Files
doc-exports/docs/dws/dev/dws_04_0891.html
luhuayi 177cd61a57 DWS DEVG 910.211 version
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: luhuayi <luhuayi@huawei.com>
Co-committed-by: luhuayi <luhuayi@huawei.com>
2025-05-05 07:44:03 +00:00

138 lines
32 KiB
HTML
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<a name="EN-US_TOPIC_0000001764491904"></a><a name="EN-US_TOPIC_0000001764491904"></a>
<h1 class="topictitle1">Communication Library Parameters</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001764491904__en-us_topic_0059778583_p54955141810">This section describes parameter settings and value ranges for communication libraries.</p>
<div class="section" id="EN-US_TOPIC_0000001764491904__s0e7f5ef30e6b4436bd8ff4eecc2b0874"><h4 class="sectiontitle">tcp_keepalives_idle</h4><p id="EN-US_TOPIC_0000001764491904__a26797864f5774ee2b34b8ff262b4d8e2"><strong id="EN-US_TOPIC_0000001764491904__en-us_topic_0059778583_a60c2f17c939047c08795c5ce96cf167e">Parameter description</strong>: Specifies the interval between keepalive signal sending in an OS that supports the <strong id="EN-US_TOPIC_0000001764491904__b842352706203218">TCP_KEEPIDLE</strong> socket parameter. If no keepalive signal is transmitted, the connection is in idle state.</p>
<p id="EN-US_TOPIC_0000001764491904__p1452911296378"><strong id="EN-US_TOPIC_0000001764491904__b189511377458">Type</strong>: USERSET</p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__n4a1b7efd51fb42d697279828521f6da4"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001764491904__u30a04cb0764b4f1cbe0f254ef29104d6"><li id="EN-US_TOPIC_0000001764491904__le71082b8085b4ee29db41a6be5b06304">If the OS does not support the <strong id="EN-US_TOPIC_0000001764491904__b842352706203234">TCP_KEEPIDLE</strong> parameter, set this parameter to <strong id="EN-US_TOPIC_0000001764491904__b20828749124512">0</strong>.</li><li id="EN-US_TOPIC_0000001764491904__le6b8dd9ee791420393e0bb189098c788">The parameter is ignored on the OS where connections are established using the Unix domain socket.</li></ul>
</div></div>
<p id="EN-US_TOPIC_0000001764491904__a8550e912907445589735dde4df6fd95d"><strong id="EN-US_TOPIC_0000001764491904__en-us_topic_0059778583_ae1fba327c9ca4d8fbdc7c3edcb5ec65f">Value range</strong>: an integer ranging from 0 to 3600. The unit is second (s).</p>
<p id="EN-US_TOPIC_0000001764491904__a021f2a2339ea44cda4be13e4a72bc2a3"><strong id="EN-US_TOPIC_0000001764491904__b13915259151516">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b842352706165429">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__s88ee62d5b677499e9268041185289d5f"><h4 class="sectiontitle">tcp_keepalives_interval</h4><p id="EN-US_TOPIC_0000001764491904__acec45ab85e1e4d658ed8cbe3d5fef5e6"><strong id="EN-US_TOPIC_0000001764491904__en-us_topic_0059778583_aed939b35e7b64a5590f7fa90d5ba7828">Parameter description:</strong> Specifies the response time before retransmission when the OS supports the <strong id="EN-US_TOPIC_0000001764491904__b842352706203243">TCP_KEEPINTVL</strong> socket parameter.</p>
<p id="EN-US_TOPIC_0000001764491904__p191029379"><strong id="EN-US_TOPIC_0000001764491904__b135119388459">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__a2eb559ab1d8c4e0c8870f3fe17932ec5"><strong id="EN-US_TOPIC_0000001764491904__b1109420104817">Value range</strong>: an integer ranging from 0 to 180. The unit is second (s).</p>
<p id="EN-US_TOPIC_0000001764491904__a07b27c9bf3d14ba0a809e6da6242ba35"><strong id="EN-US_TOPIC_0000001764491904__b586329438">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b166350413">0</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__n0e451a4b304841a3954e18f73712a6a9"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001764491904__u8d4ea242e3db4b74809bca33fb4ce71f"><li id="EN-US_TOPIC_0000001764491904__l2c38ac84d6b04e97b4e78fcdbc173727">If the OS does not support the <strong id="EN-US_TOPIC_0000001764491904__b842352706203251">TCP_KEEPINTVL</strong> parameter, set this parameter to <strong id="EN-US_TOPIC_0000001764491904__b151015371423">0</strong>.</li><li id="EN-US_TOPIC_0000001764491904__ld9ca38ec6dfe4115bd07179e031e9b67">The parameter is ignored on the OS where connections are established using the Unix domain socket.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__s3d4ec3e1bb7b4a1ab9eeb35ba8a293d4"><h4 class="sectiontitle">tcp_keepalives_count</h4><p id="EN-US_TOPIC_0000001764491904__ab28b2392e36f4a9b842bc9ef302b7fb9"><strong id="EN-US_TOPIC_0000001764491904__en-us_topic_0085032266_b716134618616">Parameter description</strong>: Specifies the number of keepalived signals that can be waited before the <span id="EN-US_TOPIC_0000001764491904__text1488884754">GaussDB(DWS)</span> server is disconnected from the client if the OS supports the <strong id="EN-US_TOPIC_0000001764491904__en-us_topic_0085032266_b842352706203257">TCP_KEEPCNT</strong> socket parameter.</p>
<p id="EN-US_TOPIC_0000001764491904__p127107914377"><strong id="EN-US_TOPIC_0000001764491904__b272313380451">Type</strong>: USERSET</p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__n3ea0fd0af7c74aca9d4922ba568a66b0"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><ul id="EN-US_TOPIC_0000001764491904__ub96bcca4d68146328088e167570146f8"><li id="EN-US_TOPIC_0000001764491904__l3f55546ee61b470bb7ee9d3e7d4e7287">If the OS does not support the <strong id="EN-US_TOPIC_0000001764491904__b84235270620334">TCP_KEEPCNT</strong> parameter, set this parameter to <strong id="EN-US_TOPIC_0000001764491904__b65501211315">0</strong>.</li><li id="EN-US_TOPIC_0000001764491904__la70f542ac82a4d74bbbf3305d868bde2">The parameter is ignored on the OS where connections are established using the Unix domain socket.</li></ul>
</div></div>
<p id="EN-US_TOPIC_0000001764491904__a2795dcf6a7a54a14b3592cb15625fe85"><strong id="EN-US_TOPIC_0000001764491904__b128153115715">Value range</strong>: an integer ranging from 0 to 100. <strong id="EN-US_TOPIC_0000001764491904__b1982011371">0</strong> indicates that the connection is immediately broken if <span id="EN-US_TOPIC_0000001764491904__text715441455">GaussDB(DWS)</span> does not receive a keepalived signal from the client.</p>
<p id="EN-US_TOPIC_0000001764491904__a728f43c74a86408789b71eeeb1592abd"><strong id="EN-US_TOPIC_0000001764491904__b103241288719">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b19324181678">0</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__s0011acc521b848fe85b25a68f534dc73"><a name="EN-US_TOPIC_0000001764491904__s0011acc521b848fe85b25a68f534dc73"></a><a name="s0011acc521b848fe85b25a68f534dc73"></a><h4 class="sectiontitle">comm_max_datanode</h4><p id="EN-US_TOPIC_0000001764491904__aaa6dd1c9c3d8452b8edd21d8d803e21e"><strong id="EN-US_TOPIC_0000001764491904__b1612595103818">Parameter description</strong>: Specifies the maximum number of DNs supported by the communication library.</p>
<p id="EN-US_TOPIC_0000001764491904__p128352383717"><strong id="EN-US_TOPIC_0000001764491904__b1587874604">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__a8b81a0eaedf04156b377e670b33f1e6d"><strong id="EN-US_TOPIC_0000001764491904__b1755519300498">Value range</strong>: an integer ranging from 1 to 8192</p>
<p id="EN-US_TOPIC_0000001764491904__a48448b884a784234b18b4bb0f23db73e"><strong id="EN-US_TOPIC_0000001764491904__b49081319145711">Default value</strong>: actual number of DNs</p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__note959519271220"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__p259517276227">Increasing this parameter value takes effect immediately, while decreasing the value takes effect after the cluster is restarted.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__s9ef3426b35d140bb934db112acc751f2"><h4 class="sectiontitle">comm_max_stream</h4><p id="EN-US_TOPIC_0000001764491904__a5ad0de68b57d4501a63e559a75f1e58b"><strong id="EN-US_TOPIC_0000001764491904__b1973111532519">Parameter description</strong>: maximum number of logical connection data structures cached in the communication library.</p>
<p id="EN-US_TOPIC_0000001764491904__p15342512133615"><strong id="EN-US_TOPIC_0000001764491904__b10541175202514">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001764491904__a90a9143d554441ce8d8e372938b11cf5"><strong id="EN-US_TOPIC_0000001764491904__b13362202192616">Value range</strong>: an integer ranging from 1 to 65535</p>
<p id="EN-US_TOPIC_0000001764491904__a4d3e94d57fc54323af104ca7b77c0f50"><strong id="EN-US_TOPIC_0000001764491904__b1592999814101810">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b1392946365101810">1024</strong></p>
<div class="note" id="EN-US_TOPIC_0000001764491904__note9292114813213"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001764491904__p71089465274">If the value of <a href="#EN-US_TOPIC_0000001764491904__s0011acc521b848fe85b25a68f534dc73">comm_max_datanode</a> is small, the process memory is sufficient. In this case, you can increase the value of <strong id="EN-US_TOPIC_0000001764491904__b8536836102718">comm_max_stream</strong>.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section16782547103210"><h4 class="sectiontitle">max_stream_pool</h4><p id="EN-US_TOPIC_0000001764491904__p478244703217"><strong id="EN-US_TOPIC_0000001764491904__b443001915411">Parameter description</strong>: Specifies the maximum number of stream threads that can be contained in a stream thread pool. This feature is supported in 8.1.2 or later.</p>
<p id="EN-US_TOPIC_0000001764491904__p1078212479322"><strong id="EN-US_TOPIC_0000001764491904__b349084420270">Type</strong>: SUSET</p>
<p id="EN-US_TOPIC_0000001764491904__p3782104718323"><strong id="EN-US_TOPIC_0000001764491904__b8008013441744">Value range</strong>: an integer ranging from 1 to INT_MAX. The values <strong id="EN-US_TOPIC_0000001764491904__b42985461141744">1</strong> and<strong id="EN-US_TOPIC_0000001764491904__b146992526341744"> 0</strong> indicate that the stream thread pool is disabled.</p>
<p id="EN-US_TOPIC_0000001764491904__p1478244714324"><strong id="EN-US_TOPIC_0000001764491904__b10231151891010">Default value</strong>:</p>
<ul id="EN-US_TOPIC_0000001764491904__ul1917120481279"><li id="EN-US_TOPIC_0000001764491904__li1817174832719">The formula for a new cluster is <strong id="EN-US_TOPIC_0000001764491904__b4930172691018">max_stream_pool=MIN(max_connections, max_process_memory/16/5MB, 1024)</strong>.</li><li id="EN-US_TOPIC_0000001764491904__li6171184832718">The formula for a cluster upgraded from versions earlier than is <strong id="EN-US_TOPIC_0000001764491904__b632832523917">max_stream_pool = MIN(max_connections, max_process_memory/16/5MB, 1024, value of the old cluster)</strong>. During the upgrade, the settings for the new cluster are forcibly used. The old value is used if it is smaller.</li></ul>
<div class="note" id="EN-US_TOPIC_0000001764491904__note1278284733213"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="EN-US_TOPIC_0000001764491904__ul17823473324"><li id="EN-US_TOPIC_0000001764491904__li4782184773212">The number of stream threads in a thread pool can be reduced in real time. If the value of this parameter is increased, the number of stream threads is increased to meet the service requirements.</li><li id="EN-US_TOPIC_0000001764491904__li478234753219">Generally, you are advised not to change the value of this parameter because the stream thread pool supports the automatic cleanup function.</li><li id="EN-US_TOPIC_0000001764491904__li29035251717">If too many idle stream threads occupy the memory, you can decrease the value of this parameter to save the memory.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section1254316303485"><h4 class="sectiontitle">enable_stream_sync_quit</h4><p id="EN-US_TOPIC_0000001764491904__p181325524489"><strong id="EN-US_TOPIC_0000001764491904__b139671250172715">Parameter description</strong>: whether the stream threads exit synchronously when the stream plan ends. This parameter is supported only by clusters of version 8.3.0 or later.</p>
<p id="EN-US_TOPIC_0000001764491904__p1813317521483"><strong id="EN-US_TOPIC_0000001764491904__b482566801">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p11135724195118"><strong id="EN-US_TOPIC_0000001764491904__b1213515242518">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001764491904__ul19135142417518"><li id="EN-US_TOPIC_0000001764491904__li81353243519"><strong id="EN-US_TOPIC_0000001764491904__b618253652818">on</strong> indicates that threads in the stream thread group exit after the stream plan ends.</li><li id="EN-US_TOPIC_0000001764491904__li928510218547"><strong id="EN-US_TOPIC_0000001764491904__b102931227297">off</strong> indicates that stream threads exit directly after the stream plan ends without waiting for the threads in the stream thread group to exit.</li></ul>
<p id="EN-US_TOPIC_0000001764491904__p11875181615418"><strong id="EN-US_TOPIC_0000001764491904__b1932085025103727">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b2132507122103727">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section15387165451117"><h4 class="sectiontitle">enable_connect_standby</h4><p id="EN-US_TOPIC_0000001764491904__p13387115471115"><strong id="EN-US_TOPIC_0000001764491904__b611785774911">Parameter description</strong>: Sets the connection between a CN and a standby DN. This parameter is supported only by clusters of version 8.3.0 or later.</p>
<p id="EN-US_TOPIC_0000001764491904__p11387135471112"><strong id="EN-US_TOPIC_0000001764491904__b741985567">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p1387754151116"><strong id="EN-US_TOPIC_0000001764491904__b1238720542118">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001764491904__ul93871654101114"><li id="EN-US_TOPIC_0000001764491904__li03871354191113"><strong id="EN-US_TOPIC_0000001764491904__b1588081113509">on</strong> indicates that the CN connects to the standby server.</li><li id="EN-US_TOPIC_0000001764491904__li13871454181120"><strong id="EN-US_TOPIC_0000001764491904__b8790824185018">off</strong> indicates that the CN connects to the primary DN.</li></ul>
<p id="EN-US_TOPIC_0000001764491904__p123874549113"><strong id="EN-US_TOPIC_0000001764491904__b855689544">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b126013487">off</strong></p>
<div class="caution" id="EN-US_TOPIC_0000001764491904__note099874510321"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><ul id="EN-US_TOPIC_0000001764491904__ul137905593320"><li id="EN-US_TOPIC_0000001764491904__li1279013503313">You are not advised to use this parameter in routine services. This parameter applies only to O&amp;M operations. You are not advised to use the <strong id="EN-US_TOPIC_0000001764491904__b1806154210501">gs_guc tool</strong> for global settings. Otherwise, problems such as data inconsistency and result set errors may occur.</li><li id="EN-US_TOPIC_0000001764491904__li57903583317">Enabling this parameter for a session with temporary tables will delete the temporary table data on DNs and prevent further actions on those tables.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__s34f28849693d456e8dbf8c8147301012"><h4 class="sectiontitle">comm_quota_size</h4><p id="EN-US_TOPIC_0000001764491904__adfd6547d569040fcac9e7bd8a793a384"><strong id="EN-US_TOPIC_0000001764491904__b15527545123816">Parameter description</strong>: Specifies the maximum size of packets that can be continuously sent by the communication library. When you use a 1GE NIC, a small value ranging from 20 KB to 40 KB is recommended.</p>
<p id="EN-US_TOPIC_0000001764491904__p18740205493511"><strong id="EN-US_TOPIC_0000001764491904__b3637174524517">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__ab2d345b5f8364a629db6aa8e973709dd"><strong id="EN-US_TOPIC_0000001764491904__b8806105145011">Value range</strong>: an integer ranging from 0 to 102400. The default unit is KB. The value <strong id="EN-US_TOPIC_0000001764491904__b88051142123015">0</strong> indicates that the quota mechanism is not used.</p>
<p id="EN-US_TOPIC_0000001764491904__aa2e4fdd7351b4393a8bb992da80d5ac7"><strong id="EN-US_TOPIC_0000001764491904__b18024168155138">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b842352706193057">1 MB</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__sfade85f464b14ac4bbb0b00be030fcbc"><h4 class="sectiontitle">comm_usable_memory</h4><p id="EN-US_TOPIC_0000001764491904__aba077b0b16da47cfb17ab42117db4134"><strong id="EN-US_TOPIC_0000001764491904__b186081716132410">Parameter description</strong>: Specifies the maximum memory that can be used by the communication library cache on a single DN.</p>
<p id="EN-US_TOPIC_0000001764491904__p432324073520"><strong id="EN-US_TOPIC_0000001764491904__b113108246241">Type</strong>: SIGHUP</p>
<p id="EN-US_TOPIC_0000001764491904__a52ca0dee530345ba918c5ddc9e1f24ab"><strong id="EN-US_TOPIC_0000001764491904__b1989824165010">Value range</strong>: an integer ranging from 1 to 256. The default unit is KB. The minimum size cannot be less than 1 GB for installation.</p>
<p id="EN-US_TOPIC_0000001764491904__ae7b9eb996c454e0d83bddb26e4832757"><strong id="EN-US_TOPIC_0000001764491904__b1150535513262">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b2505755192617">max_process_memory/8</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__n746da6d206ec4140b4d31a1be91bd1db"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__a3c346c852a1b42418faa1038327c7517">This parameter must be specifically set based on environment memory and the deployment method. If it is too large, out-of-memory (OOM) may occur. If it is too small, the performance of the communication library may deteriorate.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section10300238238"><h4 class="sectiontitle">comm_client_bind</h4><p id="EN-US_TOPIC_0000001764491904__p1544414596245"><strong id="EN-US_TOPIC_0000001764491904__b48192534313">Parameter description</strong>: Specifies whether to bind the client of the communication library to a specified IP address when the client initiates a connection.</p>
<p id="EN-US_TOPIC_0000001764491904__p62323703711"><strong id="EN-US_TOPIC_0000001764491904__b10156346104512">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p18449205913245"><strong id="EN-US_TOPIC_0000001764491904__b1866430132015">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001764491904__ul147110332071"><li id="EN-US_TOPIC_0000001764491904__li146063918717"><strong id="EN-US_TOPIC_0000001764491904__b842352706193036">on</strong> indicates that the client is bound to a specified IP address.</li><li id="EN-US_TOPIC_0000001764491904__li347243319716"><strong id="EN-US_TOPIC_0000001764491904__b201625407519323">off</strong> indicates that the client is not bound to any IP addresses.</li></ul>
<div class="notice" id="EN-US_TOPIC_0000001764491904__note847772834"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__p1847792034">If multiple IP addresses of a node in a cluster are on the same communication network segment, set this parameter to <strong id="EN-US_TOPIC_0000001764491904__b842352706193332">on</strong>. In this case, the client is bound to the IP address specified by <strong id="EN-US_TOPIC_0000001764491904__b842352706193526">listen_addresses</strong>. The concurrency performance of a cluster depends on the number of random ports because a port can be used only by one client at a time.</p>
</div></div>
<p id="EN-US_TOPIC_0000001764491904__p19456738194415"><strong id="EN-US_TOPIC_0000001764491904__b55233292105553">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b842352706172155">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section1371661611123"><h4 class="sectiontitle">comm_no_delay</h4><p id="EN-US_TOPIC_0000001764491904__p594213561126"><strong id="EN-US_TOPIC_0000001764491904__b8423527061609">Parameter description</strong>: Specifies whether to use the <strong id="EN-US_TOPIC_0000001764491904__b84235270616035">NO_DELAY</strong> attribute of the communication library connection. Restart the cluster for the setting to take effect.</p>
<p id="EN-US_TOPIC_0000001764491904__p9343161713515"><strong id="EN-US_TOPIC_0000001764491904__b1331594664519">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p56607432091"><strong id="EN-US_TOPIC_0000001764491904__b149320222010">Value range</strong>: Boolean</p>
<p id="EN-US_TOPIC_0000001764491904__p573061612123"><strong id="EN-US_TOPIC_0000001764491904__b1912974503">Default value:</strong> <strong id="EN-US_TOPIC_0000001764491904__b1613345808">off</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__note272911610123"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__p87292016151210">If packet loss occurs because a large number of packets are received per second, set this parameter to <strong id="EN-US_TOPIC_0000001764491904__b8423527061611">off</strong> to reduce the total number of packets.</p>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__sb8def77414ca46c19425b8b6365ab8e9"><h4 class="sectiontitle">comm_debug_mode</h4><p id="EN-US_TOPIC_0000001764491904__a3452b6b3223a412aba23244d00af1d65"><strong id="EN-US_TOPIC_0000001764491904__b122324715554">Parameter description</strong>: Specifies the debug mode of the communication library, that is, whether to print logs about the communication layer. The setting is effective at the session layer.</p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__n53cba812328a4483bad9bc2f0989c718"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__a356b2c184530422ea3a5ea708e345832">When the switch is set to <strong id="EN-US_TOPIC_0000001764491904__b84235270692827">on</strong>, the number of printed logs is huge, adding extra overhead and reducing database performance. Therefore, set the switch to <strong id="EN-US_TOPIC_0000001764491904__b84235270692943">on</strong> only in the debug mode.</p>
</div></div>
<p id="EN-US_TOPIC_0000001764491904__p133891517379"><strong id="EN-US_TOPIC_0000001764491904__b348594614457">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__adddaf195065044acba5256d4e701e262"><strong id="EN-US_TOPIC_0000001764491904__b166751153207">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001764491904__u18af3bbd2e3a45d39a5b18224fae0024"><li id="EN-US_TOPIC_0000001764491904__le92023613a724909941e72f8529e3360"><strong id="EN-US_TOPIC_0000001764491904__b842352706204212">on</strong> indicates the detailed debug log of the communication library is printed.</li><li id="EN-US_TOPIC_0000001764491904__lefa74aa46f5c466b9c26c206ef928c9e"><strong id="EN-US_TOPIC_0000001764491904__b751002536">off</strong> indicates the detailed debug log of the communication library is not printed.</li></ul>
<p id="EN-US_TOPIC_0000001764491904__af2013f97c9294f2597431886a67b8a24"><strong id="EN-US_TOPIC_0000001764491904__b1513318424">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b1814710380">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section1480831194112"><h4 class="sectiontitle">comm_ackchk_time</h4><p id="EN-US_TOPIC_0000001764491904__p10567191642812"><strong id="EN-US_TOPIC_0000001764491904__b106620241367">Parameter description</strong>: Specifies the duration after which the communication library server automatically triggers ACK when no data package is received.</p>
<p id="EN-US_TOPIC_0000001764491904__p7342108163510"><strong id="EN-US_TOPIC_0000001764491904__b1775822519515">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p175431345143219"><strong id="EN-US_TOPIC_0000001764491904__b7142132815113">Value range</strong>: an integer ranging from 0 to 20000. The unit is millisecond (ms). <strong id="EN-US_TOPIC_0000001764491904__b1085616280360">0</strong> indicates that automatic ACK triggering is disabled.</p>
<p id="EN-US_TOPIC_0000001764491904__p1756819164283"><strong id="EN-US_TOPIC_0000001764491904__b3187133014368">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b1318753053620">2000</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__s01da04f06f5143a691139b5908bfc29c"><h4 class="sectiontitle">comm_timer_mode</h4><p id="EN-US_TOPIC_0000001764491904__aa67a5fde2c5b44b89098c5683e732420"><strong id="EN-US_TOPIC_0000001764491904__b946110148568">Parameter description</strong>: Specifies the timer mode of the communication library, that is, whether to print timer logs in each phase of the communication layer. The setting is effective at the session layer.</p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__nee2097280bf245c19bcf07d4038f8bae"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__a950e88c4a2144128a63246a66e4ba2e7">When the switch is set to <strong id="EN-US_TOPIC_0000001764491904__b24902681">on</strong>, the number of printed logs is huge, adding extra overhead and reducing database performance. Therefore, set the switch to <strong id="EN-US_TOPIC_0000001764491904__b664914136">on</strong> only in the debug mode.</p>
</div></div>
<p id="EN-US_TOPIC_0000001764491904__p1885117216380"><strong id="EN-US_TOPIC_0000001764491904__b12833114634512">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__a156f80a602644998b77519f80e9d5bce"><strong id="EN-US_TOPIC_0000001764491904__b184937142016">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001764491904__u856013d6cff54d6192eb7fc423c8a961"><li id="EN-US_TOPIC_0000001764491904__lff68006519304e50b65c7067871b8eaa"><strong id="EN-US_TOPIC_0000001764491904__b1826794721">on</strong> indicates the detailed timer log of the communication library is printed.</li><li id="EN-US_TOPIC_0000001764491904__l1d659c4078ca474d8471b80cf6bd5e3b"><strong id="EN-US_TOPIC_0000001764491904__b679247701">off</strong> indicates the detailed timer log of the communication library is not printed.</li></ul>
<p id="EN-US_TOPIC_0000001764491904__ae15d67595cc846409c79e4c337a01b82"><strong id="EN-US_TOPIC_0000001764491904__b428541327">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b1224258519">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__sfb69d5c3242545fc87c5c68eea685a61"><h4 class="sectiontitle">comm_stat_mode</h4><p id="EN-US_TOPIC_0000001764491904__a53bd5ffbd6a0426095f38c3f8802dfe9"><strong id="EN-US_TOPIC_0000001764491904__b1299105153715">Parameter description</strong>: Specifies the stat mode of the communication library, that is, whether to print statistics about the communication layer. The setting is effective at the session layer.</p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__n3ca15f09cf374036961b7b2d4996f592"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__a5e09dbe0889a4553bc71b5ada4b98737">When the switch is set to <strong id="EN-US_TOPIC_0000001764491904__b447281105">on</strong>, the number of printed logs is huge, adding extra overhead and reducing database performance. Therefore, set the switch to <strong id="EN-US_TOPIC_0000001764491904__b971325164">on</strong> only in the debug mode.</p>
</div></div>
<p id="EN-US_TOPIC_0000001764491904__p12398211133810"><strong id="EN-US_TOPIC_0000001764491904__b11997134674517">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__a699860714a37485b8637987ed3fed0dc"><strong id="EN-US_TOPIC_0000001764491904__b1676517819203">Value range</strong>: Boolean</p>
<ul id="EN-US_TOPIC_0000001764491904__u99067cb9b5364f94b895a19be98b0a08"><li id="EN-US_TOPIC_0000001764491904__l4b7e3f02a2b44fc8b27f358a038eb9c3"><strong id="EN-US_TOPIC_0000001764491904__b1674105588">on</strong> indicates the statistics log of the communication library is printed.</li><li id="EN-US_TOPIC_0000001764491904__ld15fbab485f442ecaff0fbe5cd0b9854"><strong id="EN-US_TOPIC_0000001764491904__b434615572">off</strong> indicates the statistics log of the communication library is not printed.</li></ul>
<p id="EN-US_TOPIC_0000001764491904__a5ac642a79f734413b4438e692f20517f"><strong id="EN-US_TOPIC_0000001764491904__b1407794067">Default value:</strong> <strong id="EN-US_TOPIC_0000001764491904__b1788020107">off</strong></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section253573278"><h4 class="sectiontitle">client_connection_check_interval</h4><p id="EN-US_TOPIC_0000001764491904__p175157152712"><strong id="EN-US_TOPIC_0000001764491904__b129681733203819">Parameter description</strong>: Specifies the interval for checking the client connection status. This parameter is supported by clusters of version 8.2.0 or later.</p>
<p id="EN-US_TOPIC_0000001764491904__p356574277"><strong id="EN-US_TOPIC_0000001764491904__b531930086">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p14512572277"><strong id="EN-US_TOPIC_0000001764491904__b7565712711">Value range</strong>: an integer ranging from 0 to INT_MAX. The unit is ms. The value <strong id="EN-US_TOPIC_0000001764491904__b253876598101810">0</strong> indicates that the client connection status is not checked.</p>
<p id="EN-US_TOPIC_0000001764491904__p35165715273"><strong id="EN-US_TOPIC_0000001764491904__b5385444743057">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b107069971143057">10000</strong></p>
<div class="notice" id="EN-US_TOPIC_0000001764491904__note19619573275"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="EN-US_TOPIC_0000001764491904__p3457312123810">During a long query executed in a session where a client (such as gsql, JDBC, or ODBC) directly connects to the CN,</p>
<ul id="EN-US_TOPIC_0000001764491904__ul438803495712"><li id="EN-US_TOPIC_0000001764491904__li16389734165712">The CN checks the client connection status at the interval specified by <strong id="EN-US_TOPIC_0000001764491904__b61511625184020">client_connection_check_interval</strong>. If it detects that the client has been disconnected from the CN, the server terminates the long query and releases related resources to avoid waste of cluster resources.</li><li id="EN-US_TOPIC_0000001764491904__li17174164855717">The DN checks its connection to the CN at the interval specified by <strong id="EN-US_TOPIC_0000001764491904__b023435134010">client_connection_check_interval</strong>. If the DN detects that it has been disconnected from the CN, it terminates the long query and releases related resources to avoid waste of cluster resources.</li></ul>
</div></div>
</div>
<div class="section" id="EN-US_TOPIC_0000001764491904__section174841243195210"><h4 class="sectiontitle">conn_recycle_timeout</h4><p id="EN-US_TOPIC_0000001764491904__p164217301000"><strong id="EN-US_TOPIC_0000001764491904__b562824815369">Parameter description</strong>: the interval for reclaiming idle connections between a CN and other nodes to the connection pool. This parameter is supported only by clusters of version 8.2.1 or later.</p>
<p id="EN-US_TOPIC_0000001764491904__p1986753945615"><strong id="EN-US_TOPIC_0000001764491904__b787642567">Type</strong>: USERSET</p>
<p id="EN-US_TOPIC_0000001764491904__p37601746185112"><strong id="EN-US_TOPIC_0000001764491904__b1926053393714">Value range</strong>: an integer ranging from 0 to 3600, in second (s). <strong id="EN-US_TOPIC_0000001764491904__b144887123382">0</strong> indicates that the function of reclaiming idle connections is disabled.</p>
<p id="EN-US_TOPIC_0000001764491904__p11760114605119"><strong id="EN-US_TOPIC_0000001764491904__b988570969101810">Default value</strong>: <strong id="EN-US_TOPIC_0000001764491904__b605442527101810">30</strong></p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0888.html">Connection and Authentication</a></div>
</div>
</div>