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Lu, Huayi ef0ada5a59 DWS DEV 20240716 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>
2024-11-02 09:07:47 +00:00

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<a name="EN-US_TOPIC_0000001510522653"></a><a name="EN-US_TOPIC_0000001510522653"></a>
<h1 class="topictitle1">Resource Management</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001510522653__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_0000001510522653__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_0000001510522653__sc1692143c357427cbeadd6160010fd40"><a name="EN-US_TOPIC_0000001510522653__sc1692143c357427cbeadd6160010fd40"></a><a name="sc1692143c357427cbeadd6160010fd40"></a><h4 class="sectiontitle">use_workload_manager</h4><p id="EN-US_TOPIC_0000001510522653__a316504de19154266a6636c8d1b50369d"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p4716143414116"><strong id="EN-US_TOPIC_0000001510522653__b17311519203317">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__a6a4fa4df92ad45b481bac62a94474e39"><strong id="EN-US_TOPIC_0000001510522653__b118151824103315">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__u45d51c5a02724590866ccf03b1023e22"><li id="EN-US_TOPIC_0000001510522653__lf888c078ac404b47b69c195cf7048405"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__l3291c2651e5c4f019212d19cb7b693fd"><strong id="EN-US_TOPIC_0000001510522653__b181436343419">off</strong> indicates the resource management function is disabled.<div class="note" id="EN-US_TOPIC_0000001510522653__note2091118244406"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="EN-US_TOPIC_0000001510522653__ul1602153014301"><li id="EN-US_TOPIC_0000001510522653__li1602113013013">If method 2 in <a href="dws_04_0885.html#EN-US_TOPIC_0000001510522193__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_0000001510522653__b10447103211135">kill session</strong> or restarting the node.</li><li id="EN-US_TOPIC_0000001510522653__li976571011338">After the value of <strong id="EN-US_TOPIC_0000001510522653__b43513563410">use_workload_manager</strong> changes from <strong id="EN-US_TOPIC_0000001510522653__b14136181811341">off</strong> to <strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__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_0000001510522653__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>
</pre></div></td></tr></table></div>
</div>
</li></ul>
</div></div>
</li></ul>
<p id="EN-US_TOPIC_0000001510522653__a87e5c5017855416bb743faf01c512c3f"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b12149173155843_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613017">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s46a1cb63ed974be883cbbcf68a7278c2"><h4 class="sectiontitle">enable_perm_space</h4><p id="EN-US_TOPIC_0000001510522653__a7437a2f18290429db6b71ff0677709c1"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p36931045131313"><strong id="EN-US_TOPIC_0000001510522653__b1011411208389">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001510522653__a960fb8db6a7241ad8fea3a9d09cbda4f"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_b1102664415112">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ua6462fa046b0460e938954882d611afa"><li id="EN-US_TOPIC_0000001510522653__l9bdf184d5ca84737be389d6ce9f74d1d"><strong id="EN-US_TOPIC_0000001510522653__b1931797016">on</strong> indicates the perm space function is enabled.</li><li id="EN-US_TOPIC_0000001510522653__l6be8caa82c8647c09b2edce3e14dbcf7"><strong id="EN-US_TOPIC_0000001510522653__b4433887534714">off</strong> indicates the perm space function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_p246103015112"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967679_b2933732">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_b842352706154337">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section2515929121516"><h4 class="sectiontitle">space_once_adjust_num</h4><p id="EN-US_TOPIC_0000001510522653__p163971630131516"><strong id="EN-US_TOPIC_0000001510522653__b517513172019">Parameter description</strong>: In the space control and space statistics functions, specifies the threshold of the number of files processed each time during slow building and fine-grained calibration . This parameter is supported by version 8.1.3 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510522653__p239714307155"><strong id="EN-US_TOPIC_0000001510522653__b168481330192819">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p439710309152"><strong id="EN-US_TOPIC_0000001510522653__b14491635162817">Value range</strong>: an integer ranging from 0 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001510522653__ul143242045223"><li id="EN-US_TOPIC_0000001510522653__li138487912216">The value <strong id="EN-US_TOPIC_0000001510522653__b17969359183511">0</strong> indicates that the slow build and fine-grained calibration functions are disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p203972301156"><strong id="EN-US_TOPIC_0000001510522653__b1750415402284">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b17510174018285">300</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__note754920241335"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510522653__p1549122413313">The file quantity threshold affects database resources. You are advised to set the threshold to a proper value.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section26561757132014"><h4 class="sectiontitle">space_readjust_schedule</h4><p id="EN-US_TOPIC_0000001510522653__p56561657192011"><strong id="EN-US_TOPIC_0000001510522653__b585214290295">Parameter description</strong>: In the space control and space statistics functions, specifies the space error threshold for triggering automatic calibration. This parameter is supported by version 8.1.3 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510522653__p136561957172013"><strong id="EN-US_TOPIC_0000001510522653__b360819418587">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p5656155713206"><strong id="EN-US_TOPIC_0000001510522653__b1415174417582">Value range</strong>: string</p>
<ul id="EN-US_TOPIC_0000001510522653__ul197030396232"><li id="EN-US_TOPIC_0000001510522653__li9703183918233"><strong id="EN-US_TOPIC_0000001510522653__b2012172135915">off </strong>indicates that the automatic calibration function is disabled.</li><li id="EN-US_TOPIC_0000001510522653__li184713482237"><strong id="EN-US_TOPIC_0000001510522653__b1281912920593">auto </strong>indicates that the automatic calibration function is enabled and the error threshold for triggering automatic calibration is <strong id="EN-US_TOPIC_0000001510522653__b571813588012">1 GB</strong>.</li><li id="EN-US_TOPIC_0000001510522653__li197031439182315"><strong id="EN-US_TOPIC_0000001510522653__b1649217141629">auto (<em id="EN-US_TOPIC_0000001510522653__i2820519421">space size</em> + K/M/G)</strong> indicates that the automatic calibration is enabled and the error threshold for triggering automatic calibration is <em id="EN-US_TOPIC_0000001510522653__i11311915247">xxx</em> KB/MB/GB (user-defined). For example, <strong id="EN-US_TOPIC_0000001510522653__b19315194917413">auto(200M)</strong> indicates that the automatic calibration is enabled and the error threshold for triggering automatic calibration is <strong id="EN-US_TOPIC_0000001510522653__b270810115512">200 MB</strong>.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p86561457102013"><strong id="EN-US_TOPIC_0000001510522653__b3610141756">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b36111941511">auto</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section15853054161718"><h4 class="sectiontitle">enable_libcomm_schedule</h4><p id="EN-US_TOPIC_0000001510522653__p14849195514179"><strong id="EN-US_TOPIC_0000001510522653__b13889195303718">Parameter description</strong>: Specifies whether to enable network control. This parameter is supported by version 8.2.1 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510522653__p1384918552174"><strong id="EN-US_TOPIC_0000001510522653__b751356768">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001510522653__p98491755191716"><strong id="EN-US_TOPIC_0000001510522653__b511750143">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul156331772431"><li id="EN-US_TOPIC_0000001510522653__li1184905516175"><strong id="EN-US_TOPIC_0000001510522653__b15199162616386">on</strong> indicates that network control is enabled.</li></ul>
<ul id="EN-US_TOPIC_0000001510522653__ul1184914553173"><li id="EN-US_TOPIC_0000001510522653__li38491355191710"><strong id="EN-US_TOPIC_0000001510522653__b147533163819">off</strong> indicates that network control is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p2085018557172"><strong id="EN-US_TOPIC_0000001510522653__b1532263963">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b503711962">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s7a13b0da34a74fe886bdf7671e62019b"><h4 class="sectiontitle">max_active_statements</h4><p id="EN-US_TOPIC_0000001510522653__addc805286ca74ef9a2554b470c4fae80"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__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_0000001510522653__p16407102791018"><strong id="EN-US_TOPIC_0000001510522653__b1787012212383">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__a074267e4991b476ebb38e7061f47c80f"><strong id="EN-US_TOPIC_0000001510522653__b1333016122363">Value range</strong>: an integer ranging from –1 to INT_MAX. The values <strong id="EN-US_TOPIC_0000001510522653__b8361163317211">–1</strong> and <strong id="EN-US_TOPIC_0000001510522653__b33896379211">0</strong> indicate that the number of concurrent requests is not limited.</p>
<p id="EN-US_TOPIC_0000001510522653__a3e180989283945129914c1800c110445"><strong id="EN-US_TOPIC_0000001510522653__b109654376103">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b1852764121011">60</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__sab51422c793f40ad8958c193761edaf9"><h4 class="sectiontitle">parctl_min_cost</h4><p id="EN-US_TOPIC_0000001510522653__a15fd2f5990cc4c9c8015b21c819cfd25"><strong id="EN-US_TOPIC_0000001510522653__b7381110163815">Parameter description</strong>: Specifies the minimum estimated cost of a complex job under static resource management. Threshold for dividing simple jobs and complex jobs. A job whose estimated cost is less than the value of this parameter is a simple job, and a job whose estimated cost is larger than or equal to the value of this parameter is a complex job.</p>
<p id="EN-US_TOPIC_0000001510522653__p157803941017"><strong id="EN-US_TOPIC_0000001510522653__b1352510222389">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__aade5fd4a9a6b4ef3ba9306281eefb5a3"><strong id="EN-US_TOPIC_0000001510522653__b180196129434714">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001510522653__ul88941839114812"><li id="EN-US_TOPIC_0000001510522653__li9894183913480">If <strong id="EN-US_TOPIC_0000001510522653__b1279469394">parctl_min_cost</strong> is <strong id="EN-US_TOPIC_0000001510522653__b1925365043919">-1</strong>, all jobs are simple jobs.</li><li id="EN-US_TOPIC_0000001510522653__li15811942103013">Jobs whose estimated cost is less than 10 are simple jobs.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__ad3ea3b4b3e664405aa381a3078a4debc"><strong id="EN-US_TOPIC_0000001510522653__b83871373311">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b3387137203116">100000</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s8159a12f556d464abbf1acffe467b548"><h4 class="sectiontitle">cgroup_name</h4><p id="EN-US_TOPIC_0000001510522653__a6d50fdbf988d447dbf68bf86dbc6fa5b"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p119020197324">If you set <strong id="EN-US_TOPIC_0000001510522653__b842352706175935">cgroup_name</strong> and then <strong id="EN-US_TOPIC_0000001510522653__b842352706175940">session_respool</strong>, the Cgroups associated with <strong id="EN-US_TOPIC_0000001510522653__b8423527061803">session_respool</strong> take effect. If you reverse the order, Cgroups associated with <strong id="EN-US_TOPIC_0000001510522653__b84235270618042">cgroup_name</strong> take effect.</p>
<p id="EN-US_TOPIC_0000001510522653__p75569413347">If the Workload Cgroup level is specified during the <strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p141021638141912"><strong id="EN-US_TOPIC_0000001510522653__b206805233385">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p63212713170">You are not advised to set <strong id="EN-US_TOPIC_0000001510522653__b842352706181635">cgroup_name</strong> and <strong id="EN-US_TOPIC_0000001510522653__b842352706181640">session_respool</strong> at the same time.</p>
<p id="EN-US_TOPIC_0000001510522653__afb9148a5a4a54b2592c8b2610df13767"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b688672095621">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001510522653__a960082ccca4246e0a475c33188966896"><strong id="EN-US_TOPIC_0000001510522653__b16948152754819">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b18452203324810">DefaultClass:Medium</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__note1953653910322"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510522653__p366615446327"><strong id="EN-US_TOPIC_0000001510522653__b429654704815">DefaultClass:Medium</strong> indicates the <strong id="EN-US_TOPIC_0000001510522653__b1048713795016">Medium</strong> Cgroup belonging to the <strong id="EN-US_TOPIC_0000001510522653__b173481122135011">Timeshare</strong> Cgroup under the <strong id="EN-US_TOPIC_0000001510522653__b1824672714505">DefaultClass</strong> Cgroup.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s9224d1039e814e98adaf4ad27b6f75a8"><h4 class="sectiontitle">cpu_collect_timer</h4><p id="EN-US_TOPIC_0000001510522653__aa6156749df6b4c92b932c96a799159f1"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__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_0000001510522653__p197702445910"><strong id="EN-US_TOPIC_0000001510522653__b13991724143816">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__aba34754d9bce4b06bf6659dc7a0710c9"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__a35237e01b6844cff85b60c4854b62d6f"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967582_b40689991104939_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967582_b84235270617812_1">30</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s565c7e2c8cb34d4db165766b74a73683"><h4 class="sectiontitle">enable_cgroup_switch</h4><p id="EN-US_TOPIC_0000001510522653__a5eca9c9caeac4b98a5ae1bdee735cf0a"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b842352706192357">TopWD</strong> group when executing statements by group type.</p>
<p id="EN-US_TOPIC_0000001510522653__p241918691910"><strong id="EN-US_TOPIC_0000001510522653__b18921162543816">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__a0a1bc12cb50947aaab525684d57deda3"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_abdb6603792074f608afcc026778454fb">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__u508ca40006484f93ac6601714ce81f84"><li id="EN-US_TOPIC_0000001510522653__l24467bedd0504ff08a43c85df18138ba"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172123_3">on</strong>: The database automatically switches to the <strong id="EN-US_TOPIC_0000001510522653__b842352706192435">TopWD</strong> group when executing statements by group type.</li><li id="EN-US_TOPIC_0000001510522653__labe48b71421d46bfbf1665865f5169cf"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b84235270619276">TopWD</strong> group when executing statements by group type.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__a2fc3159e811a498cbc4238818a718375"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b5971851117846_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613313">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s99d436e056b446d19c841da7b23faae8"><h4 class="sectiontitle">memory_tracking_mode</h4><p id="EN-US_TOPIC_0000001510522653__a67919fed03e44562bea8db4b97c2e70e"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172610">Parameter description</strong>: Specifies the memory information recording mode.</p>
<p id="EN-US_TOPIC_0000001510522653__p1746473641810"><strong id="EN-US_TOPIC_0000001510522653__b1852632613389">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__a66ad8055b3f04c22bda844ba1e2493cc"><strong id="EN-US_TOPIC_0000001510522653__b25782132328">Value range</strong>:</p>
<ul id="EN-US_TOPIC_0000001510522653__ul29059994172249"><li id="EN-US_TOPIC_0000001510522653__li16695073172249"><strong id="EN-US_TOPIC_0000001510522653__b842352706105333">none</strong>: Memory statistics is not collected.</li><li id="EN-US_TOPIC_0000001510522653__li5710012517239"><strong id="EN-US_TOPIC_0000001510522653__b842352706105432">normal:</strong> Only memory statistics is collected in real time and no file is generated.</li><li id="EN-US_TOPIC_0000001510522653__li56020122172333"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__li61119980172352"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__a368ea04ff5554e6293efd92bdd49074c"><strong id="EN-US_TOPIC_0000001510522653__b10048826103114">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b110848183317">none</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s3f3dd81692d64ce08fa1a352e9ebb56f"><h4 class="sectiontitle">memory_detail_tracking</h4><p id="EN-US_TOPIC_0000001510522653__a72d25f2d0320437c992a285dcb72ce7f"><strong id="EN-US_TOPIC_0000001510522653__b1678060675144418">Parameter description</strong>: Specifies the sequence number of the memory background information distributed in the needed thread and <strong id="EN-US_TOPIC_0000001510522653__b842352706192855">plannodeid</strong> of the query where the current thread is located.</p>
<p id="EN-US_TOPIC_0000001510522653__p1245071620182"><strong id="EN-US_TOPIC_0000001510522653__b61126275389">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__af350ee0eedbe4e05b3454c4d69ce0b7c"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b37796097_1">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001510522653__a39299a499b1e41288f2d9ea1fdc82e42"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_b421586113118">Default value</strong>: empty</p>
<div class="notice" id="EN-US_TOPIC_0000001510522653__n83cc48fd8396484199f83f9de17a7247"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001510522653__a0c78987d9e3a4018abbf4890e1f7804d">It is recommended that you retain the default value for this parameter.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s9530ecdd2b0d4a98b67b66e32bf8e5d0"><a name="EN-US_TOPIC_0000001510522653__s9530ecdd2b0d4a98b67b66e32bf8e5d0"></a><a name="s9530ecdd2b0d4a98b67b66e32bf8e5d0"></a><h4 class="sectiontitle">enable_resource_track</h4><p id="EN-US_TOPIC_0000001510522653__ae718ea1b2bf14c248e8eb722b646360d"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p16411142618918"><strong id="EN-US_TOPIC_0000001510522653__b1511714282389">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__aa360558c12b34fa28006d7763756d1da"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_6">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__u3ff70c8d7adb42d0a45d5b54d7b482d6"><li id="EN-US_TOPIC_0000001510522653__l502f22098a3546a38fb609437f27473d"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__l0b48936acbbe4f13a19e6dd43f120bd5"><strong id="EN-US_TOPIC_0000001510522653__b104214192034714">off</strong> indicates the resource monitoring function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__a32291243ba3049eba8785fab5e24526b"><strong id="EN-US_TOPIC_0000001510522653__b1101529633172346">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b421067350172346">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s5f116e109a2944e3854abcc56772eaa1"><a name="EN-US_TOPIC_0000001510522653__s5f116e109a2944e3854abcc56772eaa1"></a><a name="s5f116e109a2944e3854abcc56772eaa1"></a><h4 class="sectiontitle">enable_resource_record</h4><p id="EN-US_TOPIC_0000001510522653__p1091904413"><strong id="EN-US_TOPIC_0000001510522653__b832542111412">Parameter description</strong>: Specifies whether resource monitoring records are archived. When this parameter is enabled, records that have been executed are archived to the corresponding <strong id="EN-US_TOPIC_0000001510522653__b18855101419466">INFO</strong> views (<a href="dws_04_0704.html">GS_WLM_SESSION_INFO</a> and <a href="dws_04_0701.html">GS_WLM_OPERAROR_INFO</a>). This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001510522653__p1179712121695"><strong id="EN-US_TOPIC_0000001510522653__b51611129203815">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__a2a0deb112b624e15a23774120200a46e"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_8">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__u1632ed197ebf48c5a6bc26e750b6c0ce"><li id="EN-US_TOPIC_0000001510522653__l084582a6e1e3496dbdc97769d266b4b7"><strong id="EN-US_TOPIC_0000001510522653__b96415896734714">on</strong> indicates that the resource monitoring records are archived.</li><li id="EN-US_TOPIC_0000001510522653__le34a6e152c0344d6bfc4e472e72efdeb"><strong id="EN-US_TOPIC_0000001510522653__b58509289134714">off</strong> indicates that the resource monitoring records are not archived.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__ab67a24a37b7243788a434311c708ccd4"><strong id="EN-US_TOPIC_0000001510522653__b5368154018462">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b3375640144611">on</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__note1760311247421"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510522653__p6604102414215">The default value of this parameter is <strong id="EN-US_TOPIC_0000001510522653__b063894311319">on</strong> for a new cluster. In upgrade scenarios, the default value of this parameter is the same as that of the source version.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section7181949101319"><a name="EN-US_TOPIC_0000001510522653__section7181949101319"></a><a name="section7181949101319"></a><h4 class="sectiontitle">enable_track_record_subsql</h4><p id="EN-US_TOPIC_0000001510522653__p15875120144310"><strong id="EN-US_TOPIC_0000001510522653__b15742173575018">Parameter description</strong>: Specifies whether to enable the function of recording and archiving sub-statements. When this function is enabled, sub-statements in stored procedures and anonymous blocks are recorded and archived to the corresponding <strong id="EN-US_TOPIC_0000001510522653__b96441325142220">INFO</strong> table (<a href="dws_04_0566.html">GS_WLM_SESSION_INFO</a>). This parameter is a session-level parameter. It can be configured and take effect in the session connected to the CN and affects only the statements in the session. It can also be configured on both the CN and DN and take effect globally.</p>
<p id="EN-US_TOPIC_0000001510522653__p287516202432"><strong id="EN-US_TOPIC_0000001510522653__b376280082">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p487542010431"><strong id="EN-US_TOPIC_0000001510522653__b476123165420">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul1487613201432"><li id="EN-US_TOPIC_0000001510522653__li1876620184311"><strong id="EN-US_TOPIC_0000001510522653__b1621417343549">on</strong> indicates that the sub-statement resource monitoring records are archived.</li><li id="EN-US_TOPIC_0000001510522653__li1087615201436"><strong id="EN-US_TOPIC_0000001510522653__b1353311135516">off</strong> indicates that the sub-statement resource monitoring records are not archived.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p20495182481410"><strong id="EN-US_TOPIC_0000001510522653__b6838103713583">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b8839183711589">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section827402723813"><a name="EN-US_TOPIC_0000001510522653__section827402723813"></a><a name="section827402723813"></a><h4 class="sectiontitle">enable_user_metric_persistent</h4><p id="EN-US_TOPIC_0000001510522653__p11270427183812"><strong id="EN-US_TOPIC_0000001510522653__b12224252164710">Parameter description</strong>: Specifies whether the user historical resource monitoring dumping function is enabled. When this function is enabled, data in the <a href="dws_04_0790.html">PG_TOTAL_USER_RESOURCE_INFO</a> view is periodically sampled and saved to the <a href="dws_04_0567.html">GS_WLM_USER_RESOURCE_HISTORY</a> system catalog, and data in the <a href="dws_04_0977.html">GS_RESPOOL_RESOURCE_INFO</a> view is periodically sampled and saved to the <a href="dws_04_0975.html">GS_RESPOOL_RESOURCE_HISTORY</a> system catalog.</p>
<p id="EN-US_TOPIC_0000001510522653__p1127122142015"><strong id="EN-US_TOPIC_0000001510522653__b10901163033810">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p122719274381"><strong id="EN-US_TOPIC_0000001510522653__b62701527133814">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul8271162773818"><li id="EN-US_TOPIC_0000001510522653__li027142783810"><strong id="EN-US_TOPIC_0000001510522653__b1719240197">on</strong> indicates that the user historical resource monitoring dumping function is enabled.</li><li id="EN-US_TOPIC_0000001510522653__li1127132753810"><strong id="EN-US_TOPIC_0000001510522653__b1574314220261">off</strong> indicates that the user historical resource monitoring dumping function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p1227192763813"><strong id="EN-US_TOPIC_0000001510522653__b252762322615">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b19539142312264">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section16298163313384"><h4 class="sectiontitle">user_metric_retention_time</h4><p id="EN-US_TOPIC_0000001510522653__p3294193323812"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b1115554414451">enable_user_metric_persistent</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b0588051131915">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p9741742201712"><strong id="EN-US_TOPIC_0000001510522653__b852711362126">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p12295183323817"><strong id="EN-US_TOPIC_0000001510522653__b3410547290">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001510522653__ul162957333386"><li id="EN-US_TOPIC_0000001510522653__li1729533393816">If this parameter is set to <strong id="EN-US_TOPIC_0000001510522653__b695532443012">0</strong>, user historical resource monitoring data is permanently stored.</li><li id="EN-US_TOPIC_0000001510522653__li42950332387">If the value is greater than <strong id="EN-US_TOPIC_0000001510522653__b92762472309">0</strong>, user historical resource monitoring data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p102959336388"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0058967657_b26917141">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b842352706204923">7</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section18113133910385"><h4 class="sectiontitle">enable_instance_metric_persistent</h4><p id="EN-US_TOPIC_0000001510522653__p111103911388"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p15909933122014"><strong id="EN-US_TOPIC_0000001510522653__b17956123303813">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p9112133915386"><strong id="EN-US_TOPIC_0000001510522653__b2112139103816">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul11112113912389"><li id="EN-US_TOPIC_0000001510522653__li101126395382"><strong id="EN-US_TOPIC_0000001510522653__b325929311">on</strong> indicates that the instance resource monitoring dumping function is enabled.</li><li id="EN-US_TOPIC_0000001510522653__li111283915386"><strong id="EN-US_TOPIC_0000001510522653__b612611410332">off</strong>: Specifies that the instance resource monitoring dumping function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p12112239173820"><strong id="EN-US_TOPIC_0000001510522653__b75814610348">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b069765347">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section314449385"><h4 class="sectiontitle">instance_metric_retention_time</h4><p id="EN-US_TOPIC_0000001510522653__p00124414383"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b1566282269">enable_instance_metric_persistent</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b1285521016">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p1834911203172"><strong id="EN-US_TOPIC_0000001510522653__b378725910123">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p31144411387"><strong id="EN-US_TOPIC_0000001510522653__b7851939132">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001510522653__ul4114423811"><li id="EN-US_TOPIC_0000001510522653__li41344143820">If this parameter is set to <strong id="EN-US_TOPIC_0000001510522653__b12112125643519">0</strong>, instance historical resource monitoring data is permanently stored.</li><li id="EN-US_TOPIC_0000001510522653__li7118449381">If the value is greater than <strong id="EN-US_TOPIC_0000001510522653__b138631453133614">0</strong>, the instance historical resource monitoring data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p3194419386"><strong id="EN-US_TOPIC_0000001510522653__b588931809">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b614427999">7</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section153571329142612"><a name="EN-US_TOPIC_0000001510522653__section153571329142612"></a><a name="section153571329142612"></a><h4 class="sectiontitle">resource_track_level</h4><p id="EN-US_TOPIC_0000001510522653__p735952912615"><strong id="EN-US_TOPIC_0000001510522653__b1202415493">Parameter description</strong>: Specifies the resource monitoring level of the current session. This parameter is valid only when <strong id="EN-US_TOPIC_0000001510522653__b7190191612820">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b74951311588">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p117112313179"><strong id="EN-US_TOPIC_0000001510522653__b1421443511383">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p7363172910268"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059777487_a54344496219b4074ad956d5febb62b4c">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001510522653__ul15363122916268"><li id="EN-US_TOPIC_0000001510522653__li1436322917264"><strong id="EN-US_TOPIC_0000001510522653__b41866398234714">none</strong>: Resources are not monitored.</li><li id="EN-US_TOPIC_0000001510522653__li1666725091914"><strong id="EN-US_TOPIC_0000001510522653__b137515135916">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_0000001510522653__li73310451216"><strong id="EN-US_TOPIC_0000001510522653__b1395195715598">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_0000001510522653__li17365182911264"><strong id="EN-US_TOPIC_0000001510522653__b11737431413">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_0000001510522653__p436982932619"><strong id="EN-US_TOPIC_0000001510522653__b842352706153219">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b842352706153224">query</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section17771336077"><h4 class="sectiontitle">time_track_strategy</h4><p id="EN-US_TOPIC_0000001510522653__p12101103814711"><strong id="EN-US_TOPIC_0000001510522653__b1354424210478">Parameter description</strong>: Specifies the policy used to collect the operator execution time of the current session. This parameter is supported by version 8.2.1 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510522653__p1110112389710"><strong id="EN-US_TOPIC_0000001510522653__b1725755567">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p01017387714"><strong id="EN-US_TOPIC_0000001510522653__b374024431">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001510522653__ul17101163816711"><li id="EN-US_TOPIC_0000001510522653__li1410119388712"><strong id="EN-US_TOPIC_0000001510522653__b1696103525113">tsc</strong>: Use Time-Stamp Counter (TSC) to collect the operator execution time. This method is applicable to perf-level top SQL statements and EXPLAIN and applies only to non-vectorized operators. In other scenarios, the time function is still used.</li><li id="EN-US_TOPIC_0000001510522653__li16102193812718"><strong id="EN-US_TOPIC_0000001510522653__b1516114595617">vector</strong>: Disable the collection of the execution time of the non-vectorized operators in the top SQL statements at the perf level. Other scenarios use the time function perform collection and are not affected.</li><li id="EN-US_TOPIC_0000001510522653__li710217383715"><strong id="EN-US_TOPIC_0000001510522653__b177095301407">timer</strong>: The time function used in all scenarios to collect the operator execution time. In cluster 8.2.0 and earlier versions, only this method is used.</li><li id="EN-US_TOPIC_0000001510522653__li133211438185014"><strong id="EN-US_TOPIC_0000001510522653__b223485321914">opt</strong>: The database prioritizes selecting TSC for operator self-timing collection based on node conditions. If TSC is not available, the default time function is used for time collection. This policy is supported only by 8.2.1.230 clusters.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p11020381576"><strong id="EN-US_TOPIC_0000001510522653__b122891215126">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b185765171523">timer</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__note69661324132015"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="EN-US_TOPIC_0000001510522653__ul14828017142120"><li id="EN-US_TOPIC_0000001510522653__li88281917112111">The TSC has two methods of converting the time, including the TSC frequency and TSC conversion factors. By default, only the TSC frequency can be used on the x86 platform, and the TSC conversion factor is prioritized on the ARM platform. You can view the TSC conversion information for the current or all nodes through TSC-related views or functions.</li></ul>
<ul id="EN-US_TOPIC_0000001510522653__ul14985621132118"><li id="EN-US_TOPIC_0000001510522653__li12985521122114">In a cluster installation scenario, the default value of this parameter is <strong id="EN-US_TOPIC_0000001510522653__b1550843010191">tsc</strong>. In an upgrade scenario, the default value of this parameter is <strong id="EN-US_TOPIC_0000001510522653__b41481856171911">timer</strong> to ensure forward compatibility.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section1089022732713"><a name="EN-US_TOPIC_0000001510522653__section1089022732713"></a><a name="section1089022732713"></a><h4 class="sectiontitle">resource_track_cost</h4><p id="EN-US_TOPIC_0000001510522653__p10896172717275"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b14246261586">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b192611269815">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p14848174121618"><strong id="EN-US_TOPIC_0000001510522653__b1482133513382">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p4901127122712"><strong id="EN-US_TOPIC_0000001510522653__b1161683134">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001510522653__ul118701111164912"><li id="EN-US_TOPIC_0000001510522653__li16870811194919"><strong id="EN-US_TOPIC_0000001510522653__b498193110483">–1</strong> indicates that resource monitoring is disabled.</li><li id="EN-US_TOPIC_0000001510522653__li95612483106">A value greater than or equal to <strong id="EN-US_TOPIC_0000001510522653__b1476354145012">0</strong> indicates that statements whose execution cost exceeds this value will be monitored.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p11911192752714"><strong id="EN-US_TOPIC_0000001510522653__b1820213476599">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b22022470591">0</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__note129932011337"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510522653__p179930118337">The default value of this parameter is <strong id="EN-US_TOPIC_0000001510522653__b1827533371712">0</strong> for a new cluster. In upgrade scenarios, the default value of this parameter is the same as that of the source version.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section347574425112"><a name="EN-US_TOPIC_0000001510522653__section347574425112"></a><a name="section347574425112"></a><h4 class="sectiontitle">resource_track_duration</h4><p id="EN-US_TOPIC_0000001510522653__p1479644125111"><strong id="EN-US_TOPIC_0000001510522653__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_0000001460722660__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_0000001510522653__b42981326135716">statistics</strong>) to a historical view (with the suffix <strong id="EN-US_TOPIC_0000001510522653__b183001261575">history</strong>) if the statement execution time is no less than this value. This parameter is valid only when <strong id="EN-US_TOPIC_0000001510522653__b15432114710">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b45017114716">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p1569071491619"><strong id="EN-US_TOPIC_0000001510522653__b15574600396">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p84841144145112"><strong id="EN-US_TOPIC_0000001510522653__b63362351318">Value range</strong>: an integer ranging from 0 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001510522653__ul817641714915"><li id="EN-US_TOPIC_0000001510522653__li617601754918"><strong id="EN-US_TOPIC_0000001510522653__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_0000001460722660__table16116143418462">Table 1</a>) will be archived into historical views.</li><li id="EN-US_TOPIC_0000001510522653__li12176417164910">If the value is greater than <strong id="EN-US_TOPIC_0000001510522653__b17583134610111">0</strong>, information about statements recorded in the real-time resource monitoring view (see <a href="dws_04_0397.html#EN-US_TOPIC_0000001460722660__table16116143418462">Table 1</a>), whose execution time exceeds this value will be archived into historical views.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p3489114412516"><strong id="EN-US_TOPIC_0000001510522653__b842352706185119">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059778244_b15310055141954">60s</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section177585466812"><a name="EN-US_TOPIC_0000001510522653__section177585466812"></a><a name="section177585466812"></a><h4 class="sectiontitle">resource_track_subsql_duration</h4><p id="EN-US_TOPIC_0000001510522653__p20886191517283"><strong id="EN-US_TOPIC_0000001510522653__b3317124781814">Parameter description</strong>: Filters the minimum execution time of substatements in a stored procedure. This parameter is supported by version 8.2.1 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510522653__p575864615811">If the execution time of a sub-statement in a stored procedure is greater than the value of this parameter, the job information is archived to the Top SQL table. This parameter takes effect only when <a href="#EN-US_TOPIC_0000001510522653__section7181949101319">enable_track_record_subsql</a> is set to <strong id="EN-US_TOPIC_0000001510522653__b653410518233">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p77581646488"><strong id="EN-US_TOPIC_0000001510522653__b1193317559">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p57581846984"><strong id="EN-US_TOPIC_0000001510522653__b578157686">Value range</strong>: an integer ranging from 0 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001510522653__ul9758246288"><li id="EN-US_TOPIC_0000001510522653__li10758174616818">If the value is <strong id="EN-US_TOPIC_0000001510522653__b189313517306">0</strong>, historical information about all substatements in the stored procedure is archived.</li><li id="EN-US_TOPIC_0000001510522653__li275834617819">If the value is greater than <strong id="EN-US_TOPIC_0000001510522653__b176511815203017">0</strong>, historical information is archived when the execution time of a substatement in a stored procedure exceeds the value of this parameter.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p117588462814"><strong id="EN-US_TOPIC_0000001510522653__b1940454263013">Default value</strong>: 180s</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section18735205251810"><h4 class="sectiontitle">query_exception_count_limit</h4><p id="EN-US_TOPIC_0000001510522653__p34800532183"><strong id="EN-US_TOPIC_0000001510522653__b477368762">Parameter description</strong>: Specifies the maximum number of times that a job triggers an exception rule. If the number of times that a job triggers an exception rule reaches the upper limit, the job will be automatically added to the blocklist and cannot be executed anymore. The job can be resumed only after it is removed from the blocklist.</p>
<p id="EN-US_TOPIC_0000001510522653__p1948025315187"><strong id="EN-US_TOPIC_0000001510522653__b2025936761">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p94801053131815"><strong id="EN-US_TOPIC_0000001510522653__b139098608043159">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001510522653__ul948005314188"><li id="EN-US_TOPIC_0000001510522653__li348065391818">If the value is <strong id="EN-US_TOPIC_0000001510522653__b1484523195711">-1</strong>, the number of times that a job triggers an exception rule is not limited. That is, the job will not be automatically added to blocklist even if it triggers an exception rule for many times.</li><li id="EN-US_TOPIC_0000001510522653__li5481185318188">If the value is greater than or equal to <strong id="EN-US_TOPIC_0000001510522653__b162552813592">0</strong>, the job will be added to the blocklist immediately when the number of times it triggers an exception rule reaches the threshold. The values <strong id="EN-US_TOPIC_0000001510522653__b196363165013">0</strong> and <strong id="EN-US_TOPIC_0000001510522653__b138865171901">1</strong> both indicate that a job is added to blocklist once the job triggers an exception rule.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p7481135301816"><strong id="EN-US_TOPIC_0000001510522653__b215507543159">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b211545708643159">–1</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section104016114237"><h4 class="sectiontitle">dynamic_memory_quota</h4><p id="EN-US_TOPIC_0000001510522653__p14418175713620"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p159991748202013"><strong id="EN-US_TOPIC_0000001510522653__b1574317111397">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p6446211172319"><strong id="EN-US_TOPIC_0000001510522653__b13451161192319">Value range</strong>: an integer ranging from 1 to 100</p>
<p id="EN-US_TOPIC_0000001510522653__p1585722371119"><strong id="EN-US_TOPIC_0000001510522653__b55291462334714">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b213900953134714">80</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section174761723101217"><h4 class="sectiontitle">disable_memory_protect</h4><p id="EN-US_TOPIC_0000001510522653__p8480142318127"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__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_0000001510522653__b184955762934714">off</strong> in other scenarios.</p>
<p id="EN-US_TOPIC_0000001510522653__p27124510150"><strong id="EN-US_TOPIC_0000001510522653__b115746263918">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p18492172391214"><strong id="EN-US_TOPIC_0000001510522653__b747792483">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul18295447181311"><li id="EN-US_TOPIC_0000001510522653__li1429784791313"><strong id="EN-US_TOPIC_0000001510522653__b26312387934714">on</strong> indicates that memory protection stops.</li><li id="EN-US_TOPIC_0000001510522653__li12305747131314"><strong id="EN-US_TOPIC_0000001510522653__b151718890734714">off</strong> indicates that memory is protected.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p2049718238123"><strong id="EN-US_TOPIC_0000001510522653__b1574869013">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b1921003920">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section631565955912"><h4 class="sectiontitle">query_band</h4><p id="EN-US_TOPIC_0000001510522653__p831816598591"><strong id="EN-US_TOPIC_0000001510522653__b03183591590">Parameter description</strong>: Specifies the job type of the current session.</p>
<p id="EN-US_TOPIC_0000001510522653__p1159102281513"><strong id="EN-US_TOPIC_0000001510522653__b1234913113914">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p18321155915599"><strong id="EN-US_TOPIC_0000001510522653__b203046458">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001510522653__p1232185914598"><strong id="EN-US_TOPIC_0000001510522653__b4976537817215">Default value</strong>: empty</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section15334124411419"><a name="EN-US_TOPIC_0000001510522653__section15334124411419"></a><a name="section15334124411419"></a><h4 class="sectiontitle">enable_dynamic_workload</h4><p id="EN-US_TOPIC_0000001510522653__p113372044141412"><strong id="EN-US_TOPIC_0000001510522653__b2006426535">Parameter description</strong>: Specifies whether to enable the dynamic workload management function.</p>
<p id="EN-US_TOPIC_0000001510522653__p19268144813616"><strong id="EN-US_TOPIC_0000001510522653__b498711519394">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001510522653__p1334010443148"><strong id="EN-US_TOPIC_0000001510522653__b957369554">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul19341134431413"><li id="EN-US_TOPIC_0000001510522653__li183421544101416"><strong id="EN-US_TOPIC_0000001510522653__b842352706193247">on</strong> indicates the dynamic workload management function is enabled.</li><li id="EN-US_TOPIC_0000001510522653__li8343184412143"><strong id="EN-US_TOPIC_0000001510522653__b591929003">off</strong> indicates the dynamic workload management function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p19345444141417"><strong id="EN-US_TOPIC_0000001510522653__b1544954218411">Default value:</strong> <strong id="EN-US_TOPIC_0000001510522653__b344944218419">on</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001510522653__note1157234191015"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001510522653__ul11572044103"><li id="EN-US_TOPIC_0000001510522653__li2572164111014">If memory adaptation is enabled, you do not need to use <strong id="EN-US_TOPIC_0000001510522653__b116644279586">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_0000001510522653__li205729412103">The optimizer may not 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_0000001510522653__b63381985219">query_max_mem</strong>. For details, see <a href="dws_04_0453.html">Adjusting Key Parameters During SQL Tuning</a>.</li><li id="EN-US_TOPIC_0000001510522653__li106611320381">As the memory estimated by the optimizer may be inaccurate, in cluster versions earlier than 8.2.1, the <strong id="EN-US_TOPIC_0000001510522653__b827481681618">enable_dynamic_workload</strong> parameter needs to be disabled to prevent CCN global queuing. This will cause the dynamic load management function to be unavailable. Therefore, <a href="#EN-US_TOPIC_0000001510522653__section13214421174719">enable_global_memctl</a> is introduced in 8.2.1. When a CCN exception occurs, you can disable the <strong id="EN-US_TOPIC_0000001510522653__b1552732112415">enable_global_memctl</strong> parameter so that jobs can be delivered to and run in the resource pool.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section13214421174719"><a name="EN-US_TOPIC_0000001510522653__section13214421174719"></a><a name="section13214421174719"></a><h4 class="sectiontitle">enable_global_memctl</h4><p id="EN-US_TOPIC_0000001510522653__p16411955568"><strong id="EN-US_TOPIC_0000001510522653__b15534204842216">Parameter description</strong>: Specifies whether to enable the global memory management function. This parameter is supported by version 8.2.1 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510522653__p247565112470"><strong id="EN-US_TOPIC_0000001510522653__b769733496">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p1532245654818"><strong id="EN-US_TOPIC_0000001510522653__b839525834">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul133221856174811"><li id="EN-US_TOPIC_0000001510522653__li93226562485"><strong id="EN-US_TOPIC_0000001510522653__b614312472243">on</strong> indicates that the global memory management is enabled.</li><li id="EN-US_TOPIC_0000001510522653__li23223563488"><strong id="EN-US_TOPIC_0000001510522653__b202241318192519">off</strong> indicates that global memory management is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p151621829115516"><strong id="EN-US_TOPIC_0000001510522653__b1122379533">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b1025744807">on</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__note3413846135018"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510522653__p3717754349">The dynamic load function consists of two layers of memory management: global memory management and resource pool management. Global memory management determines whether a job can be delivered based on its estimated memory. Resource pool management determines whether a job can be delivered based on resource pool parameters. In versions earlier than 8.2.1, the global memory management function is enabled by default after the dynamic load management function is enabled. The statement memory usage may be underestimated or overestimated by the optimizer. As a result, jobs are queued in the global memory management queue on the CCN. In GaussDB 8.2.1, this parameter is used to control whether to enable the global memory management to improve job efficiency and reduce CCN queue exceptions.</p>
</div></div>
</div>
<div class="caution" id="EN-US_TOPIC_0000001510522653__note1766171223218"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><p id="EN-US_TOPIC_0000001510522653__p15194426133318">Pay attention to the following when modifying this parameter:</p>
<ol id="EN-US_TOPIC_0000001510522653__ol14301333199"><li id="EN-US_TOPIC_0000001510522653__li19430123171917">Disabling this parameter will deactivate the CCN management function and prevent the CCN memory negative feedback mechanism from functioning.</li><li id="EN-US_TOPIC_0000001510522653__li1943033171919">When a job is running, if the value of GUC is changed from <strong id="EN-US_TOPIC_0000001510522653__b86837481974">OFF</strong> to <strong id="EN-US_TOPIC_0000001510522653__b158353502715">ON</strong>, the CCN memory negative feedback mechanism takes effect. If the concurrency is high, the memory may be temporarily unavailable. After the running job is done, the dynamic load function recovers.</li><li id="EN-US_TOPIC_0000001510522653__li144318311192">When a job is running and most jobs are delivered by users from the default resource pool, you are not advised to change the GUC parameter from <strong id="EN-US_TOPIC_0000001510522653__b1949141851010">enabled </strong>to <strong id="EN-US_TOPIC_0000001510522653__b762612207105">disabled </strong>. It may cause a memory error. When there is no job delivered by users from the default resource pool, then you can change the parameter. You are advised to bind a user resource pool before delivering jobs.</li></ol>
</div></div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section1845219402118"><h4 class="sectiontitle">enable_wlm_internal_memory_limit</h4><p id="EN-US_TOPIC_0000001510522653__p14529081234"><strong id="EN-US_TOPIC_0000001510522653__b77341577816">Parameter description</strong>: Specifies whether to enable the built-in limit on estimated statement memory usage in load management. (This parameter is supported by version 8.2.0 or later clusters.)</p>
<p id="EN-US_TOPIC_0000001510522653__p1163852062117">In the memory management module of load management, some built-in restrictions are imposed on the estimated memory of statements. For example:</p>
<ul id="EN-US_TOPIC_0000001510522653__ul381794112215"><li id="EN-US_TOPIC_0000001510522653__li581744172118">The estimated memory of statements cannot exceed 80% of the memory upper limit of the associated resource pool.</li><li id="EN-US_TOPIC_0000001510522653__li1081713414217">If the concurrency control parameter <strong id="EN-US_TOPIC_0000001510522653__b92941515112810">active_statements</strong> of the resource pool is not set to <strong id="EN-US_TOPIC_0000001510522653__b1931152115288">1</strong>, the estimated memory of the statement cannot exceed 40% of the memory upper limit of the associated resource pool.</li><li id="EN-US_TOPIC_0000001510522653__li2181184317247">During the estimation of statement memory usage, a range is provided first. The maximum value indicates the memory required for optimal statement running performance. The minimum value indicates the memory required for statement running when data spilling is allowed. The final estimation will be within this range. The maximum estimated memory cannot exceed 90% of the memory upper limit of the associated resource pool.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p1211144173720">These built-in restrictions can prevent overestimation of statement memory. If memory usage is overestimated, statements will preoccupy too much memory, causing subsequent jobs to queue and affecting resource utilization. To avoid such problems, the kernel limits the estimated memory usage of a single statement. Execution plans under the built-in restrictions may not be optimal, and may affect the performance of a statement. The memory negative feedback mechanism is provided in 8.2.0 and later cluster versions to alleviate this problem. The <strong id="EN-US_TOPIC_0000001510522653__b632720113424">enable_wlm_internal_memory_limit</strong> parameter is added in 8.2.0 and later versions. You can determine whether to enable the built-in restrictions.</p>
<p id="EN-US_TOPIC_0000001510522653__p1095014571112"><strong id="EN-US_TOPIC_0000001510522653__b617472989">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p19950114513115"><strong id="EN-US_TOPIC_0000001510522653__b343415275">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul1695015452116"><li id="EN-US_TOPIC_0000001510522653__li9950154551120"><strong id="EN-US_TOPIC_0000001510522653__b0422274217">on</strong> indicates that the built-in restrictions on statement memory estimation are enabled.</li><li id="EN-US_TOPIC_0000001510522653__li159501245151117"><strong id="EN-US_TOPIC_0000001510522653__b1367765784213">off</strong> indicates that the built-in restrictions on statement memory estimation are disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p14950164517119"><strong id="EN-US_TOPIC_0000001510522653__b1179264176">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b729014330">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section513575412220"><h4 class="sectiontitle">enable_strict_memory_expansion</h4><p id="EN-US_TOPIC_0000001510522653__p5929355172817"><strong id="EN-US_TOPIC_0000001510522653__b13452121014310">Parameter description</strong>: Specifies whether to enable strict control over the increase of statement memory usage. (This parameter is supported by version 8.2.0 or later clusters.)</p>
<p id="EN-US_TOPIC_0000001510522653__p15558135762214">The CN calculates the estimated memory for a statement and preempts memory accordingly. If there is sufficient memory, the DN can increase the memory used for a statement to facilitate its execution. If this parameter is enabled, the increase of memory usage for a statement will be strictly controlled. The memory usage of a statement will not be allowed to exceed its estimated maximum usage. The memory usage of an operator is increased proportionally each time, so the memory usage after an increase may exceed the allowed maximum, but to a limited extent.</p>
<p id="EN-US_TOPIC_0000001510522653__p5559165713229"><strong id="EN-US_TOPIC_0000001510522653__b1764705062">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p1582518426327"><strong id="EN-US_TOPIC_0000001510522653__b1765622534">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul11825542153217"><li id="EN-US_TOPIC_0000001510522653__li13825124283213"><strong id="EN-US_TOPIC_0000001510522653__b12748114344319">on</strong> indicates that strict control over statement memory usage is enabled.</li><li id="EN-US_TOPIC_0000001510522653__li082564213325"><strong id="EN-US_TOPIC_0000001510522653__b207841046184316">off</strong> indicates that strict control over statement memory usage is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p1582517425327"><strong id="EN-US_TOPIC_0000001510522653__b1666691630">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b1743352315">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section575182810238"><h4 class="sectiontitle">allow_zero_estimate_memory</h4><p id="EN-US_TOPIC_0000001510522653__p103719092910"><strong id="EN-US_TOPIC_0000001510522653__b1069565934318">Parameter description</strong>: Specifies whether the estimated memory usage of a statement can be 0. (This parameter is supported by version 8.2.0 or later clusters.)</p>
<p id="EN-US_TOPIC_0000001510522653__p11193192972312">If the table queried by a statement does not contain statistics, the estimated memory of the statement on the CN may be 0. In this case, the memory usage of operators in the statement is limited by <a href="dws_04_0893.html#EN-US_TOPIC_0000001460563104__s7be4202f202f4ccc8ecee5816cf7b2ab">work_mem</a>. (<strong id="EN-US_TOPIC_0000001510522653__b161581105136">work_mem</strong> is not recommended for operator memory usage control). If <strong id="EN-US_TOPIC_0000001510522653__b626911412138">work_mem</strong> is large and there are many operators in a statement, the actual memory of the statement will be large. If this parameter is set to <strong id="EN-US_TOPIC_0000001510522653__b18975123516131">off</strong>, the estimated memory usage cannot be 0 for queries that have not been analyzed. This setting can help reduce unexpected problems.</p>
<p id="EN-US_TOPIC_0000001510522653__p81939292235"><strong id="EN-US_TOPIC_0000001510522653__b1734084417">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p9408194543617"><strong id="EN-US_TOPIC_0000001510522653__b743603398">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul1440854593619"><li id="EN-US_TOPIC_0000001510522653__li184081451360"><strong id="EN-US_TOPIC_0000001510522653__b19799345204417">on</strong> indicates that the estimated memory usage of a statement can be 0.</li><li id="EN-US_TOPIC_0000001510522653__li9408114593616"><strong id="EN-US_TOPIC_0000001510522653__b2036334112456">off</strong> indicates that the estimated memory usage of a statement cannot be 0.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p24082454366"><strong id="EN-US_TOPIC_0000001510522653__b37547251">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b2135024210">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section14382217494"><h4 class="sectiontitle">wlm_memory_feedback_adjust</h4><p id="EN-US_TOPIC_0000001510522653__p3381622492"><strong id="EN-US_TOPIC_0000001510522653__b691313712818">Parameter description</strong>: Specifies whether to enable memory negative feedback in dynamic load management. (This parameter is supported by version 8.2.0 or later clusters.)</p>
<p id="EN-US_TOPIC_0000001510522653__p12444182816515">Memory is preempted based on the estimated statement memory usage calculated on the CN. If the estimated memory usage of a statement is too high, it will preempt too much memory, causing subsequent jobs to be queued. With the negative memory feedback mechanism, if the cluster memory usage has been overestimated for a period of time, the CCN node will dynamically release some memory for subsequent jobs, improving resource utilization.</p>
<p id="EN-US_TOPIC_0000001510522653__p1382211494"><strong id="EN-US_TOPIC_0000001510522653__b470354693">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p18381223493"><strong id="EN-US_TOPIC_0000001510522653__b1528851771">Value range</strong>: string</p>
<ul id="EN-US_TOPIC_0000001510522653__ul8380224912"><li id="EN-US_TOPIC_0000001510522653__li18380254916"><strong id="EN-US_TOPIC_0000001510522653__b1497615915509">on</strong> indicates that memory negative feedback is enabled.</li><li id="EN-US_TOPIC_0000001510522653__li4391284918"><strong id="EN-US_TOPIC_0000001510522653__b420051011515">off</strong> indicates that memory negative feedback is disabled.</li><li id="EN-US_TOPIC_0000001510522653__li1817319521247"><strong id="EN-US_TOPIC_0000001510522653__b42316564444">on</strong><strong id="EN-US_TOPIC_0000001510522653__b1323235654418">(</strong><em id="EN-US_TOPIC_0000001510522653__i82321056184411">Time_required_for_triggering_negative_feedback</em>, <em id="EN-US_TOPIC_0000001510522653__i15232165615443">Estimated_memory_percentage_required_for_triggering_negative_feedback</em><strong id="EN-US_TOPIC_0000001510522653__b2232155694415">)</strong> indicates that memory negative feedback is enabled. For example, <strong id="EN-US_TOPIC_0000001510522653__b12298934199">on(60,50)</strong> indicates that to trigger the negative feedback mechanism, the memory must be overestimated for 60 consecutive seconds, and the preempted memory needs must exceed 50% of the available memory. By default, the wait time before the negative feedback mechanism takes effect is 50 seconds. The minimum estimated total memory usage for triggering the mechanism is over 40% of the available system memory.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p18395220496"><strong id="EN-US_TOPIC_0000001510522653__b1312074847">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b1894872872">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__s49ffefbc1d7e4261a3b9b6bde1e9a147"><h4 class="sectiontitle">bbox_dump_count</h4><p id="EN-US_TOPIC_0000001510522653__ad31ef0c87e1744859be6dbfec2e978c0"><strong id="EN-US_TOPIC_0000001510522653__b92572581368">Parameter description</strong>: Specifies the maximum number of core files that are generated by <span id="EN-US_TOPIC_0000001510522653__text425719581561">GaussDB(DWS)</span> and can be stored in the path specified by <strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b19565330473">enable_bbox_dump</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b12566530572">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p74798402510"><strong id="EN-US_TOPIC_0000001510522653__b18943938183913">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__a44e616b37b524be99d1e4e1cf8d29578"><strong id="EN-US_TOPIC_0000001510522653__b15123128115616">Value range</strong>: an integer ranging from 1 to 20</p>
<p id="EN-US_TOPIC_0000001510522653__add923227fd1148f9a00db57996e3c3ff"><strong id="EN-US_TOPIC_0000001510522653__b1413578664144214">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b578690575144214">8</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510522653__ncdaf889bc5bd4b0e9b36c618b7241881"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b2005970014144133">bbox_dump_count</strong>.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section1148143712203"><h4 class="sectiontitle">io_limits</h4><p id="EN-US_TOPIC_0000001510522653__p12501837102015"><strong id="EN-US_TOPIC_0000001510522653__b10888359144812">Parameter description</strong>: This parameter has been discarded in version 8.1.2 and is reserved for compatibility with earlier versions. This parameter is invalid in the current version.</p>
<p id="EN-US_TOPIC_0000001510522653__p11335216520"><strong id="EN-US_TOPIC_0000001510522653__b5683154023910">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p2353169278"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p18641037102016"><strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059778487_a023402ff020d43919b2d4639671ceb32">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__en-us_topic_0059778487_en-us_topic_0058967649_b842352706195030">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section0751123912227"><h4 class="sectiontitle">io_priority</h4><p id="EN-US_TOPIC_0000001510522653__p652216533225"><strong id="EN-US_TOPIC_0000001510522653__b1890855918487">Parameter description</strong>: This parameter has been discarded in version 8.1.2 and is reserved for compatibility with earlier versions. This parameter is invalid in the current version.</p>
<p id="EN-US_TOPIC_0000001510522653__p19172056519"><strong id="EN-US_TOPIC_0000001510522653__b1124334173913">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p075714396226"><strong id="EN-US_TOPIC_0000001510522653__b113660499">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001510522653__ul584258251503"><li id="EN-US_TOPIC_0000001510522653__li1136775412577">None</li><li id="EN-US_TOPIC_0000001510522653__li327400081503">Low</li><li id="EN-US_TOPIC_0000001510522653__li266002731506">Medium</li><li id="EN-US_TOPIC_0000001510522653__li587127221508">High</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p1675915397225"><strong id="EN-US_TOPIC_0000001510522653__b12034753911539">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b152401163719">None</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section2673131522715"><h4 class="sectiontitle">session_respool</h4><p id="EN-US_TOPIC_0000001510522653__p067531572720"><strong id="EN-US_TOPIC_0000001510522653__b842352706194554">Parameter description</strong>: Specifies the resource pool associated with the current session.</p>
<p id="EN-US_TOPIC_0000001510522653__p76261753133513"><strong id="EN-US_TOPIC_0000001510522653__b478114411391">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p165805713355">If you set <strong id="EN-US_TOPIC_0000001510522653__b1686193681">cgroup_name</strong> and then <strong id="EN-US_TOPIC_0000001510522653__b1902167859">session_respool</strong>, the Cgroups associated with <strong id="EN-US_TOPIC_0000001510522653__b1867507798">session_respool</strong> take effect. If you reverse the order, Cgroups associated with <strong id="EN-US_TOPIC_0000001510522653__b203648348">cgroup_name</strong> take effect.</p>
<p id="EN-US_TOPIC_0000001510522653__p5591757183516">If the Workload Cgroup level is specified during the <strong id="EN-US_TOPIC_0000001510522653__b1565417688">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_0000001510522653__p7223154111811">You are not advised to set <strong id="EN-US_TOPIC_0000001510522653__b1179987391">cgroup_name</strong> and <strong id="EN-US_TOPIC_0000001510522653__b318118625">session_respool</strong> at the same time.</p>
<p id="EN-US_TOPIC_0000001510522653__p168061522714"><strong id="EN-US_TOPIC_0000001510522653__b842352706194349">Value range</strong>: a string. This parameter can be set to the resource pool configured through <strong id="EN-US_TOPIC_0000001510522653__b842352706194528">create resource pool</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p968301582711"><strong id="EN-US_TOPIC_0000001510522653__b267379058">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b1391625156">invalid_pool</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section106864402366"><h4 class="sectiontitle">enable_transaction_parctl</h4><p id="EN-US_TOPIC_0000001510522653__p1968613403367"><strong id="EN-US_TOPIC_0000001510522653__b10392155641511">Parameter description</strong>: whether to control transaction block statements and stored procedure statements.</p>
<p id="EN-US_TOPIC_0000001510522653__p135009518411"><strong id="EN-US_TOPIC_0000001510522653__b2052904283914">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p56861040103620"><strong id="EN-US_TOPIC_0000001510522653__b577286554">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510522653__ul16861640113613"><li id="EN-US_TOPIC_0000001510522653__li12686040183613"><strong id="EN-US_TOPIC_0000001510522653__b110355215161">on</strong>: Transaction block statements and stored procedure statements are controlled.</li><li id="EN-US_TOPIC_0000001510522653__li19686174013617"><strong id="EN-US_TOPIC_0000001510522653__b1344353011171">off</strong>: Transaction block statements and stored procedure statements are not controlled.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p168764003610"><strong id="EN-US_TOPIC_0000001510522653__b383242522">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b197361252">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section27306369458"><a name="EN-US_TOPIC_0000001510522653__section27306369458"></a><a name="section27306369458"></a><h4 class="sectiontitle">session_history_memory</h4><p id="EN-US_TOPIC_0000001510522653__p10730143684512"><strong id="EN-US_TOPIC_0000001510522653__b81703241277">Parameter description</strong>: Specifies the memory size of a historical query view.</p>
<p id="EN-US_TOPIC_0000001510522653__p99441634935"><strong id="EN-US_TOPIC_0000001510522653__b12848124318395">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p273193613458"><strong id="EN-US_TOPIC_0000001510522653__b16919152612815">Value range</strong>: an integer ranging from 10 MB to 50% of <strong id="EN-US_TOPIC_0000001510522653__b292110261582">max_process_memory</strong></p>
<p id="EN-US_TOPIC_0000001510522653__p1373114364453"><strong id="EN-US_TOPIC_0000001510522653__b1228652820814">Default value:</strong> <strong id="EN-US_TOPIC_0000001510522653__b1328712282819">100MB</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section2570135114116"><h4 class="sectiontitle">topsql_retention_time</h4><p id="EN-US_TOPIC_0000001510522653__p0613161384"><strong id="EN-US_TOPIC_0000001510522653__b61401423114716">Parameter description</strong>: Specifies the retention period of historical Top SQL data in the <strong id="EN-US_TOPIC_0000001510522653__b6592135012479">gs_wlm_session_info</strong> and <strong id="EN-US_TOPIC_0000001510522653__b20547105474716">gs_wlm_operator_info</strong> tables.</p>
<p id="EN-US_TOPIC_0000001510522653__p252917217319"><strong id="EN-US_TOPIC_0000001510522653__b1327894433918">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p176131643817"><strong id="EN-US_TOPIC_0000001510522653__b111145313377">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001510522653__ul24731743104213"><li id="EN-US_TOPIC_0000001510522653__li047315438424">If it is set to <strong id="EN-US_TOPIC_0000001510522653__b139411713133218">0</strong>, the data is stored permanently.</li><li id="EN-US_TOPIC_0000001510522653__li1473104310427">If the value is greater than <strong id="EN-US_TOPIC_0000001510522653__b1834015160386">0</strong>, the data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001510522653__p13691613386"><strong id="EN-US_TOPIC_0000001510522653__b13915259151516">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b842352706165429">30</strong></p>
<div class="caution" id="EN-US_TOPIC_0000001510522653__note2020576431"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><ul id="EN-US_TOPIC_0000001510522653__ul5138104893711"><li id="EN-US_TOPIC_0000001510522653__li1613874817375">Before setting this GUC parameter to enable the data retention function, delete data from the <strong id="EN-US_TOPIC_0000001510522653__b1105445507101833">gs_wlm_session_info</strong> and <strong id="EN-US_TOPIC_0000001510522653__b1161883884101833">gs_wlm_operator_info</strong> tables.</li><li id="EN-US_TOPIC_0000001510522653__li1762712504377">The default value of this parameter is <strong id="EN-US_TOPIC_0000001510522653__b643676245101833">30</strong> for a new cluster. In upgrade scenarios, the default value of this parameter is the same as that of the source version.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section1835116504363"><h4 class="sectiontitle">transaction_pending_time</h4><p id="EN-US_TOPIC_0000001510522653__p335185043614"><strong id="EN-US_TOPIC_0000001510522653__b965356141816">Parameter description</strong>: maximum queuing time of transaction block statements and stored procedure statements if <strong id="EN-US_TOPIC_0000001510522653__b8106111214191">enable_transaction_parctl</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b25061918161919">on</strong>.</p>
<p id="EN-US_TOPIC_0000001510522653__p12603151319214"><strong id="EN-US_TOPIC_0000001510522653__b1439412454391">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510522653__p335111501361"><strong id="EN-US_TOPIC_0000001510522653__b1289665073815">Value range</strong>: an integer ranging from –1 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001510522653__ul13351150103610"><li id="EN-US_TOPIC_0000001510522653__li1335116502368"><strong id="EN-US_TOPIC_0000001510522653__b119721869208">–1</strong> or <strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__li163511950193616">Value greater than <strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p183511250113616"><strong id="EN-US_TOPIC_0000001510522653__b1259144474">Default value</strong>: <strong id="EN-US_TOPIC_0000001510522653__b2136485750">0</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001510522653__ne7dee8ee88ce4d6299b8651b0fa820d1"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b967924916202">enqueue</strong> value (for details, see <a href="dws_04_0749.html">PG_SESSION_WLMSTAT</a>) is <strong id="EN-US_TOPIC_0000001510522653__b102210162116">Transaction</strong> or <strong id="EN-US_TOPIC_0000001510522653__b17188114112119">StoredProc</strong>.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510522653__section3917839115"><a name="EN-US_TOPIC_0000001510522653__section3917839115"></a><a name="section3917839115"></a><h4 class="sectiontitle">wlm_sql_allow_list</h4><p id="EN-US_TOPIC_0000001510522653__p11917153151119"><strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__p391715312119"><strong id="EN-US_TOPIC_0000001510522653__b541917222208">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510522653__p159171731117"><strong id="EN-US_TOPIC_0000001510522653__b879416210211">Value range</strong>: a string, which contains a maximum of 1,024 characters</p>
<p id="EN-US_TOPIC_0000001510522653__p1391863111111"><strong id="EN-US_TOPIC_0000001510522653__b19149202516179">Default value</strong>: empty</p>
<div class="notice" id="EN-US_TOPIC_0000001510522653__note49182314117"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001510522653__ul1426521191610"><li id="EN-US_TOPIC_0000001510522653__li1726142118164">One or more whitelisted SQL statements can be specified in <strong id="EN-US_TOPIC_0000001510522653__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_0000001510522653__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_0000001510522653__b189983319173">wlm_sql_allow_list</strong> is set to <strong id="EN-US_TOPIC_0000001510522653__b1110593321715">'SELECT'</strong>, all <strong id="EN-US_TOPIC_0000001510522653__b1310673321712">SELECT</strong> statements are not monitored by the resource management module.</li><li id="EN-US_TOPIC_0000001510522653__li16872734174116">The system identifies spaces at the beginning of the parameter value. For example, <strong id="EN-US_TOPIC_0000001510522653__b819075117405">'SELECT'</strong> and <strong id="EN-US_TOPIC_0000001510522653__b17437109174119">' SELECT'</strong> have different representations. <strong id="EN-US_TOPIC_0000001510522653__b468553984120">' SELECT'</strong> filters only the <strong id="EN-US_TOPIC_0000001510522653__b28145479419">SELECT</strong> statements with spaces at the beginning.</li><li id="EN-US_TOPIC_0000001510522653__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_0000001510522653__b1793820378172">gs_wlm_sql_allow</strong>.</li><li id="EN-US_TOPIC_0000001510522653__li466922215340">New SQL statements cannot be appended to the whitelisted SQL statements specified by <strong id="EN-US_TOPIC_0000001510522653__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>
</div></div>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0883.html">GUC Parameters of the GaussDB(DWS) Database</a></div>
</div>
</div>
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