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Lu, Huayi e6fa411af0 DWS DEV 830.201 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>
2024-05-16 07:24:04 +00:00

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<a name="EN-US_TOPIC_0000001188482304"></a><a name="EN-US_TOPIC_0000001188482304"></a>
<h1 class="topictitle1">Statement Behavior</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_p13341214819">This section describes related default parameters involved in the execution of SQL statements.</p>
<div class="section" id="EN-US_TOPIC_0000001188482304__sc0cb61109de045049d5802f668be2392"><h4 class="sectiontitle">search_path</h4><p id="EN-US_TOPIC_0000001188482304__a5d608020961c414b8141d5be1d21cfa4"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b18846194">Parameter description</strong>: Specifies the order in which schemas are searched when an object is referenced with no schema specified. The value of this parameter consists of one or more schema names. Different schema names are separated by commas (,).</p>
<p id="EN-US_TOPIC_0000001188482304__ac39170eab2164cb2a3a7b0b647b25a93"><strong id="EN-US_TOPIC_0000001188482304__b194831361133">Type</strong>: USERSET</p>
<ul id="EN-US_TOPIC_0000001188482304__u5a44e0ba7fbf4140b39373c0d9977703"><li id="EN-US_TOPIC_0000001188482304__li387717311810">If the schema of a temporary table exists in the current session, the scheme can be listed in <strong id="EN-US_TOPIC_0000001188482304__b95933381417">search_path</strong> by using the alias <strong id="EN-US_TOPIC_0000001188482304__b7593113811417">pg_temp</strong>, for example, <strong id="EN-US_TOPIC_0000001188482304__b125931238144114">'pg_temp,public'</strong>. The schema of a temporary table has the highest search priority and is always searched before all the schemas specified in <strong id="EN-US_TOPIC_0000001188482304__b1677510294569">pg_catalog</strong> and <strong id="EN-US_TOPIC_0000001188482304__b777512935616">search_path</strong>. Therefore, do not explicitly specify <strong id="EN-US_TOPIC_0000001188482304__b842352706171134">pg_temp</strong> to be searched after other schemas in <strong id="EN-US_TOPIC_0000001188482304__b842352706171141">search_path</strong>. This setting will not take effect and an error message will be displayed. If the alias <strong id="EN-US_TOPIC_0000001188482304__b842352706183225">pg_temp</strong> is used, the temporary schema will be only searched for database objects, including tables, views, and data types. Functions or operator names will not be searched for.</li><li id="EN-US_TOPIC_0000001188482304__l1aa5991b650b413fb2cb932323b19b8f">The schema of a system catalog, <strong id="EN-US_TOPIC_0000001188482304__b842352706175824">pg_catalog</strong>, has the second highest search priority and is the first to be searched among all the schemas, excluding <strong id="EN-US_TOPIC_0000001188482304__b842352706175829">pg_temp</strong>, specified in <strong id="EN-US_TOPIC_0000001188482304__b842352706175833">search_path</strong>. Therefore, do not explicitly specify <strong id="EN-US_TOPIC_0000001188482304__b67431624">pg_catalog</strong> to be searched after other schemas in <strong id="EN-US_TOPIC_0000001188482304__b10763726">search_path</strong>. This setting will not take effect and an error message will be displayed.</li><li id="EN-US_TOPIC_0000001188482304__la69ffd2497974687a2df6445537372eb">When an object is created without specifying a particular schema, the object will be placed in the first valid schema listed in <strong id="EN-US_TOPIC_0000001188482304__b34116455018">search_path</strong>. An error will be reported if the search path is empty.</li><li id="EN-US_TOPIC_0000001188482304__l34dacabdf243448995a38701a20d016d">The current effective value of the search path can be examined through the SQL function current_schema. This is different from examining the value of <strong id="EN-US_TOPIC_0000001188482304__b84235270613237">search_path</strong>, because the current_schema function displays the first valid schema name in <strong id="EN-US_TOPIC_0000001188482304__b84235270613249">search_path</strong>.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__adf092580cac04d3a85e382368bf46a4a"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b23397570_2">Value range</strong>: a string</p>
<div class="note" id="EN-US_TOPIC_0000001188482304__n8ea4402852644604a8e8ffec7b42cfd5"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="EN-US_TOPIC_0000001188482304__ul426175843811"><li id="EN-US_TOPIC_0000001188482304__li19895153315391">When this parameter is set to <strong id="EN-US_TOPIC_0000001188482304__b7273194913295">"$user", public</strong>, a database can be shared (where no users have private schemas, and all share use of public), and private per-user schemas and combinations of them are supported. Other effects can be obtained by modifying the default search path setting, either globally or per-user.</li><li id="EN-US_TOPIC_0000001188482304__li154361649104018">When this parameter is set to a null string (''), the system automatically converts it into a pair of double quotation marks ("").</li><li id="EN-US_TOPIC_0000001188482304__li11436549184017">If the content contains double quotation marks, the system considers them as insecure characters and converts each double quotation mark into a pair of double quotation marks.</li></ul>
</div></div>
<p id="EN-US_TOPIC_0000001188482304__p1583135414306"><strong id="EN-US_TOPIC_0000001188482304__b191531026144317">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b318753574312">"$user",public</strong></p>
<div class="note" id="EN-US_TOPIC_0000001188482304__note936532212316"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001188482304__p636542283116"><strong id="EN-US_TOPIC_0000001188482304__b13918851126">$user</strong> indicates the name of the schema with the same name as the current session user. If the schema does not exist, <strong id="EN-US_TOPIC_0000001188482304__b76691039123">$user</strong> will be ignored.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__sb21a5c07aa404790aa662f4d0e38d44f"><h4 class="sectiontitle">current_schema</h4><p id="EN-US_TOPIC_0000001188482304__af42c3e31748348b09f1b5fc77dcf1768"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b787602078162323">Parameter description</strong>: Specifies the current schema.</p>
<p id="EN-US_TOPIC_0000001188482304__ad49bf6e5ec4841fa909f229513759c62"><strong id="EN-US_TOPIC_0000001188482304__b1491944581311">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a309b73009a134922870143ed41903146"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b23397570_4">Value range</strong>: a string</p>
<p id="EN-US_TOPIC_0000001188482304__p9498201082913"><strong id="EN-US_TOPIC_0000001188482304__b769218562433">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b191636110445">"$user",public</strong></p>
<div class="note" id="EN-US_TOPIC_0000001188482304__note787714672912"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001188482304__p178762463294"><strong id="EN-US_TOPIC_0000001188482304__b187421142445">$user</strong> indicates the name of the schema with the same name as the current session user. If the schema does not exist, <strong id="EN-US_TOPIC_0000001188482304__b67439416445">$user</strong> will be ignored.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s2bc15c6041414a058ad5e1738739a120"><a name="EN-US_TOPIC_0000001188482304__s2bc15c6041414a058ad5e1738739a120"></a><a name="s2bc15c6041414a058ad5e1738739a120"></a><h4 class="sectiontitle">default_tablespace</h4><p id="EN-US_TOPIC_0000001188482304__a3f111825a7bb454daa3bc1481f2b0554"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b15652134">Parameter description</strong>: Specifies the default tablespace of the created objects (tables and indexes) when a <strong id="EN-US_TOPIC_0000001188482304__b84235270611349">CREATE</strong> command does not explicitly specify a tablespace.</p>
<ul id="EN-US_TOPIC_0000001188482304__uae40740ddc344f8ca4af0273c6f5d0de"><li id="EN-US_TOPIC_0000001188482304__li3486123916464">The value of this parameter is either the name of a tablespace, or an empty string that specifies the use of the default tablespace of the current database. If a non-default tablespace is specified, users must have CREATE privilege for it. Otherwise, creation attempts will fail.</li><li id="EN-US_TOPIC_0000001188482304__lae527d61abe541f48e0e10c2b7e886b5">This parameter is not used for temporary tables. For them, the <a href="#EN-US_TOPIC_0000001188482304__sf6153b3838a045159743f7f32e69ffa3">temp_tablespaces</a> is consulted instead.</li><li id="EN-US_TOPIC_0000001188482304__li1697373142116">This parameter is not used when users create databases. By default, a new database inherits its tablespace setting from the template database.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__p23804417345"><strong id="EN-US_TOPIC_0000001188482304__b20296452171317">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a30ac04d60d444f258f8eba77da2a686c"><strong id="EN-US_TOPIC_0000001188482304__b1717481217442">Value range</strong>: a string. An empty string indicates that the default tablespace is used.</p>
<p id="EN-US_TOPIC_0000001188482304__a124df414405c4e628e0aa5e7e8a103ad"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b61397973">Default value</strong>: empty</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__section1785192713303"><h4 class="sectiontitle">default_storage_nodegroup</h4><p id="EN-US_TOPIC_0000001188482304__p887202714307"><strong id="EN-US_TOPIC_0000001188482304__b3871127103019">Parameter description</strong>: Specifies the Node Group where a table is created by default. This parameter takes effect only for ordinary tables.</p>
<p id="EN-US_TOPIC_0000001188482304__p1012432613412"><strong id="EN-US_TOPIC_0000001188482304__b872241715272">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__p993192783010"><strong id="EN-US_TOPIC_0000001188482304__b1671688963">Value range</strong>: a string</p>
<ul id="EN-US_TOPIC_0000001188482304__ul15661192162519"><li id="EN-US_TOPIC_0000001188482304__li8662421182514"><strong id="EN-US_TOPIC_0000001188482304__b33818323211">installation</strong>: indicates that the table is created in the installed Node Group by default.</li><li id="EN-US_TOPIC_0000001188482304__li866232182518"><strong id="EN-US_TOPIC_0000001188482304__b59767911227">random_node_group</strong>: indicates that the table is created in a randomly selected Node Group by default. This feature is supported in 8.1.2 or later and is used only in the test environment.</li><li id="EN-US_TOPIC_0000001188482304__li566222112255"><strong id="EN-US_TOPIC_0000001188482304__b199021815238">roach_group</strong>: indicates that the table is created in all nodes by default. This value is reserved for the Roach tool and cannot be used in other scenarios.</li><li id="EN-US_TOPIC_0000001188482304__li66622213251">A value other than the preceding three options indicates that the table is created in a specified Node Group.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__p129522715307"><strong id="EN-US_TOPIC_0000001188482304__b55233292105553">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b842352706172155">installation</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__section774811124918"><h4 class="sectiontitle">default_colversion</h4><p id="EN-US_TOPIC_0000001188482304__p133308341911"><strong id="EN-US_TOPIC_0000001188482304__b518618584435">Parameter description</strong>: Sets the storage format version of the column-store table that is created by default.</p>
<p id="EN-US_TOPIC_0000001188482304__p419390101017"><strong id="EN-US_TOPIC_0000001188482304__b17677103184414">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001188482304__p42569318105"><strong id="EN-US_TOPIC_0000001188482304__b1888773394414">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001188482304__ul1389225015106"><li id="EN-US_TOPIC_0000001188482304__li1789265081015"><strong id="EN-US_TOPIC_0000001188482304__b295183614412">1.0</strong>: Each column in a column-store table is stored in a separate file. The file name is <strong id="EN-US_TOPIC_0000001188482304__b12951143654419">relfilenode.C1.0</strong>, <strong id="EN-US_TOPIC_0000001188482304__b4951336154417">relfilenode.C2.0</strong>, <strong id="EN-US_TOPIC_0000001188482304__b18951113634412">relfilenode.C3.0</strong>, or similar.</li><li id="EN-US_TOPIC_0000001188482304__li492121591115"><strong id="EN-US_TOPIC_0000001188482304__b7151115744410">2.0</strong>: All columns of a column-store table are combined and stored in a file. The file is named <strong id="EN-US_TOPIC_0000001188482304__b18151957154410">relfilenode.C1.0</strong>.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__p77073541697"><strong id="EN-US_TOPIC_0000001188482304__b3158552610564">Default value:</strong> <strong id="EN-US_TOPIC_0000001188482304__b842352706173228">2.0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__sf6153b3838a045159743f7f32e69ffa3"><a name="EN-US_TOPIC_0000001188482304__sf6153b3838a045159743f7f32e69ffa3"></a><a name="sf6153b3838a045159743f7f32e69ffa3"></a><h4 class="sectiontitle">temp_tablespaces</h4><p id="EN-US_TOPIC_0000001188482304__a4cc22ac8ca31400a9e2b2bfbf1998491"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b11570559">Parameter description</strong>: Specifies tablespaces to which temporary objects will be created (temporary tables and their indexes) when a <strong id="EN-US_TOPIC_0000001188482304__b842352706114223">CREATE</strong> command does not explicitly specify a tablespace. Temporary files for sorting large data are created in these tablespaces.</p>
<p id="EN-US_TOPIC_0000001188482304__a24a9c6430217489b89d2aa4eae55303e">The value of this parameter is a list of names of tablespaces. When there is more than one name in the list, <span id="EN-US_TOPIC_0000001188482304__text2103397368">GaussDB(DWS)</span> chooses a random tablespace from the list upon the creation of a temporary object each time. Except that within a transaction, successively created temporary objects are placed in successive tablespaces in the list. If the element selected from the list is an empty string, <span id="EN-US_TOPIC_0000001188482304__text493827490">GaussDB(DWS)</span> will automatically use the default tablespace of the current database instead.</p>
<p id="EN-US_TOPIC_0000001188482304__ab3221092989549f7a13049f81bcec944"><strong id="EN-US_TOPIC_0000001188482304__b273219505447">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__abe84e30afa444d62aada12e71896a70f"><strong id="EN-US_TOPIC_0000001188482304__b7848851114418">Value range</strong>: a string An empty string indicates that all temporary objects are created only in the default tablespace of the current database. For details, see <a href="#EN-US_TOPIC_0000001188482304__s2bc15c6041414a058ad5e1738739a120">default_tablespace</a>.</p>
<p id="EN-US_TOPIC_0000001188482304__p764313512101"><strong id="EN-US_TOPIC_0000001188482304__b86432357106">Default value</strong>: empty</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s3158c34da4b243b6861ef663bd35f750"><h4 class="sectiontitle">check_function_bodies</h4><p id="EN-US_TOPIC_0000001188482304__aafe0bcc96d4649ab86e4e4d68efe86bd"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b84235270619452">Parameter description</strong>: Specifies whether to enable validation of the function body string during the execution of <strong id="EN-US_TOPIC_0000001188482304__b842352706114439">CREATE FUNCTION</strong>. Verification is occasionally disabled to avoid problems, such as forward references when you restore function definitions from a dump.</p>
<p id="EN-US_TOPIC_0000001188482304__a81502ac57d314dd0a936c2bd81a279dc"><strong id="EN-US_TOPIC_0000001188482304__b1080505361316">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a4363adac4d954c79a0dcceff18d50d76"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b45718858_2">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482304__u6b19712b3b0d4576ab91699e6e45d128"><li id="EN-US_TOPIC_0000001188482304__l3a828d2c963947c0ad43d3bbf5809199"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706202013">on</strong> indicates that validation of the function body string is enabled during the execution of <strong id="EN-US_TOPIC_0000001188482304__b842352706114631">CREATE FUNCTION</strong>.</li><li id="EN-US_TOPIC_0000001188482304__l64c44541a17e471f86a5bfc7523f7a47"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706202016">off</strong> indicates that validation of the function body string is disabled during the execution of <strong id="EN-US_TOPIC_0000001188482304__b842352706114710">CREATE FUNCTION</strong>.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__a1aaa7e076fa049ba9c84e763b99fc114"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b13364462">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706131429">on</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__sf217b9b59d7a45b3966142e544129182"><h4 class="sectiontitle">default_transaction_isolation</h4><p id="EN-US_TOPIC_0000001188482304__a39b95213492c475ea122ad7935391138"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b35889067">Parameter description</strong>: Specifies the default isolation level of each transaction.</p>
<p id="EN-US_TOPIC_0000001188482304__p54641741132111"><strong id="EN-US_TOPIC_0000001188482304__b17213754201315">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a47f5166428d446afbad75937f0335203"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059777487_a54344496219b4074ad956d5febb62b4c">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001188482304__u8cf9c299d00e4872972212187e82db0c"><li id="EN-US_TOPIC_0000001188482304__li18934145519418"><strong id="EN-US_TOPIC_0000001188482304__b842352706154357">READ COMMITTED</strong>: Only committed data is read. This is the default.</li><li id="EN-US_TOPIC_0000001188482304__li15934155516411"><strong id="EN-US_TOPIC_0000001188482304__b1018874910379">READ UNCOMMITTED</strong>: <span id="EN-US_TOPIC_0000001188482304__text1036721649">GaussDB(DWS)</span> does not support <strong id="EN-US_TOPIC_0000001188482304__b785805216376">READ UNCOMMITTED</strong>. If <strong id="EN-US_TOPIC_0000001188482304__b10834155693720">READ UNCOMMITTED</strong> is set, <strong id="EN-US_TOPIC_0000001188482304__b12291722113916">READ COMMITTED</strong> is executed instead.</li><li id="EN-US_TOPIC_0000001188482304__li10935555244"><strong id="EN-US_TOPIC_0000001188482304__b5453172914197">REPEATABLE READ</strong>: Only the data committed before transaction start is read. Uncommitted data or data committed in other concurrent transactions cannot be read.</li><li id="EN-US_TOPIC_0000001188482304__li593511551545"><strong id="EN-US_TOPIC_0000001188482304__b15369211388">SERIALIZABLE</strong>: <span id="EN-US_TOPIC_0000001188482304__text1046926804">GaussDB(DWS)</span> does not support <strong id="EN-US_TOPIC_0000001188482304__b14367144493811">SERIALIZABLE</strong>. If <strong id="EN-US_TOPIC_0000001188482304__b11278104917388">SERIALIZABLE</strong> is set, <strong id="EN-US_TOPIC_0000001188482304__b3405135423816">REPEATABLE READ</strong> is executed instead.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__af70897100c1842958a0c379f4297ff0e"><strong id="EN-US_TOPIC_0000001188482304__b668613178458">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b86871172453">READ COMMITTED</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s4446682a09794103b0e6ccc84eef4829"><h4 class="sectiontitle">default_transaction_read_only</h4><p id="EN-US_TOPIC_0000001188482304__aaa023cb03bdd45ed9a55c97107cdbeed"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b10134485">Parameter description</strong>: Specifies whether each new transaction is in read-only state.</p>
<p id="EN-US_TOPIC_0000001188482304__a719083bf6f3d45b39a1378d6a4044e91"><strong id="EN-US_TOPIC_0000001188482304__b2993115411313">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001188482304__ac5672230083f4c7cab04d271aca98ced"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b45718858_4">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482304__u635db24b7cd2454aaa21906b6d2a0655"><li id="EN-US_TOPIC_0000001188482304__lc2aaed3637f9427088b1a3aec79d5e10"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b1613261131202829">on</strong> indicates the transaction is in read-only state.</li><li id="EN-US_TOPIC_0000001188482304__l27ba187280614658ab5af874b5a1203b"><strong id="EN-US_TOPIC_0000001188482304__b2043514265155452">off</strong> indicates the transaction is in read/write state.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__aaf6c7d16e6d040b28c22faf68eb1b838"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b48894767_2">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706131445">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s05ef9312d74143928830d7d459cdc63a"><a name="EN-US_TOPIC_0000001188482304__s05ef9312d74143928830d7d459cdc63a"></a><a name="s05ef9312d74143928830d7d459cdc63a"></a><h4 class="sectiontitle">default_transaction_deferrable</h4><p id="EN-US_TOPIC_0000001188482304__af96cc68cd8f54dbfb4bc8e597aef9a22"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b1096467">Parameter description</strong>: Specifies the default delaying state of each new transaction. It currently has no effect on read-only transactions or those running at isolation levels lower than serializable.</p>
<p id="EN-US_TOPIC_0000001188482304__a239fff9a32b34a609af091b6601a9e92"><span id="EN-US_TOPIC_0000001188482304__text96199921">GaussDB(DWS)</span> does not support the serializable isolation level of each transaction. The parameter is insignificant.</p>
<p id="EN-US_TOPIC_0000001188482304__p15809191814227"><strong id="EN-US_TOPIC_0000001188482304__b12197165981318">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a6edee73a8e5b4b5aad2e69cd633c1afd"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b45718858_6">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001188482304__u195d5954167844f09642682f08958694"><li id="EN-US_TOPIC_0000001188482304__l51067fa9ce394d628dea7c5ca7ecba68"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b84235270616446_1">on</strong> indicates a transaction is delayed by default.</li><li id="EN-US_TOPIC_0000001188482304__l3a59983931b34debb183a563ceb13895"><strong id="EN-US_TOPIC_0000001188482304__b1264690294155545">off</strong> indicates a transaction is not delayed by default.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__aac040ba905d84cceaa25a4d0ae8f42e8"><strong id="EN-US_TOPIC_0000001188482304__b462853846">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b813992808">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s4f6f3d215ea949e8a820a43ea286b64e"><h4 class="sectiontitle">session_replication_role</h4><p id="EN-US_TOPIC_0000001188482304__a2a87507d201d468c93263158cb1e7f9a"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b13484904">Parameter description</strong>: Specifies the behavior of replication-related triggers and rules for the current session.</p>
<p id="EN-US_TOPIC_0000001188482304__p41972024162215"><strong id="EN-US_TOPIC_0000001188482304__b107490593132">Type</strong>: USERSET</p>
<div class="notice" id="EN-US_TOPIC_0000001188482304__n06bf19bea1a24f509aab9f4f18f4e74b"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001188482304__ad9dc8328276e4e1da8a3c4c4a6d2e5c7">Setting this parameter will discard all the cached execution plans.</p>
</div></div>
<p id="EN-US_TOPIC_0000001188482304__adff366f055204b5083ccff50de774338"><strong id="EN-US_TOPIC_0000001188482304__b37931265272">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001188482304__u543e3b32eb1045269a8bae80bd4c8487"><li id="EN-US_TOPIC_0000001188482304__ldca1984fd00d4badbec2d0ea623ff0cc"><strong id="EN-US_TOPIC_0000001188482304__b125534021734217">origin</strong> indicates that the system copies operations such as insert, delete, and update from the current session.</li><li id="EN-US_TOPIC_0000001188482304__lff66bc0bc1054201b624d6c8312fe056"><strong id="EN-US_TOPIC_0000001188482304__b172156279734217">replica</strong> indicates that the system copies operations such as insert, delete, and update from other places to the current session.</li><li id="EN-US_TOPIC_0000001188482304__lf5c0ef1164de47b5b6adb0740f9862eb"><strong id="EN-US_TOPIC_0000001188482304__b207289212134217">local</strong> indicates that the system will detect the role that has logged in to the database when using the function to copy operations and will perform related operations.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__a67560890abb54c4696ae26940da099ec"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b4605672135217">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706142431">origin</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__sac44592a68f14f1ea1263edb171f7a5e"><h4 class="sectiontitle">statement_timeout</h4><p id="EN-US_TOPIC_0000001188482304__a6d41eb43baa94af29db08d67afea6bc7"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b84235270617125">Parameter description</strong>: If the statement execution time (starting when the server receives the command) is longer than the duration specified by the parameter, error information is displayed when you attempt to execute the statement and the statement then exits.</p>
<p id="EN-US_TOPIC_0000001188482304__p8883331162213"><strong id="EN-US_TOPIC_0000001188482304__b8261190161416">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a6628bfb0c8ed4222a1e68ffb0b4e8693"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059778102_a47abd39c97f042919e698a6a149bf0c1">Value range</strong>: an integer ranging from 0 to 2147483647. The unit is ms.</p>
<p id="EN-US_TOPIC_0000001188482304__a83406dcc7f704b6c8ab609e8cbed44d7"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b39494173173638_2">Default value</strong>:</p>
<ul id="EN-US_TOPIC_0000001188482304__ul159063464418"><li id="EN-US_TOPIC_0000001188482304__li164061033184410">If the current cluster is upgraded from an earlier version to 8.1.3, the value in the earlier version is inherited. The default value is <strong id="EN-US_TOPIC_0000001188482304__b1211274135111">0</strong>.</li><li id="EN-US_TOPIC_0000001188482304__li99071041448">If the current cluster version is 8.1.3, the default value is <strong id="EN-US_TOPIC_0000001188482304__b164641244195115">24h</strong>.</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s60c327b1bf584520b7c50f6825260841"><h4 class="sectiontitle">vacuum_freeze_min_age</h4><p id="EN-US_TOPIC_0000001188482304__a39afba159d6248f0b31381f42faf5676"><strong id="EN-US_TOPIC_0000001188482304__b1549347507172246">Parameter description</strong>: Specifies the minimum cutoff age (in the same transaction), based on which <strong id="EN-US_TOPIC_0000001188482304__b67147212318729">VACUUM</strong> decides whether to replace transaction IDs with FrozenXID while scanning a table.</p>
<p id="EN-US_TOPIC_0000001188482304__p1838293882214"><strong id="EN-US_TOPIC_0000001188482304__b143714051415">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a7d3d50d7722142cbae888a9e0e3296e0"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0085031947_b1266317910515">Value range</strong>: an integer from 0 to 576460752303423487.</p>
<div class="note" id="EN-US_TOPIC_0000001188482304__na0212ff4124c44a2bee04ee8c6646f59"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001188482304__ab8a5417101244e35b50a8090f5184e31">Although you can set this parameter to a value ranging from <strong id="EN-US_TOPIC_0000001188482304__b53731211482">0</strong> to <strong id="EN-US_TOPIC_0000001188482304__b237319119818">1000000000</strong> anytime, <strong id="EN-US_TOPIC_0000001188482304__b193741711888">VACUUM</strong> will limit the effective value to half the value of autovacuum_freeze_max_age by default.</p>
</div></div>
<p id="EN-US_TOPIC_0000001188482304__ad94f06a58ee64a71a2f740c8de8d8cdd"><strong id="EN-US_TOPIC_0000001188482304__b1831333134514">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b783193354510">5000000000</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__sa1686e53db434395af3e6f459e0fc2c3"><h4 class="sectiontitle">vacuum_freeze_table_age</h4><p id="EN-US_TOPIC_0000001188482304__ab23559a3081542549d34744576f6a2cb"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b9350525">Parameter description</strong>: Specifies the time that VACUUM freezes tuples while scanning the whole table. <strong id="EN-US_TOPIC_0000001188482304__b8423527061718">VACUUM</strong> performs a whole-table scan if the value of the <a href="dws_04_0578.html">pg_class</a><strong id="EN-US_TOPIC_0000001188482304__b8423527061713">.relfrozenxid</strong> column of the table has reached the specified time.</p>
<p id="EN-US_TOPIC_0000001188482304__p9252344132220"><strong id="EN-US_TOPIC_0000001188482304__b12599190121419">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__af99a616f4d0147b8bc6e48c1fe512473"><strong id="EN-US_TOPIC_0000001188482304__b10541637164513">Value range</strong>: an integer from 0 to 576460752303423487.</p>
<div class="note" id="EN-US_TOPIC_0000001188482304__ne3b06ca8c99843f986886bb50b65b850"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001188482304__ad4c6be4e918e4b3e8bfd83c46c2bb674">Although users can set this parameter to a value ranging from <strong id="EN-US_TOPIC_0000001188482304__b206872364817">0</strong> to <strong id="EN-US_TOPIC_0000001188482304__b469363615815">2000000000</strong> anytime, <strong id="EN-US_TOPIC_0000001188482304__b4694133611810">VACUUM</strong> will limit the effective value to 95% of autovacuum_freeze_max_age by default. Therefore, a periodic manual VACUUM has a chance to run before an anti-wraparound autovacuum is launched for the table.</p>
</div></div>
<p id="EN-US_TOPIC_0000001188482304__aae9d67a7c9db48ccaaa231e872eab251"><strong id="EN-US_TOPIC_0000001188482304__b153111242204517">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b2312442154511">15000000000</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s9aacf51840d94834bc02170df0ca2567"><h4 class="sectiontitle">bytea_output</h4><p id="EN-US_TOPIC_0000001188482304__a7a8e1246022a4219ba6dd028a0819832"><strong id="EN-US_TOPIC_0000001188482304__b20724497716117">Parameter description</strong>: Specifies the output format for values of the bytea type.</p>
<p id="EN-US_TOPIC_0000001188482304__p118087413235"><strong id="EN-US_TOPIC_0000001188482304__b77581015148">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__ab5e8e758e0e04a3bb3876a850cf2b0b4"><strong id="EN-US_TOPIC_0000001188482304__b1776733419275">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001188482304__u9f275b45fd254aca8b647a54dada1855"><li id="EN-US_TOPIC_0000001188482304__l7f7fb43e34bc42108522f813ad195e25"><strong id="EN-US_TOPIC_0000001188482304__b44120600316133">hex</strong> indicates the binary data is converted to the two-byte hexadecimal digit.</li><li id="EN-US_TOPIC_0000001188482304__l1cc082563b054140b2e8fe41b12a7036"><strong id="EN-US_TOPIC_0000001188482304__b25352759716131">escape</strong> indicates the traditional PostgreSQL format is used. It takes the approach of representing a binary string as a sequence of ASCII characters, while converting those bytes that cannot be represented as an ASCII character into special escape sequences.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__a3b24d1f3ada7491da94dd64072561cac"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b39494173173638_4">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706131745">hex</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s0cb95cc81bac415aa5dbdee799009781"><h4 class="sectiontitle">xmlbinary</h4><p id="EN-US_TOPIC_0000001188482304__a707e5779ab304c82b5e4a0974ef86b88"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b268070428161452">Parameter description</strong>: Specifies how binary values are to be encoded in XML.</p>
<p id="EN-US_TOPIC_0000001188482304__p24002107236"><strong id="EN-US_TOPIC_0000001188482304__b291012001414">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a247c2eb9c91b4eb58f933996852aceea"><strong id="EN-US_TOPIC_0000001188482304__b43921936112710">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001188482304__u0396a52f99bb41fdaa0caedd41007f83"><li id="EN-US_TOPIC_0000001188482304__l0561aeb30c4b4cfa8ecf293a5b72e460">base64</li><li id="EN-US_TOPIC_0000001188482304__l2a791a2ad7f240d3b9424d95916098dc">hex</li></ul>
<p id="EN-US_TOPIC_0000001188482304__a3aaebcb9cb6b425ea4fcbe1fef96cefb"><strong id="EN-US_TOPIC_0000001188482304__b19135459601632">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__b20773832181632">base64</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__sf6e61c8608cc4df681c09dbf51328be9"><h4 class="sectiontitle">xmloption</h4><p id="EN-US_TOPIC_0000001188482304__a099d09f8471f40e2bc4509c8427e8c02"><strong id="EN-US_TOPIC_0000001188482304__b21284796391637">Parameter description</strong>: Specifies whether DOCUMENT or CONTENT is implicit when converting between XML and string values.</p>
<p id="EN-US_TOPIC_0000001188482304__p10143181715234"><strong id="EN-US_TOPIC_0000001188482304__b1469612146">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__abdcf26212f0145fcb273aa2a2a2e3884"><strong id="EN-US_TOPIC_0000001188482304__b1675637162715">Value range</strong>: enumerated values</p>
<ul id="EN-US_TOPIC_0000001188482304__u5f6bb676a2b84c1ea2189455d8886dc0"><li id="EN-US_TOPIC_0000001188482304__lf622b393de3f4eeaaee637b7dfa55a02"><strong id="EN-US_TOPIC_0000001188482304__b16110056916326">document</strong> indicates an HTML document.</li><li id="EN-US_TOPIC_0000001188482304__l0b079b3dbb0f4276bc06f37685963fe7"><strong id="EN-US_TOPIC_0000001188482304__b153712290716324">content</strong> indicates a common string.</li></ul>
<p id="EN-US_TOPIC_0000001188482304__a682dfe3a1b4f443e9b0fb5dc7bdcb939"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b39494173173638_8">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706131823">content</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001188482304__s679bf6c822c74a92876eef9e9e2bfeec"><h4 class="sectiontitle">gin_pending_list_limit</h4><p id="EN-US_TOPIC_0000001188482304__ae94af689be4e47e381c83899ac45eef2"><strong id="EN-US_TOPIC_0000001188482304__b516525610393">Parameter description</strong>: Specifies the maximum size of the GIN pending list which is used when <strong id="EN-US_TOPIC_0000001188482304__b143239116216440">fastupdate</strong> is enabled. If the list grows larger than this maximum size, it is cleaned up by moving the entries in it to the main GIN data structure in batches. This setting can be overridden for individual GIN indexes by modifying index storage parameters.</p>
<p id="EN-US_TOPIC_0000001188482304__p19959424122313"><strong id="EN-US_TOPIC_0000001188482304__b1783212181415">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001188482304__a848e96507acf46839be6527189bb40c2"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0085033176_en-us_topic_0059778686_a8791c882938f4e6c9ae407641e405449">Value range</strong>: an integer ranging from 64 to INT_MAX. The unit is KB.</p>
<p id="EN-US_TOPIC_0000001188482304__a1606b96a5b8141b1b7ad45b5a36b9507"><strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b39494173173638_10">Default value</strong>: <strong id="EN-US_TOPIC_0000001188482304__en-us_topic_0059779117_en-us_topic_0058967725_b842352706131935">4 MB</strong></p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0924.html">Default Settings of Client Connection</a></div>
</div>
</div>
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