span class="token function">addToTemplate</span><span class="token punctuation">(</span>nodeX<span class="token punctuation">)</span><span class="token punctuation">;</span>
 template<span class="token punctuation">.</span><span class="token function">addToTemplate</span><span class="token punctuation">(</span>nodeY<span class="token punctuation">)</span><span class="token punctuation">;</span>
 template<span class="token punctuation">.</span><span class="token function">addToTemplate</span><span class="token punctuation">(</span>nodeSpeed<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token function">createSchemaTemplate</span><span class="token punctuation">(</span>flatTemplate<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></div><p>You can query measurements inside templates with these APIS:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token comment">// Return the amount of measurements inside a template</span>
 <span class="token keyword">int</span> <span class="token function">countMeasurementsInTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// Returns true if path points to a measurement, otherwise it returns false</span>
 <span class="token keyword">boolean</span> <span class="token function">isMeasurementInTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">,</span> <span class="token class-name">String</span> path<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// Returns true if path exists in template, otherwise it returns false</span>
 <span class="token keyword">boolean</span> <span class="token function">isPathExistInTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">,</span> <span class="token class-name">String</span> path<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// Return all measurement paths inside a given template</span>
 <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> <span class="token function">showMeasurementsInTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token comment">// Return all measurement paths matching the designated pattern inside a given template</span>
 <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> <span class="token function">showMeasurementsInTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">,</span> <span class="token class-name">String</span> pattern<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></div><p>To use a schema template, you can set the measurement template named <code>templateName</code> at path <code>prefixPath</code>.</p><blockquote><p><strong>Please notice that, we strongly recommend not setting templates on the nodes above the database to accommodate future updates and collaboration between modules.</strong></p></blockquote><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">setSchemaTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">,</span> <span class="token class-name">String</span> prefixPath<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Before using a template, you should first create the template using the following example:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">createSchemaTemplate</span><span class="token punctuation">(</span><span class="token class-name">Template</span> template<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>After assigning template to a certain path, you can use the template to create a timeseries for given device paths using the following call:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">createTimeseriesUsingSchemaTemplate</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">String</span><span class="token punctuation">&gt;</span></span> devicePathList<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Alternatively you can write data directly without creating the timeseies firs hereby triggering the timeseries auto-creation, which automatically uses the template assigned to the provided path.</p><p>After setting template to a certain path, you can query for info about template using the interface in the following example:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token doc-comment comment">/** <span class="token keyword">@return</span> All template names. */</span>
 <span class="token keyword">public</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> <span class="token function">showAllTemplates</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token doc-comment comment">/** <span class="token keyword">@return</span> All paths have been set to designated template. */</span>
 <span class="token keyword">public</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> <span class="token function">showPathsTemplateSetOn</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token doc-comment comment">/** <span class="token keyword">@return</span> All paths are using designated template. */</span>
 <span class="token keyword">public</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> <span class="token function">showPathsTemplateUsingOn</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<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></div><p>If you to remove a schema template, you can drop it with following interface.<br> Make sure the template you are trying to remove has been unset from MTree and is no longer used.</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">unsetSchemaTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> prefixPath<span class="token punctuation">,</span> <span class="token class-name">String</span> templateName<span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">dropSchemaTemplate</span><span class="token punctuation">(</span><span class="token class-name">String</span> templateName<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>Unset the schema template named <code>templateName</code> from path <code>prefixPath</code>.<br> When you issue this interface, you should assure that there is a template named <code>templateName</code> set at the path <code>prefixPath</code>.</p><blockquote><p>Attention: Unsetting a template from node a path or descendant nodes which already contain data referencing this template is <strong>not supported</strong></p></blockquote><h3 id="data-manipulation-interface-dmi" tabindex="-1"><a class="header-anchor" href="#data-manipulation-interface-dmi" aria-hidden="true">#</a> Data Manipulation Interface (DMI)</h3><h4 id="insert" tabindex="-1"><a class="header-anchor" href="#insert" aria-hidden="true">#</a> Insert</h4><p>It is recommended to use insertTablet to help improve write efficiency.</p><ul><li>Insert a Tablet，which contains multiple rows for a device. Each row has the same measurements: <ul><li><strong>Better Write Performance</strong></li><li><strong>Support batch write</strong></li><li><strong>Support null values</strong>: fill the null value with any value, and then mark the null value via BitMap</li></ul></li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertTablet</span><span class="token punctuation">(</span><span class="token class-name">Tablet</span> tablet<span class="token punctuation">)</span>

 <span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Tablet</span> <span class="token punctuation">{</span>
   <span class="token doc-comment comment">/** deviceId of this tablet */</span>
   <span class="token keyword">public</span> <span class="token class-name">String</span> prefixPath<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** the list of measurement schemas for creating the tablet */</span>
   <span class="token keyword">private</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">MeasurementSchema</span><span class="token punctuation">&gt;</span></span> schemas<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** timestamps in this tablet */</span>
   <span class="token keyword">public</span> <span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** each object is a primitive type array, which represents values of one measurement */</span>
   <span class="token keyword">public</span> <span class="token class-name">Object</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** each bitmap represents the existence of each value in the current column. */</span>
   <span class="token keyword">public</span> <span class="token class-name">BitMap</span><span class="token punctuation">[</span><span class="token punctuation">]</span> bitMaps<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** the number of rows to include in this tablet */</span>
   <span class="token keyword">public</span> <span class="token keyword">int</span> rowSize<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** the maximum number of rows for this tablet */</span>
   <span class="token keyword">private</span> <span class="token keyword">int</span> maxRowNumber<span class="token punctuation">;</span>
   <span class="token doc-comment comment">/** whether this tablet store data of aligned timeseries or not */</span>
   <span class="token keyword">private</span> <span class="token keyword">boolean</span> isAligned<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></div><ul><li>Insert multiple Tablets</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertTablets</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">Tablet</span><span class="token punctuation">&gt;</span></span> tablet<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li><p>Insert a Record, which contains multiple measurement values for a device at a given time.</p><p>The correspondence between the Object type and the TSDataType type is shown in the following table.</p><table><thead><tr><th>TSDataType</th><th>Object</th></tr></thead><tbody><tr><td>BOOLEAN</td><td>Boolean</td></tr><tr><td>INT32</td><td>Integer</td></tr><tr><td>INT64</td><td>Long</td></tr><tr><td>FLOAT</td><td>Float</td></tr><tr><td>DOUBLE</td><td>Double</td></tr><tr><td>TEXT</td><td>String, Binary</td></tr></tbody></table></li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertRecord</span><span class="token punctuation">(</span><span class="token class-name">String</span> deviceId<span class="token punctuation">,</span>
    <span class="token keyword">long</span> time<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">String</span><span class="token punctuation">&gt;</span></span> measurements<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">TSDataType</span><span class="token punctuation">&gt;</span></span> types<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">Object</span><span class="token punctuation">&gt;</span></span> values<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></div><ul><li>Insert multiple Records</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertRecords</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">String</span><span class="token punctuation">&gt;</span></span> deviceIds<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">Long</span><span class="token punctuation">&gt;</span></span> times<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> measurementsList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">TSDataType</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> typesList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">Object</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> valuesList<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></div><ul><li>Insert multiple Records that belong to the same device.</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertRecordsOfOneDevice</span><span class="token punctuation">(</span><span class="token class-name">String</span> deviceId<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">Long</span><span class="token punctuation">&gt;</span></span> times<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> measurementsList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">TSDataType</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> typesList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">Object</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> valuesList<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></div><h4 id="insert-with-type-inference" tabindex="-1"><a class="header-anchor" href="#insert-with-type-inference" aria-hidden="true">#</a> Insert with type inference</h4><p>If type-information is not present, all values will be converted to their <code>String</code> representation.<br> The server then performs type inference to guess the datatype, based on this string-representation.<br> For example, if value string equals &quot;true&quot;, it can be automatically inferred to be a <code>Boolean</code> type. If string value is &quot;3.2&quot;, it can be automatically inferred as a <code>Float</code> type.<br> However, please keep in mind, that this process of guessing the type for a given value comes at a performance cost.</p><p>The following variants demonstrate the insertion of data, using type inference:</p><ul><li>Insert a Record, which contains multiple measurement values for a device at given times:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertRecord</span><span class="token punctuation">(</span><span class="token class-name">String</span> prefixPath<span class="token punctuation">,</span> <span class="token keyword">long</span> time<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">String</span><span class="token punctuation">&gt;</span></span> measurements<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">String</span><span class="token punctuation">&gt;</span></span> values<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>Insert multiple Records:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertRecords</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">String</span><span class="token punctuation">&gt;</span></span> deviceIds<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">Long</span><span class="token punctuation">&gt;</span></span> times<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> measurementsList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> valuesList<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><ul><li>Insert multiple Records that belong to the same device:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">insertStringRecordsOfOneDevice</span><span class="token punctuation">(</span><span class="token class-name">String</span> deviceId<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">Long</span><span class="token punctuation">&gt;</span></span> times<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> measurementsList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> valuesList<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><h4 id="insert-of-aligned-timeseries" tabindex="-1"><a class="header-anchor" href="#insert-of-aligned-timeseries" aria-hidden="true">#</a> Insert of Aligned Timeseries</h4><p>The insertion of aligned timeseries uses interfaces like <code>insertAlignedXXX</code>, and others similar to the above interfaces:</p><ul><li>insertAlignedRecord</li><li>insertAlignedRecords</li><li>insertAlignedRecordsOfOneDevice</li><li>insertAlignedStringRecordsOfOneDevice</li><li>insertAlignedTablet</li><li>insertAlignedTablets</li></ul><h4 id="delete" tabindex="-1"><a class="header-anchor" href="#delete" aria-hidden="true">#</a> Delete</h4><ul><li>Delete data with timestamps before or equal to a given timestamp of one or several timeseries:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">deleteData</span><span class="token punctuation">(</span><span class="token class-name">String</span> path<span class="token punctuation">,</span> <span class="token keyword">long</span> time<span class="token punctuation">)</span>
 <span class="token keyword">void</span> <span class="token function">deleteData</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">String</span><span class="token punctuation">&gt;</span></span> paths<span class="token punctuation">,</span> <span class="token keyword">long</span> time<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><h4 id="query" tabindex="-1"><a class="header-anchor" href="#query" aria-hidden="true">#</a> Query</h4><ul><li>Time-series raw data query with time range:</li></ul><ul><li>The specified query time-range is a left-closed right-open interval, including the start time but excluding the end time.</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">SessionDataSet</span> <span class="token function">executeRawDataQuery</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">String</span><span class="token punctuation">&gt;</span></span> paths<span class="token punctuation">,</span> <span class="token keyword">long</span> startTime<span class="token punctuation">,</span> <span class="token keyword">long</span> endTime<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><ul><li><p>Last query:</p><ul><li>Query the last data, whose timestamp is greater than or equal lastTime.<div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">SessionDataSet</span> <span class="token function">executeLastDataQuery</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">String</span><span class="token punctuation">&gt;</span></span> paths<span class="token punctuation">,</span> <span class="token keyword">long</span> lastTime<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></li><li>Query the latest point of the specified series of single device quickly, and support redirection;<br> If you are sure that the query path is valid, set &#39;isLegalPathNodes&#39; to true to avoid performance penalties from path verification.<div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">SessionDataSet</span> <span class="token function">executeLastDataQueryForOneDevice</span><span class="token punctuation">(</span>
     <span class="token class-name">String</span> db<span class="token punctuation">,</span> <span class="token class-name">String</span> device<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">String</span><span class="token punctuation">&gt;</span></span> sensors<span class="token punctuation">,</span> <span class="token keyword">boolean</span> isLegalPathNodes<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></li><li><p>Aggregation query:</p><ul><li>Support specified query time range: The specified query time range is a left-closed right-open interval, including the start time but not the end time.</li><li>Support GROUP BY TIME.</li></ul></li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">SessionDataSet</span> <span class="token function">executeAggregationQuery</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">String</span><span class="token punctuation">&gt;</span></span> paths<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">Aggregation</span><span class="token punctuation">&gt;</span></span> aggregations<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token class-name">SessionDataSet</span> <span class="token function">executeAggregationQuery</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">String</span><span class="token punctuation">&gt;</span></span> paths<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">Aggregation</span><span class="token punctuation">&gt;</span></span> aggregations<span class="token punctuation">,</span> <span class="token keyword">long</span> startTime<span class="token punctuation">,</span> <span class="token keyword">long</span> endTime<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token class-name">SessionDataSet</span> <span class="token function">executeAggregationQuery</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">String</span><span class="token punctuation">&gt;</span></span> paths<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">Aggregation</span><span class="token punctuation">&gt;</span></span> aggregations<span class="token punctuation">,</span>
     <span class="token keyword">long</span> startTime<span class="token punctuation">,</span>
     <span class="token keyword">long</span> endTime<span class="token punctuation">,</span>
     <span class="token keyword">long</span> interval<span class="token punctuation">)</span><span class="token punctuation">;</span>

 <span class="token class-name">SessionDataSet</span> <span class="token function">executeAggregationQuery</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">String</span><span class="token punctuation">&gt;</span></span> paths<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">Aggregation</span><span class="token punctuation">&gt;</span></span> aggregations<span class="token punctuation">,</span>
     <span class="token keyword">long</span> startTime<span class="token punctuation">,</span>
     <span class="token keyword">long</span> endTime<span class="token punctuation">,</span>
     <span class="token keyword">long</span> interval<span class="token punctuation">,</span>
     <span class="token keyword">long</span> slidingStep<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></div><h3 id="iotdb-sql-interface" tabindex="-1"><a class="header-anchor" href="#iotdb-sql-interface" aria-hidden="true">#</a> IoTDB-SQL Interface</h3><ul><li>Execute query statement</li></ul><p>Query statements return data.</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token class-name">SessionDataSet</span> <span class="token function">executeQueryStatement</span><span class="token punctuation">(</span><span class="token class-name">String</span> sql<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>Execute non query statement</li></ul><p>Non-Query statements don&#39;t return data (Delete, Create, ... statements)</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">executeNonQueryStatement</span><span class="token punctuation">(</span><span class="token class-name">String</span> sql<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h3 id="write-test-interface-to-profile-network-cost" tabindex="-1"><a class="header-anchor" href="#write-test-interface-to-profile-network-cost" aria-hidden="true">#</a> Write Test Interface (to profile network cost)</h3><p>These methods <strong>don&#39;t</strong> insert data into database.<br> The server just return after accepting the request.</p><ul><li>Test the network and client cost of insertRecord</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">testInsertRecord</span><span class="token punctuation">(</span><span class="token class-name">String</span> deviceId<span class="token punctuation">,</span> <span class="token keyword">long</span> time<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">String</span><span class="token punctuation">&gt;</span></span> measurements<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">String</span><span class="token punctuation">&gt;</span></span> values<span class="token punctuation">)</span>

 <span class="token keyword">void</span> <span class="token function">testInsertRecord</span><span class="token punctuation">(</span><span class="token class-name">String</span> deviceId<span class="token punctuation">,</span> <span class="token keyword">long</span> time<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">String</span><span class="token punctuation">&gt;</span></span> measurements<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">TSDataType</span><span class="token punctuation">&gt;</span></span> types<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">Object</span><span class="token punctuation">&gt;</span></span> values<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><ul><li>Test the network and client cost of insertRecords</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">testInsertRecords</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">String</span><span class="token punctuation">&gt;</span></span> deviceIds<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">Long</span><span class="token punctuation">&gt;</span></span> times<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> measurementsList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> valuesList<span class="token punctuation">)</span>

 <span class="token keyword">void</span> <span class="token function">testInsertRecords</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">String</span><span class="token punctuation">&gt;</span></span> deviceIds<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">Long</span><span class="token punctuation">&gt;</span></span> times<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> measurementsList<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">List</span><span class="token punctuation">&lt;</span><span class="token class-name">TSDataType</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> typesList
         <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">List</span><span class="token punctuation">&lt;</span><span class="token class-name">Object</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> valuesList<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></div><ul><li>Test the network and client cost of insertTablet</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">testInsertTablet</span><span class="token punctuation">(</span><span class="token class-name">Tablet</span> tablet<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>Test the network and client cost of insertTablets</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token keyword">void</span> <span class="token function">testInsertTablets</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">Tablet</span><span class="token punctuation">&gt;</span></span> tablets<span class="token punctuation">)</span>
 </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h3 id="coding-examples" tabindex="-1"><a class="header-anchor" href="#coding-examples" aria-hidden="true">#</a> Coding Examples</h3><p>To get more information about the following methods, please have a look at <a href="https://github.com/apache/iotdb/blob/master/iotdb-client/session/src/main/java/org/apache/iotdb/session/Session.java" target="_blank" rel="noopener noreferrer">Session.java<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>.</p><p>The sample code for using these methods is located in <a href="https://github.com/apache/iotdb/blob/master/example/session/src/main/java/org/apache/iotdb/SessionExample.java" target="_blank" rel="noopener noreferrer">SessionExample.java<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>，which provides an example of how to open an IoTDB session and execute a batch insertion.</p><p>For examples of aligned timeseries and schema template, you can refer to <a href="https://github.com/apache/iotdb/blob/master/example/session/src/main/java/org/apache/iotdb/AlignedTimeseriesSessionExample.java" target="_blank" rel="noopener noreferrer">AlignedTimeseriesSessionExample.java<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>.</p><h2 id="session-pool-for-native-api" tabindex="-1"><a class="header-anchor" href="#session-pool-for-native-api" aria-hidden="true">#</a> Session Pool for Native API</h2><p>We provide a connection pool (<code>SessionPool</code>) for Native API.<br> When creating such a SessionPool, you need to define the pool size.</p><p>If you can not get a session connection within 60 seconds, a warning will be logged but the program will hang.</p><p>If a session has finished an operation, it will be put back to the pool automatically.</p><p>If a session connection is broken, the session will be removed automatically and the pool will try to create a new session and redo the operation.</p><p>You can also specify an url list of multiple reachable nodes when creating a SessionPool, just as you would, when creating a Session to ensure high availability of clients in distributed cluster environments.</p><p>For query operations:</p><ol><li>When using SessionPool to query data, the result set is <code>SessionDataSetWrapper</code>.</li><li>Given a <code>SessionDataSetWrapper</code>, if you have not scanned all the data in it and stop to use it, you have to call <code>SessionPool.closeResultSet(wrapper)</code> manually.</li><li>When you call <code>hasNext()</code> and <code>next()</code> of a <code>SessionDataSetWrapper</code> and there is an exception, then you have to call <code>SessionPool.closeResultSet(wrapper)</code> manually.</li><li>You can call <code>getColumnNames()</code> of <code>SessionDataSetWrapper</code> to get the column names of query result.</li></ol><p>Examples: <a href="https://github.com/apache/iotdb/blob/master/iotdb-client/session/src/test/java/org/apache/iotdb/session/pool/SessionPoolTest.java" target="_blank" rel="noopener noreferrer">SessionPoolTest.java<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a><br> Or: <a href="https://github.com/apache/iotdb/blob/master/example/session/src/main/java/org/apache/iotdb/SessionPoolExample.java" target="_blank" rel="noopener noreferrer">SessionPoolExample.java<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a></p><h2 id="cluster-information-related-apis-only-works-in-the-cluster-mode" tabindex="-1"><a class="header-anchor" href="#cluster-information-related-apis-only-works-in-the-cluster-mode" aria-hidden="true">#</a> Cluster information related APIs (only works in the cluster mode)</h2><p>Cluster information related APIs allow users to retrieve information about the cluster like where a database will be persisted to or the status of each node in the cluster.</p><p>To use the APIs, please add the following dependency in your pom file:</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>dependencies</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>
       <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>iotdb-thrift-cluster<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>
 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependencies</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></div><p>How to open a connection:</p><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><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>thrift<span class="token punctuation">.</span>protocol<span class="token punctuation">.</span></span><span class="token class-name">TBinaryProtocol</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>thrift<span class="token punctuation">.</span>transport<span class="token punctuation">.</span></span><span class="token class-name">TSocket</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>thrift<span class="token punctuation">.</span>transport<span class="token punctuation">.</span></span><span class="token class-name">TTransport</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>thrift<span class="token punctuation">.</span>transport<span class="token punctuation">.</span></span><span class="token class-name">TTransportException</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>rpc<span class="token punctuation">.</span></span><span class="token class-name">RpcTransportFactory</span></span><span class="token punctuation">;</span>

 <span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">CluserInfoClient</span> <span class="token punctuation">{</span>
   <span class="token class-name">TTransport</span> transport<span class="token punctuation">;</span>
   <span class="token class-name">ClusterInfoService<span class="token punctuation">.</span>Client</span> client<span class="token punctuation">;</span>
   <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">connect</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
     transport <span class="token operator">=</span>
             <span class="token class-name">RpcTransportFactory</span><span class="token punctuation">.</span><span class="token constant">INSTANCE</span><span class="token punctuation">.</span><span class="token function">getTransport</span><span class="token punctuation">(</span>
                     <span class="token keyword">new</span> <span class="token class-name">TSocket</span><span class="token punctuation">(</span>
                             <span class="token comment">// the RPC address</span>
                             <span class="token class-name">IoTDBDescriptor</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><span class="token function">getRpcAddress</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
                             <span class="token comment">// the RPC port</span>
                             <span class="token class-name">ClusterDescriptor</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><span class="token function">getClusterRpcPort</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 keyword">try</span> <span class="token punctuation">{</span>
       transport<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token punctuation">}</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">TTransportException</span> e<span class="token punctuation">)</span> <span class="token punctuation">{</span>
       <span class="token class-name">Assert</span><span class="token punctuation">.</span><span class="token function">fail</span><span class="token punctuation">(</span>e<span class="token punctuation">.</span><span class="token function">getMessage</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 comment">//get the client</span>
     client <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ClusterInfoService<span class="token punctuation">.</span>Client</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">TBinaryProtocol</span><span class="token punctuation">(</span>transport<span class="token punctuation">)</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">void</span> <span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
     transport<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></div><p>APIs in <code>ClusterInfoService.Client</code>:</p><ul><li>Get the physical hash ring of the cluster:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code>list<span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Node</span><span class="token punctuation">&gt;</span></span> <span class="token function">getRing</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></div><ul><li>Get data partition information of input path and time range:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token doc-comment comment">/**
  * <span class="token keyword">@param</span> <span class="token parameter">path</span> input path (should contains a database name as its prefix)
  * <span class="token keyword">@return</span> the data partition info. If the time range only covers one data partition, the the size
  * of the list is one.
  */</span>
 list<span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">DataPartitionEntry</span><span class="token punctuation">&gt;</span></span> <span class="token function">getDataPartition</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token operator">:</span>string path<span class="token punctuation">,</span> <span class="token number">2</span><span class="token operator">:</span><span class="token keyword">long</span> startTime<span class="token punctuation">,</span> <span class="token number">3</span><span class="token operator">:</span><span class="token keyword">long</span> endTime<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></div><ul><li>Get metadata partition information of input path:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token doc-comment comment">/**
  * <span class="token keyword">@param</span> <span class="token parameter">path</span> input path (should contains a database name as its prefix)
  * <span class="token keyword">@return</span> metadata partition information
  */</span>
 list<span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Node</span><span class="token punctuation">&gt;</span></span> <span class="token function">getMetaPartition</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token operator">:</span>string path<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></div><ul><li>Get the status (alive or not) of all nodes:</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token doc-comment comment">/**
  * <span class="token keyword">@return</span> key: node, value: live or not
  */</span>
 map<span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Node</span><span class="token punctuation">,</span> bool<span class="token punctuation">&gt;</span></span> <span class="token function">getAllNodeStatus</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></div><ul><li>get the raft group info (voteFor, term, etc..) of the connected node<br> (Notice that this API is rarely used by users):</li></ul><div class="language-java line-numbers-mode" data-ext="java"><pre class="language-java"><code><span class="token doc-comment comment">/**
  * <span class="token keyword">@return</span> A multi-line string with each line representing the total time consumption, invocation
  *     number, and average time consumption.
  */</span>
 string <span class="token function">getInstrumentingInfo</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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