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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_0000001622401169"></a><a name="EN-US_TOPIC_0000001622401169"></a>
<h1 class="topictitle1">Hot and Cold Table Functions</h1>
<div id="body0000001622401169"><div class="section" id="EN-US_TOPIC_0000001622401169__section78612133302"><h4 class="sectiontitle">pg_obs_cold_refresh_time(table_name, time)</h4><p id="EN-US_TOPIC_0000001622401169__p12732409111">Description: Modifies the time when cold data in a multi-temperature table is migrated to OBS. The default value is 00:00 every day.</p>
<p id="EN-US_TOPIC_0000001622401169__p117315402115"><strong id="EN-US_TOPIC_0000001622401169__b14126166125328">table_name</strong> indicates the name of the multi-temperature table, and the type is Name. <strong id="EN-US_TOPIC_0000001622401169__b5997263375328">time</strong> indicates the time when the data switchover task is scheduled, and the type is Time.</p>
<p id="EN-US_TOPIC_0000001622401169__p12851940311">Return value: SUCCESS. The time is successfully modified.</p>
<p id="EN-US_TOPIC_0000001622401169__p14937112117266">Example:</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001622401169__screen2937152122611"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span></pre></div></td><td class="code"><div><pre><span></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">pg_obs_cold_refresh_time</span><span class="p">(</span><span class="s1">'lifecycle_table'</span><span class="p">,</span><span class="w"> </span><span class="s1">'06:30:00'</span><span class="p">);</span>
<span class="n">pg_obs_cold_refresh_time</span>
<span class="c1">--------------------------</span>
<span class="w"> </span><span class="n">SUCCESS</span>
<span class="p">(</span><span class="mi">1</span><span class="w"> </span><span class="k">row</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</div>
<div class="section" id="EN-US_TOPIC_0000001622401169__section13322172611308"><h4 class="sectiontitle">pg_refresh_storage()</h4><p id="EN-US_TOPIC_0000001622401169__p1286840519">Description: Switches hot data to cold data on all hot and cold tables (in OBS).</p>
<p id="EN-US_TOPIC_0000001622401169__p138619401012">Return type: int</p>
<p id="EN-US_TOPIC_0000001622401169__p13861740614">Fields in the returned value</p>
<ul id="EN-US_TOPIC_0000001622401169__ul28615406118"><li id="EN-US_TOPIC_0000001622401169__li148654015119">success_count int: indicates the number of tables that are successfully switched.</li><li id="EN-US_TOPIC_0000001622401169__li17871240312">failed_count int: indicates the number of tables that fail to be switched.</li></ul>
<p id="EN-US_TOPIC_0000001622401169__p19601638132314">Example:</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001622401169__screen13601123832316"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span></pre></div></td><td class="code"><div><pre><span></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">pg_refresh_storage</span><span class="p">();</span>
<span class="w"> </span><span class="n">success_count</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">failed_count</span>
<span class="c1">---------------+--------------</span>
<span class="w"> </span><span class="mi">1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span>
<span class="p">(</span><span class="mi">1</span><span class="w"> </span><span class="k">row</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</div>
<div class="section" id="EN-US_TOPIC_0000001622401169__section15517162412388"><h4 class="sectiontitle">pg_lifecycle_table_data_distribute(table_name)</h4><p id="EN-US_TOPIC_0000001622401169__p451712443811">Description: Views the data distribution of a cold or hot table.</p>
<p id="EN-US_TOPIC_0000001622401169__p13517024173816"><strong id="EN-US_TOPIC_0000001622401169__b36952066103">table_name</strong> indicates the table name and cannot be left blank.</p>
<p id="EN-US_TOPIC_0000001622401169__p5517924203814">Return value: record</p>
<p id="EN-US_TOPIC_0000001622401169__p89221921174416">Example: Multiple records are generated based on the number of nodes. The following example shows the data distribution in the <strong id="EN-US_TOPIC_0000001622401169__b20999181251110">w1</strong> table when there is only one DN node.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001622401169__screen292213211449"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span></pre></div></td><td class="code"><div><pre><span></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">pg_catalog</span><span class="p">.</span><span class="n">pg_lifecycle_table_data_distribute</span><span class="p">(</span><span class="s1">'w1'</span><span class="p">);</span>
<span class="w"> </span><span class="n">schemaname</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">tablename</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">nodename</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">hotpartition</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">coldpartition</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">switchablepartition</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">hotdatasize</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">colddatasize</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">switchabledatasize</span><span class="w"> </span>
<span class="c1">------------+-----------+----------+--------------+---------------+---------------------+-------------+--------------+--------------------</span>
<span class="w"> </span><span class="k">public</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">w1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">dn_1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">p2</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">p1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">80</span><span class="w"> </span><span class="n">KB</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="n">bytes</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="n">bytes</span>
<span class="p">(</span><span class="mi">1</span><span class="w"> </span><span class="k">row</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</div>
<div class="section" id="EN-US_TOPIC_0000001622401169__section883111803917"><h4 class="sectiontitle">pg_lifecycle_node_data_distribute()</h4><p id="EN-US_TOPIC_0000001622401169__p1293193010556">Description: Views the data distribution of all hot and cold tables.</p>
<p id="EN-US_TOPIC_0000001622401169__p683214813391">Return value: record</p>
<p id="EN-US_TOPIC_0000001622401169__p49891132104015">Example: There are two cold and hot tables in the database. The data distribution is as follows:</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001622401169__screen18989632154014"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span>
<span class="normal">6</span></pre></div></td><td class="code"><div><pre><span></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">pg_catalog</span><span class="p">.</span><span class="n">pg_lifecycle_node_data_distribute</span><span class="p">();</span>
<span class="w"> </span><span class="n">schemaname</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">tablename</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">nodename</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">hotpartition</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">coldpartition</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">switchablepartition</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">hotdatasize</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">colddatasize</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">switchabledatasize</span><span class="w"> </span>
<span class="c1">------------+-----------+----------+--------------+---------------+---------------------+-------------+--------------+--------------------</span>
<span class="w"> </span><span class="k">public</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">w1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">dn_1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">p2</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">p1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">81920</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span>
<span class="w"> </span><span class="k">public</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">w2</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">dn_1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">p2</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">p1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">81920</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span>
<span class="p">(</span><span class="mi">2</span><span class="w"> </span><span class="k">rows</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_06_0058.html">Database Object Functions</a></div>
</div>
</div>
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