forked from docs/doc-exports
Lu, Huayi
ef0ada5a59
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>
45 lines
10 KiB
HTML
45 lines
10 KiB
HTML
<a name="EN-US_TOPIC_0000001460722472"></a><a name="EN-US_TOPIC_0000001460722472"></a>
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<h1 class="topictitle1">Connection Settings</h1>
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<div id="body8662426"><p id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_p69637310112">This section describes parameters related to the connection mode between the client and server.</p>
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<div class="section" id="EN-US_TOPIC_0000001460722472__s2d671f584b5647a19255e7c6a3d116aa"><a name="EN-US_TOPIC_0000001460722472__s2d671f584b5647a19255e7c6a3d116aa"></a><a name="s2d671f584b5647a19255e7c6a3d116aa"></a><h4 class="sectiontitle">max_connections</h4><p id="EN-US_TOPIC_0000001460722472__ab16a7d2206574058af94fc0babfc9b1f"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_en-us_topic_0058967724_b47196620">Parameter description</strong>: Specifies the maximum number of allowed parallel connections to the database. This parameter influences the concurrent processing capability of the cluster.</p>
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<p id="EN-US_TOPIC_0000001460722472__p251615331917"><strong id="EN-US_TOPIC_0000001460722472__b1979991434417">Type</strong>: POSTMASTER</p>
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<p id="EN-US_TOPIC_0000001460722472__a033c8330e03f412884a1742780878208"><strong id="EN-US_TOPIC_0000001460722472__b10860327208">Value range</strong>: an integer. For CNs, the value ranges from 100 to 16384. For DNs, the value ranges from 100 to 262143. Because there are internal connections in the cluster, the maximum value is rarely reached. If <strong id="EN-US_TOPIC_0000001460722472__b15480194712915">invalid value for parameter "max_connections"</strong> is displayed in the log, you need to decrease the <strong id="EN-US_TOPIC_0000001460722472__b191029547308">max_connections</strong> value for DNs.</p>
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<p id="EN-US_TOPIC_0000001460722472__a6484ecbf671a458e9a42c04454e43c13"><strong id="EN-US_TOPIC_0000001460722472__b921920118155">Default value</strong>: <strong id="EN-US_TOPIC_0000001460722472__b113751017161512">800</strong> for CNs and <strong id="EN-US_TOPIC_0000001460722472__b16256203151">5000</strong> for DNs. If the default value is greater than the maximum value supported by kernel (determined when the <strong id="EN-US_TOPIC_0000001460722472__b172191611121517">gs_initdb</strong> command is executed), an error message will be displayed.</p>
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<p id="EN-US_TOPIC_0000001460722472__ae4c883e2202045a4bb9b28ed591664f9"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_b2809270516346">Setting suggestions</strong>:</p>
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<p id="EN-US_TOPIC_0000001460722472__p452615084415">Retain the default value of this parameter on CNs. On a DN, the value of this parameter is calculated as follows:</p>
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<p id="EN-US_TOPIC_0000001460722472__p1360914569443">dop_limit x 20 x 6 + 24: <strong id="EN-US_TOPIC_0000001460722472__b1645312717397">dop_limit</strong> indicates the number of CPUs of each DN in the cluster. It is calculated as follows: <strong id="EN-US_TOPIC_0000001460722472__b1445319278393">dop_limit</strong> = Number of logical CPU cores of a single server/Number of DNs of a single server.</p>
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<p id="EN-US_TOPIC_0000001460722472__p6610826174512">The minimum value is 5000.</p>
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<p id="EN-US_TOPIC_0000001460722472__a8efe0f70507c49cbb33c51a772b37b6a">If the parameter is set to a large value, <span id="EN-US_TOPIC_0000001460722472__text2034046385">GaussDB(DWS)</span> requires more SystemV shared memories or semaphores, which may exceed the maximum default configuration of the OS. In this case, modify the value as needed.</p>
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<div class="notice" id="EN-US_TOPIC_0000001460722472__note51821344104916"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001460722472__p7182154416496">The value of <strong id="EN-US_TOPIC_0000001460722472__b183671349093">max_connections</strong> is related to <a href="dws_04_0893.html#EN-US_TOPIC_0000001460563104__s7f44489cfdce4bbea287150fb7333b9e">max_prepared_transactions</a>. Before setting <strong id="EN-US_TOPIC_0000001460722472__b4358142916109">max_connections</strong>, ensure that the value of <strong id="EN-US_TOPIC_0000001460722472__b9768541131019">max_prepared_transactions</strong> is greater than or equal to that of <strong id="EN-US_TOPIC_0000001460722472__b1721635171119">max_connections</strong>. In this way, each session has a prepared transaction in the waiting state.</p>
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</div></div>
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</div>
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<div class="section" id="EN-US_TOPIC_0000001460722472__s3c7b3697f6a748f0baf5754e3c4b5d19"><h4 class="sectiontitle">sysadmin_reserved_connections</h4><p id="EN-US_TOPIC_0000001460722472__a8db7e896c45c42d2b5db52e5c5d1cf92"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_a4b31a78195104adf92b9eed83bdbcd10">Parameter description</strong>: Specifies the minimum number of connections reserved for administrators.</p>
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<p id="EN-US_TOPIC_0000001460722472__p733324718917"><strong id="EN-US_TOPIC_0000001460722472__b1997610149441">Type</strong>: POSTMASTER</p>
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<p id="EN-US_TOPIC_0000001460722472__a6186f83bbb8144a69a55c8242f481fdc"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777487_en-us_topic_0058967566_b6696864">Value range</strong>: an integer ranging from 0 to 262143</p>
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<p id="EN-US_TOPIC_0000001460722472__a26b5925222734322a475d763ec44953c"><strong id="EN-US_TOPIC_0000001460722472__b842352706185015">Default value</strong>: <strong id="EN-US_TOPIC_0000001460722472__b842352706185018">3</strong></p>
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</div>
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<div class="section" id="EN-US_TOPIC_0000001460722472__sb9319017186d42d3bb1352d83a3c8b79"><h4 class="sectiontitle">application_name</h4><p id="EN-US_TOPIC_0000001460722472__ae39b72730bb945799b082fcf0b231f5d"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_a256c2bab538d4586b07e2db0ba045933">Parameter description</strong>: Specifies the name of the client program connecting to the database.</p>
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<p id="EN-US_TOPIC_0000001460722472__p1727443129"><strong id="EN-US_TOPIC_0000001460722472__b612055616446">Type</strong>: USERSET</p>
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<p id="EN-US_TOPIC_0000001460722472__a76b2373b366e484f8a7ffc17a9e5c14d"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_a0569bf5cd0fd491c8868b390ab1eed54">Value range</strong>: a string</p>
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<p id="EN-US_TOPIC_0000001460722472__a341a9547ac924967a40f75d151e44b80"><strong id="EN-US_TOPIC_0000001460722472__en-us_topic_0059777636_a0bdfce78fa494bdd8c2c0156c1a0393d">Default value</strong>: <strong id="EN-US_TOPIC_0000001460722472__b842352706202555">gsql</strong></p>
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</div>
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<div class="section" id="EN-US_TOPIC_0000001460722472__section4834457114318"><a name="EN-US_TOPIC_0000001460722472__section4834457114318"></a><a name="section4834457114318"></a><h4 class="sectiontitle">connection_info</h4><p id="EN-US_TOPIC_0000001460722472__p209712583437"><strong id="EN-US_TOPIC_0000001460722472__b550332111816">Parameter description</strong>: Specifies the database connection information, including the driver type, driver version, driver deployment path, and process owner. (This is an O&M parameter. Do not configure it by yourself.)</p>
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<p id="EN-US_TOPIC_0000001460722472__p727782016135"><strong id="EN-US_TOPIC_0000001460722472__b15716105614419">Type</strong>: USERSET</p>
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<p id="EN-US_TOPIC_0000001460722472__p1697185824318"><strong id="EN-US_TOPIC_0000001460722472__b920319251182">Value range</strong>: a string</p>
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<p id="EN-US_TOPIC_0000001460722472__p7971145894312"><strong id="EN-US_TOPIC_0000001460722472__b1334182615182">Default value</strong>: an empty string</p>
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<div class="note" id="EN-US_TOPIC_0000001460722472__note11998020131414"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="EN-US_TOPIC_0000001460722472__ul5214929175810"><li id="EN-US_TOPIC_0000001460722472__li1221452917581">An empty string indicates that the driver connected to the database does not support automatic setting of the <strong id="EN-US_TOPIC_0000001460722472__b124851628181817">connection_info</strong> parameter or the parameter is not set by users in applications.</li><li id="EN-US_TOPIC_0000001460722472__li421462916588">The following is an example of the concatenated value of <strong id="EN-US_TOPIC_0000001460722472__b7810143041810">connection_info</strong>:<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001460722472__screen36131149104519"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="err">{</span><span class="ss">"driver_name"</span><span class="p">:</span><span class="ss">"ODBC"</span><span class="p">,</span><span class="ss">"driver_version"</span><span class="p">:</span><span class="w"> </span><span class="ss">"(GaussDB x.x.x build 39137c2d) compiled at 2022-09-23 15:43:11 commit 3629 last mr 5138 debug"</span><span class="p">,</span><span class="ss">"driver_path"</span><span class="p">:</span><span class="ss">"/usr/local/lib/psqlodbcw.so"</span><span class="p">,</span><span class="ss">"os_user"</span><span class="p">:</span><span class="ss">"omm"</span><span class="err">}</span>
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</pre></div></td></tr></table></div>
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</div>
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<p id="EN-US_TOPIC_0000001460722472__p14858414192914">For ODBC, JDBC, and GSQL connections, <strong id="EN-US_TOPIC_0000001460722472__b1167610324316">driver_name</strong>, <strong id="EN-US_TOPIC_0000001460722472__b177710720439">driver_version</strong>, <strong id="EN-US_TOPIC_0000001460722472__b109171010184317">driver_path</strong>, and <strong id="EN-US_TOPIC_0000001460722472__b19871914114316">os_user</strong> are displayed by default. For other interface connections, <strong id="EN-US_TOPIC_0000001460722472__b1775692464315">driver_name</strong> and <strong id="EN-US_TOPIC_0000001460722472__b1575511279430">driver_version</strong> are displayed by default. The display of <strong id="EN-US_TOPIC_0000001460722472__b1860224219434">driver_path</strong> and <strong id="EN-US_TOPIC_0000001460722472__b1411474610434">os_user</strong> is specified by users.</p>
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</li></ul>
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</div></div>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0888.html">Connection and Authentication</a></div>
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</div>
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</div>
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