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sgode-patch-2
doc-exports/docs/dws/dev/dws_04_0922.html
luhuayi 177cd61a57 DWS DEVG 910.211 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: luhuayi <luhuayi@huawei.com>
Co-committed-by: luhuayi <luhuayi@huawei.com>
2025-05-05 07:44:03 +00:00

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<a name="EN-US_TOPIC_0000001811490709"></a><a name="EN-US_TOPIC_0000001811490709"></a>
<h1 class="topictitle1">Resource Management</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001811490709__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_0000001811490709__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_0000001811490709__section2515929121516"><h4 class="sectiontitle">space_once_adjust_num</h4><p id="EN-US_TOPIC_0000001811490709__p163971630131516"><strong id="EN-US_TOPIC_0000001811490709__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 only by clusters of version 8.1.3 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p239714307155"><strong id="EN-US_TOPIC_0000001811490709__b168481330192819">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p439710309152"><strong id="EN-US_TOPIC_0000001811490709__b14491635162817">Value range</strong>: an integer ranging from 0 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001811490709__ul143242045223"><li id="EN-US_TOPIC_0000001811490709__li138487912216">The value <strong id="EN-US_TOPIC_0000001811490709__b17969359183511">0</strong> indicates that the slow build and fine-grained calibration functions are disabled.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p203972301156"><strong id="EN-US_TOPIC_0000001811490709__b1750415402284">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b17510174018285">300</strong></p>
<div class="note" id="EN-US_TOPIC_0000001811490709__note754920241335"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001811490709__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_0000001811490709__section1739119376529"><h4 class="sectiontitle">default_partition_cache_strategy</h4><p id="EN-US_TOPIC_0000001811490709__p93907370525"><strong id="EN-US_TOPIC_0000001811490709__b106511317113212">Parameter description</strong>: Specifies the default policy for controlling partition caching. This parameter is supported only by clusters of version 8.3.0 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p339013717522"><strong id="EN-US_TOPIC_0000001811490709__b9390737205214">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p1039117377527"><strong id="EN-US_TOPIC_0000001811490709__b1239023715521">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001811490709__ul1239113712520"><li id="EN-US_TOPIC_0000001811490709__li1239116371526"><strong id="EN-US_TOPIC_0000001811490709__b92234414012">cache_each_partition_as_possible</strong> enables maximum data caching. Data may not be written to CUs when being inserted into different partitions.</li><li id="EN-US_TOPIC_0000001811490709__li139133715524"><strong id="EN-US_TOPIC_0000001811490709__b2902283456">flush_when_switch_partition</strong> indicates that data is written to CUs if the data belongs to different partitions during insertion.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p15391103735213"><strong id="EN-US_TOPIC_0000001811490709__b166171653104412">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b3433134174517">cache_each_partition_as_possible</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s7a13b0da34a74fe886bdf7671e62019b"><h4 class="sectiontitle">max_active_statements</h4><p id="EN-US_TOPIC_0000001811490709__addc805286ca74ef9a2554b470c4fae80"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b84235270617340">Parameter description</strong>: Specifies the maximum global concurrency. This parameter applies to a job on a CN.</p>
<p id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p16407102791018"><strong id="EN-US_TOPIC_0000001811490709__b1787012212383">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__a074267e4991b476ebb38e7061f47c80f"><strong id="EN-US_TOPIC_0000001811490709__b1333016122363">Value range</strong>: an integer ranging from –1 to INT_MAX. The values <strong id="EN-US_TOPIC_0000001811490709__b8361163317211">–1</strong> and <strong id="EN-US_TOPIC_0000001811490709__b33896379211">0</strong> indicate that the number of concurrent requests is not limited.</p>
<p id="EN-US_TOPIC_0000001811490709__a3e180989283945129914c1800c110445"><strong id="EN-US_TOPIC_0000001811490709__b109654376103">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b1852764121011">60</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s8159a12f556d464abbf1acffe467b548"><h4 class="sectiontitle">cgroup_name</h4><p id="EN-US_TOPIC_0000001811490709__a6d50fdbf988d447dbf68bf86dbc6fa5b"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p119020197324">If you set <strong id="EN-US_TOPIC_0000001811490709__b842352706175935">cgroup_name</strong> and then <strong id="EN-US_TOPIC_0000001811490709__b842352706175940">session_respool</strong>, the Cgroups associated with <strong id="EN-US_TOPIC_0000001811490709__b8423527061803">session_respool</strong> take effect. If you reverse the order, Cgroups associated with <strong id="EN-US_TOPIC_0000001811490709__b84235270618042">cgroup_name</strong> take effect.</p>
<p id="EN-US_TOPIC_0000001811490709__p75569413347">If the Workload Cgroup level is specified during the <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p141021638141912"><strong id="EN-US_TOPIC_0000001811490709__b206805233385">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p63212713170">You are not advised to set <strong id="EN-US_TOPIC_0000001811490709__b842352706181635">cgroup_name</strong> and <strong id="EN-US_TOPIC_0000001811490709__b842352706181640">session_respool</strong> at the same time.</p>
<p id="EN-US_TOPIC_0000001811490709__afb9148a5a4a54b2592c8b2610df13767"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b688672095621">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001811490709__a960082ccca4246e0a475c33188966896"><strong id="EN-US_TOPIC_0000001811490709__b16948152754819">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b18452203324810">DefaultClass:Medium</strong></p>
<div class="note" id="EN-US_TOPIC_0000001811490709__note1953653910322"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001811490709__p366615446327"><strong id="EN-US_TOPIC_0000001811490709__b429654704815">DefaultClass:Medium</strong> indicates the <strong id="EN-US_TOPIC_0000001811490709__b1048713795016">Medium</strong> Cgroup belonging to the <strong id="EN-US_TOPIC_0000001811490709__b173481122135011">Timeshare</strong> Cgroup under the <strong id="EN-US_TOPIC_0000001811490709__b1824672714505">DefaultClass</strong> Cgroup.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s565c7e2c8cb34d4db165766b74a73683"><h4 class="sectiontitle">enable_cgroup_switch</h4><p id="EN-US_TOPIC_0000001811490709__a5eca9c9caeac4b98a5ae1bdee735cf0a"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b842352706192357">TopWD</strong> group when executing statements by group type.</p>
<p id="EN-US_TOPIC_0000001811490709__p241918691910"><strong id="EN-US_TOPIC_0000001811490709__b18921162543816">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__a0a1bc12cb50947aaab525684d57deda3"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_abdb6603792074f608afcc026778454fb">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__u508ca40006484f93ac6601714ce81f84"><li id="EN-US_TOPIC_0000001811490709__l24467bedd0504ff08a43c85df18138ba"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172123_3">on</strong>: The database automatically switches to the <strong id="EN-US_TOPIC_0000001811490709__b842352706192435">TopWD</strong> group when executing statements by group type.</li><li id="EN-US_TOPIC_0000001811490709__labe48b71421d46bfbf1665865f5169cf"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b84235270619276">TopWD</strong> group when executing statements by group type.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__a2fc3159e811a498cbc4238818a718375"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b5971851117846_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b84235270613313">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s99d436e056b446d19c841da7b23faae8"><h4 class="sectiontitle">memory_tracking_mode</h4><p id="EN-US_TOPIC_0000001811490709__a67919fed03e44562bea8db4b97c2e70e"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b842352706172610">Parameter description</strong>: Specifies the memory information recording mode.</p>
<p id="EN-US_TOPIC_0000001811490709__p1746473641810"><strong id="EN-US_TOPIC_0000001811490709__b1852632613389">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__a66ad8055b3f04c22bda844ba1e2493cc"><strong id="EN-US_TOPIC_0000001811490709__b25782132328">Value range</strong>:</p>
<ul id="EN-US_TOPIC_0000001811490709__ul29059994172249"><li id="EN-US_TOPIC_0000001811490709__li16695073172249"><strong id="EN-US_TOPIC_0000001811490709__b842352706105333">none</strong>: Memory statistics is not collected.</li><li id="EN-US_TOPIC_0000001811490709__li5710012517239"><strong id="EN-US_TOPIC_0000001811490709__b842352706105432">normal:</strong> Only memory statistics is collected in real time and no file is generated.</li><li id="EN-US_TOPIC_0000001811490709__li56020122172333"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__li61119980172352"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__a368ea04ff5554e6293efd92bdd49074c"><strong id="EN-US_TOPIC_0000001811490709__b10048826103114">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b110848183317">none</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s3f3dd81692d64ce08fa1a352e9ebb56f"><h4 class="sectiontitle">memory_detail_tracking</h4><p id="EN-US_TOPIC_0000001811490709__a72d25f2d0320437c992a285dcb72ce7f"><strong id="EN-US_TOPIC_0000001811490709__b1678060675144418">Parameter description</strong>: Specifies the sequence number of the memory background information distributed in the needed thread and <strong id="EN-US_TOPIC_0000001811490709__b842352706192855">plannodeid</strong> of the query where the current thread is located.</p>
<p id="EN-US_TOPIC_0000001811490709__p1245071620182"><strong id="EN-US_TOPIC_0000001811490709__b61126275389">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__af350ee0eedbe4e05b3454c4d69ce0b7c"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b37796097_1">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001811490709__a39299a499b1e41288f2d9ea1fdc82e42"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_b421586113118">Default value</strong>: empty</p>
<div class="notice" id="EN-US_TOPIC_0000001811490709__n83cc48fd8396484199f83f9de17a7247"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001811490709__a0c78987d9e3a4018abbf4890e1f7804d">It is recommended that you retain the default value for this parameter.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s9530ecdd2b0d4a98b67b66e32bf8e5d0"><a name="EN-US_TOPIC_0000001811490709__s9530ecdd2b0d4a98b67b66e32bf8e5d0"></a><a name="s9530ecdd2b0d4a98b67b66e32bf8e5d0"></a><h4 class="sectiontitle">enable_resource_track</h4><p id="EN-US_TOPIC_0000001811490709__ae718ea1b2bf14c248e8eb722b646360d"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p16411142618918"><strong id="EN-US_TOPIC_0000001811490709__b1511714282389">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__aa360558c12b34fa28006d7763756d1da"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_6">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__u3ff70c8d7adb42d0a45d5b54d7b482d6"><li id="EN-US_TOPIC_0000001811490709__l502f22098a3546a38fb609437f27473d"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__l0b48936acbbe4f13a19e6dd43f120bd5"><strong id="EN-US_TOPIC_0000001811490709__b104214192034714">off</strong> indicates the resource monitoring function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__a32291243ba3049eba8785fab5e24526b"><strong id="EN-US_TOPIC_0000001811490709__b1101529633172346">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b421067350172346">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s5f116e109a2944e3854abcc56772eaa1"><a name="EN-US_TOPIC_0000001811490709__s5f116e109a2944e3854abcc56772eaa1"></a><a name="s5f116e109a2944e3854abcc56772eaa1"></a><h4 class="sectiontitle">enable_resource_record</h4><p id="EN-US_TOPIC_0000001811490709__p1091904413"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b18855101419466">INFO</strong> views (<a href="dws_04_0704.html">GS_WLM_SESSION_INFO</a> and <a href="dws_04_0701.html">GS_WLM_OPERATOR_INFO</a>). This parameter must be applied on both CNs and DNs.</p>
<p id="EN-US_TOPIC_0000001811490709__p1179712121695"><strong id="EN-US_TOPIC_0000001811490709__b51611129203815">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__a2a0deb112b624e15a23774120200a46e"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059777791_en-us_topic_0058967586_b24458229162831_8">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__u1632ed197ebf48c5a6bc26e750b6c0ce"><li id="EN-US_TOPIC_0000001811490709__l084582a6e1e3496dbdc97769d266b4b7"><strong id="EN-US_TOPIC_0000001811490709__b96415896734714">on</strong> indicates that the resource monitoring records are archived.</li><li id="EN-US_TOPIC_0000001811490709__le34a6e152c0344d6bfc4e472e72efdeb"><strong id="EN-US_TOPIC_0000001811490709__b58509289134714">off</strong> indicates that the resource monitoring records are not archived.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__ab67a24a37b7243788a434311c708ccd4"><strong id="EN-US_TOPIC_0000001811490709__b5368154018462">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b3375640144611">on</strong></p>
<div class="note" id="EN-US_TOPIC_0000001811490709__note1760311247421"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001811490709__p6604102414215">The default value of this parameter is <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__section7181949101319"><a name="EN-US_TOPIC_0000001811490709__section7181949101319"></a><a name="section7181949101319"></a><h4 class="sectiontitle">enable_track_record_subsql</h4><p id="EN-US_TOPIC_0000001811490709__p15875120144310"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b693711194413">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_0000001811490709__p287516202432"><strong id="EN-US_TOPIC_0000001811490709__b1916871689">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p487542010431"><strong id="EN-US_TOPIC_0000001811490709__b476123165420">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__ul1487613201432"><li id="EN-US_TOPIC_0000001811490709__li1876620184311"><strong id="EN-US_TOPIC_0000001811490709__b1621417343549">on</strong> indicates that the sub-statement resource monitoring records are archived.</li><li id="EN-US_TOPIC_0000001811490709__li1087615201436"><strong id="EN-US_TOPIC_0000001811490709__b1353311135516">off</strong> indicates that the sub-statement resource monitoring records are not archived.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p20495182481410"><strong id="EN-US_TOPIC_0000001811490709__b19573715114114">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b842352706172116">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section288791354111"><h4 class="sectiontitle">block_rule_cost</h4><p id="EN-US_TOPIC_0000001811490709__p86646242418"><strong id="EN-US_TOPIC_0000001811490709__b19664152416414">Parameter description</strong>: Specifies the minimum cost to trigger a query filter. This is supported only by clusters of version 9.1.0.200 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p1666462418418"><strong id="EN-US_TOPIC_0000001811490709__b1212902226">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p96642242412"><strong id="EN-US_TOPIC_0000001811490709__b5179121975910">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001811490709__ul16664172413418"><li id="EN-US_TOPIC_0000001811490709__li1716091154412">Value <strong id="EN-US_TOPIC_0000001811490709__b62484910153">–1</strong> indicates that the system filters all statements without considering the cost.</li><li id="EN-US_TOPIC_0000001811490709__li10796276166">Value <strong id="EN-US_TOPIC_0000001811490709__b745601119194">0</strong> indicates that all statements whose cost is greater than 0 are intercepted, but special statements (whose cost is 0) are not intercepted.</li><li id="EN-US_TOPIC_0000001811490709__li616161115447">If the value is greater than <strong id="EN-US_TOPIC_0000001811490709__b10764338209">0</strong> and the statement cost is less than the value of <strong id="EN-US_TOPIC_0000001811490709__b159774712014">block_rule_cost</strong>, the statement is not intercepted; otherwise, it is intercepted.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p3664152414414"><strong id="EN-US_TOPIC_0000001811490709__b53628433514291">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b164450946414291">–1</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section827402723813"><a name="EN-US_TOPIC_0000001811490709__section827402723813"></a><a name="section827402723813"></a><h4 class="sectiontitle">enable_user_metric_persistent</h4><p id="EN-US_TOPIC_0000001811490709__p11270427183812"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p1127122142015"><strong id="EN-US_TOPIC_0000001811490709__b10901163033810">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p122719274381"><strong id="EN-US_TOPIC_0000001811490709__b62701527133814">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__ul8271162773818"><li id="EN-US_TOPIC_0000001811490709__li027142783810"><strong id="EN-US_TOPIC_0000001811490709__b1719240197">on</strong> indicates that the user historical resource monitoring dumping function is enabled.</li><li id="EN-US_TOPIC_0000001811490709__li1127132753810"><strong id="EN-US_TOPIC_0000001811490709__b1574314220261">off</strong> indicates that the user historical resource monitoring dumping function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p1227192763813"><strong id="EN-US_TOPIC_0000001811490709__b252762322615">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b19539142312264">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section16298163313384"><h4 class="sectiontitle">user_metric_retention_time</h4><p id="EN-US_TOPIC_0000001811490709__p3294193323812"><strong id="EN-US_TOPIC_0000001811490709__b535910298266">Parameter description</strong>: Specifies the retention time of the user historical resource monitoring data. </p>
<p id="EN-US_TOPIC_0000001811490709__p9741742201712"><strong id="EN-US_TOPIC_0000001811490709__b852711362126">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p12295183323817"><strong id="EN-US_TOPIC_0000001811490709__b3410547290">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001811490709__ul162957333386"><li id="EN-US_TOPIC_0000001811490709__li1729533393816">If this parameter is set to <strong id="EN-US_TOPIC_0000001811490709__b695532443012">0</strong>, user historical resource monitoring data is permanently stored.</li><li id="EN-US_TOPIC_0000001811490709__li42950332387">If the value is greater than <strong id="EN-US_TOPIC_0000001811490709__b92762472309">0</strong>, user historical resource monitoring data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p102959336388"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0058967657_b26917141">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b842352706204923">7</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section153571329142612"><a name="EN-US_TOPIC_0000001811490709__section153571329142612"></a><a name="section153571329142612"></a><h4 class="sectiontitle">resource_track_level</h4><p id="EN-US_TOPIC_0000001811490709__p735952912615"><strong id="EN-US_TOPIC_0000001811490709__b2093276329">Parameter description</strong>: Specifies the resource monitoring level of the current session. This parameter is valid only when <strong id="EN-US_TOPIC_0000001811490709__b7190191612820">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001811490709__b74951311588">on</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p117112313179"><strong id="EN-US_TOPIC_0000001811490709__b1421443511383">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p7363172910268"><strong id="EN-US_TOPIC_0000001811490709__b46939731984842">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001811490709__ul15363122916268"><li id="EN-US_TOPIC_0000001811490709__li1436322917264"><strong id="EN-US_TOPIC_0000001811490709__b41866398234714">none</strong>: Resources are not monitored.</li><li id="EN-US_TOPIC_0000001811490709__li1666725091914"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__li73310451216"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__li267675715428"><strong id="EN-US_TOPIC_0000001811490709__b15673051508">operator_realtime</strong>: enables the operator-level resource monitoring. If this function is enabled, the operator information of jobs running in real time is recorded in the top SQL statements, but is not persisted to the historical top SQL statements.</li><li id="EN-US_TOPIC_0000001811490709__li17365182911264"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p436982932619"><strong id="EN-US_TOPIC_0000001811490709__b842352706153219">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b842352706153224">query</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section722434420511"><h4 class="sectiontitle">fast_obs_tablesize_method</h4><p id="EN-US_TOPIC_0000001811490709__p019094616511"><strong id="EN-US_TOPIC_0000001811490709__b17355195924512">Parameter description</strong>: Specifies the method for quickly calculating the size of column-store V3 and V3 HStore Opt tables. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p7190346135116"><strong id="EN-US_TOPIC_0000001811490709__b744078675">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p7190246125110"><strong id="EN-US_TOPIC_0000001811490709__b202159455184842">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001811490709__ul12190194616515"><li id="EN-US_TOPIC_0000001811490709__li41901146135114"><strong id="EN-US_TOPIC_0000001811490709__b27261220174616">0</strong>: The table size is calculated by listing OBS files.</li><li id="EN-US_TOPIC_0000001811490709__li219094655115"><strong id="EN-US_TOPIC_0000001811490709__b4281751124610">1</strong>: The table size is calculated through WLM background statistics using <strong id="EN-US_TOPIC_0000001811490709__b16308174405020">pg_relfilenode_size</strong>.</li><li id="EN-US_TOPIC_0000001811490709__li15190646135113"><strong id="EN-US_TOPIC_0000001811490709__b10644501515">2</strong>: The table size is estimated by calculating the maximum offset of each file in cudesc.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p81905461516"><strong id="EN-US_TOPIC_0000001811490709__b119895241518">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b11990124135115">2</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section95151651185119"><h4 class="sectiontitle">fast_obs_dbsize_method</h4><p id="EN-US_TOPIC_0000001811490709__p551511515514"><strong id="EN-US_TOPIC_0000001811490709__b1254920324519">Parameter description</strong>: Specifies the method for quickly calculating the size of database data on OBS. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p1151512516519"><strong id="EN-US_TOPIC_0000001811490709__b1347058938">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p8515251195115"><strong id="EN-US_TOPIC_0000001811490709__b202636673884842">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001811490709__ul351505118511"><li id="EN-US_TOPIC_0000001811490709__li14515185175116"><strong id="EN-US_TOPIC_0000001811490709__b13606151915310">0</strong>: The size of the database is directly estimated based on the OBS bucket.</li><li id="EN-US_TOPIC_0000001811490709__li1429473818170"><strong id="EN-US_TOPIC_0000001811490709__b10732105919535">1</strong>: The size of the entire database is normally calculated in regular mode.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p25151051195114"><strong id="EN-US_TOPIC_0000001811490709__b197041050162813">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b139534810162813">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section1089022732713"><a name="EN-US_TOPIC_0000001811490709__section1089022732713"></a><a name="section1089022732713"></a><h4 class="sectiontitle">resource_track_cost</h4><p id="EN-US_TOPIC_0000001811490709__p10896172717275"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b14246261586">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001811490709__b192611269815">on</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p14848174121618"><strong id="EN-US_TOPIC_0000001811490709__b1482133513382">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p4901127122712"><strong id="EN-US_TOPIC_0000001811490709__b1161683134">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001811490709__ul118701111164912"><li id="EN-US_TOPIC_0000001811490709__li16870811194919"><strong id="EN-US_TOPIC_0000001811490709__b498193110483">–1</strong> indicates that resource monitoring is disabled.</li><li id="EN-US_TOPIC_0000001811490709__li95612483106">A value greater than or equal to <strong id="EN-US_TOPIC_0000001811490709__b1476354145012">0</strong> indicates that statements whose execution cost exceeds this value will be monitored.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p11911192752714"><strong id="EN-US_TOPIC_0000001811490709__b1820213476599">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b22022470591">0</strong></p>
<div class="note" id="EN-US_TOPIC_0000001811490709__note129932011337"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001811490709__p179930118337">The default value of this parameter is <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__section347574425112"><a name="EN-US_TOPIC_0000001811490709__section347574425112"></a><a name="section347574425112"></a><h4 class="sectiontitle">resource_track_duration</h4><p id="EN-US_TOPIC_0000001811490709__p1479644125111"><strong id="EN-US_TOPIC_0000001811490709__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_0000001764491512__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_0000001811490709__b42981326135716">statistics</strong>) to a historical view (with the suffix <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b15432114710">enable_resource_track</strong> is set to <strong id="EN-US_TOPIC_0000001811490709__b45017114716">on</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p1569071491619"><strong id="EN-US_TOPIC_0000001811490709__b15574600396">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p84841144145112"><strong id="EN-US_TOPIC_0000001811490709__b63362351318">Value range</strong>: an integer ranging from 0 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001811490709__ul817641714915"><li id="EN-US_TOPIC_0000001811490709__li617601754918"><strong id="EN-US_TOPIC_0000001811490709__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_0000001764491512__table16116143418462">Table 1</a>) will be archived into historical views.</li><li id="EN-US_TOPIC_0000001811490709__li12176417164910">If the value is greater than <strong id="EN-US_TOPIC_0000001811490709__b1137517417231">0</strong>, the system archives historical information if the total execution and queuing time of statements in the real-time resource monitoring view (<a href="dws_04_0397.html#EN-US_TOPIC_0000001764491512__table16116143418462">Table 1</a>) goes over the parameter value.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p3489114412516"><strong id="EN-US_TOPIC_0000001811490709__b842352706185119">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059778244_b15310055141954">60s</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section177585466812"><a name="EN-US_TOPIC_0000001811490709__section177585466812"></a><a name="section177585466812"></a><h4 class="sectiontitle">resource_track_subsql_duration</h4><p id="EN-US_TOPIC_0000001811490709__p20886191517283"><strong id="EN-US_TOPIC_0000001811490709__b3317124781814">Parameter description</strong>: Filters the minimum execution time of substatements in a stored procedure. This parameter is supported only by clusters of version 8.2.1 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__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 dumped to the top SQL archive table. This parameter takes effect only when <a href="#EN-US_TOPIC_0000001811490709__section7181949101319">enable_track_record_subsql</a> is set to <strong id="EN-US_TOPIC_0000001811490709__b653410518233">on</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p77581646488"><strong id="EN-US_TOPIC_0000001811490709__b1701409681">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p57581846984"><strong id="EN-US_TOPIC_0000001811490709__b1037730879">Value range</strong>: an integer ranging from 0 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001811490709__ul9758246288"><li id="EN-US_TOPIC_0000001811490709__li10758174616818">If the value is <strong id="EN-US_TOPIC_0000001811490709__b189313517306">0</strong>, historical information about all substatements in the stored procedure is archived.</li><li id="EN-US_TOPIC_0000001811490709__li275834617819">If the value is greater than <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p117588462814"><strong id="EN-US_TOPIC_0000001811490709__b1940454263013">Default value</strong>: 180s</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section18735205251810"><h4 class="sectiontitle">query_exception_count_limit</h4><p id="EN-US_TOPIC_0000001811490709__p34800532183"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p1948025315187"><strong id="EN-US_TOPIC_0000001811490709__b2080754909">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p94801053131815"><strong id="EN-US_TOPIC_0000001811490709__b139098608043159">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001811490709__ul948005314188"><li id="EN-US_TOPIC_0000001811490709__li348065391818">If the value is <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__li5481185318188">If the value is greater than or equal to <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b196363165013">0</strong> and <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p7481135301816"><strong id="EN-US_TOPIC_0000001811490709__b215507543159">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b211545708643159">–1</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section174761723101217"><h4 class="sectiontitle">disable_memory_protect</h4><p id="EN-US_TOPIC_0000001811490709__p8480142318127"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__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_0000001811490709__b184955762934714">off</strong> in other scenarios.</p>
<p id="EN-US_TOPIC_0000001811490709__p27124510150"><strong id="EN-US_TOPIC_0000001811490709__b115746263918">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p18492172391214"><strong id="EN-US_TOPIC_0000001811490709__b1288788128">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__ul18295447181311"><li id="EN-US_TOPIC_0000001811490709__li1429784791313"><strong id="EN-US_TOPIC_0000001811490709__b26312387934714">on</strong> indicates that memory protection stops.</li><li id="EN-US_TOPIC_0000001811490709__li12305747131314"><strong id="EN-US_TOPIC_0000001811490709__b151718890734714">off</strong> indicates that memory is protected.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p2049718238123"><strong id="EN-US_TOPIC_0000001811490709__b911062147">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b1747112839">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section631565955912"><h4 class="sectiontitle">query_band</h4><p id="EN-US_TOPIC_0000001811490709__p831816598591"><strong id="EN-US_TOPIC_0000001811490709__b14199539194212">Parameter description</strong>: Specifies the job type of the current session.</p>
<p id="EN-US_TOPIC_0000001811490709__p1159102281513"><strong id="EN-US_TOPIC_0000001811490709__b1234913113914">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p18321155915599"><strong id="EN-US_TOPIC_0000001811490709__b1770811827">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001811490709__p1232185914598"><strong id="EN-US_TOPIC_0000001811490709__b4976537817215">Default value</strong>: empty</p>
</div>
<div class="caution" id="EN-US_TOPIC_0000001811490709__note1766171223218"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><p id="EN-US_TOPIC_0000001811490709__p15194426133318">Pay attention to the following when modifying this parameter:</p>
<ol id="EN-US_TOPIC_0000001811490709__ol14301333199"><li id="EN-US_TOPIC_0000001811490709__li19430123171917">When this parameter is disabled, it means that the user does not need CCN control function, and the CCN memory negative feedback mechanism will be invalid.</li><li id="EN-US_TOPIC_0000001811490709__li1943033171919">When a job is running, if the value of GUC is changed from <strong id="EN-US_TOPIC_0000001811490709__b86837481974">OFF</strong> to <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__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_0000001811490709__b1949141851010">enabled </strong>to <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__section14382217494"><h4 class="sectiontitle">wlm_memory_feedback_adjust</h4><p id="EN-US_TOPIC_0000001811490709__p3381622492"><strong id="EN-US_TOPIC_0000001811490709__b691313712818">Parameter description</strong>: Specifies whether to enable memory negative feedback in dynamic load management. (This parameter is supported only by clusters of version 8.2.0 or later.)</p>
<p id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p1382211494"><strong id="EN-US_TOPIC_0000001811490709__b1516317765">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p18381223493"><strong id="EN-US_TOPIC_0000001811490709__b489962014195">Value range</strong>: a string</p>
<ul id="EN-US_TOPIC_0000001811490709__ul8380224912"><li id="EN-US_TOPIC_0000001811490709__li18380254916"><strong id="EN-US_TOPIC_0000001811490709__b1497615915509">on</strong> indicates that memory negative feedback is enabled.</li><li id="EN-US_TOPIC_0000001811490709__li4391284918"><strong id="EN-US_TOPIC_0000001811490709__b420051011515">off</strong> indicates that memory negative feedback is disabled.</li><li id="EN-US_TOPIC_0000001811490709__li1817319521247"><strong id="EN-US_TOPIC_0000001811490709__b67813181553">on()</strong> enables the memory negative feedback function and specifies the time and estimated memory percentage parameter required to trigger the negative feedback. For example, <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p18395220496"><strong id="EN-US_TOPIC_0000001811490709__b1663048994">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b99207111">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__s49ffefbc1d7e4261a3b9b6bde1e9a147"><h4 class="sectiontitle">bbox_dump_count</h4><p id="EN-US_TOPIC_0000001811490709__ad31ef0c87e1744859be6dbfec2e978c0"><strong id="EN-US_TOPIC_0000001811490709__b92572581368">Parameter description</strong>: Specifies the maximum number of core files that are generated by <span id="EN-US_TOPIC_0000001811490709__text425719581561">GaussDB(DWS)</span> and can be stored in the path specified by <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b19565330473">enable_bbox_dump</strong> is set to <strong id="EN-US_TOPIC_0000001811490709__b12566530572">on</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p74798402510"><strong id="EN-US_TOPIC_0000001811490709__b18943938183913">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__a44e616b37b524be99d1e4e1cf8d29578"><strong id="EN-US_TOPIC_0000001811490709__b15123128115616">Value range</strong>: an integer ranging from 1 to 20</p>
<p id="EN-US_TOPIC_0000001811490709__add923227fd1148f9a00db57996e3c3ff"><strong id="EN-US_TOPIC_0000001811490709__b1413578664144214">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b578690575144214">8</strong></p>
<div class="note" id="EN-US_TOPIC_0000001811490709__ncdaf889bc5bd4b0e9b36c618b7241881"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b2005970014144133">bbox_dump_count</strong>.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section1148143712203"><h4 class="sectiontitle">io_limits</h4><p id="EN-US_TOPIC_0000001811490709__p12501837102015"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p11335216520"><strong id="EN-US_TOPIC_0000001811490709__b5683154023910">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p2353169278"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p18641037102016"><strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059778487_a023402ff020d43919b2d4639671ceb32">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__en-us_topic_0059778487_en-us_topic_0058967649_b842352706195030">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section0751123912227"><h4 class="sectiontitle">io_priority</h4><p id="EN-US_TOPIC_0000001811490709__p652216533225"><strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p19172056519"><strong id="EN-US_TOPIC_0000001811490709__b1124334173913">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p075714396226"><strong id="EN-US_TOPIC_0000001811490709__b79325816784842">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001811490709__ul584258251503"><li id="EN-US_TOPIC_0000001811490709__li1136775412577">None</li><li id="EN-US_TOPIC_0000001811490709__li327400081503">Low</li><li id="EN-US_TOPIC_0000001811490709__li266002731506">Medium</li><li id="EN-US_TOPIC_0000001811490709__li587127221508">High</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p1675915397225"><strong id="EN-US_TOPIC_0000001811490709__b12034753911539">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b152401163719">None</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section2673131522715"><h4 class="sectiontitle">session_respool</h4><p id="EN-US_TOPIC_0000001811490709__p067531572720"><strong id="EN-US_TOPIC_0000001811490709__b842352706194554">Parameter description</strong>: Specifies the resource pool associated with the current session.</p>
<p id="EN-US_TOPIC_0000001811490709__p76261753133513"><strong id="EN-US_TOPIC_0000001811490709__b478114411391">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p165805713355">If you set <strong id="EN-US_TOPIC_0000001811490709__b376033858">cgroup_name</strong> and then <strong id="EN-US_TOPIC_0000001811490709__b653024607">session_respool</strong>, the Cgroups associated with <strong id="EN-US_TOPIC_0000001811490709__b595394484">session_respool</strong> take effect. If you reverse the order, Cgroups associated with <strong id="EN-US_TOPIC_0000001811490709__b1760148534">cgroup_name</strong> take effect.</p>
<p id="EN-US_TOPIC_0000001811490709__p5591757183516">If the Workload Cgroup level is specified during the <strong id="EN-US_TOPIC_0000001811490709__b303996227">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_0000001811490709__p7223154111811">You are not advised to set <strong id="EN-US_TOPIC_0000001811490709__b1600926561">cgroup_name</strong> and <strong id="EN-US_TOPIC_0000001811490709__b1316363857">session_respool</strong> at the same time.</p>
<p id="EN-US_TOPIC_0000001811490709__p168061522714"><strong id="EN-US_TOPIC_0000001811490709__b842352706194349">Value range</strong>: a string. This parameter can be set to the resource pool configured through <strong id="EN-US_TOPIC_0000001811490709__b842352706194528">create resource pool</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p968301582711"><strong id="EN-US_TOPIC_0000001811490709__b1948979257">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b888896910">invalid_pool</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section106864402366"><h4 class="sectiontitle">enable_transaction_parctl</h4><p id="EN-US_TOPIC_0000001811490709__p1968613403367"><strong id="EN-US_TOPIC_0000001811490709__b10392155641511">Parameter description</strong>: whether to control transaction block statements and stored procedure statements.</p>
<p id="EN-US_TOPIC_0000001811490709__p135009518411"><strong id="EN-US_TOPIC_0000001811490709__b2052904283914">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p56861040103620"><strong id="EN-US_TOPIC_0000001811490709__b1862118837">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__ul16861640113613"><li id="EN-US_TOPIC_0000001811490709__li12686040183613"><strong id="EN-US_TOPIC_0000001811490709__b110355215161">on</strong>: Transaction block statements and stored procedure statements are controlled.</li><li id="EN-US_TOPIC_0000001811490709__li19686174013617"><strong id="EN-US_TOPIC_0000001811490709__b1344353011171">off</strong>: Transaction block statements and stored procedure statements are not controlled.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p168764003610"><strong id="EN-US_TOPIC_0000001811490709__b405684906">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b1788963243">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section27306369458"><a name="EN-US_TOPIC_0000001811490709__section27306369458"></a><a name="section27306369458"></a><h4 class="sectiontitle">session_history_memory</h4><p id="EN-US_TOPIC_0000001811490709__p10730143684512"><strong id="EN-US_TOPIC_0000001811490709__b81703241277">Parameter description</strong>: Specifies the memory size of a historical query view.</p>
<p id="EN-US_TOPIC_0000001811490709__p99441634935"><strong id="EN-US_TOPIC_0000001811490709__b12848124318395">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p273193613458"><strong id="EN-US_TOPIC_0000001811490709__b16919152612815">Value range</strong>: an integer ranging from 10 MB to 50% of <strong id="EN-US_TOPIC_0000001811490709__b292110261582">max_process_memory</strong></p>
<p id="EN-US_TOPIC_0000001811490709__p1373114364453"><strong id="EN-US_TOPIC_0000001811490709__b1228652820814">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b1328712282819">100MB</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section2570135114116"><h4 class="sectiontitle">topsql_retention_time</h4><p id="EN-US_TOPIC_0000001811490709__p0613161384"><strong id="EN-US_TOPIC_0000001811490709__b61401423114716">Parameter description</strong>: Specifies the retention period of historical Top SQL data in the <strong id="EN-US_TOPIC_0000001811490709__b6592135012479">gs_wlm_session_info</strong> and <strong id="EN-US_TOPIC_0000001811490709__b20547105474716">gs_wlm_operator_info</strong> tables.</p>
<p id="EN-US_TOPIC_0000001811490709__p252917217319"><strong id="EN-US_TOPIC_0000001811490709__b1327894433918">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p176131643817"><strong id="EN-US_TOPIC_0000001811490709__b111145313377">Value range</strong>: an integer ranging from 0 to 3650. The unit is day.</p>
<ul id="EN-US_TOPIC_0000001811490709__ul24731743104213"><li id="EN-US_TOPIC_0000001811490709__li047315438424">If it is set to <strong id="EN-US_TOPIC_0000001811490709__b139411713133218">0</strong>, the data is stored permanently.</li><li id="EN-US_TOPIC_0000001811490709__li1473104310427">If the value is greater than <strong id="EN-US_TOPIC_0000001811490709__b1834015160386">0</strong>, the data is stored for the specified number of days.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p13691613386"><strong id="EN-US_TOPIC_0000001811490709__b13915259151516">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b842352706165429">30</strong></p>
<div class="caution" id="EN-US_TOPIC_0000001811490709__note2020576431"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><ul id="EN-US_TOPIC_0000001811490709__ul5138104893711"><li id="EN-US_TOPIC_0000001811490709__li1613874817375">Before setting this GUC parameter to enable the data retention function, delete data from the <strong id="EN-US_TOPIC_0000001811490709__b1105445507101833">gs_wlm_session_info</strong> and <strong id="EN-US_TOPIC_0000001811490709__b1161883884101833">gs_wlm_operator_info</strong> tables.</li><li id="EN-US_TOPIC_0000001811490709__li1762712504377">The default value of this parameter is <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__section1835116504363"><h4 class="sectiontitle">transaction_pending_time</h4><p id="EN-US_TOPIC_0000001811490709__p335185043614"><strong id="EN-US_TOPIC_0000001811490709__b965356141816">Parameter description</strong>: maximum queuing time of transaction block statements and stored procedure statements if <strong id="EN-US_TOPIC_0000001811490709__b8106111214191">enable_transaction_parctl</strong> is set to <strong id="EN-US_TOPIC_0000001811490709__b25061918161919">on</strong>.</p>
<p id="EN-US_TOPIC_0000001811490709__p12603151319214"><strong id="EN-US_TOPIC_0000001811490709__b1439412454391">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001811490709__p335111501361"><strong id="EN-US_TOPIC_0000001811490709__b1289665073815">Value range</strong>: an integer ranging from –1 to INT_MAX. The unit is second (s).</p>
<ul id="EN-US_TOPIC_0000001811490709__ul13351150103610"><li id="EN-US_TOPIC_0000001811490709__li1335116502368"><strong id="EN-US_TOPIC_0000001811490709__b119721869208">–1</strong> or <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__li163511950193616">Value greater than <strong id="EN-US_TOPIC_0000001811490709__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_0000001811490709__p183511250113616"><strong id="EN-US_TOPIC_0000001811490709__b698412381">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b1721152402">0</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001811490709__ne7dee8ee88ce4d6299b8651b0fa820d1"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001811490709__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_0000001811490709__b967924916202">enqueue</strong> value (for details, see <a href="dws_04_0749.html">PG_SESSION_WLMSTAT</a>) is <strong id="EN-US_TOPIC_0000001811490709__b102210162116">Transaction</strong> or <strong id="EN-US_TOPIC_0000001811490709__b17188114112119">StoredProc</strong>.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section104522041163417"><h4 class="sectiontitle">enable_concurrency_scaling</h4><p id="EN-US_TOPIC_0000001811490709__p133308341911"><strong id="EN-US_TOPIC_0000001811490709__b247623313517">Parameter description</strong>: Specifies whether to enable the elastic concurrent expansion function. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p419390101017"><strong id="EN-US_TOPIC_0000001811490709__b1500973100">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p42569318105"><strong id="EN-US_TOPIC_0000001811490709__b131866104104341">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001811490709__ul340513615368"><li id="EN-US_TOPIC_0000001811490709__li1140566103618"><strong id="EN-US_TOPIC_0000001811490709__b16499152857">on</strong> indicates that the elastic concurrent expansion function is enabled.</li><li id="EN-US_TOPIC_0000001811490709__li1774112963611"><strong id="EN-US_TOPIC_0000001811490709__b628111571351">off</strong> indicates that the elastic concurrent expansion function is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p77073541697"><strong id="EN-US_TOPIC_0000001811490709__b158780310091014">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b207457413891014">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section1299725711392"><h4 class="sectiontitle">concurrency_scaling_max_idle_time</h4><p id="EN-US_TOPIC_0000001811490709__p872419916405"><strong id="EN-US_TOPIC_0000001811490709__b166887911610">Parameter description</strong>: Specifies the maximum idle time of the elastic logical cluster created for concurrent expansion. If it exceeds the set value of this parameter, it will enter the process of destroying the elastic logical cluster. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p1561461213401"><strong id="EN-US_TOPIC_0000001811490709__b1910569670">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p1862731584010"><strong id="EN-US_TOPIC_0000001811490709__b1162731544016">Value range</strong>: an integer ranging from 0 to 60, in minutes. The value <strong id="EN-US_TOPIC_0000001811490709__b12419145714164">0</strong> indicates that the elastic logical cluster created during concurrent expansion will not be destroyed. Exercise caution when setting this value.</p>
<p id="EN-US_TOPIC_0000001811490709__p1888345174018"><strong id="EN-US_TOPIC_0000001811490709__b19438125315182">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b11439175315186">5</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section5545183154011"><h4 class="sectiontitle">concurrency_scaling_limit_per_main_vw</h4><p id="EN-US_TOPIC_0000001811490709__p20765337134019"><strong id="EN-US_TOPIC_0000001811490709__b1916985919188">Parameter description</strong>: Specifies the maximum number of concurrent elastic logical clusters that can be created for each classic logical cluster. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p1535313615411"><strong id="EN-US_TOPIC_0000001811490709__b1911796589">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p13315135814483"><strong id="EN-US_TOPIC_0000001811490709__b16765137194013">Value range</strong>: an integer ranging from 0 to 32</p>
<p id="EN-US_TOPIC_0000001811490709__p4765103710405"><strong id="EN-US_TOPIC_0000001811490709__b914745514183">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b0147155111813">5</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section387134914011"><h4 class="sectiontitle">concurrency_scaling_max_vw_active_statements</h4><p id="EN-US_TOPIC_0000001811490709__p16865814212"><strong id="EN-US_TOPIC_0000001811490709__b8560931132013">Parameter description</strong>: Specifies the maximum number of concurrent tasks that can be executed in an elastic logical cluster. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p162821355194017"><strong id="EN-US_TOPIC_0000001811490709__b1039366636">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p8191173234312"><strong id="EN-US_TOPIC_0000001811490709__b1816514478323">Value range</strong>: an integer ranging from –1 to INT_MAX</p>
<ul id="EN-US_TOPIC_0000001811490709__ul12989152713169"><li id="EN-US_TOPIC_0000001811490709__li1598932713166">Value <strong id="EN-US_TOPIC_0000001811490709__b17974145413218">0</strong> indicates that the elastic logical cluster does not execute any jobs. Exercise caution when setting this value.</li><li id="EN-US_TOPIC_0000001811490709__li69891927141613"><strong id="EN-US_TOPIC_0000001811490709__b13652201515337">–1</strong> indicates that the elastic logical cluster is not under concurrency control. Exercise caution when setting this value. This value is supported only by clusters of version 9.1.0.200 or later.</li></ul>
<p id="EN-US_TOPIC_0000001811490709__p628318555407"><strong id="EN-US_TOPIC_0000001811490709__b13121123983313">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b1312253919330">60</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001811490709__section944041013411"><h4 class="sectiontitle">concurrency_scaling_max_waiting_statements</h4><p id="EN-US_TOPIC_0000001811490709__p113891552172710"><strong id="EN-US_TOPIC_0000001811490709__b5777751192210">Parameter description</strong>: Specifies the number of queued elastic jobs in the global queue that trigger the creation process of the elastic logical cluster for concurrent expansion. This parameter is supported only by clusters of version 9.1.0.100 or later.</p>
<p id="EN-US_TOPIC_0000001811490709__p449492912473">If the number of queued elastic jobs is greater than or equal to the value set for this parameter, and the number of concurrently created elastic logical clusters does not exceed the value set for <strong id="EN-US_TOPIC_0000001811490709__b1119973692718">concurrency_scaling_limit_per_main_vw</strong>, the process of creating a concurrent expansion elastic logical cluster will be triggered automatically.</p>
<p id="EN-US_TOPIC_0000001811490709__p9551143255513"><strong id="EN-US_TOPIC_0000001811490709__b1942944858">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001811490709__p3767415104117"><strong id="EN-US_TOPIC_0000001811490709__b360610210214">Value range</strong>: an integer ranging from 0 to INT_MAX. The value <strong id="EN-US_TOPIC_0000001811490709__b1827145812714">0</strong> indicates that an elastic logical cluster is created even if there are no queued jobs. If set to <strong id="EN-US_TOPIC_0000001811490709__b15711145413288">0</strong>, a large number of resources are consumed. Exercise caution when setting this value.</p>
<p id="EN-US_TOPIC_0000001811490709__p1767181534118"><strong id="EN-US_TOPIC_0000001811490709__b56706366288">Default value</strong>: <strong id="EN-US_TOPIC_0000001811490709__b18670136132813">10</strong></p>
</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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