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Lu, Huayi e6fa411af0 DWS DEV 830.201 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2024-05-16 07:24:04 +00:00

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<a name="EN-US_TOPIC_0000001188482190"></a><a name="EN-US_TOPIC_0000001188482190"></a>
<h1 class="topictitle1">Exporting Data</h1>
<div id="body8662426"><div class="section" id="EN-US_TOPIC_0000001188482190__s99e15cc874f543108afae0ed2d488f9d"><h4 class="sectiontitle">Prerequisites</h4><p id="EN-US_TOPIC_0000001188482190__a212f249a9b9b420582b2f8b1e727d3b1">Ensure that the IP addresses and ports of servers where CNs and DNs are deployed can connect to those of the GDS server.</p>
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<div class="section" id="EN-US_TOPIC_0000001188482190__sd83c905305044697b6c38ee7e3f6a2d3"><h4 class="sectiontitle">Syntax</h4><div class="p" id="EN-US_TOPIC_0000001188482190__p1698442154416"><strong id="EN-US_TOPIC_0000001188482190__b98560214267">Run the following command to export data:</strong><div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188482190__screen1217773755513"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="p">[</span><span class="k">Foreign</span><span class="w"> </span><span class="k">table</span><span class="w"> </span><span class="n">name</span><span class="p">]</span><span class="w"> </span><span class="k">SELECT</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="p">[</span><span class="k">Source</span><span class="w"> </span><span class="k">table</span><span class="w"> </span><span class="n">name</span><span class="p">];</span>
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<div class="note" id="EN-US_TOPIC_0000001188482190__note4178183715515"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001188482190__p1317983745513">Create batch processing scripts to export data in parallel. The degree of parallelism depends on the server resource usage. You can test several tables and monitor resource usage to determine whether to increase or reduce the amount. Common resource monitoring commands include <strong id="EN-US_TOPIC_0000001188482190__b11701106249">top</strong> for memory and CPU usage, <strong id="EN-US_TOPIC_0000001188482190__b8701709241">iostat</strong> for I/O usage, and <strong id="EN-US_TOPIC_0000001188482190__b1370112016245">sar</strong> for networks. For details about application cases, see <a href="dws_04_0268.html#EN-US_TOPIC_0000001188482140__s855daf73006d4e05ba6d04f8db74e7f6">Exporting Data Using Multiple Threads</a>.</p>
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<div class="section" id="EN-US_TOPIC_0000001188482190__s27b48dc313654a5ba14e644f5dc861f8"><h4 class="sectiontitle">Examples</h4><ul id="EN-US_TOPIC_0000001188482190__u77380fc72e5d4011952b7ffef1c0d3ed"><li id="EN-US_TOPIC_0000001188482190__l40b1177e4b124ebabc0e49596aa99dd0"><strong id="EN-US_TOPIC_0000001188482190__b22929371178">Example 1</strong>: Export data from the <strong id="EN-US_TOPIC_0000001188482190__b84235270616375">reason</strong> table to data files through the <strong id="EN-US_TOPIC_0000001188482190__b158231254164410">foreign_tpcds_reasons</strong> foreign table.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188482190__s9a25ffa431a04fadb87d6aeb12fdecd0"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="n">foreign_tpcds_reasons</span><span class="w"> </span><span class="k">SELECT</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">tpcds</span><span class="p">.</span><span class="n">reason</span><span class="p">;</span>
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</li><li id="EN-US_TOPIC_0000001188482190__l366d3a1c1e4447aa8301be56c9c26824"><strong id="EN-US_TOPIC_0000001188482190__b436115021172">Example 2</strong>: Export part of the data to data files by specifying the filter condition <strong id="EN-US_TOPIC_0000001188482190__b842352706163759">r_reason_sk =1</strong>.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188482190__sea5ffb60423e4756b8fe475f204dbe97"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="n">foreign_tpcds_reasons</span><span class="w"> </span><span class="k">SELECT</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">tpcds</span><span class="p">.</span><span class="n">reason</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">r_reason_sk</span><span class="o">=</span><span class="mi">1</span><span class="p">;</span>
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</li><li id="EN-US_TOPIC_0000001188482190__l1f2963ef8aa54b87aed1e01acfc156b9"><strong id="EN-US_TOPIC_0000001188482190__en-us_topic_0117443421_b9038655183151">Example 3</strong>: Data of a special type, such as RAW, is exported as a binary file, which cannot be recognized by the import tool. You need to use the RAWTOHEX() function to convert it to hexadecimal the format before export.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188482190__s4f9161f29cfe4a13814417d3c31b7689"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">INSERT</span><span class="w"> </span><span class="k">INTO</span><span class="w"> </span><span class="n">foreign_tpcds_reasons</span><span class="w"> </span><span class="k">SELECT</span><span class="w"> </span><span class="n">RAWTOHEX</span><span class="p">(</span><span class="k">c</span><span class="p">)</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">tpcds</span><span class="p">.</span><span class="n">reason</span><span class="p">;</span><span class="w"> </span>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0261.html">Using GDS to Export Data to a Remote Server</a></div>
</div>
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