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doc-exports/docs/dws/dev/dws_04_0922.html
Lu, Huayi a24ca60074 DWS DEVELOPER 811 version 
Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2023-01-19 13:37:49 +00:00

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<a name="EN-US_TOPIC_0000001145694507"></a><a name="EN-US_TOPIC_0000001145694507"></a>
<h1 class="topictitle1">Workload Management</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_p618513518710">If database resource usage is not controlled, concurrent tasks easily preempt resources. As a result, the OS will be overloaded and cannot respond to user tasks; or even crash and cannot provide any services to users. The <span id="EN-US_TOPIC_0000001145694507__text763749">GaussDB(DWS)</span> workload management function balances the database workload based on available resources to avoid database overloading.</p>
<div class="section" id="EN-US_TOPIC_0000001145694507__sc1692143c357427cbeadd6160010fd40"><a name="EN-US_TOPIC_0000001145694507__sc1692143c357427cbeadd6160010fd40"></a><a name="sc1692143c357427cbeadd6160010fd40"></a><h4 class="sectiontitle">use_workload_manager</h4><p id="EN-US_TOPIC_0000001145694507__a316504de19154266a6636c8d1b50369d"><strong id="EN-US_TOPIC_0000001145694507__b652788289142544">Parameter description</strong>: Specifies whether to enable the resource management function. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p4716143414116"><strong id="EN-US_TOPIC_0000001145694507__b17311519203317">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__a6a4fa4df92ad45b481bac62a94474e39"><strong id="EN-US_TOPIC_0000001145694507__b118151824103315">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__u45d51c5a02724590866ccf03b1023e22"><li id="EN-US_TOPIC_0000001145694507__lf888c078ac404b47b69c195cf7048405"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706152821_1">on</strong> indicates the resource management function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__l3291c2651e5c4f019212d19cb7b693fd"><strong id="EN-US_TOPIC_0000001145694507__b181436343419">off</strong> indicates the resource management function is disabled.<div class="note" id="EN-US_TOPIC_0000001145694507__note2091118244406"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="EN-US_TOPIC_0000001145694507__ul1602153014301"><li id="EN-US_TOPIC_0000001145694507__li1602113013013">If a method in <a href="dws_04_0885.html#EN-US_TOPIC_0000001145814675__s8adb68393b48467a948956afaaaf8589">Setting GUC Parameters</a> is used to change the parameter value, the new value takes effect only for the threads that are started after the change. In addition, the new value does not take effect for new jobs that are executed by backend threads and reused threads. You can make the new value take effect for these threads by using <strong id="EN-US_TOPIC_0000001145694507__b10447103211135">kill session</strong> or restarting the node.</li><li id="EN-US_TOPIC_0000001145694507__li976571011338">After the value of <strong id="EN-US_TOPIC_0000001145694507__b43513563410">use_workload_manager</strong> changes from <strong id="EN-US_TOPIC_0000001145694507__b14136181811341">off</strong> to <strong id="EN-US_TOPIC_0000001145694507__b10122202118346">on</strong>, the resource management view becomes available, and you can query the storage resource usage collected in the <strong id="EN-US_TOPIC_0000001145694507__b106581334135218">off</strong> state. If there are slight errors and the storage resource usage needs to be corrected, run the following command. If data is inserted into the table during the command execution, the statistics may be inaccurate.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001145694507__screen543292811347"><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">select</span><span class="w"> </span><span class="n">gs_wlm_readjust_user_space</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span><span class="w"></span>
</pre></div></td></tr></table></div>
</div>
</li></ul>
</div></div>
</li></ul>
<p id="EN-US_TOPIC_0000001145694507__a87e5c5017855416bb743faf01c512c3f"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b12149173155843_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613017">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s39ebfe72e74648fb81f92fa564b9d39e"><h4 class="sectiontitle">enable_control_group</h4><p id="EN-US_TOPIC_0000001145694507__ad5284729289048e2b4f7eb112f42e6ab"><strong id="EN-US_TOPIC_0000001145694507__b29061023201313">Parameter description</strong>: Specifies whether to enable the Cgroup management function. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p151621540121"><strong id="EN-US_TOPIC_0000001145694507__b91371710143715">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__a838a482a501c49218bb74c2c5f2df3db"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_4">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__uad3f115a20364324b5f0221faece3bc6"><li id="EN-US_TOPIC_0000001145694507__l9dce0aeca41c46eabcd7e7e1f730cd50"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706152821_3">on</strong> indicates the Cgroup management function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__lfa3c37995fb14b5a876fdedb67bb0985"><strong id="EN-US_TOPIC_0000001145694507__b4363056125518">off</strong> indicates the Cgroup management function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__ada6c94e46b3e4baa98b34fa8148b338e"><strong id="EN-US_TOPIC_0000001145694507__b24231419414">Default value</strong>: on</p>
<div class="note" id="EN-US_TOPIC_0000001145694507__note1841083419401"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001145694507__p3583455175111">If a method in <a href="dws_04_0885.html#EN-US_TOPIC_0000001145814675__s8adb68393b48467a948956afaaaf8589">Setting GUC Parameters</a> is used to change the parameter value, the new value takes effect only for the threads that are started after the change. In addition, the new value does not take effect for new jobs that are executed by backend threads and reused threads. You can make the new value take effect for these threads by using <strong id="EN-US_TOPIC_0000001145694507__b053151116166">kill session</strong> or restarting the node.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__sd69ee7d7896a492fb47b3977f1cc0d64"><h4 class="sectiontitle">enable_backend_control</h4><p id="EN-US_TOPIC_0000001145694507__a415d4558eda84a58b976d1492207203f"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b8423527061625_1">Parameter description</strong>: Specifies whether to control the database permanent thread to the <strong id="EN-US_TOPIC_0000001145694507__b842352706191222">DefaultBackend</strong> Cgroup. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__a27c2ab222fa64f2f9e0158545d224405"><strong id="EN-US_TOPIC_0000001145694507__b2932417103819">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001145694507__af0635b889a0b42a1ab6ddb2f9eef6039"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_a680a24aa162b4e7584b5f9bc4be4bca7">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__uc6d879f6b847443ab147f469af3ed9ec"><li id="EN-US_TOPIC_0000001145694507__lc97a270344314b5095ad98fa0f017d53"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706161233">on</strong>: Controls the permanent thread to the <strong id="EN-US_TOPIC_0000001145694507__b842352706191416">DefaultBackend</strong> Cgroup.</li><li id="EN-US_TOPIC_0000001145694507__l3d67d717aa02400aac1d7c817e619279"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706161238">off</strong>: Does not control the permanent thread to the <strong id="EN-US_TOPIC_0000001145694507__b842352706191452">DefaultBackend</strong> Cgroup.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__adad89d368d7b4a35ab8358bfade03992"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_aeb2b50c132ce4f71b8a1582542cef1ac">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613137">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s0e0660e7300f4bf88f3a315b35fca5d2"><h4 class="sectiontitle">enable_vacuum_control</h4><p id="EN-US_TOPIC_0000001145694507__a7e3b3e8003174e789370d1d59409eef8"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b8423527061625_3">Parameter description</strong>: Specifies whether to control the database permanent thread autoVacuumWorker to the <strong id="EN-US_TOPIC_0000001145694507__b842352706191040">Vacuum</strong> Cgroup. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p8884154161216"><strong id="EN-US_TOPIC_0000001145694507__b1909013370">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001145694507__a6ecc9a1ee5924ebea3a1a5a202fb493d"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_a1d4b6429d75a4a9eade72b4bcc518630">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__u704e6d7b678247b497f45a9e504d66cc"><li id="EN-US_TOPIC_0000001145694507__l8651e4b645d545f586262e4b2e4fe39b"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b8423527061625_5">on</strong>: Controls the database permanent thread autoVacuumWorker to the <strong id="EN-US_TOPIC_0000001145694507__b842352706191537">Vacuum</strong> Cgroup.</li><li id="EN-US_TOPIC_0000001145694507__lea0e70c2ed484f83afa25eb75fb3b4c7"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b8423527061625_7">off</strong>: Does not control the database permanent thread autoVacuumWorker to the <strong id="EN-US_TOPIC_0000001145694507__b842352706191545">Vacuum</strong> Cgroup.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__a955a0271dc6544f4b1ac26a44dac5110"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b15854097155846_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706141744">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s46a1cb63ed974be883cbbcf68a7278c2"><h4 class="sectiontitle">enable_perm_space</h4><p id="EN-US_TOPIC_0000001145694507__a7437a2f18290429db6b71ff0677709c1"><strong id="EN-US_TOPIC_0000001145694507__b1462576847142759">Parameter description</strong>: Specifies whether to enable the perm space function. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p36931045131313"><strong id="EN-US_TOPIC_0000001145694507__b1011411208389">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001145694507__a960fb8db6a7241ad8fea3a9d09cbda4f"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_b1102664415112">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ua6462fa046b0460e938954882d611afa"><li id="EN-US_TOPIC_0000001145694507__l9bdf184d5ca84737be389d6ce9f74d1d"><strong id="EN-US_TOPIC_0000001145694507__b551791272">on</strong> indicates the perm space function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__l6be8caa82c8647c09b2edce3e14dbcf7"><strong id="EN-US_TOPIC_0000001145694507__b4433887534714">off</strong> indicates the perm space function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_p246103015112"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967679_b2933732">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_b842352706154337">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section13219124221519"><h4 class="sectiontitle">enable_verify_active_statements</h4><p id="EN-US_TOPIC_0000001145694507__p363315511184"><strong id="EN-US_TOPIC_0000001145694507__b46816572334714">Parameter description</strong>: Specifies whether to enable the background calibration function in static adaptive load scenarios. This parameter must be used on CNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p2633251141811"><strong id="EN-US_TOPIC_0000001145694507__b10411621183811">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p10262174221519"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_2">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ul12736420156"><li id="EN-US_TOPIC_0000001145694507__li10279134219158"><strong id="EN-US_TOPIC_0000001145694507__b4972265134714">on</strong> indicates the background calibration function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__li1229364210151"><strong id="EN-US_TOPIC_0000001145694507__b90450464934714">off</strong> indicates the background calibration function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p203071425155"><strong id="EN-US_TOPIC_0000001145694507__b2017362501">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b450662564">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s7a13b0da34a74fe886bdf7671e62019b"><h4 class="sectiontitle">max_active_statements</h4><p id="EN-US_TOPIC_0000001145694507__addc805286ca74ef9a2554b470c4fae80"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b84235270617340">Parameter description</strong>: Specifies the maximum global concurrency. This parameter applies to one CN.</p>
<p id="EN-US_TOPIC_0000001145694507__a447d771bfc8d4fe4aaf11bd98cf5fed4">The database administrator changes the value of this parameter based on system resources (for example, CPU, I/O, and memory resources) so that the system fully supports the concurrency tasks and avoids too many concurrency tasks resulting in system crash.</p>
<p id="EN-US_TOPIC_0000001145694507__p16407102791018"><strong id="EN-US_TOPIC_0000001145694507__b1787012212383">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__a074267e4991b476ebb38e7061f47c80f"><strong id="EN-US_TOPIC_0000001145694507__b1190172722719">Value range</strong>: an integer ranging from -1 to INT_MAX. The values <strong id="EN-US_TOPIC_0000001145694507__b8361163317211">-1</strong> and <strong id="EN-US_TOPIC_0000001145694507__b33896379211">0</strong> indicate that the number of concurrent requests is not limited.</p>
<p id="EN-US_TOPIC_0000001145694507__a3e180989283945129914c1800c110445"><strong id="EN-US_TOPIC_0000001145694507__b109654376103">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b1852764121011">60</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__sab51422c793f40ad8958c193761edaf9"><h4 class="sectiontitle">parctl_min_cost</h4><p id="EN-US_TOPIC_0000001145694507__a15fd2f5990cc4c9c8015b21c819cfd25"><strong id="EN-US_TOPIC_0000001145694507__b84235270617380">Parameter description</strong>: Specifies the minimum execution cost of a statement under the concurrency control of a resource pool.</p>
<p id="EN-US_TOPIC_0000001145694507__p157803941017"><strong id="EN-US_TOPIC_0000001145694507__b1352510222389">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__aade5fd4a9a6b4ef3ba9306281eefb5a3"><strong id="EN-US_TOPIC_0000001145694507__b180196129434714">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001145694507__ul88941839114812"><li id="EN-US_TOPIC_0000001145694507__li9894183913480">If the value is <strong id="EN-US_TOPIC_0000001145694507__b1522646042">–1</strong> or the cost of executing statements is less than 10, the job is controlled by the fast lane.</li><li id="EN-US_TOPIC_0000001145694507__li178941139194811">If the value is greater than or equal to <strong id="EN-US_TOPIC_0000001145694507__b16646110850">0</strong>, and the cost of executing statements exceeds the value and is greater than or equal to 10, the statements are subject to the concurrent limit of a resource pool.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__ad3ea3b4b3e664405aa381a3078a4debc"><strong id="EN-US_TOPIC_0000001145694507__b83871373311">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b3387137203116">100000</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s8159a12f556d464abbf1acffe467b548"><h4 class="sectiontitle">cgroup_name</h4><p id="EN-US_TOPIC_0000001145694507__a6d50fdbf988d447dbf68bf86dbc6fa5b"><strong id="EN-US_TOPIC_0000001145694507__a522d727b6be540ffb963a801b2f48052">Parameter description</strong>: Specifies the name of the Cgroup in use. It can be used to change the priorities of jobs in the queue of a Cgroup.</p>
<p id="EN-US_TOPIC_0000001145694507__p119020197324">If you set <strong id="EN-US_TOPIC_0000001145694507__b842352706175935">cgroup_name</strong> and then <strong id="EN-US_TOPIC_0000001145694507__b842352706175940">session_respool</strong>, the Cgroups associated with <strong id="EN-US_TOPIC_0000001145694507__b8423527061803">session_respool</strong> take effect. If you reverse the order, Cgroups associated with <strong id="EN-US_TOPIC_0000001145694507__b84235270618042">cgroup_name</strong> take effect.</p>
<p id="EN-US_TOPIC_0000001145694507__p75569413347">If the Workload Cgroup level is specified during the <strong id="EN-US_TOPIC_0000001145694507__b1631274119139">cgroup_name</strong> change, the database does not check the Cgroup level. The level ranges from 1 to 10.</p>
<p id="EN-US_TOPIC_0000001145694507__p141021638141912"><strong id="EN-US_TOPIC_0000001145694507__b206805233385">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p63212713170">You are not advised to set <strong id="EN-US_TOPIC_0000001145694507__b842352706181635">cgroup_name</strong> and <strong id="EN-US_TOPIC_0000001145694507__b842352706181640">session_respool</strong> at the same time.</p>
<p id="EN-US_TOPIC_0000001145694507__afb9148a5a4a54b2592c8b2610df13767"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b688672095621">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001145694507__a960082ccca4246e0a475c33188966896"><strong id="EN-US_TOPIC_0000001145694507__b16948152754819">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b18452203324810">DefaultClass:Medium</strong></p>
<div class="note" id="EN-US_TOPIC_0000001145694507__note1953653910322"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001145694507__p366615446327"><strong id="EN-US_TOPIC_0000001145694507__b429654704815">DefaultClass:Medium</strong> indicates the <strong id="EN-US_TOPIC_0000001145694507__b1048713795016">Medium</strong> Cgroup belonging to the <strong id="EN-US_TOPIC_0000001145694507__b173481122135011">Timeshare</strong> Cgroup under the <strong id="EN-US_TOPIC_0000001145694507__b1824672714505">DefaultClass</strong> Cgroup.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s9224d1039e814e98adaf4ad27b6f75a8"><h4 class="sectiontitle">cpu_collect_timer</h4><p id="EN-US_TOPIC_0000001145694507__aa6156749df6b4c92b932c96a799159f1"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b84235270617952">Parameter description</strong>: Specifies how frequently CPU data is collected during statement execution on DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__a3fdc9e4f16ad491d803cf5410e50e0f7">The database administrator changes the value of this parameter based on system resources (for example, CPU, I/O, and memory resources) so that the system fully supports the concurrency tasks and avoids too many concurrency tasks resulting in system crash.</p>
<p id="EN-US_TOPIC_0000001145694507__p197702445910"><strong id="EN-US_TOPIC_0000001145694507__b13991724143816">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__aba34754d9bce4b06bf6659dc7a0710c9"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967791_b23455951">Value range</strong>: an integer ranging from -1 to INT_MAX. The unit is second.</p>
<p id="EN-US_TOPIC_0000001145694507__a35237e01b6844cff85b60c4854b62d6f"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967582_b40689991104939_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967582_b84235270617812_1">30</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s565c7e2c8cb34d4db165766b74a73683"><h4 class="sectiontitle">enable_cgroup_switch</h4><p id="EN-US_TOPIC_0000001145694507__a5eca9c9caeac4b98a5ae1bdee735cf0a"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172123_1">Parameter description</strong>: Specifies whether the database automatically switches to the <strong id="EN-US_TOPIC_0000001145694507__b842352706192357">TopWD</strong> group when executing statements by group type.</p>
<p id="EN-US_TOPIC_0000001145694507__p241918691910"><strong id="EN-US_TOPIC_0000001145694507__b18921162543816">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__a0a1bc12cb50947aaab525684d57deda3"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_abdb6603792074f608afcc026778454fb">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__u508ca40006484f93ac6601714ce81f84"><li id="EN-US_TOPIC_0000001145694507__l24467bedd0504ff08a43c85df18138ba"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172123_3">on</strong>: The database automatically switches to the <strong id="EN-US_TOPIC_0000001145694507__b842352706192435">TopWD</strong> group when executing statements by group type.</li><li id="EN-US_TOPIC_0000001145694507__labe48b71421d46bfbf1665865f5169cf"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172123_5">off</strong>: The database does not automatically switch to the <strong id="EN-US_TOPIC_0000001145694507__b84235270619276">TopWD</strong> group when executing statements by group type.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__a2fc3159e811a498cbc4238818a718375"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b5971851117846_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613313">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s99d436e056b446d19c841da7b23faae8"><h4 class="sectiontitle">memory_tracking_mode</h4><p id="EN-US_TOPIC_0000001145694507__a67919fed03e44562bea8db4b97c2e70e"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172610">Parameter description</strong>: Specifies the memory information recording mode.</p>
<p id="EN-US_TOPIC_0000001145694507__p1746473641810"><strong id="EN-US_TOPIC_0000001145694507__b1852632613389">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__a66ad8055b3f04c22bda844ba1e2493cc"><strong id="EN-US_TOPIC_0000001145694507__b25782132328">Value range</strong>:</p>
<ul id="EN-US_TOPIC_0000001145694507__ul29059994172249"><li id="EN-US_TOPIC_0000001145694507__li16695073172249"><strong id="EN-US_TOPIC_0000001145694507__b842352706105333">none</strong>: Memory statistics is not collected.</li><li id="EN-US_TOPIC_0000001145694507__li5710012517239"><strong id="EN-US_TOPIC_0000001145694507__b842352706105432">normal:</strong> Only memory statistics is collected in real time and no file is generated.</li><li id="EN-US_TOPIC_0000001145694507__li56020122172333"><strong id="EN-US_TOPIC_0000001145694507__b842352706105529">executor:</strong> The statistics file is generated, containing the context information about all allocated memory used by the execution layer.</li><li id="EN-US_TOPIC_0000001145694507__li61119980172352"><strong id="EN-US_TOPIC_0000001145694507__b842352706112725">fullexec</strong>: The generated file includes the information about all memory contexts requested by the execution layer.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__a368ea04ff5554e6293efd92bdd49074c"><strong id="EN-US_TOPIC_0000001145694507__b10048826103114">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b110848183317">none</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s3f3dd81692d64ce08fa1a352e9ebb56f"><h4 class="sectiontitle">memory_detail_tracking</h4><p id="EN-US_TOPIC_0000001145694507__a72d25f2d0320437c992a285dcb72ce7f"><strong id="EN-US_TOPIC_0000001145694507__b1678060675144418">Parameter description</strong>: Specifies the sequence number of the memory background information distributed in the needed thread and <strong id="EN-US_TOPIC_0000001145694507__b842352706192855">plannodeid</strong> of the query where the current thread is located.</p>
<p id="EN-US_TOPIC_0000001145694507__p1245071620182"><strong id="EN-US_TOPIC_0000001145694507__b61126275389">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__af350ee0eedbe4e05b3454c4d69ce0b7c"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b37796097_1">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001145694507__a39299a499b1e41288f2d9ea1fdc82e42"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_b421586113118">Default value</strong>: empty</p>
<div class="notice" id="EN-US_TOPIC_0000001145694507__n83cc48fd8396484199f83f9de17a7247"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001145694507__a0c78987d9e3a4018abbf4890e1f7804d">It is recommended that you retain the default value for this parameter.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s9530ecdd2b0d4a98b67b66e32bf8e5d0"><a name="EN-US_TOPIC_0000001145694507__s9530ecdd2b0d4a98b67b66e32bf8e5d0"></a><a name="s9530ecdd2b0d4a98b67b66e32bf8e5d0"></a><h4 class="sectiontitle">enable_resource_track</h4><p id="EN-US_TOPIC_0000001145694507__ae718ea1b2bf14c248e8eb722b646360d"><strong id="EN-US_TOPIC_0000001145694507__b1681868811144355">Parameter description</strong>: Specifies whether the real-time resource monitoring function is enabled. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p16411142618918"><strong id="EN-US_TOPIC_0000001145694507__b1511714282389">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__aa360558c12b34fa28006d7763756d1da"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_6">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__u3ff70c8d7adb42d0a45d5b54d7b482d6"><li id="EN-US_TOPIC_0000001145694507__l502f22098a3546a38fb609437f27473d"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b842352706152821_5">on</strong> indicates the resource monitoring function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__l0b48936acbbe4f13a19e6dd43f120bd5"><strong id="EN-US_TOPIC_0000001145694507__b104214192034714">off</strong> indicates the resource monitoring function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__a32291243ba3049eba8785fab5e24526b"><strong id="EN-US_TOPIC_0000001145694507__b1101529633172346">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b421067350172346">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s5f116e109a2944e3854abcc56772eaa1"><h4 class="sectiontitle">enable_resource_record</h4><p id="EN-US_TOPIC_0000001145694507__p1091904413"><strong id="EN-US_TOPIC_0000001145694507__b832542111412">Parameter description</strong>: Specifies whether resource monitoring records are archived. If this parameter is set to <strong id="EN-US_TOPIC_0000001145694507__b383935210484">on</strong>, records in the <strong id="EN-US_TOPIC_0000001145694507__b1984015211483">history</strong> views (<strong id="EN-US_TOPIC_0000001145694507__b1840752104820">GS_WLM_SESSION_HISTORY</strong> and <strong id="EN-US_TOPIC_0000001145694507__b184165217481">GS_WLM_OPERATOR_HISTORY</strong>) are archived to the corresponding <strong id="EN-US_TOPIC_0000001145694507__b1984215521488">info</strong> views (<strong id="EN-US_TOPIC_0000001145694507__b38426525481">GS_WLM_SESSION_INFO</strong> and <strong id="EN-US_TOPIC_0000001145694507__b084345214810">GS_WLM_OPERATOR_INFO</strong>) at an interval of 3 minutes. After being archived, the records are deleted from the <strong id="EN-US_TOPIC_0000001145694507__b98491052194818">history</strong> views. This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p1179712121695"><strong id="EN-US_TOPIC_0000001145694507__b51611129203815">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__a2a0deb112b624e15a23774120200a46e"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_8">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__u1632ed197ebf48c5a6bc26e750b6c0ce"><li id="EN-US_TOPIC_0000001145694507__l084582a6e1e3496dbdc97769d266b4b7"><strong id="EN-US_TOPIC_0000001145694507__b96415896734714">on</strong> indicates that the resource monitoring records are archived.</li><li id="EN-US_TOPIC_0000001145694507__le34a6e152c0344d6bfc4e472e72efdeb"><strong id="EN-US_TOPIC_0000001145694507__b58509289134714">off</strong> indicates that the resource monitoring records are not archived.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__ab67a24a37b7243788a434311c708ccd4"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b5971851117846_4">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613657">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section827402723813"><h4 class="sectiontitle">enable_user_metric_persistent</h4><p id="EN-US_TOPIC_0000001145694507__p11270427183812"><strong id="EN-US_TOPIC_0000001145694507__b12224252164710">Parameter description</strong>: Specifies whether the user historical resource monitoring dumping function is enabled. If this function is enabled, data in view <a href="dws_04_0790.html">PG_TOTAL_USER_RESOURCE_INFO</a> is periodically sampled and saved to system catalog <a href="dws_04_0567.html">GS_WLM_USER_RESOURCE_HISTORY</a>.</p>
<p id="EN-US_TOPIC_0000001145694507__p1127122142015"><strong id="EN-US_TOPIC_0000001145694507__b10901163033810">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p122719274381"><strong id="EN-US_TOPIC_0000001145694507__b62701527133814">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ul8271162773818"><li id="EN-US_TOPIC_0000001145694507__li027142783810"><strong id="EN-US_TOPIC_0000001145694507__b1719240197">on</strong> indicates that the user historical resource monitoring dumping function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__li1127132753810"><strong id="EN-US_TOPIC_0000001145694507__b1574314220261">off</strong> indicates that the user historical resource monitoring dumping function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p1227192763813"><strong id="EN-US_TOPIC_0000001145694507__b252762322615">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b19539142312264">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section16298163313384"><h4 class="sectiontitle">user_metric_retention_time</h4><p id="EN-US_TOPIC_0000001145694507__p3294193323812"><strong id="EN-US_TOPIC_0000001145694507__b535910298266">Parameter description</strong>: Specifies the retention time of the user historical resource monitoring data. This parameter is valid only when <strong id="EN-US_TOPIC_0000001145694507__b1115554414451">enable_user_metric_persistent</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b0588051131915">on</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p9741742201712"><strong id="EN-US_TOPIC_0000001145694507__b852711362126">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p12295183323817"><strong id="EN-US_TOPIC_0000001145694507__b3410547290">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001145694507__ul162957333386"><li id="EN-US_TOPIC_0000001145694507__li1729533393816">If this parameter is set to <strong id="EN-US_TOPIC_0000001145694507__b695532443012">0</strong>, user historical resource monitoring data is permanently stored.</li><li id="EN-US_TOPIC_0000001145694507__li42950332387">If the value is greater than <strong id="EN-US_TOPIC_0000001145694507__b92762472309">0</strong>, user historical resource monitoring data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p102959336388"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0058967657_b26917141">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b842352706204923">7</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section18113133910385"><h4 class="sectiontitle">enable_instance_metric_persistent</h4><p id="EN-US_TOPIC_0000001145694507__p111103911388"><strong id="EN-US_TOPIC_0000001145694507__b6373122616317">Parameter description</strong>: Specifies whether the instance resource monitoring dumping function is enabled. When this function is enabled, the instance monitoring data is saved to the system catalog <a href="dws_04_0564.html">GS_WLM_INSTANCE_HISTORY</a>.</p>
<p id="EN-US_TOPIC_0000001145694507__p15909933122014"><strong id="EN-US_TOPIC_0000001145694507__b17956123303813">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p9112133915386"><strong id="EN-US_TOPIC_0000001145694507__b2112139103816">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ul11112113912389"><li id="EN-US_TOPIC_0000001145694507__li101126395382"><strong id="EN-US_TOPIC_0000001145694507__b384572402">on</strong> indicates that the instance resource monitoring dumping function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__li111283915386"><strong id="EN-US_TOPIC_0000001145694507__b612611410332">off</strong>: Specifies that the instance resource monitoring dumping function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p12112239173820"><strong id="EN-US_TOPIC_0000001145694507__b75814610348">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b069765347">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section314449385"><h4 class="sectiontitle">instance_metric_retention_time</h4><p id="EN-US_TOPIC_0000001145694507__p00124414383"><strong id="EN-US_TOPIC_0000001145694507__b1853993015344">Parameter description</strong>: Specifies the retention time of the instance historical resource monitoring data. This parameter is valid only when <strong id="EN-US_TOPIC_0000001145694507__b1998886519">enable_instance_metric_persistent</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b1851832146">on</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p1834911203172"><strong id="EN-US_TOPIC_0000001145694507__b378725910123">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p31144411387"><strong id="EN-US_TOPIC_0000001145694507__b7851939132">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001145694507__ul4114423811"><li id="EN-US_TOPIC_0000001145694507__li41344143820">If this parameter is set to <strong id="EN-US_TOPIC_0000001145694507__b12112125643519">0</strong>, instance historical resource monitoring data is permanently stored.</li><li id="EN-US_TOPIC_0000001145694507__li7118449381">If the value is greater than <strong id="EN-US_TOPIC_0000001145694507__b138631453133614">0</strong>, the instance historical resource monitoring data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p3194419386"><strong id="EN-US_TOPIC_0000001145694507__b451793320">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b66610560">7</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section153571329142612"><a name="EN-US_TOPIC_0000001145694507__section153571329142612"></a><a name="section153571329142612"></a><h4 class="sectiontitle">resource_track_level</h4><p id="EN-US_TOPIC_0000001145694507__p735952912615"><strong id="EN-US_TOPIC_0000001145694507__b741103941">Parameter description</strong>: Specifies the resource monitoring level of the current session. This parameter is valid only when <strong id="EN-US_TOPIC_0000001145694507__b7190191612820">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b74951311588">on</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p117112313179"><strong id="EN-US_TOPIC_0000001145694507__b1421443511383">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p7363172910268"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777487_a54344496219b4074ad956d5febb62b4c">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001145694507__ul15363122916268"><li id="EN-US_TOPIC_0000001145694507__li1436322917264"><strong id="EN-US_TOPIC_0000001145694507__b41866398234714">none</strong>: Resources are not monitored.</li><li id="EN-US_TOPIC_0000001145694507__li1666725091914"><strong id="EN-US_TOPIC_0000001145694507__b5647222324">query</strong>: Enables query-level resource monitoring. If this function is enabled, the plan information (similar to the output information of EXPLAIN) of SQL statements will be recorded in top SQL statements.</li><li id="EN-US_TOPIC_0000001145694507__li73310451216"><strong id="EN-US_TOPIC_0000001145694507__b1577665715312">perf</strong>: Enables the perf-level resource monitoring. If this function is enabled, the plan information (similar to the output information of EXPLAIN ANALYZE) that contains the actual execution time and the number of execution rows will be recorded in the top SQL.</li><li id="EN-US_TOPIC_0000001145694507__li17365182911264"><strong id="EN-US_TOPIC_0000001145694507__b5168191310520">operator</strong>: enables the operator-level resource monitoring. If this function is enabled, not only the information including the actual execution time and number of execution rows is recorded in the top SQL statement, but also the operator-level execution information is updated to the top SQL statement.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p436982932619"><strong id="EN-US_TOPIC_0000001145694507__b842352706153219">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b842352706153224">query</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section1089022732713"><a name="EN-US_TOPIC_0000001145694507__section1089022732713"></a><a name="section1089022732713"></a><h4 class="sectiontitle">resource_track_cost</h4><p id="EN-US_TOPIC_0000001145694507__p10896172717275"><strong id="EN-US_TOPIC_0000001145694507__b14896152782710">Parameter description</strong>: Specifies the minimum execution cost for resource monitoring on statements in the current session. This parameter is valid only when <strong id="EN-US_TOPIC_0000001145694507__b14246261586">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b192611269815">on</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p14848174121618"><strong id="EN-US_TOPIC_0000001145694507__b1482133513382">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p4901127122712"><strong id="EN-US_TOPIC_0000001145694507__b1161683134">Value range</strong>: an integer ranging from -1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001145694507__ul118701111164912"><li id="EN-US_TOPIC_0000001145694507__li16870811194919"><strong id="EN-US_TOPIC_0000001145694507__b498193110483">–1</strong> indicates that resource monitoring is disabled.</li><li id="EN-US_TOPIC_0000001145694507__li95612483106">A value greater than or equal to <strong id="EN-US_TOPIC_0000001145694507__b1476354145012">0</strong> indicates that statements whose execution cost exceeds this value will be monitored.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p11911192752714"><strong id="EN-US_TOPIC_0000001145694507__b1820213476599">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b22022470591">100000</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section347574425112"><a name="EN-US_TOPIC_0000001145694507__section347574425112"></a><a name="section347574425112"></a><h4 class="sectiontitle">resource_track_duration</h4><p id="EN-US_TOPIC_0000001145694507__p1479644125111"><strong id="EN-US_TOPIC_0000001145694507__b152714715574">Parameter description</strong>: Specifies the minimum statement execution time that determines whether information about jobs of a statement recorded in the real-time view (see <a href="dws_04_0397.html#EN-US_TOPIC_0000001098974816__table16116143418462">Table 1</a>) will be dumped to a historical view after the statement is executed. Job information will be dumped from the real-time view (with the suffix <strong id="EN-US_TOPIC_0000001145694507__b42981326135716">statistics</strong>) to a historical view (with the suffix <strong id="EN-US_TOPIC_0000001145694507__b183001261575">history</strong>) if the statement execution time is no less than this value. </p>
<p id="EN-US_TOPIC_0000001145694507__p1569071491619"><strong id="EN-US_TOPIC_0000001145694507__b15574600396">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p84841144145112"><strong id="EN-US_TOPIC_0000001145694507__b63362351318">Value range</strong>: an integer ranging from 0 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001145694507__ul817641714915"><li id="EN-US_TOPIC_0000001145694507__li617601754918"><strong id="EN-US_TOPIC_0000001145694507__b842352706194922">0</strong> indicates that information about all statements recorded in the real-time resource monitoring view (see <a href="dws_04_0397.html#EN-US_TOPIC_0000001098974816__table16116143418462">Table 1</a>) will be archived into historical views.</li><li id="EN-US_TOPIC_0000001145694507__li12176417164910">If the value is greater than <strong id="EN-US_TOPIC_0000001145694507__b17583134610111">0</strong>, information about statements recorded in the real-time resource monitoring view (see <a href="dws_04_0397.html#EN-US_TOPIC_0000001098974816__table16116143418462">Table 1</a>), whose execution time exceeds this value will be archived into historical views.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p3489114412516"><strong id="EN-US_TOPIC_0000001145694507__b842352706185119">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059778244_b15310055141954">1min</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section104016114237"><h4 class="sectiontitle">dynamic_memory_quota</h4><p id="EN-US_TOPIC_0000001145694507__p14418175713620"><strong id="EN-US_TOPIC_0000001145694507__b041719571368">Parameter description</strong>: Specifies the memory quota in adaptive load scenarios, that is, the proportion of maximum available memory to total system memory.</p>
<p id="EN-US_TOPIC_0000001145694507__p159991748202013"><strong id="EN-US_TOPIC_0000001145694507__b1574317111397">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p6446211172319"><strong id="EN-US_TOPIC_0000001145694507__b13451161192319">Value range</strong>: an integer ranging from 1 to 100</p>
<p id="EN-US_TOPIC_0000001145694507__p1585722371119"><strong id="EN-US_TOPIC_0000001145694507__b55291462334714">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b213900953134714">80</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section174761723101217"><h4 class="sectiontitle">disable_memory_protect</h4><p id="EN-US_TOPIC_0000001145694507__p8480142318127"><strong id="EN-US_TOPIC_0000001145694507__b548232351218">Parameter description:</strong> Stops memory protection. To query system views when system memory is insufficient, set this parameter to <strong id="EN-US_TOPIC_0000001145694507__b196820715134714">on</strong> to stop memory protection. This parameter is used only to diagnose and debug the system when system memory is insufficient. Set it to <strong id="EN-US_TOPIC_0000001145694507__b184955762934714">off</strong> in other scenarios.</p>
<p id="EN-US_TOPIC_0000001145694507__p27124510150"><strong id="EN-US_TOPIC_0000001145694507__b115746263918">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p18492172391214"><strong id="EN-US_TOPIC_0000001145694507__b943622892">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ul18295447181311"><li id="EN-US_TOPIC_0000001145694507__li1429784791313"><strong id="EN-US_TOPIC_0000001145694507__b26312387934714">on</strong> indicates that memory protection stops.</li><li id="EN-US_TOPIC_0000001145694507__li12305747131314"><strong id="EN-US_TOPIC_0000001145694507__b151718890734714">off</strong> indicates that memory is protected.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p2049718238123"><strong id="EN-US_TOPIC_0000001145694507__b107246176">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b126441285">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section631565955912"><h4 class="sectiontitle">query_band</h4><p id="EN-US_TOPIC_0000001145694507__p831816598591"><strong id="EN-US_TOPIC_0000001145694507__b03183591590">Parameter description</strong>: Specifies the job type of the current session.</p>
<p id="EN-US_TOPIC_0000001145694507__p1159102281513"><strong id="EN-US_TOPIC_0000001145694507__b1234913113914">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p18321155915599"><strong id="EN-US_TOPIC_0000001145694507__b890366342">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001145694507__p1232185914598"><strong id="EN-US_TOPIC_0000001145694507__b4976537817215">Default value</strong>: empty</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s8683aa29b8104ebf8bbb0a493688881d"><h4 class="sectiontitle">enable_bbox_dump</h4><p id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_p199220525113"><strong id="EN-US_TOPIC_0000001145694507__b79904029414435">Parameter description</strong>: Specifies whether the black box function is enabled. The core files can be generated even through the core dump mechanism is not configured in the system. This parameter must be simultaneously used on CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001145694507__p2039402411715"><strong id="EN-US_TOPIC_0000001145694507__b1690011463917">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_p69226524112"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_10">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__uffc10316a39e481091933ecfd644607a"><li id="EN-US_TOPIC_0000001145694507__l9338f705cbbf4aebbee9b7f81e64c37c"><strong id="EN-US_TOPIC_0000001145694507__b86671272734714">on</strong> indicates that the black box function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__ldec21fcf18be47e0966a86535b15fd0d"><strong id="EN-US_TOPIC_0000001145694507__b82409685134714">off</strong> indicates that the black box function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777791_p19224527112"><strong id="EN-US_TOPIC_0000001145694507__b761417118">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b421642118">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section15334124411419"><h4 class="sectiontitle">enable_dynamic_workload</h4><p id="EN-US_TOPIC_0000001145694507__p113372044141412"><strong id="EN-US_TOPIC_0000001145694507__b1103965523">Parameter description</strong>: Specifies whether to enable the dynamic workload management function.</p>
<p id="EN-US_TOPIC_0000001145694507__p19268144813616"><strong id="EN-US_TOPIC_0000001145694507__b498711519394">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001145694507__p1334010443148"><strong id="EN-US_TOPIC_0000001145694507__b116398083">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ul19341134431413"><li id="EN-US_TOPIC_0000001145694507__li183421544101416"><strong id="EN-US_TOPIC_0000001145694507__b842352706193247">on</strong> indicates the dynamic workload management function is enabled.</li><li id="EN-US_TOPIC_0000001145694507__li8343184412143"><strong id="EN-US_TOPIC_0000001145694507__b123083784">off</strong> indicates the dynamic workload management function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p19345444141417"><strong id="EN-US_TOPIC_0000001145694507__b1544954218411">Default value:</strong> <strong id="EN-US_TOPIC_0000001145694507__b344944218419">on</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001145694507__note1157234191015"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001145694507__ul11572044103"><li id="EN-US_TOPIC_0000001145694507__li2572164111014">If memory adaptation is enabled, you do not need to use <strong id="EN-US_TOPIC_0000001145694507__b135065662334714">work_mem</strong> to optimize the operator memory usage after collecting statistics. The system will generate a plan for each statement based on the current load, estimating the memory used by each operator and by the entire statement. In a concurrency scenario, statements are queued based on the system load and their memory usage.</li><li id="EN-US_TOPIC_0000001145694507__li205729412103">The optimizer cannot accurately estimate the number of rows and will probably underestimate or overestimate memory usage. If the memory usage is underestimated, the allocated memory will be automatically increased during statement running. If the memory usage is overestimated, system resources will not be fully used, and the number of statements waiting in a queue will increase, which probably results in low performance. To improve performance, identify the statements whose estimated memory usage is much greater than the DN peak memory and adjust the value of <strong id="EN-US_TOPIC_0000001145694507__b118001836171213">query_max_mem</strong>. For details, see <a href="dws_04_0453.html">Adjusting Key Parameters During SQL Tuning</a>.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__s49ffefbc1d7e4261a3b9b6bde1e9a147"><h4 class="sectiontitle">bbox_dump_count</h4><p id="EN-US_TOPIC_0000001145694507__ad31ef0c87e1744859be6dbfec2e978c0"><strong id="EN-US_TOPIC_0000001145694507__b92572581368">Parameter description</strong>: Specifies the maximum number of core files that are generated by <span id="EN-US_TOPIC_0000001145694507__text425719581561">GaussDB(DWS)</span> and can be stored in the path specified by <strong id="EN-US_TOPIC_0000001145694507__b23981313672">bbox_dump_path</strong>. If the number of core files exceeds this value, old core files will be deleted. This parameter is valid only if <strong id="EN-US_TOPIC_0000001145694507__b19565330473">enable_bbox_dump</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b12566530572">on</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p74798402510"><strong id="EN-US_TOPIC_0000001145694507__b18943938183913">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__a44e616b37b524be99d1e4e1cf8d29578"><strong id="EN-US_TOPIC_0000001145694507__b15123128115616">Value range</strong>: an integer ranging from 1 to 20</p>
<p id="EN-US_TOPIC_0000001145694507__add923227fd1148f9a00db57996e3c3ff"><strong id="EN-US_TOPIC_0000001145694507__b1413578664144214">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b578690575144214">8</strong></p>
<div class="note" id="EN-US_TOPIC_0000001145694507__ncdaf889bc5bd4b0e9b36c618b7241881"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001145694507__a1526da0b291442fa916ba5b03aedd1cc">When core files are generated during concurrent SQL statement execution, the number of files may be larger than the value of <strong id="EN-US_TOPIC_0000001145694507__b2005970014144133">bbox_dump_count</strong>.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section1148143712203"><h4 class="sectiontitle">io_limits</h4><p id="EN-US_TOPIC_0000001145694507__p12501837102015"><strong id="EN-US_TOPIC_0000001145694507__b842352706193728">Parameter description</strong>: Specifies the upper limit of IOPS triggered.</p>
<p id="EN-US_TOPIC_0000001145694507__p11335216520"><strong id="EN-US_TOPIC_0000001145694507__b5683154023910">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p2353169278"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059777487_en-us_topic_0058967566_b6696864">Value range</strong>: an integer ranging from 0 to 1073741823</p>
<p id="EN-US_TOPIC_0000001145694507__p18641037102016"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059778487_a023402ff020d43919b2d4639671ceb32">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059778487_en-us_topic_0058967649_b842352706195030">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section0751123912227"><h4 class="sectiontitle">io_priority</h4><p id="EN-US_TOPIC_0000001145694507__p652216533225"><strong id="EN-US_TOPIC_0000001145694507__b3941371851">Parameter description</strong>: Specifies the I/O priority for jobs that consume many I/O resources. It takes effect when the I/O usage reaches 90%.</p>
<p id="EN-US_TOPIC_0000001145694507__p19172056519"><strong id="EN-US_TOPIC_0000001145694507__b1124334173913">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p075714396226"><strong id="EN-US_TOPIC_0000001145694507__b1286223381">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001145694507__ul584258251503"><li id="EN-US_TOPIC_0000001145694507__li1136775412577"><strong id="EN-US_TOPIC_0000001145694507__b842352706194045">None</strong> indicates no control.</li><li id="EN-US_TOPIC_0000001145694507__li327400081503"><strong id="EN-US_TOPIC_0000001145694507__b115361852567">Low</strong> indicates that the IOPS is reduced to 20% of the original value.</li><li id="EN-US_TOPIC_0000001145694507__li266002731506"><strong id="EN-US_TOPIC_0000001145694507__b880675479">Medium</strong> indicates that the IOPS is reduced to 50% of the original value.</li><li id="EN-US_TOPIC_0000001145694507__li587127221508"><strong id="EN-US_TOPIC_0000001145694507__b904446926">High</strong> indicates that the IOPS is reduced to 80% of the original value.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p1675915397225"><strong id="EN-US_TOPIC_0000001145694507__b12034753911539">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b152401163719">None</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section2673131522715"><h4 class="sectiontitle">session_respool</h4><p id="EN-US_TOPIC_0000001145694507__p067531572720"><strong id="EN-US_TOPIC_0000001145694507__b842352706194554">Parameter description</strong>: Specifies the resource pool associated with the current session.</p>
<p id="EN-US_TOPIC_0000001145694507__p76261753133513"><strong id="EN-US_TOPIC_0000001145694507__b478114411391">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p165805713355">If you set <strong id="EN-US_TOPIC_0000001145694507__b790499049">cgroup_name</strong> and then <strong id="EN-US_TOPIC_0000001145694507__b353690084">session_respool</strong>, the Cgroups associated with <strong id="EN-US_TOPIC_0000001145694507__b1139247576">session_respool</strong> take effect. If you reverse the order, Cgroups associated with <strong id="EN-US_TOPIC_0000001145694507__b1659190090">cgroup_name</strong> take effect.</p>
<p id="EN-US_TOPIC_0000001145694507__p5591757183516">If the Workload Cgroup level is specified during the <strong id="EN-US_TOPIC_0000001145694507__b1136555769">cgroup_name</strong> change, the database does not check the Cgroup level. The level ranges from 1 to 10.</p>
<p id="EN-US_TOPIC_0000001145694507__p7223154111811">You are not advised to set <strong id="EN-US_TOPIC_0000001145694507__b377176030">cgroup_name</strong> and <strong id="EN-US_TOPIC_0000001145694507__b1563060739">session_respool</strong> at the same time.</p>
<p id="EN-US_TOPIC_0000001145694507__p168061522714"><strong id="EN-US_TOPIC_0000001145694507__b842352706194349">Value range</strong>: a string. This parameter can be set to the resource pool configured through <strong id="EN-US_TOPIC_0000001145694507__b842352706194528">create resource pool</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p968301582711"><strong id="EN-US_TOPIC_0000001145694507__b1236521377">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b1140673706">invalid_pool</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section106864402366"><h4 class="sectiontitle">enable_transaction_parctl</h4><p id="EN-US_TOPIC_0000001145694507__p1968613403367"><strong id="EN-US_TOPIC_0000001145694507__b10392155641511">Parameter description</strong>: whether to control transaction block statements and stored procedure statements.</p>
<p id="EN-US_TOPIC_0000001145694507__p135009518411"><strong id="EN-US_TOPIC_0000001145694507__b2052904283914">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p56861040103620"><strong id="EN-US_TOPIC_0000001145694507__b176564490">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001145694507__ul16861640113613"><li id="EN-US_TOPIC_0000001145694507__li12686040183613"><strong id="EN-US_TOPIC_0000001145694507__b110355215161">on</strong>: Transaction block statements and stored procedure statements are controlled.</li><li id="EN-US_TOPIC_0000001145694507__li19686174013617"><strong id="EN-US_TOPIC_0000001145694507__b1344353011171">off</strong>: Transaction block statements and stored procedure statements are not controlled.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p168764003610"><strong id="EN-US_TOPIC_0000001145694507__b1528961362">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b370256598">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section4520191223820"><a name="EN-US_TOPIC_0000001145694507__section4520191223820"></a><a name="section4520191223820"></a><h4 class="sectiontitle">session_statistics_memory</h4><p id="EN-US_TOPIC_0000001145694507__p552161293819"><strong id="EN-US_TOPIC_0000001145694507__b391159272">Parameter description</strong>: Specifies the memory size of a real-time query view.</p>
<p id="EN-US_TOPIC_0000001145694507__p13522246734"><strong id="EN-US_TOPIC_0000001145694507__b1127217436392">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p175211312193814"><strong id="EN-US_TOPIC_0000001145694507__b113271521481">Value range</strong>: an integer ranging from 5 MB to 50% of <strong id="EN-US_TOPIC_0000001145694507__b532932118810">max_process_memory</strong></p>
<p id="EN-US_TOPIC_0000001145694507__p5521121293817"><strong id="EN-US_TOPIC_0000001145694507__b873711221885">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b107381722587">5 MB</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section27306369458"><h4 class="sectiontitle">session_history_memory</h4><p id="EN-US_TOPIC_0000001145694507__p10730143684512"><strong id="EN-US_TOPIC_0000001145694507__b81703241277">Parameter description</strong>: Specifies the memory size of a historical query view.</p>
<p id="EN-US_TOPIC_0000001145694507__p99441634935"><strong id="EN-US_TOPIC_0000001145694507__b12848124318395">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p273193613458"><strong id="EN-US_TOPIC_0000001145694507__b16919152612815">Value range</strong>: an integer ranging from 10 MB to 50% of <strong id="EN-US_TOPIC_0000001145694507__b292110261582">max_process_memory</strong></p>
<p id="EN-US_TOPIC_0000001145694507__p1373114364453"><strong id="EN-US_TOPIC_0000001145694507__b1228652820814">Default value:</strong> <strong id="EN-US_TOPIC_0000001145694507__b1328712282819">100 MB</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145694507__section2570135114116"><h4 class="sectiontitle">topsql_retention_time</h4><p id="EN-US_TOPIC_0000001145694507__p0613161384"><strong id="EN-US_TOPIC_0000001145694507__b61401423114716">Parameter description</strong>: Specifies the retention period of historical TopSQL data in the <strong id="EN-US_TOPIC_0000001145694507__b6592135012479">gs_wlm_session_info</strong> and <strong id="EN-US_TOPIC_0000001145694507__b20547105474716">gs_wlm_operator_info</strong> tables.</p>
<p id="EN-US_TOPIC_0000001145694507__p252917217319"><strong id="EN-US_TOPIC_0000001145694507__b1327894433918">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p176131643817"><strong id="EN-US_TOPIC_0000001145694507__b111145313377">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001145694507__ul24731743104213"><li id="EN-US_TOPIC_0000001145694507__li047315438424">If it is set to <strong id="EN-US_TOPIC_0000001145694507__b139411713133218">0</strong>, the data is stored permanently.</li><li id="EN-US_TOPIC_0000001145694507__li1473104310427">If the value is greater than <strong id="EN-US_TOPIC_0000001145694507__b1834015160386">0</strong>, the data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p13691613386"><strong id="EN-US_TOPIC_0000001145694507__b13915259151516">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b842352706165429">0</strong></p>
<div class="caution" id="EN-US_TOPIC_0000001145694507__note2020576431"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><p id="EN-US_TOPIC_0000001145694507__p12165734317">Before setting this GUC parameter to enable the data retention function, delete data from the <strong id="EN-US_TOPIC_0000001145694507__b1100652183314">gs_wlm_session_info</strong> and <strong id="EN-US_TOPIC_0000001145694507__b531435533318">gs_wlm_operator_info</strong> tables.</p>
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<div class="section" id="EN-US_TOPIC_0000001145694507__section1835116504363"><h4 class="sectiontitle">transaction_pending_time</h4><p id="EN-US_TOPIC_0000001145694507__p335185043614"><strong id="EN-US_TOPIC_0000001145694507__b965356141816">Parameter description</strong>: maximum queuing time of transaction block statements and stored procedure statements if <strong id="EN-US_TOPIC_0000001145694507__b8106111214191">enable_transaction_parctl</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b25061918161919">on</strong>.</p>
<p id="EN-US_TOPIC_0000001145694507__p12603151319214"><strong id="EN-US_TOPIC_0000001145694507__b1439412454391">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001145694507__p335111501361"><strong id="EN-US_TOPIC_0000001145694507__b218764790">Value range</strong>: an integer ranging from –1 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001145694507__ul13351150103610"><li id="EN-US_TOPIC_0000001145694507__li1335116502368"><strong id="EN-US_TOPIC_0000001145694507__b119721869208">–1</strong> or <strong id="EN-US_TOPIC_0000001145694507__b3276613192010">0</strong>: No queuing timeout is specified for transaction block statements and stored procedure statements. The statements can be executed when resources are available.</li><li id="EN-US_TOPIC_0000001145694507__li163511950193616">Value greater than <strong id="EN-US_TOPIC_0000001145694507__b97628503212">0</strong>: If transaction block statements and stored procedure statements have been queued for a time longer than the specified value, they are forcibly executed regardless of the current resource situation.</li></ul>
<p id="EN-US_TOPIC_0000001145694507__p183511250113616"><strong id="EN-US_TOPIC_0000001145694507__b1385743173">Default value</strong>: <strong id="EN-US_TOPIC_0000001145694507__b1726250947">0</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001145694507__ne7dee8ee88ce4d6299b8651b0fa820d1"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001145694507__p429891617354">This parameter is valid only for internal statements of stored procedures and transaction blocks. That is, this parameter takes effect only for the statements whose <strong id="EN-US_TOPIC_0000001145694507__b967924916202">enqueue</strong> value (for details, see <a href="dws_04_0749.html">PG_SESSION_WLMSTAT</a>) is <strong id="EN-US_TOPIC_0000001145694507__b102210162116">Transaction</strong> or <strong id="EN-US_TOPIC_0000001145694507__b17188114112119">StoredProc</strong>.</p>
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<div class="section" id="EN-US_TOPIC_0000001145694507__section3917839115"><h4 class="sectiontitle">wlm_sql_allow_list</h4><p id="EN-US_TOPIC_0000001145694507__p11917153151119"><strong id="EN-US_TOPIC_0000001145694507__b116921625176">Parameter description</strong>: Specifies whitelisted SQL statements for resource management. Whitelisted SQL statements are not monitored by resource management.</p>
<p id="EN-US_TOPIC_0000001145694507__p391715312119"><strong id="EN-US_TOPIC_0000001145694507__b541917222208">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001145694507__p159171731117"><strong id="EN-US_TOPIC_0000001145694507__en-us_topic_0059778871_en-us_topic_0058967732_b842352706112225">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001145694507__p1391863111111"><strong id="EN-US_TOPIC_0000001145694507__b19149202516179">Default value</strong>: empty</p>
<div class="notice" id="EN-US_TOPIC_0000001145694507__note49182314117"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001145694507__ul1426521191610"><li id="EN-US_TOPIC_0000001145694507__li1726142118164">One or more whitelisted SQL statements can be specified in <strong id="EN-US_TOPIC_0000001145694507__b1649182991718">wlm_sql_allow_list</strong>. If multiple SQL statements are to be whitelisted, use semicolons (;) to separate them.</li><li id="EN-US_TOPIC_0000001145694507__li122752116166">The system determines whether SQL statements are monitored based on the prefix match. The SQL statements are case insensitive. For example, if <strong id="EN-US_TOPIC_0000001145694507__b189983319173">wlm_sql_allow_list</strong> is set to <strong id="EN-US_TOPIC_0000001145694507__b1110593321715">'SELECT'</strong>, all <strong id="EN-US_TOPIC_0000001145694507__b1310673321712">SELECT</strong> statements are not monitored by the resource management module.</li><li id="EN-US_TOPIC_0000001145694507__li16872734174116">The system identifies spaces at the beginning of the parameter value. For example, <strong id="EN-US_TOPIC_0000001145694507__b819075117405">'SELECT'</strong> and <strong id="EN-US_TOPIC_0000001145694507__b17437109174119">' SELECT'</strong> have different representations. <strong id="EN-US_TOPIC_0000001145694507__b468553984120">' SELECT'</strong> filters only the <strong id="EN-US_TOPIC_0000001145694507__b28145479419">SELECT</strong> statements with spaces at the beginning.</li><li id="EN-US_TOPIC_0000001145694507__li172712113168">The system has some whitelisted SQL statements by default, which cannot be modified. You can query the default whitelisted SQL statements and the SQL statements that have been successfully added to the whitelist by GUC through the system view <strong id="EN-US_TOPIC_0000001145694507__b1793820378172">gs_wlm_sql_allow</strong>.</li><li id="EN-US_TOPIC_0000001145694507__li466922215340">New SQL statements cannot be appended to the whitelisted SQL statements specified by <strong id="EN-US_TOPIC_0000001145694507__b1036494361712">wlm_sql_allow_list</strong> but can be set only through overwriting. To add an SQL statement, query the original GUC value, add the new statement to the end of the original value, separate the statements with a semicolon (;), and set the GUC value again.</li></ul>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0883.html">GUC Parameters</a></div>
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