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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_0000001510402605"></a><a name="EN-US_TOPIC_0000001510402605"></a>
<h1 class="topictitle1">Hybrid Data Warehouse GUC Parameters</h1>
<div id="body0000001440655546"><div class="section" id="EN-US_TOPIC_0000001510402605__section192946226431"><h4 class="sectiontitle">autovacuum</h4><p id="EN-US_TOPIC_0000001510402605__p12294142210437"><strong id="EN-US_TOPIC_0000001510402605__b3718585326">Parameter description</strong>: Specifies whether to start the automatic cleanup process (<strong id="EN-US_TOPIC_0000001510402605__b13719586325">autovacuum</strong>).</p>
<p id="EN-US_TOPIC_0000001510402605__p1029482214312"><strong id="EN-US_TOPIC_0000001510402605__b1614361133320">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p16294722154312"><strong id="EN-US_TOPIC_0000001510402605__b11973152133318">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510402605__ul621525117437"><li id="EN-US_TOPIC_0000001510402605__li321555117435"><strong id="EN-US_TOPIC_0000001510402605__b13919114123312">on</strong> indicates the database automatic cleanup process is enabled.</li><li id="EN-US_TOPIC_0000001510402605__li10215125114313"><strong id="EN-US_TOPIC_0000001510402605__b1655179334">off</strong> indicates that the database automatic cleanup process is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001510402605__p202951122164320"><strong id="EN-US_TOPIC_0000001510402605__b46431296339">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b1864459113314">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section58821328135013"><h4 class="sectiontitle">autovacuum_compaction_rows_limit</h4><p id="EN-US_TOPIC_0000001510402605__p128823286506"><strong id="EN-US_TOPIC_0000001510402605__b9190715191510">Parameter description</strong>: Specifies the threshold of a small CU. A CU whose number of live tuples is less than the value of this parameter is considered as a small CU. This parameter is supported only by clusters of version 8.2.1.200 or later.</p>
<p id="EN-US_TOPIC_0000001510402605__p16882928205019"><strong id="EN-US_TOPIC_0000001510402605__b204821135185714">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001510402605__p158822281507"><strong id="EN-US_TOPIC_0000001510402605__b1554134831515">Value range</strong>: an integer ranging from -1 to 5000</p>
<p id="EN-US_TOPIC_0000001510402605__p1088212284501"><strong id="EN-US_TOPIC_0000001510402605__b12358523418">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b17235652248">–1</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section9668103420502"><h4 class="sectiontitle">autovacuum_compaction_time_limit</h4><p id="EN-US_TOPIC_0000001510402605__p9668183413508"><strong id="EN-US_TOPIC_0000001510402605__b20901135711158">Parameter description</strong>: Specifies the interval for clearing small CUs. Small CUs are merged at a specified interval. This parameter is supported only by clusters of version 8.2.1.200 or later.</p>
<p id="EN-US_TOPIC_0000001510402605__p1668133435012"><strong id="EN-US_TOPIC_0000001510402605__b643773145712">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p196681334165018"><strong id="EN-US_TOPIC_0000001510402605__b18209152217163">Value range</strong>: an integer ranging from 0 to 10080. The unit is minute.</p>
<p id="EN-US_TOPIC_0000001510402605__p10668183416506"><strong id="EN-US_TOPIC_0000001510402605__b787219561844">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b108722056143">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section4366198112115"><h4 class="sectiontitle">autovacuum_max_workers</h4><p id="EN-US_TOPIC_0000001510402605__p23665812110"><strong id="EN-US_TOPIC_0000001510402605__b1928121233316">Parameter description</strong>: Specifies the maximum number of autovacuum worker threads that can run at the same time. The upper limit of this parameter is related to the values of <strong id="EN-US_TOPIC_0000001510402605__b5291912193312">max_connections</strong> and <strong id="EN-US_TOPIC_0000001510402605__b23051219337">job_queue_processes</strong>.</p>
<p id="EN-US_TOPIC_0000001510402605__p63674882117"><strong id="EN-US_TOPIC_0000001510402605__b1515812232339">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p1536718842114"><strong id="EN-US_TOPIC_0000001510402605__b1022142519336">Value range</strong>: an integer</p>
<ul id="EN-US_TOPIC_0000001510402605__ul14959122443415"><li id="EN-US_TOPIC_0000001510402605__li2252132813411">The minimum value is <strong id="EN-US_TOPIC_0000001510402605__b11881192993316">0</strong>, indicating that autovacuum is not automatically performed.</li><li id="EN-US_TOPIC_0000001510402605__li15221853183613">The theoretical maximum value is <strong id="EN-US_TOPIC_0000001510402605__b4778134143314">262143</strong>, and the actual maximum value dynamically changes. Formula: 262143 - <strong id="EN-US_TOPIC_0000001510402605__b986634310341">max_inner_tool_connections</strong> - <strong id="EN-US_TOPIC_0000001510402605__b3559546143415">max_connections</strong> - <strong id="EN-US_TOPIC_0000001510402605__b421024918341">job_queue_processes</strong> - <strong id="EN-US_TOPIC_0000001510402605__b131528528341">auxiliary threads</strong> - <strong id="EN-US_TOPIC_0000001510402605__b16151135963415">Number of autovacuum launcher threads</strong> - 1. The number of auxiliary threads and the number of autovacuum launcher threads are specified by two macros. Their default values in the current version are <strong id="EN-US_TOPIC_0000001510402605__b9698104311355">20</strong> and <strong id="EN-US_TOPIC_0000001510402605__b14470114516354">2</strong>, respectively.</li></ul>
<p id="EN-US_TOPIC_0000001510402605__p0583795373"><strong id="EN-US_TOPIC_0000001510402605__b158971614347">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b19898206183412">4</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section12149133813371"><h4 class="sectiontitle">autovacuum_max_workers_hstore</h4><p id="EN-US_TOPIC_0000001510402605__p10150538193717"><strong id="EN-US_TOPIC_0000001510402605__b10306522153114">Parameter description</strong>: Specifies the maximum number of concurrent automatic cleanup threads used for hstore tables in <strong id="EN-US_TOPIC_0000001510402605__b730615225315">autovacuum_max_workers</strong>.</p>
<p id="EN-US_TOPIC_0000001510402605__p1815063833715"><strong id="EN-US_TOPIC_0000001510402605__b14419148346">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p61501838123717"><strong id="EN-US_TOPIC_0000001510402605__b15566181512344">Value range</strong>: an integer</p>
<p id="EN-US_TOPIC_0000001510402605__p915014381378"><strong id="EN-US_TOPIC_0000001510402605__b92928177340">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b029311171346">1</strong></p>
<div class="note" id="EN-US_TOPIC_0000001510402605__note715413610418"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001510402605__p181164934111">To use HStore tables, set the following parameters, or the HStore performance will deteriorate severely. The recommended settings are as follows:</p>
<p id="EN-US_TOPIC_0000001510402605__p81178984113"><strong id="EN-US_TOPIC_0000001510402605__b1250165883614">autovacuum_max_workers_hstore=3, autovacuum_max_workers=6, autovacuum=true</strong></p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section1865114592412"><h4 class="sectiontitle">enable_hstore_lightupdate</h4><p id="EN-US_TOPIC_0000001510402605__p17865154519246"><strong id="EN-US_TOPIC_0000001510402605__b7174937370">Parameter description</strong>: Specifies whether to enable lightweight UPDATE for an HStore table. (When an UPDATE operation is performed on an HStore table, the system automatically determines whether lightweight UPDATE is required.)</p>
<p id="EN-US_TOPIC_0000001510402605__p686514454243"><strong id="EN-US_TOPIC_0000001510402605__b13979113153711">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p78651145102410"><strong id="EN-US_TOPIC_0000001510402605__b0845121513377">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510402605__ul12944474214"><li id="EN-US_TOPIC_0000001510402605__li72941471225"><strong id="EN-US_TOPIC_0000001510402605__b18452172073713">on</strong> indicates that lightweight UPDATE is enabled for hstore tables.</li><li id="EN-US_TOPIC_0000001510402605__li4294154717213"><strong id="EN-US_TOPIC_0000001510402605__b574843019376">off</strong> indicates that lightweight UPDATE is disabled for hstore tables.</li></ul>
<p id="EN-US_TOPIC_0000001510402605__p10865124552418"><strong id="EN-US_TOPIC_0000001510402605__b913513263716">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b201361032133714">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section18130651182419"><h4 class="sectiontitle">enable_hstore_merge_keepgtm</h4><p id="EN-US_TOPIC_0000001510402605__p1613015192412"><strong id="EN-US_TOPIC_0000001510402605__b178219378371">Parameter description</strong>: Specifies whether the MERGE in the autovacuum operation on column-store and hstore tables occupies slots in the GTM.</p>
<p id="EN-US_TOPIC_0000001510402605__p313055182410"><strong id="EN-US_TOPIC_0000001510402605__b12841630124114">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p413035117243"><strong id="EN-US_TOPIC_0000001510402605__b52665323416">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001510402605__ul18409944927"><li id="EN-US_TOPIC_0000001510402605__li1740912448213"><strong id="EN-US_TOPIC_0000001510402605__b185022038124118">true</strong> indicates that it occupies slots in the GTM.</li><li id="EN-US_TOPIC_0000001510402605__li94091744723"><strong id="EN-US_TOPIC_0000001510402605__b2122175117411">false</strong> indicates that it does not occupy slots in the GTM.</li></ul>
<p id="EN-US_TOPIC_0000001510402605__p913095182418"><strong id="EN-US_TOPIC_0000001510402605__b15191208425">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b17520908427">true</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section0777161451"><h4 class="sectiontitle">hstore_buffer_size</h4><p id="EN-US_TOPIC_0000001510402605__p1131010562425"><strong id="EN-US_TOPIC_0000001510402605__b113101556134216">Parameter description</strong>: Specifies the number of HStore CU slots. The slots are used to store the update chain of each CU, which significantly improves the update and query efficiency.</p>
<p id="EN-US_TOPIC_0000001510402605__p123101956114211">To prevent excessive memory usage, the system calculates a slot value based on the memory size, compares the slot value with the value of this parameter, and uses the smaller value of the two.</p>
<p id="EN-US_TOPIC_0000001510402605__p1131095624220"><strong id="EN-US_TOPIC_0000001510402605__b5310125644216">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001510402605__p63102056114216"><strong id="EN-US_TOPIC_0000001510402605__b3310125615422">Value range</strong>: an integer ranging from 100 to 100000</p>
<p id="EN-US_TOPIC_0000001510402605__p7310756184220"><strong id="EN-US_TOPIC_0000001510402605__b2122513565">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b318068549">true</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section1829265915552"><h4 class="sectiontitle">gtm_option</h4><p id="EN-US_TOPIC_0000001510402605__p16193348450"><strong id="EN-US_TOPIC_0000001510402605__b9292459105512">Parameter description</strong>: Specifies the GTM running mode in GaussDB(DWS). This parameter is supported by version 8.2.1 or later clusters.</p>
<ul id="EN-US_TOPIC_0000001510402605__ul1337770104818"><li id="EN-US_TOPIC_0000001510402605__li13775034813">GTM mode: In this mode, the GTM manages running transactions and allocates XIDs and CSNs in a unified manner.</li><li id="EN-US_TOPIC_0000001510402605__li2037750184819">GTM-Lite mode: The GTM is only responsible for XID allocation and CSN update, and is no longer responsible for global transaction management. The GTM-Lite mode applies to TP scenarios with high concurrency and short queries. It can improve query performance while ensuring transaction consistency.</li><li id="EN-US_TOPIC_0000001510402605__li1377170124815">GTM-Free mode: For details, see the description of <strong id="EN-US_TOPIC_0000001510402605__b19475610205912">enable_gtm_fre</strong><strong id="EN-US_TOPIC_0000001510402605__b14936615145915">e</strong>.</li></ul>
<p id="EN-US_TOPIC_0000001510402605__p14293105985513"><strong id="EN-US_TOPIC_0000001510402605__b2010174843">Type</strong>: POSTMASTER</p>
<p id="EN-US_TOPIC_0000001510402605__p15293145919557"><strong id="EN-US_TOPIC_0000001510402605__b1473815226595">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001510402605__ul192931359145513"><li id="EN-US_TOPIC_0000001510402605__li729375935510"><strong id="EN-US_TOPIC_0000001510402605__b700798971111443">gtm</strong> or <strong id="EN-US_TOPIC_0000001510402605__b1170612863111443">0</strong>: The GTM mode is enabled.</li><li id="EN-US_TOPIC_0000001510402605__li8963524175918"><strong id="EN-US_TOPIC_0000001510402605__b231054681111443">gtm-lite</strong> or <strong id="EN-US_TOPIC_0000001510402605__b244690914111443">1</strong>: The GTM-Lite mode is enabled.</li><li id="EN-US_TOPIC_0000001510402605__li11789134625916"><strong id="EN-US_TOPIC_0000001510402605__b1646180808111443">gtm-free</strong> or <strong id="EN-US_TOPIC_0000001510402605__b103052066111443">2</strong>: The GTM-Free mode starts.</li></ul>
<p id="EN-US_TOPIC_0000001510402605__p1293115975519"><strong id="EN-US_TOPIC_0000001510402605__b1170845728111443">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b1045361745111443">gtm</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001510402605__note11408142525717"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ol id="EN-US_TOPIC_0000001510402605__ol174061646102919"><li id="EN-US_TOPIC_0000001510402605__li1340664632918">Both <span id="EN-US_TOPIC_0000001510402605__text1393791718111443">GaussDB(DWS)</span> and GTM have the <strong id="EN-US_TOPIC_0000001510402605__b1411920690111443">gtm_option</strong> parameter with the same meaning. For GTM and GTM-Lite, the same mode must be set on GaussDB(DWS) and GTM. Otherwise, service errors may occur.</li><li id="EN-US_TOPIC_0000001510402605__li97811853162913">The GTM-Free mode can be enabled by setting <strong id="EN-US_TOPIC_0000001510402605__b14378011111443">enable_gtm_free</strong> to <strong id="EN-US_TOPIC_0000001510402605__b1338048790111443">on</strong> or <strong id="EN-US_TOPIC_0000001510402605__b578755777111443">gtm_option</strong> to <strong id="EN-US_TOPIC_0000001510402605__b1357386071111443">gtm-free</strong>.</li><li id="EN-US_TOPIC_0000001510402605__li10545180183013">To set the non-GTM-Free modes, set <strong id="EN-US_TOPIC_0000001510402605__b998954553920">enable_gtm_free</strong> to <strong id="EN-US_TOPIC_0000001510402605__b19989124512394">off</strong>.</li><li id="EN-US_TOPIC_0000001510402605__li1071886305">The GTM-Free mode takes effect only in hybrid cloud and ESL scenarios.</li></ol>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001510402605__section13515145885113"><h4 class="sectiontitle">defer_xid_cleanup_time</h4><p id="EN-US_TOPIC_0000001510402605__p1851510584517"><strong id="EN-US_TOPIC_0000001510402605__b195157582519">Parameter description</strong>: Specifies the global OldestXmin maintenance period in GTM-Lite mode in the hybrid data warehouse. In each maintenance period, the CCN or FCN collects and delivers the values of global <strong id="EN-US_TOPIC_0000001510402605__b723113206111443">OldestXmin</strong>. This parameter is supported by version 8.2.1 or later clusters.</p>
<p id="EN-US_TOPIC_0000001510402605__p75463305020">This parameter takes effect only in GTM-Lite mode. You are advised not to modify this parameter.</p>
<p id="EN-US_TOPIC_0000001510402605__p2515115816516"><strong id="EN-US_TOPIC_0000001510402605__b1679410813">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001510402605__p12515115825116"><strong id="EN-US_TOPIC_0000001510402605__b951565817517">Value range</strong>: an integer ranging from 1 to INT_MAX. The unit is ms.</p>
<p id="EN-US_TOPIC_0000001510402605__p1751605865119"><strong id="EN-US_TOPIC_0000001510402605__b2038629317111443">Default value</strong>: <strong id="EN-US_TOPIC_0000001510402605__b192770003111443">5,000</strong>.</p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_1023.html">Hybrid Data Warehouse</a></div>
</div>
</div>
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