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disable"></nav><div class="vp-page-title"><h1><!---->Frequently Asked Questions</h1><div class="page-info"><!----><!----><span class="page-date-info" aria-label="Writing Date"><svg xmlns="http://www.w3.org/2000/svg" class="icon calendar-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="calendar icon"><path d="M716.4 110.137c0-18.753-14.72-33.473-33.472-33.473-18.753 0-33.473 14.72-33.473 33.473v33.473h66.993v-33.473zm-334.87 0c0-18.753-14.72-33.473-33.473-33.473s-33.52 14.72-33.52 33.473v33.473h66.993v-33.473zm468.81 33.52H716.4v100.465c0 18.753-14.72 33.473-33.472 33.473a33.145 33.145 0 01-33.473-33.473V143.657H381.53v100.465c0 18.753-14.72 33.473-33.473 33.473a33.145 33.145 0 01-33.473-33.473V143.657H180.6A134.314 134.314 0 0046.66 277.595v535.756A134.314 134.314 0 00180.6 947.289h669.74a134.36 134.36 0 00133.94-133.938V277.595a134.314 134.314 0 00-133.94-133.938zm33.473 267.877H147.126a33.145 33.145 0 01-33.473-33.473c0-18.752 14.72-33.473 33.473-33.473h736.687c18.752 0 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19.03v5.825h566.49v-5.825c0-7.379-2.849-13.981-7.509-18.9-5.049-193.016-97.867-351.985-220.2-389.527 123.24-37.67 216.446-198.453 220.588-392.892zM531.16 450.445v352.632c117.674 1.553 211.787 40.778 211.787 88.676H304.097c0-48.286 95.149-87.382 213.728-88.676V450.445c-93.077-3.107-167.901-81.297-167.901-177.093 0-8.803 6.99-15.793 15.793-15.793 8.803 0 15.794 6.99 15.794 15.793 0 80.261 63.69 145.635 142.01 145.635s142.011-65.374 142.011-145.635c0-8.803 6.99-15.793 15.794-15.793s15.793 6.99 15.793 15.793c0 95.019-73.789 172.82-165.96 177.093z"></path></svg><span>About 2 min</span><meta property="timeRequired" content="PT2M"></span><!----><!----></div><hr></div><!----><!--[--><!----><!--]--><div class="theme-hope-content"><h1 id="frequently-asked-questions" tabindex="-1"><a class="header-anchor" href="#frequently-asked-questions"><span>Frequently Asked Questions</span></a></h1><p><strong>How can I identify my version of IoTDB?</strong></p><p>There are several ways to identify the version of IoTDB that you are using:</p><ul><li>Launch IoTDB&#39;s Command Line Interface:</li></ul><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>&gt; ./start-cli.sh -p 6667 -pw root -u root -h localhost
 _____       _________  ______   ______    
|_   _|     |  _   _  ||_   _ `.|_   _ \   
  | |   .--.|_/ | | \_|  | | `. \ | |_) |  
  | | / .&#39;`\ \  | |      | |  | | |  __&#39;.  
 _| |_| \__. | _| |_    _| |_.&#39; /_| |__) | 
|_____|&#39;.__.&#39; |_____|  |______.&#39;|_______/  version x.x.x
</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><ul><li>Check pom.xml file:</li></ul><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>&lt;version&gt;x.x.x&lt;/version&gt;
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>Use JDBC API:</li></ul><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>String iotdbVersion = tsfileDatabaseMetadata.getDatabaseProductVersion();
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>Use Command Line Interface:</li></ul><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>IoTDB&gt; show version
show version
+---------------+
|version        |
+---------------+
|x.x.x          |
+---------------+
Total line number = 1
It costs 0.241s
</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></div><p><strong>Where can I find IoTDB logs?</strong></p><p>Suppose your root directory is:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>$ pwd
/workspace/iotdb

$ ls -l
server/
cli/
pom.xml
Readme.md
...
</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></div><p>Let <code>$IOTDB_HOME = /workspace/iotdb/server/target/iotdb-server-{project.version}</code></p><p>Let <code>$IOTDB_CLI_HOME = /workspace/iotdb/cli/target/iotdb-cli-{project.version}</code></p><p>By default settings, the logs are stored under <code>IOTDB_HOME/logs</code>. You can change log level and storage path by configuring <code>logback.xml</code> under <code>IOTDB_HOME/conf</code>.</p><p><strong>Where can I find IoTDB data files?</strong></p><p>By default settings, the data files (including tsfile, metadata, and WAL files) are stored under <code>IOTDB_HOME/data/datanode</code>.</p><p><strong>How do I know how many time series are stored in IoTDB?</strong></p><p>Use IoTDB&#39;s Command Line Interface:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>IoTDB&gt; show timeseries root
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>In the result, there is a statement shows <code>Total timeseries number</code>, this number is the timeseries number in IoTDB.</p><p>In the current version, IoTDB supports querying the number of time series. Use IoTDB&#39;s Command Line Interface:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>IoTDB&gt; count timeseries root
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>If you are using Linux, you can use the following shell command:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>&gt; grep &quot;0,root&quot; $IOTDB_HOME/data/system/schema/mlog.txt |  wc -l
&gt;   6
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Can I use Hadoop and Spark to read TsFile in IoTDB?</strong></p><p>Yes. IoTDB has intense integration with Open Source Ecosystem. IoTDB supports <a href="https://github.com/apache/iotdb/tree/master/hadoop" target="_blank" rel="noopener noreferrer">Hadoop<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>, <a href="https://github.com/apache/iotdb/tree/master/spark-tsfile" target="_blank" rel="noopener noreferrer">Spark<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> and <a href="https://github.com/apache/iotdb/tree/master/grafana-plugin" target="_blank" rel="noopener noreferrer">Grafana<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> visualization tool.</p><p><strong>How does IoTDB handle duplicate points?</strong></p><p>A data point is uniquely identified by a full time series path (e.g. <code>root.vehicle.d0.s0</code>) and timestamp. If you submit a new point with the same path and timestamp as an existing point, IoTDB updates the value of this point instead of inserting a new point.</p><p><strong>How can I tell what type of the specific timeseries?</strong></p><p>Use <code>SHOW TIMESERIES &lt;timeseries path&gt;</code> SQL in IoTDB&#39;s Command Line Interface:</p><p>For example, if you want to know the type of all timeseries, the &lt;timeseries path&gt; should be <code>root</code>. The statement will be:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>IoTDB&gt; show timeseries root
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>If you want to query specific sensor, you can replace the &lt;timeseries path&gt; with the sensor name. For example:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>IoTDB&gt; show timeseries root.fit.d1.s1
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Otherwise, you can also use wildcard in timeseries path:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>IoTDB&gt; show timeseries root.fit.d1.*
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p><strong>How can I change IoTDB&#39;s Cli time display format?</strong></p><p>The default IoTDB&#39;s Cli time display format is readable (e.g. <code>1970-01-01T08:00:00.001</code>), if you want to display time in timestamp type or other readable format, add parameter <code>-disableISO8601</code> in start command:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>&gt; $IOTDB_CLI_HOME/sbin/start-cli.sh -h 127.0.0.1 -p 6667 -u root -pw root -disableISO8601
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p><strong>How to handle error <code>IndexOutOfBoundsException</code> from <code>org.apache.ratis.grpc.server.GrpcLogAppender</code>?</strong></p><p>It is an internal error introduced by Ratis 2.4.1 dependency, and we can safely ignore this exception as it will<br> not affect normal operations. We will fix this message in the incoming releases.</p></div><!--[--><!----><!--]--><footer class="vp-page-meta"><div class="vp-meta-item edit-link"><a href="https://github.com/apache/iotdb-docs/edit/main/src/UserGuide/V1.1.x/FAQ/Frequently-asked-questions.md" rel="noopener noreferrer" target="_blank" aria-label="Found Error? Edit this page on GitHub" class="nav-link vp-meta-label"><!--[--><svg xmlns="http://www.w3.org/2000/svg" class="icon edit-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="edit icon"><path d="M430.818 653.65a60.46 60.46 0 0 1-50.96-93.281l71.69-114.012 7.773-10.365L816.038 80.138A60.46 60.46 0 0 1 859.225 62a60.46 60.46 0 0 1 43.186 18.138l43.186 43.186a60.46 60.46 0 0 1 0 86.373L588.879 565.55l-8.637 8.637-117.466 68.234a60.46 60.46 0 0 1-31.958 11.229z"></path><path d="M728.802 962H252.891A190.883 190.883 0 0 1 62.008 771.98V296.934a190.883 190.883 0 0 1 190.883-192.61h267.754a60.46 60.46 0 0 1 0 120.92H252.891a69.962 69.962 0 0 0-69.098 69.099V771.98a69.962 69.962 0 0 0 69.098 69.098h475.911A69.962 69.962 0 0 0 797.9 771.98V503.363a60.46 60.46 0 1 1 120.922 0V771.98A190.883 190.883 0 0 1 728.802 962z"></path></svg><!--]-->Found Error? Edit this page on GitHub<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></div><div class="vp-meta-item git-info"><div class="update-time"><span class="vp-meta-label">Last update: </span><!----></div><!----></div></footer><nav class="vp-page-nav"><!----><a class="route-link nav-link next" href="/UserGuide/V1.1.x/FAQ/FAQ-for-cluster-setup.html" aria-label="FAQ for cluster setup"><div class="hint">Next<span class="arrow end"></span></div><div class="link">FAQ for cluster setup<!----></div></a></nav><!----><!--[--><!----><!--]--><!--]--></main><!--]--><footer style="padding-bottom:2rem;"><span id="doc-version" style="display:none;">rel/1.1</span><p style="text-align:center;color:#909399;font-size:12px;margin:0 30px;">Copyright © 2024 The Apache Software Foundation.<br> Apache and the Apache feather logo are trademarks of The Apache Software Foundation</p><p style="text-align:center;margin-top:10px;color:#909399;font-size:12px;margin:0 30px;"><strong>Have a question?</strong> Connect with us on QQ, WeChat, or Slack. <a href="https://github.com/apache/iotdb/issues/1995">Join the community</a> now.</p></footer></div><!--]--><!--]--><!--[--><!----><!--]--><!--]--></div>
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