doc-exports/docs/dws/dev/dws_04_0909.html

<a name="EN-US_TOPIC_0000001188482092"></a><a name="EN-US_TOPIC_0000001188482092"></a>

<h1 class="topictitle1">Optimizer Method Configuration</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_p318945515">These configuration parameters provide a crude method of influencing the query plans chosen by the query optimizer. If the default plan chosen by the optimizer for a particular query is not optimal, a temporary solution is to use one of these configuration parameters to force the optimizer to choose a different plan. Better ways include adjusting the optimizer cost constants, manually running <strong id="EN-US_TOPIC_0000001188482092__b91137528207">ANALYZE</strong>, increasing the value of the <a href="dws_04_0912.html#EN-US_TOPIC_0000001188323574__sa5c1527051e54fbdb6c5346d54bcbf5a">default_statistics_target</a> configuration parameter, and adding the statistics collected in a specific column using <strong id="EN-US_TOPIC_0000001188482092__b61131852152018">ALTER TABLE SET STATISTICS</strong>.</p>
<div class="section" id="EN-US_TOPIC_0000001188482092__s61c2f3870a4a45b7b92e186c4e6037a7"><h4 class="sectiontitle">enable_bitmapscan</h4><p id="EN-US_TOPIC_0000001188482092__a2075cc5e286649bfb8421648b506b3f7"><strong id="EN-US_TOPIC_0000001188482092__b1061519514172">Parameter description</strong>: Controls whether the query optimizer uses the bitmap-scan plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p624153517198"><strong id="EN-US_TOPIC_0000001188482092__b89211962125">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a96e3a2acc5ea411080df76a1b1e13fe3"><strong id="EN-US_TOPIC_0000001188482092__b1872913092114">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ubdaa96b4e18a4122ad56efc974500c1a"><li id="EN-US_TOPIC_0000001188482092__l26dbbe6b618449dc823a68f6546c567b"><strong id="EN-US_TOPIC_0000001188482092__b118862122111">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l4eaa87836bf24c61942700028e5fcf71"><strong id="EN-US_TOPIC_0000001188482092__b18928319210">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a0014e3426a374260a91ffef1b9e1689a"><strong id="EN-US_TOPIC_0000001188482092__b14457111617210">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b5462216152118">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s8d922e5a221548c2b399032bce2cc840"><h4 class="sectiontitle">enable_hashagg</h4><p id="EN-US_TOPIC_0000001188482092__aec9fcdb6b2b4410b899d49ed9a03b64e"><strong id="EN-US_TOPIC_0000001188482092__b17519532132019">Parameter description</strong>: Controls whether the query optimizer uses the Hash aggregation plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p8293115416253"><strong id="EN-US_TOPIC_0000001188482092__b66161778128">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a0d0c94e9e01a435b94ad76e19dec9ffc"><strong id="EN-US_TOPIC_0000001188482092__b1150081715213">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u43706081ab2347bcb2d8e119ae6adfc8"><li id="EN-US_TOPIC_0000001188482092__ld08ba9ef862c4ed9b44ab0479996b169"><strong id="EN-US_TOPIC_0000001188482092__b145881184217">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__la2f40fe78142412ca7474f8b6365b5f7"><strong id="EN-US_TOPIC_0000001188482092__b148801119202114">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a3866647b152a40a68af7c53f37d0fb57"><strong id="EN-US_TOPIC_0000001188482092__b8444211217">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b18445217219">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s99d549c6e4364cd9b4424c14ba0229fe"><h4 class="sectiontitle">enable_hashjoin</h4><p id="EN-US_TOPIC_0000001188482092__a51f63ff195204e92a892468f869f55a3"><strong id="EN-US_TOPIC_0000001188482092__b5346136693">Parameter description</strong>: Controls whether the query optimizer uses the Hash-join plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p062113115263"><strong id="EN-US_TOPIC_0000001188482092__b9653681124">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a57e6585946314838be9b04c834abb735"><strong id="EN-US_TOPIC_0000001188482092__b1592316215214">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u97d1d12ca9d5421ca9786b8cc0b4f129"><li id="EN-US_TOPIC_0000001188482092__l87a85d137f3742689034f608b6bb6fff"><strong id="EN-US_TOPIC_0000001188482092__b12901142232117">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__lc46a77bf3b76490aa750760692cb6947"><strong id="EN-US_TOPIC_0000001188482092__b617142416218">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__aaddc60b59cfb425888e824fa2c2e80fe"><strong id="EN-US_TOPIC_0000001188482092__b12834224162114">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b148341724182111">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s9dc36ace96544fda934bb7954e566fdc"><h4 class="sectiontitle">enable_indexscan</h4><p id="EN-US_TOPIC_0000001188482092__a47f2cb95851a42dc9bb7b327884ae14c"><strong id="EN-US_TOPIC_0000001188482092__b529421151919">Parameter description</strong>: Controls whether the query optimizer uses the index-scan plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p9560131082619"><strong id="EN-US_TOPIC_0000001188482092__b38668871216">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a8f26b472e7e74133b1eb592a13e1f09b"><strong id="EN-US_TOPIC_0000001188482092__b38401025202115">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u349a1e7f29fc49f898e71d0b722a9d46"><li id="EN-US_TOPIC_0000001188482092__lb9cfd69359114f2eb79cdb1ca72a5d7f"><strong id="EN-US_TOPIC_0000001188482092__b1381592672116">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__ld5656fd0bd5048969afc5e734c3b9f3c"><strong id="EN-US_TOPIC_0000001188482092__b36981427192118">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a3493b947c40b4c498804ea573ee24a77"><strong id="EN-US_TOPIC_0000001188482092__b764110280218">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b364192815216">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sb0947e54fce74d5cbae91de6dbe43364"><h4 class="sectiontitle">enable_indexonlyscan</h4><p id="EN-US_TOPIC_0000001188482092__a7b01140bbe1d4310a72d5126864f9145"><strong id="EN-US_TOPIC_0000001188482092__b1485623415197">Parameter description</strong>: Controls whether the query optimizer uses the index-only-scan plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p11537201862614"><strong id="EN-US_TOPIC_0000001188482092__b18541597122">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a081ada0222344683bd8f9d26323eff11"><strong id="EN-US_TOPIC_0000001188482092__b1546542915218">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u7c6dd66eb9824652b4bebf5385876c51"><li id="EN-US_TOPIC_0000001188482092__l7540a0be7eb74a0bbc06120b9d8a32d9"><strong id="EN-US_TOPIC_0000001188482092__b17534183082118">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__lf791df992e924e649a702fd4b5172d5d"><strong id="EN-US_TOPIC_0000001188482092__b20518631142118">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__aedf7a46da03f49bb8ba742131229b612"><strong id="EN-US_TOPIC_0000001188482092__b5615432102118">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b19616113262112">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s154630d1b7a9430b8a8af02779d56078"><h4 class="sectiontitle">enable_material</h4><p id="EN-US_TOPIC_0000001188482092__a2b12adc9025b418a96c17953642467ef"><strong id="EN-US_TOPIC_0000001188482092__b3433181419203">Parameter description</strong>: Controls whether the query optimizer uses materialization. It is impossible to suppress materialization entirely, but setting this parameter to <strong id="EN-US_TOPIC_0000001188482092__b948853837162936">off</strong> prevents the optimizer from inserting materialized nodes.</p>
<p id="EN-US_TOPIC_0000001188482092__p1334832717267"><strong id="EN-US_TOPIC_0000001188482092__b21982921217">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__aef434c6ecedf41ca9ee3b8c2bbc2ee44"><strong id="EN-US_TOPIC_0000001188482092__b1431113332117">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u57ab4d99caae468b93acd9f64dc9330d"><li id="EN-US_TOPIC_0000001188482092__l5939ba51dccb4fd5a94a9bf40e3b80cb"><strong id="EN-US_TOPIC_0000001188482092__b193680342216">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l12e155b3e6f44cb3a374088aead59721"><strong id="EN-US_TOPIC_0000001188482092__b743414357214">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a055c8e5bd8094bf3bcca93fb2a3c9635"><strong id="EN-US_TOPIC_0000001188482092__b1447017366213">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1247015360215">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sfd907746eb8144138a76026cb15b15c7"><h4 class="sectiontitle">enable_mergejoin</h4><p id="EN-US_TOPIC_0000001188482092__a4b5e5b3400af4afa8e1ef9265d5955c5"><strong id="EN-US_TOPIC_0000001188482092__b1311703282115">Parameter description</strong>: Controls whether the query optimizer uses the merge-join plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p48113713263"><strong id="EN-US_TOPIC_0000001188482092__b13374196128">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a4fcf70191c0d472b8dfe68fb28fd03fc"><strong id="EN-US_TOPIC_0000001188482092__b14487137122118">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u0141d3ba7cb34e9a9141261e88375a6b"><li id="EN-US_TOPIC_0000001188482092__l20c8751fb54f49b0b5dac30deefa9731"><strong id="EN-US_TOPIC_0000001188482092__b35151638132111">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l44f836bfcbae4a09913ebc0b34b74560"><strong id="EN-US_TOPIC_0000001188482092__b1045633932114">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__ae0d999cedb914cb3989a08714395c107"><strong id="EN-US_TOPIC_0000001188482092__b12529164011219">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1553017401219">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s1bef702ce82b497eb5a4a69f47a13a10"><h4 class="sectiontitle">enable_nestloop</h4><p id="EN-US_TOPIC_0000001188482092__aea64a8a96c74429d9afbe1f4b4eee993"><strong id="EN-US_TOPIC_0000001188482092__b10360172971117">Parameter description</strong>: Controls whether the query optimizer uses the nested-loop join plan type to fully scan internal tables. It is impossible to suppress nested-loop joins entirely, but setting this parameter to <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b60095344152658">off</strong> allows the optimizer to choose other methods if available.</p>
<p id="EN-US_TOPIC_0000001188482092__p1569917451261"><strong id="EN-US_TOPIC_0000001188482092__b195529971213">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__ad4bc105fd5174e2cb533c466f58771a3"><strong id="EN-US_TOPIC_0000001188482092__b18444154111213">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u8f60fadc48a74b66ae4aca46f54f129e"><li id="EN-US_TOPIC_0000001188482092__l3c7c268553474161afe812de75628a7d"><strong id="EN-US_TOPIC_0000001188482092__b262144292112">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l268ebe7ef3684073a6bcad5952af7566"><strong id="EN-US_TOPIC_0000001188482092__b278318435217">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a7f9c0e81ef3b4e70ad08a291e9dcebb1"><strong id="EN-US_TOPIC_0000001188482092__b16653134422118">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b365404415218">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section1584803291014"><h4 class="sectiontitle">enable_index_nestloop</h4><p id="EN-US_TOPIC_0000001188482092__p862223691014"><strong id="EN-US_TOPIC_0000001188482092__b1818584515120">Parameter description</strong>: Controls whether the query optimizer uses the nested-loop join plan type to scan the parameterized indexes of internal tables.</p>
<p id="EN-US_TOPIC_0000001188482092__p268912202720"><strong id="EN-US_TOPIC_0000001188482092__b108071591123">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p6483286691014"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778871_en-us_topic_0058967732_b10741640_1">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ul1697081291014"><li id="EN-US_TOPIC_0000001188482092__li1851958391014"><strong id="EN-US_TOPIC_0000001188482092__b84510594127">on</strong> indicates the query optimizer uses the nested-loop join plan type.</li><li id="EN-US_TOPIC_0000001188482092__li3245852291014"><strong id="EN-US_TOPIC_0000001188482092__b1081041281319">off</strong> indicates the query optimizer does not use the nested-loop join plan type.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p99851452104214"><strong id="EN-US_TOPIC_0000001188482092__b81176504579">Default value</strong>: The default value for a newly installed cluster is <strong id="EN-US_TOPIC_0000001188482092__b21173505575">on</strong>. If the cluster is upgraded from R8C10, the forward compatibility is retained. If the version is upgraded from R7C10 or an earlier version, the default value is <strong id="EN-US_TOPIC_0000001188482092__b19410127175820">off</strong>.</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sc4e3e214b4354ad680b7147e8c460658"><h4 class="sectiontitle">enable_seqscan</h4><p id="EN-US_TOPIC_0000001188482092__a6716155c25b04ddeb91e286042301734"><strong id="EN-US_TOPIC_0000001188482092__b0555633122216">Parameter description</strong>: Controls whether the query optimizer uses the sequential scan plan type. It is impossible to suppress sequential scans entirely, but setting this variable to <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b41076330152658">off</strong> allows the optimizer to preferentially choose other methods if available.</p>
<p id="EN-US_TOPIC_0000001188482092__p189394210274"><strong id="EN-US_TOPIC_0000001188482092__b175910171211">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a7c6c308c03ce4d259ac1596bbe056e30"><strong id="EN-US_TOPIC_0000001188482092__b252019455213">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u0b50a3e74213486aae0d0aa3201e3473"><li id="EN-US_TOPIC_0000001188482092__l53a46ccc02cb4a648e3089ed325fc879"><strong id="EN-US_TOPIC_0000001188482092__b860314642115">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l83e91d6809c547fab017c38c201119d4"><strong id="EN-US_TOPIC_0000001188482092__b3385194762112">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__ad97d9a1b7325471d89c8e1c57a2289f6"><strong id="EN-US_TOPIC_0000001188482092__b1440310481214">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b3403114818213">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sdc6a03a94d3743e8a856428f604446c9"><h4 class="sectiontitle">enable_sort</h4><p id="EN-US_TOPIC_0000001188482092__ad163bc65ab2a46c899ee2f2cf1ad973e"><strong id="EN-US_TOPIC_0000001188482092__b8260144182911">Parameter description</strong>: Controls whether the query optimizer uses the sort method. It is impossible to suppress explicit sorts entirely, but setting this variable to <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b22292535152658">off</strong> allows the optimizer to preferentially choose other methods if available.</p>
<p id="EN-US_TOPIC_0000001188482092__p115641322276"><strong id="EN-US_TOPIC_0000001188482092__b1116119104122">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__af060df14d0b14373911d679f8009b46d"><strong id="EN-US_TOPIC_0000001188482092__b937212495219">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__uf16166d1d6d0473fad1bf487da14dd63"><li id="EN-US_TOPIC_0000001188482092__l23dc33774a364ad59529ccb4c237246d"><strong id="EN-US_TOPIC_0000001188482092__b727395082117">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l1bf836e102384c38b3230eab301f7372"><strong id="EN-US_TOPIC_0000001188482092__b5291175119212">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a82f1fc8013664bdfa3ef77236f8027b5"><strong id="EN-US_TOPIC_0000001188482092__b10982052152110">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b299252172113">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s9dc942e0972446d2b2adb1590b43f077"><h4 class="sectiontitle">enable_tidscan</h4><p id="EN-US_TOPIC_0000001188482092__ad094a3fb762b4940b8376c63938611bf"><strong id="EN-US_TOPIC_0000001188482092__b13810173110299">Parameter description</strong>: Controls whether the query optimizer uses the Tuple ID (TID) scan plan type.</p>
<p id="EN-US_TOPIC_0000001188482092__p9707440182719"><strong id="EN-US_TOPIC_0000001188482092__b4312131011126">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a7032ae392d864a0a838ead04fff628ee"><strong id="EN-US_TOPIC_0000001188482092__b16701953142117">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ue4d8cfce487f4c2c9cb889fa47fc01b1"><li id="EN-US_TOPIC_0000001188482092__l2d14d5397a7842bea1898c1006b74f51"><strong id="EN-US_TOPIC_0000001188482092__b149111536219">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l0f8361f8a5e84a90acd04f8facda640a"><strong id="EN-US_TOPIC_0000001188482092__b1979125412212">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a3dcd7522fae7440682d6bb5b13081af1"><strong id="EN-US_TOPIC_0000001188482092__b1494115514212">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1194185519211">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s5da1e5bd74434dcba5b3448d18057102"><h4 class="sectiontitle">enable_kill_query</h4><p id="EN-US_TOPIC_0000001188482092__afca0c49423754aa5a7b1b38a7ee1f641"><strong id="EN-US_TOPIC_0000001188482092__b14916845434656">Parameter description</strong>: In CASCADE mode, when a user is deleted, all the objects belonging to the user are deleted. This parameter specifies whether the queries of the objects belonging to the user can be unlocked when the user is deleted.</p>
<p id="EN-US_TOPIC_0000001188482092__p66828511278"><strong id="EN-US_TOPIC_0000001188482092__b999051081216">Type</strong>: SUSET</p>
<p id="EN-US_TOPIC_0000001188482092__a8cbdba0ede5249f4b1ec7679d1534b56"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b6625143011450_23">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u1daeaac11dac44f28cc29c18750728df"><li id="EN-US_TOPIC_0000001188482092__le69abcd2b42047a3b7922ffe21528cd3"><strong id="EN-US_TOPIC_0000001188482092__b192688057634656">on</strong> indicates the unlocking is allowed.</li><li id="EN-US_TOPIC_0000001188482092__l17ec89e6ef5e4d689a63c082f1de8a5b"><strong id="EN-US_TOPIC_0000001188482092__b140256454434656">off</strong> indicates the unlocking is not allowed.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a2aa9b9ead2bf4eaeb66c8ed773a1eca5"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b49259546">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b84235270611220">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s9d86a26098fc4e0f90cb9d8d91359482"><h4 class="sectiontitle">enforce_oracle_behavior</h4><p id="EN-US_TOPIC_0000001188482092__a9524c4b2154e4f6097dac7bc14be5d53"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_a09e28664a0d347bd9e7f7f2b23539645">Parameter description</strong>: Controls the rule matching modes of regular expressions.</p>
<p id="EN-US_TOPIC_0000001188482092__p839611498289"><strong id="EN-US_TOPIC_0000001188482092__b1319320113126">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a08948b7c15744058a01f00101649f885"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b6625143011450_25">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u08d008be00774e6fa3f3c85b2bc0bd8c"><li id="EN-US_TOPIC_0000001188482092__lbf08104e9fbe4a39aec173b6847c72f4"><strong id="EN-US_TOPIC_0000001188482092__b13876105173915">on</strong> indicates that the ORACLE matching rule is used.</li><li id="EN-US_TOPIC_0000001188482092__l52949c930c3041f79b96a86bee6c7acf"><strong id="EN-US_TOPIC_0000001188482092__b17792181220417">off</strong> indicates that the POSIX matching rule is used.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a320abb2b12cc4dd5a1a884a48ce611eb"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b26996297_1">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b842352706111724">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section3886652184817"><h4 class="sectiontitle">enable_stream_concurrent_update</h4><p id="EN-US_TOPIC_0000001188482092__p14886195254818"><strong id="EN-US_TOPIC_0000001188482092__b114961945104314">Parameter description</strong>: Controls the use of <strong id="EN-US_TOPIC_0000001188482092__b574523164615">stream</strong> in concurrent updates. This parameter is restricted by the <a href="#EN-US_TOPIC_0000001188482092__se97ba22fff0144d784f5363903a1f584">enable_stream_operator</a> parameter.</p>
<p id="EN-US_TOPIC_0000001188482092__p1988565710283"><strong id="EN-US_TOPIC_0000001188482092__b163210116123">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p288816520486"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b60355922">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ul148881952174815"><li id="EN-US_TOPIC_0000001188482092__li1588917529485"><strong id="EN-US_TOPIC_0000001188482092__b1828345544418">on</strong> indicates that the optimizer can generate stream plans for the <strong id="EN-US_TOPIC_0000001188482092__b15375181812456">UPDATE</strong> statement.</li><li id="EN-US_TOPIC_0000001188482092__li588925264817"><strong id="EN-US_TOPIC_0000001188482092__b966772310459">off</strong> indicates that the optimizer can generate only non-stream plans for the <strong id="EN-US_TOPIC_0000001188482092__b13481348144519">UPDATE</strong> statement.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p488914522488"><strong id="EN-US_TOPIC_0000001188482092__b1469416713">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1656841074">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section684911518381"><h4 class="sectiontitle">enable_stream_ctescan</h4><p id="EN-US_TOPIC_0000001188482092__p7850555383"><strong id="EN-US_TOPIC_0000001188482092__b1599485231316">Parameter description</strong>: Specifies whether a stream plan supports <strong id="EN-US_TOPIC_0000001188482092__b197678301307">ctescan</strong>.</p>
<p id="EN-US_TOPIC_0000001188482092__p98503593814"><strong id="EN-US_TOPIC_0000001188482092__b042415262148">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p188501756382"><strong id="EN-US_TOPIC_0000001188482092__b188211274141">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ul285095173819"><li id="EN-US_TOPIC_0000001188482092__li585012533813"><strong id="EN-US_TOPIC_0000001188482092__b366564951419">on</strong> indicates that <strong id="EN-US_TOPIC_0000001188482092__b196331636203012">ctescan </strong>is supported for the stream plan.</li><li id="EN-US_TOPIC_0000001188482092__li1985018513389"><strong id="EN-US_TOPIC_0000001188482092__b1164276131515">off</strong> indicates that <strong id="EN-US_TOPIC_0000001188482092__b356134033018">ctescan </strong>is not supported for the stream plan.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p985055193810"><strong id="EN-US_TOPIC_0000001188482092__b1168319593019">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b26831954303">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__se97ba22fff0144d784f5363903a1f584"><a name="EN-US_TOPIC_0000001188482092__se97ba22fff0144d784f5363903a1f584"></a><a name="se97ba22fff0144d784f5363903a1f584"></a><h4 class="sectiontitle">enable_stream_operator</h4><p id="EN-US_TOPIC_0000001188482092__a15bc037edf79486caebcf9ff70e9c5f4"><strong id="EN-US_TOPIC_0000001188482092__b11295822103012">Parameter description:</strong> Controls whether the query optimizer uses streams.</p>
<p id="EN-US_TOPIC_0000001188482092__p1845717520293"><strong id="EN-US_TOPIC_0000001188482092__b17821191131211">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a330dd23b039f4f6cbec53bf6d5992a62"><strong id="EN-US_TOPIC_0000001188482092__b1197111314221">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u88fc88d8f85d40288ce47c2c9368f896"><li id="EN-US_TOPIC_0000001188482092__lad918382791e4cbd8943adaa06c1e1b7"><strong id="EN-US_TOPIC_0000001188482092__b597015420227">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l0f9f4ab8d87341fd909820de15d9ec74"><strong id="EN-US_TOPIC_0000001188482092__b73515617222">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a24c301487204418abd758704789aff13"><strong id="EN-US_TOPIC_0000001188482092__b1988812615228">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b988856112213">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section141901419113317"><h4 class="sectiontitle">enable_stream_recursive</h4><p id="EN-US_TOPIC_0000001188482092__p8190119193320"><strong id="EN-US_TOPIC_0000001188482092__b133071167518">Parameter description</strong>: Specifies whether to push <strong id="EN-US_TOPIC_0000001188482092__b43081561551">WITH RECURSIVE</strong> join queries to DNs for processing.</p>
<p id="EN-US_TOPIC_0000001188482092__p573851516290"><strong id="EN-US_TOPIC_0000001188482092__b399151111217">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p1219081973315"><strong id="EN-US_TOPIC_0000001188482092__b1768839527">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ul91901019103316"><li id="EN-US_TOPIC_0000001188482092__li6190219193313"><strong id="EN-US_TOPIC_0000001188482092__b6371134968">on</strong>: <strong id="EN-US_TOPIC_0000001188482092__b29655491669">WITH RECURSIVE</strong> join queries will be pushed down to DNs.</li><li id="EN-US_TOPIC_0000001188482092__li151901019123312"><strong id="EN-US_TOPIC_0000001188482092__b82513918714">off</strong>: <strong id="EN-US_TOPIC_0000001188482092__b174512261672">WITH RECURSIVE</strong> join queries will not be pushed down to DNs.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p5190019173317"><strong id="EN-US_TOPIC_0000001188482092__b1002004357">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b765895078">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section333410396346"><h4 class="sectiontitle">max_recursive_times</h4><p id="EN-US_TOPIC_0000001188482092__p16334183983417"><strong id="EN-US_TOPIC_0000001188482092__b03713400710">Parameter description</strong>: Specifies the maximum number of <strong id="EN-US_TOPIC_0000001188482092__b1637212404712">WITH RECURSIVE</strong> iterations.</p>
<p id="EN-US_TOPIC_0000001188482092__p11184824112915"><strong id="EN-US_TOPIC_0000001188482092__b4150201271214">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p11226150183517"><strong id="EN-US_TOPIC_0000001188482092__b102266023511">Value range</strong>: an integer ranging from 0 to INT_MAX</p>
<p id="EN-US_TOPIC_0000001188482092__p15334203914348"><strong id="EN-US_TOPIC_0000001188482092__b19441124916719">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b44441491971">200</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sb6526e37d99f4be8a9dc9b4739a76077"><h4 class="sectiontitle">enable_vector_engine</h4><p id="EN-US_TOPIC_0000001188482092__a1f79cf6106db443cafdb19a7f735f92a"><strong id="EN-US_TOPIC_0000001188482092__b1826611718311">Parameter description</strong>: Controls whether the query optimizer uses the vectorized executor.</p>
<p id="EN-US_TOPIC_0000001188482092__p16168442172916"><strong id="EN-US_TOPIC_0000001188482092__b193381112101214">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a9b0b6101f0364471b616207ba6f70631"><strong id="EN-US_TOPIC_0000001188482092__b199792711227">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u1d0b3c41b1dd4deaa1fd713dcb5438ad"><li id="EN-US_TOPIC_0000001188482092__l1b83edbe0f9b4cb48674b9ad3d6699f0"><strong id="EN-US_TOPIC_0000001188482092__b118075872214">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l6351e66e45834c4f9a2fd8b3f4de4de3"><strong id="EN-US_TOPIC_0000001188482092__b1875213910224">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a0e8a3b85d75e41e4a813ee56b5125d66"><strong id="EN-US_TOPIC_0000001188482092__b8656171015224">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1865641011228">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s4500e9c69a874ebf84590371d8404791"><h4 class="sectiontitle">enable_broadcast</h4><p id="EN-US_TOPIC_0000001188482092__add4fba2275bb465bba1e99c8711f985d"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b842352706201758">Parameter description</strong>: Controls whether the query optimizer uses the broadcast distribution method when it evaluates the cost of stream.</p>
<p id="EN-US_TOPIC_0000001188482092__p1642264982916"><strong id="EN-US_TOPIC_0000001188482092__b14511111281213">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__ab95d4efb036e4cad9dcf096fe371bfad"><strong id="EN-US_TOPIC_0000001188482092__b175851311112210">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__uf9e97ee192b34a73b21161a64e803e33"><li id="EN-US_TOPIC_0000001188482092__l03543e4d30264764987df824ea90f8b8"><strong id="EN-US_TOPIC_0000001188482092__b1838120121223">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__le54c9c99f136451dbe66d26278955021"><strong id="EN-US_TOPIC_0000001188482092__b5369191322219">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__adbfd042a91344a4383fe39ac763c3925"><strong id="EN-US_TOPIC_0000001188482092__b1663171416228">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b46325147221">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sa3d7337362cf4789bf45cc4ee30dc475"><h4 class="sectiontitle">enable_change_hjcost</h4><p id="EN-US_TOPIC_0000001188482092__afe9b1d31dec14cc1ab573802b736526c"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b842352706978">Parameter description</strong>: Specifies whether the optimizer excludes internal table running costs when selecting the Hash Join cost path. If it is set to <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b842352706155359">on</strong>, tables with a few records and high running costs are more possible to be selected.</p>
<p id="EN-US_TOPIC_0000001188482092__p374810105307"><strong id="EN-US_TOPIC_0000001188482092__b1277364925814">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a673709746e654a8bb0e14ceff634419f"><strong id="EN-US_TOPIC_0000001188482092__b254011518228">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u4a13fa5f7e964977bcdafca2b3c03df1"><li id="EN-US_TOPIC_0000001188482092__l55e8d4f5bfcb465a89396c9371e50320"><strong id="EN-US_TOPIC_0000001188482092__b1648421672210">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l0244d9b980f74674835c3ead6a0831aa"><strong id="EN-US_TOPIC_0000001188482092__b742111174228">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a2c5cecfe26644356a768f80449393080"><strong id="EN-US_TOPIC_0000001188482092__b8259218122217">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b22601218152217">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s4dab13535595427c962b6199de100d91"><h4 class="sectiontitle">enable_fstream</h4><p id="EN-US_TOPIC_0000001188482092__a72bed8b7151d4dcda16481b7197790d3"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b84235270691356">Parameter description</strong>: Controls whether the query optimizer uses streams when it delivers statements. This parameter is only used for external HDFS tables.</p>
<p id="EN-US_TOPIC_0000001188482092__adb187ad07a7843e38309d96bbf10cc4c">This parameter has been discarded. To reserve forward compatibility, set this parameter to <strong id="EN-US_TOPIC_0000001188482092__b20396203610910">on</strong>, but the setting does not make a difference.</p>
<p id="EN-US_TOPIC_0000001188482092__p10800824133016"><strong id="EN-US_TOPIC_0000001188482092__b1389891251217">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__aec600014105848b9aede8a3c1afbf6c0"><strong id="EN-US_TOPIC_0000001188482092__b16258719112218">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__uf4e8e760bcbc4574be9752da25fdc247"><li id="EN-US_TOPIC_0000001188482092__lcfda252151d049ec856602726f3e14da"><strong id="EN-US_TOPIC_0000001188482092__b1920912017227">on</strong> indicates it is enabled.</li><li id="EN-US_TOPIC_0000001188482092__l0ced2bb93a0349dc836583ea80beacbf"><strong id="EN-US_TOPIC_0000001188482092__b09671920132212">off</strong> indicates it is disabled.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a30e06ee1c5ff45fbaa684eec054e2b96"><strong id="EN-US_TOPIC_0000001188482092__b1497512215223">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b697614214224">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s3d76d6e1b1804c148ec9df86569ff5b7"><h4 class="sectiontitle">best_agg_plan</h4><div class="p" id="EN-US_TOPIC_0000001188482092__ada3283facf984429b50f00d7501ea286"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b84235270692319">Parameter description</strong>: The query optimizer generates three plans for the aggregate operation under the stream:<ol id="EN-US_TOPIC_0000001188482092__o2fc6c049bba74dd1be921e303b3386cc"><li id="EN-US_TOPIC_0000001188482092__l5c4e3d28ce8047a49b90beb7b9baadd0">hashagg+gather(redistribute)+hashagg</li><li id="EN-US_TOPIC_0000001188482092__le0e3e33df31349e8904f4a94c677c07d">redistribute+hashagg(+gather)</li><li id="EN-US_TOPIC_0000001188482092__l2b8b7e8ded5f406a8c4cfebae9845f58">hashagg+redistribute+hashagg(+gather).</li></ol>
</div>
<p id="EN-US_TOPIC_0000001188482092__a0079f0fa868d45a1ab69c74c8ffe975e">This parameter is used to control the query optimizer to generate which type of hashagg plans.</p>
<p id="EN-US_TOPIC_0000001188482092__p01172014133120"><strong id="EN-US_TOPIC_0000001188482092__b01621310122">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a260a2b8c442c49e08530df3b0ba1f3db"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b66499804">Value range</strong>: an integer ranging from 0 to 3.</p>
<ul id="EN-US_TOPIC_0000001188482092__u3f6854a7b6f544ea98b24fefa622a447"><li id="EN-US_TOPIC_0000001188482092__le9e06f01e091426682ed144d8438787e">When the value is set to <strong id="EN-US_TOPIC_0000001188482092__b93285805111552">1</strong>, the first plan is forcibly generated.</li><li id="EN-US_TOPIC_0000001188482092__l4ff4f36f60d74e81bb7795d463b217ef">When the value is set to <strong id="EN-US_TOPIC_0000001188482092__b102009829511538">2</strong> and if the <strong id="EN-US_TOPIC_0000001188482092__b173301864011538">group by</strong> column can be redistributed, the second plan is forcibly generated. Otherwise, the first plan is generated.</li><li id="EN-US_TOPIC_0000001188482092__lc8704bd8068d423a8ef41f61c804a5ba">When the value is set to <strong id="EN-US_TOPIC_0000001188482092__b52680902711522">3</strong> and if the <strong id="EN-US_TOPIC_0000001188482092__b203914458711522">group by</strong> column can be redistributed, the third plan is generated. Otherwise, the first plan is generated.</li><li id="EN-US_TOPIC_0000001188482092__l297286a8e0524e668133af48de3556e4">When the value is set to <strong id="EN-US_TOPIC_0000001188482092__b84235270694450">0</strong>, the query optimizer chooses the most optimal plan based on the estimated costs of the three plans above.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__ae54108f6f4724d1596626a133ab8af18"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b455675178231">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b842352706114645">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__s07f6d660ef88443aba81be9841fb2449"><h4 class="sectiontitle">agg_redistribute_enhancement</h4><p id="EN-US_TOPIC_0000001188482092__a2667108f1a134936b390980dd4d8f8ab"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b84235270694930">Parameter description</strong>: When the aggregate operation is performed, which contains multiple <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b84235270695020">group by</strong> columns and all of the columns are not in the distribution column, you need to select one <strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b84235270695323">group by</strong> column for redistribution. This parameter controls the policy of selecting a redistribution column.</p>
<p id="EN-US_TOPIC_0000001188482092__p106451222113118"><strong id="EN-US_TOPIC_0000001188482092__b1918301318127">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a429363b0f0cc42f1b81e10076c4ac95d"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b6625143011450_37">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u90753ae1a3cc425cbc1998b3f05a5f29"><li id="EN-US_TOPIC_0000001188482092__la4f3abf671a04f71b07ae66864d7b675"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b8423527061003">on</strong> indicates the column that can be redistributed and evaluates the most distinct value for redistribution.</li><li id="EN-US_TOPIC_0000001188482092__la5e539e18c594bd784954f6b58779bbe"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b8423527061031">off</strong> indicates the first column that can be redistributed for redistribution.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a83d49873cd6e4c7c9525f544c8dffe18"><strong id="EN-US_TOPIC_0000001188482092__b639401646">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1443108235">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__sa17caa9eb29547669e8d2fe19f4321c8"><h4 class="sectiontitle">enable_valuepartition_pruning</h4><p id="EN-US_TOPIC_0000001188482092__a05b27236bf584cd1b2d48f74f8c253ad"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_b1569690523111828">Parameter description</strong>: Specifies whether the DFS partitioned table is dynamically or statically optimized.</p>
<p id="EN-US_TOPIC_0000001188482092__p38994153112"><strong id="EN-US_TOPIC_0000001188482092__b1249619130127">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a7e3e95d8cd474c1bb2e328bb654307bd"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_b17431449101331">Value range:</strong> Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__u29a168ea3e8b4921a7c9d64de7294eb5"><li id="EN-US_TOPIC_0000001188482092__l83a1f21d7c3646f6b800a219734523e8"><strong id="EN-US_TOPIC_0000001188482092__b798317581">on</strong> indicates that the DFS partitioned table is dynamically or statically optimized.</li><li id="EN-US_TOPIC_0000001188482092__l8fe473b282e245dcab5f31477fb15689"><strong id="EN-US_TOPIC_0000001188482092__b329376961">off</strong> indicates that the DFS partitioned table is not dynamically or statically optimized.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__aa3e4cfa9730e43759718983f8958a8cf"><strong id="EN-US_TOPIC_0000001188482092__b2093735689">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1723897450">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section746841514523"><a name="EN-US_TOPIC_0000001188482092__section746841514523"></a><a name="section746841514523"></a><h4 class="sectiontitle">expected_computing_nodegroup</h4><p id="EN-US_TOPIC_0000001188482092__p99241701345"><strong id="EN-US_TOPIC_0000001188482092__b2092416053419">Parameter description</strong>: Specifies a computing Node Group or the way to choose such a group. The Node Group mechanism is now for internal use only. You do not need to set it.</p>
<p id="EN-US_TOPIC_0000001188482092__p98131843917">During join or aggregation operations, a Node Group can be selected in four modes. In each mode, the specified candidate computing Node Groups are listed for the optimizer to select an appropriate one for the current operator.</p>
<p id="EN-US_TOPIC_0000001188482092__p14297105043110"><strong id="EN-US_TOPIC_0000001188482092__b66711213171217">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a3d8c820d08c0489ba6c10a47476f8b23"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059777791_en-us_topic_0058967586_b688672095621">Value range</strong>: a string</p>
<ul id="EN-US_TOPIC_0000001188482092__u582a49208d014b459af16e68a402d6df"><li id="EN-US_TOPIC_0000001188482092__l809bf5bea254485d9ac4dc25947b5c18"><strong id="EN-US_TOPIC_0000001188482092__b962218129612">optimal</strong>: The list of candidate computing Node Groups consists of the Node Group where the operator's operation objects are located and the DNs in the Node Groups on which the current user has the COMPUTE permission.</li><li id="EN-US_TOPIC_0000001188482092__l23cd64e035524005929848d0127b3d8e"><strong id="EN-US_TOPIC_0000001188482092__b141595160612">query</strong>: The list of candidate computing Node Groups consists of the Node Group where the operator's operation objects are located and the DNs in the Node Groups where base tables involved in the query are located.</li><li id="EN-US_TOPIC_0000001188482092__li168897411428"><strong id="EN-US_TOPIC_0000001188482092__b21821241662">bind</strong>: If the current session user is a logical cluster user, the candidate computing Node Group is the Node Group of the logical cluster associated with the current user. If the session user is not a logical cluster user, the candidate computing Node Group selection rule is the same as that when this parameter is set to <strong id="EN-US_TOPIC_0000001188482092__b699811401962">query</strong>.</li><li id="EN-US_TOPIC_0000001188482092__li71490412910">Node Group name:<ul id="EN-US_TOPIC_0000001188482092__ul5251419201"><li id="EN-US_TOPIC_0000001188482092__li14884205891915">If <a href="#EN-US_TOPIC_0000001188482092__section1426622145210">enable_nodegroup_debug</a> is set to <strong id="EN-US_TOPIC_0000001188482092__b206472014719">off</strong>, the list of candidate computing Node Groups consists of the Node Group where the operator's operation objects are located and the specified Node Group.</li><li id="EN-US_TOPIC_0000001188482092__li1990917581195">If <a href="#EN-US_TOPIC_0000001188482092__section1426622145210">enable_nodegroup_debug</a> is set to <strong id="EN-US_TOPIC_0000001188482092__b1035181461520">on</strong>, the specified Node Group is used as the candidate Node Group.</li></ul>
</li></ul>
<p id="EN-US_TOPIC_0000001188482092__a97c28ae246e3464aa63de98c910603c4"><strong id="EN-US_TOPIC_0000001188482092__b842352706153219">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b842352706153224">bind</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section1426622145210"><a name="EN-US_TOPIC_0000001188482092__section1426622145210"></a><a name="section1426622145210"></a><h4 class="sectiontitle">enable_nodegroup_debug</h4><p id="EN-US_TOPIC_0000001188482092__p1248710216535"><strong id="EN-US_TOPIC_0000001188482092__b94888220534">Parameter description</strong>: Specifies whether the optimizer assigns computing workloads to a specific Node Group when multiple Node Groups exist in an environment. The Node Group mechanism is now for internal use only. You do not need to set it.</p>
<p id="EN-US_TOPIC_0000001188482092__p8421114485619">This parameter takes effect only when <a href="#EN-US_TOPIC_0000001188482092__section746841514523">expected_computing_nodegroup</a> is set to a specific Node Group.</p>
<p id="EN-US_TOPIC_0000001188482092__p131469593317"><strong id="EN-US_TOPIC_0000001188482092__b19866151319127">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p20491152165318"><strong id="EN-US_TOPIC_0000001188482092__en-us_topic_0059778346_en-us_topic_0058967673_b6625143011450_1">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482092__ul1449316295319"><li id="EN-US_TOPIC_0000001188482092__li12495182145315"><strong id="EN-US_TOPIC_0000001188482092__b842352706153524">on</strong> indicates that computing workloads are assigned to the Node Group specified by <strong id="EN-US_TOPIC_0000001188482092__b842352706153618">expected_computing_nodegroup</strong>.</li><li id="EN-US_TOPIC_0000001188482092__li1149710205315"><strong id="EN-US_TOPIC_0000001188482092__b1239936307154553">off</strong> indicates no Node Group is specified to compute.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p849917295316"><strong id="EN-US_TOPIC_0000001188482092__b1489099297">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b1801079313">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section142331927115214"><h4 class="sectiontitle">stream_multiple</h4><p id="EN-US_TOPIC_0000001188482092__a823749263dcf480d87015cebb3d21907"><strong id="EN-US_TOPIC_0000001188482092__b842352706154610">Parameter description</strong>: Specifies the weight used for optimizer to calculate the final cost of stream operators.</p>
<p id="EN-US_TOPIC_0000001188482092__p76371053324">The base stream cost is multiplied by this weight to make the final cost.</p>
<p id="EN-US_TOPIC_0000001188482092__p9113615153214"><strong id="EN-US_TOPIC_0000001188482092__b740414151215">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__a3eb9ce875ece46a9b52c18cc8f2b7b59"><strong id="EN-US_TOPIC_0000001188482092__b842352706155342">Value range</strong>: a floating point number ranging from 0 to DBL_MAX</p>
<p id="EN-US_TOPIC_0000001188482092__aa92db8f81a9d44719aeeec06c0ec218c"><strong id="EN-US_TOPIC_0000001188482092__b66927520111326">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b842352706122628">1</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001188482092__note4849184882913"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001188482092__p9748916445">This parameter is applicable only to Redistribute and Broadcast streams.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section207996212178"><h4 class="sectiontitle">qrw_inlist2join_optmode</h4><p id="EN-US_TOPIC_0000001188482092__p07995213179"><strong id="EN-US_TOPIC_0000001188482092__b638072535319">Parameter description</strong>: Specifies whether enable inlist-to-join (inlist2join) query rewriting.</p>
<p id="EN-US_TOPIC_0000001188482092__p6802114273211"><strong id="EN-US_TOPIC_0000001188482092__b14209111421218">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p18799221141716"><strong id="EN-US_TOPIC_0000001188482092__b1226897392">Value range</strong>: a string</p>
<ul id="EN-US_TOPIC_0000001188482092__ul826711518189"><li id="EN-US_TOPIC_0000001188482092__li142671651111819"><strong id="EN-US_TOPIC_0000001188482092__b193124191558">disable</strong>: inlist2join disabled</li><li id="EN-US_TOPIC_0000001188482092__li192673514184"><strong id="EN-US_TOPIC_0000001188482092__b583904415518">cost_base</strong>: cost-based inlist2join query rewriting</li><li id="EN-US_TOPIC_0000001188482092__li62672518185"><strong id="EN-US_TOPIC_0000001188482092__b13548179105610">rule_base</strong>: forcible rule-based inlist2join query rewriting</li><li id="EN-US_TOPIC_0000001188482092__li6267751141814">A positive integer: threshold of Inlist2join query rewriting. If the number of elements in the list is greater than the threshold, the rewriting is performed.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p19799152117179"><strong id="EN-US_TOPIC_0000001188482092__b5750214">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482092__b84235270617717">cost_base</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482092__section1211182712176"><a name="EN-US_TOPIC_0000001188482092__section1211182712176"></a><a name="section1211182712176"></a><h4 class="sectiontitle">skew_option</h4><p id="EN-US_TOPIC_0000001188482092__p131156271171"><strong id="EN-US_TOPIC_0000001188482092__b6506181813572">Parameter description</strong>: Specifies whether an optimization policy is used</p>
<p id="EN-US_TOPIC_0000001188482092__p1841374916324"><strong id="EN-US_TOPIC_0000001188482092__b9378171441216">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482092__p411902711174"><strong id="EN-US_TOPIC_0000001188482092__b848802468">Value range</strong>: a string</p>
<ul id="EN-US_TOPIC_0000001188482092__ul9122142741716"><li id="EN-US_TOPIC_0000001188482092__li19123112714178"><strong id="EN-US_TOPIC_0000001188482092__b1680514483576">off</strong>: policy disabled</li><li id="EN-US_TOPIC_0000001188482092__li612772711711"><strong id="EN-US_TOPIC_0000001188482092__b683816522579">normal</strong>: radical policy. All possible skews are optimized.</li><li id="EN-US_TOPIC_0000001188482092__li5131142721714"><strong id="EN-US_TOPIC_0000001188482092__b380633010585">lazy</strong>: conservative policy. Uncertain skews are ignored.</li></ul>
<p id="EN-US_TOPIC_0000001188482092__p12134102711710"><strong id="EN-US_TOPIC_0000001188482092__b71351827151719">Default value:</strong> <strong id="EN-US_TOPIC_0000001188482092__b1833214160599">normal</strong></p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0908.html">Query Planning</a></div>
</div>
</div>