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doc-exports/docs/dws/dev/dws_06_0139.html
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_0000001188270512"></a><a name="EN-US_TOPIC_0000001188270512"></a>
<h1 class="topictitle1">ALTER SESSION</h1>
<div id="body8662426"><div class="section" id="EN-US_TOPIC_0000001188270512__s16bb1a2b120748559a4fd2cfe746c9f2"><h4 class="sectiontitle">Function</h4><p id="EN-US_TOPIC_0000001188270512__a6145022253704fc3a1a3e997a0a278ee"><strong id="EN-US_TOPIC_0000001188270512__en-us_topic_0058965705_b3749138185119">ALTER SESSION</strong> defines or modifies the conditions or parameters that affect the current session. Modified session parameters are kept until the current session is disconnected.</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188270512__sa9e57724d49846aabc39ec8fb33baf00"><h4 class="sectiontitle">Precautions</h4><ul id="EN-US_TOPIC_0000001188270512__ubfbd159c84e645bb8dfae1c544f68ca8"><li id="EN-US_TOPIC_0000001188270512__l60a5cbd492204b129033d7d44bffd078">If the <strong id="EN-US_TOPIC_0000001188270512__b31046844133636">START TRANSACTION</strong> command is not executed before the <strong id="EN-US_TOPIC_0000001188270512__b15556199533636">SET TRANSACTION</strong> command, the transaction is ended instantly and the command does not take effect.</li><li id="EN-US_TOPIC_0000001188270512__le2176e8a5b5d4dc28a5cbf7ef8db37cc">You can use the transaction_mode(s) method declared in the <strong id="EN-US_TOPIC_0000001188270512__b187899938933636">START TRANSACTION</strong> command to avoid using the <strong id="EN-US_TOPIC_0000001188270512__b54144424033636">SET TRANSACTION</strong> command.</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001188270512__s54a8c87c07c143fc82d827afa3845b22"><h4 class="sectiontitle">Syntax</h4><ul id="EN-US_TOPIC_0000001188270512__ubb3e96b2a1bb49aeb2a1bb1869662602"><li id="EN-US_TOPIC_0000001188270512__l44fe53fc0dcc42a2b7b7ccd9e09a095b">Set transaction parameters of a session.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__sa18a57883e4b4f628aa7d0756ae880e8"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">CHARACTERISTICS</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="k">TRANSACTION</span>
<span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">ISOLATION</span><span class="w"> </span><span class="k">LEVEL</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">COMMITTED</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">UNCOMMITTED</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">ONLY</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">WRITE</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="p">[,</span><span class="w"> </span><span class="p">...]</span><span class="w"> </span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001188270512__l0599e1b59d8a407487f1be9678b7715c">Set other running parameters of a session.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__s1fcd1764d0fa410e880854be030d11d6"><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>
<span class="normal"> 7</span>
<span class="normal"> 8</span>
<span class="normal"> 9</span>
<span class="normal">10</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span>
<span class="w"> </span><span class="err">{{</span><span class="n">config_parameter</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="n">value</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DEFAULT</span><span class="w"> </span><span class="err">}</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="k">CURRENT</span><span class="w"> </span><span class="err">}}</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">CURRENT_SCHEMA</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">schema</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DEFAULT</span><span class="w"> </span><span class="err">}</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">TIME</span><span class="w"> </span><span class="k">ZONE</span><span class="w"> </span><span class="n">time_zone</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">SCHEMA</span><span class="w"> </span><span class="k">schema</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">NAMES</span><span class="w"> </span><span class="n">encoding_name</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">ROLE</span><span class="w"> </span><span class="n">role_name</span><span class="w"> </span><span class="n">PASSWORD</span><span class="w"> </span><span class="s1">'password'</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">AUTHORIZATION</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="n">role_name</span><span class="w"> </span><span class="n">PASSWORD</span><span class="w"> </span><span class="s1">'password'</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DEFAULT</span><span class="w"> </span><span class="err">}</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">XML</span><span class="w"> </span><span class="k">OPTION</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="n">DOCUMENT</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">CONTENT</span><span class="w"> </span><span class="err">}</span>
<span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001188270512__section1075742392018"><h4 class="sectiontitle">Parameter Description</h4><ul id="EN-US_TOPIC_0000001188270512__uaef51370c2e94ba5ad424d790db475df"><li id="EN-US_TOPIC_0000001188270512__ld65b9af41f26448bbf29330fa8be13ae"><strong id="EN-US_TOPIC_0000001188270512__a0c502c453b9a4f43bba4ccbde47534c0">SESSION</strong><p id="EN-US_TOPIC_0000001188270512__a9942dfc426bd497eb76bfef4505cd053">Indicates that the specified parameters take effect for the current session. This is the default value if neither <strong id="EN-US_TOPIC_0000001188270512__b86873433922024">SESSION</strong> nor <strong id="EN-US_TOPIC_0000001188270512__b74456331422024">LOCAL</strong> appears.</p>
<p id="EN-US_TOPIC_0000001188270512__a2015b612098943e79d706d69b0ca68ec">If <strong id="EN-US_TOPIC_0000001188270512__b179387676222024">SET</strong> or <strong id="EN-US_TOPIC_0000001188270512__b16080222422024">SET SESSION</strong> is executed within a transaction that is later aborted, the effects of the <strong id="EN-US_TOPIC_0000001188270512__b45663112222024">SET</strong> command disappear when the transaction is rolled back. Once the surrounding transaction is committed, the effects will persist until the end of the session, unless overridden by another <strong id="EN-US_TOPIC_0000001188270512__b108112517022024">SET</strong>.</p>
</li><li id="EN-US_TOPIC_0000001188270512__lbaf981aced3246faa389d671a78e6963"><strong id="EN-US_TOPIC_0000001188270512__a0e80736ca13c4261b8ddf9cba22fefd9">config_parameter</strong><p id="EN-US_TOPIC_0000001188270512__ab003c4b5277140e091ac396112e16b6d">Indicates the configurable run-time parameters. You can use <strong id="EN-US_TOPIC_0000001188270512__b132617331622024">SHOW ALL</strong> to view available run-time parameters.</p>
<div class="note" id="EN-US_TOPIC_0000001188270512__nef4970e499f644de8aeb492b47cee4fe"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001188270512__a1f0a0e82e34144d9b5bea5c4e42fbf47">Some parameters that viewed by <strong id="EN-US_TOPIC_0000001188270512__b109918614322024">SHOW ALL</strong> cannot be set by <strong id="EN-US_TOPIC_0000001188270512__b109007970122024">SET</strong>. For example, <strong id="EN-US_TOPIC_0000001188270512__b195840721622024">max_datanodes</strong>.</p>
</div></div>
</li><li id="EN-US_TOPIC_0000001188270512__li11211144692214"><strong id="EN-US_TOPIC_0000001188270512__ae5e4910cff034d1f82227ef97023aba7">value</strong><p id="EN-US_TOPIC_0000001188270512__p15211646132212">Indicates the new value of the <strong id="EN-US_TOPIC_0000001188270512__b142329543022024">config_parameter</strong> parameter. This parameter can be specified as string constants, identifiers, numbers, or comma-separated lists of these. <strong id="EN-US_TOPIC_0000001188270512__b69084596322024">DEFAULT</strong> can be written to indicate resetting the parameter to its default value.</p>
</li><li id="EN-US_TOPIC_0000001188270512__leeb7d19987ab4946ac17f92144a612d0"><strong id="EN-US_TOPIC_0000001188270512__a15b39046fdf2417c898d01be5f45574f">TIME ZONE timezone</strong><p id="EN-US_TOPIC_0000001188270512__acaaf7f048bec4354a6b2a2eb945b7359">Indicates the local time zone for the current session.</p>
<p id="EN-US_TOPIC_0000001188270512__a1fc2504fe345415a8fafea6348a80f41">Value range: A valid local time zone. The corresponding run-time parameter is <strong id="EN-US_TOPIC_0000001188270512__b53988880922024">TimeZone</strong>. The default value is <strong id="EN-US_TOPIC_0000001188270512__b109128292822024">PRC</strong>.</p>
</li><li id="EN-US_TOPIC_0000001188270512__lf8fede1df65341a6bdf1ca72054ae1b5"><strong id="EN-US_TOPIC_0000001188270512__a76c688f0a800438f8eb3a6a1a9c484c6">CURRENT_SCHEMA</strong><p id="EN-US_TOPIC_0000001188270512__a2a80039f78b546d180a0ec9dc54611ff">Indicates the current schema.</p>
<p id="EN-US_TOPIC_0000001188270512__a8c062f091e2b496087978383add05be6">Value range: An existing schema name.</p>
</li><li id="EN-US_TOPIC_0000001188270512__l63483e54edaa458894ff7619bd3cbd0d"><strong id="EN-US_TOPIC_0000001188270512__a2637ea846f064755a4c2097a5ddeec91">SCHEMA schema</strong><p id="EN-US_TOPIC_0000001188270512__ac830ab894acc442e8932330b9faa0d07">Indicates the current schema. Here the schema is a string.</p>
<p id="EN-US_TOPIC_0000001188270512__a44e32318da5c4682a2b08e95148d7b9b">Example: set schema 'public';</p>
</li><li id="EN-US_TOPIC_0000001188270512__lf94a02aa3d774d639fad101cbc7aa358"><strong id="EN-US_TOPIC_0000001188270512__a50d01f392eca439d8a67f97f2384b4f2">NAMES encoding_name</strong><p id="EN-US_TOPIC_0000001188270512__a276c75e1746a49139802fc6cb36c0fa9">Indicates the client character encoding name. This command is equivalent to <strong id="EN-US_TOPIC_0000001188270512__b156293856322024">set client_encoding to encoding_name</strong>.</p>
<p id="EN-US_TOPIC_0000001188270512__a2bd2df70f3694afaa46a425a0f3af6c8">Value range: A valid character encoding name. The run-time parameter corresponding to this option is <strong id="EN-US_TOPIC_0000001188270512__b191399498522024">client_encoding</strong>. The default encoding is <strong id="EN-US_TOPIC_0000001188270512__b101472430422024">UTF8</strong>.</p>
</li><li id="EN-US_TOPIC_0000001188270512__l2f8c73b884ac49b0a520091637b134a6"><strong id="EN-US_TOPIC_0000001188270512__a863e38dde47c4b15b512c77d81e6ac4f">XML OPTION option</strong><p id="EN-US_TOPIC_0000001188270512__a0d698c5ebaef4f1289c663c1eb087e74">Indicates the XML resolution mode.</p>
<p id="EN-US_TOPIC_0000001188270512__aa4856683df67450aa3cf07022a3dc3c8">Value range: <strong id="EN-US_TOPIC_0000001188270512__b110977466022024">CONTENT</strong> (default), <strong id="EN-US_TOPIC_0000001188270512__b96181714322024">DOCUMENT</strong></p>
</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001188270512__sa9f477c6b0de4cba9ff01c597dbcb9dd"><h4 class="sectiontitle">Examples</h4><p id="EN-US_TOPIC_0000001188270512__p1998146131318">Create the <strong id="EN-US_TOPIC_0000001188270512__b186909514933636">ds</strong> schema.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen6139135510134"><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">CREATE</span><span class="w"> </span><span class="k">SCHEMA</span><span class="w"> </span><span class="n">ds</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p1699812469136">Set the search path of the schema.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen196013071410"><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">SET</span><span class="w"> </span><span class="n">SEARCH_PATH</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="n">ds</span><span class="p">,</span><span class="w"> </span><span class="k">public</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p189985460135">Set the time/date type to the traditional postgres format (date before month).</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen7235751141"><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">SET</span><span class="w"> </span><span class="n">DATESTYLE</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="n">postgres</span><span class="p">,</span><span class="w"> </span><span class="n">dmy</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p10998146181310">Set the character code of the current session to UTF8.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen4803101271411"><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">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="k">NAMES</span><span class="w"> </span><span class="s1">'UTF8'</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p3998194612134">Set the time zone to Berkeley of California.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen1246201981413"><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">SET</span><span class="w"> </span><span class="k">TIME</span><span class="w"> </span><span class="k">ZONE</span><span class="w"> </span><span class="s1">'PST8PDT'</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p29981646151317">Set the time zone to Italy.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen9629142415149"><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">SET</span><span class="w"> </span><span class="k">TIME</span><span class="w"> </span><span class="k">ZONE</span><span class="w"> </span><span class="s1">'Europe/Rome'</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p1999824615134">Set the current schema.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen11892163017142"><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">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="n">CURRENT_SCHEMA</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="n">tpcds</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p89981946101317">Set <strong id="EN-US_TOPIC_0000001188270512__b92304356133636">XML OPTION</strong> to <strong id="EN-US_TOPIC_0000001188270512__b148560588033636">DOCUMENT</strong>.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen18556163691420"><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">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="n">XML</span><span class="w"> </span><span class="k">OPTION</span><span class="w"> </span><span class="n">DOCUMENT</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p1099814618135">Create the role <strong id="EN-US_TOPIC_0000001188270512__b27676880433636">joe</strong>, and set the session role to <strong id="EN-US_TOPIC_0000001188270512__b0950510192415">joe</strong>.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen10150164541419"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">ROLE</span><span class="w"> </span><span class="n">joe</span><span class="w"> </span><span class="k">WITH</span><span class="w"> </span><span class="n">PASSWORD</span><span class="w"> </span><span class="s1">'{Password}'</span><span class="p">;</span>
<span class="k">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">AUTHORIZATION</span><span class="w"> </span><span class="n">joe</span><span class="w"> </span><span class="n">PASSWORD</span><span class="w"> </span><span class="s1">'{Password}'</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001188270512__p1299715463133">Switch to the default user.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001188270512__screen076175181413"><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">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">AUTHORIZATION</span><span class="w"> </span><span class="k">default</span><span class="p">;</span>
</pre></div></td></tr></table></div>
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<div class="section" id="EN-US_TOPIC_0000001188270512__sa427c8fd0e23481ba0ff89ec7361782f"><h4 class="sectiontitle">Helpful Links</h4><p id="EN-US_TOPIC_0000001188270512__a3f81ee95a4ac4e618d597a92fa80785f"><a href="dws_06_0220.html">SET</a></p>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_06_0118.html">DDL Syntax</a></div>
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