forked from docs/doc-exports
Lu, Huayi
a24ca60074
Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com> Co-authored-by: Lu, Huayi <luhuayi@huawei.com> Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
22 lines
4.1 KiB
HTML
22 lines
4.1 KiB
HTML
<a name="EN-US_TOPIC_0000001100991256"></a><a name="EN-US_TOPIC_0000001100991256"></a>
|
|
|
|
|
|
<h1 class="topictitle1">Suggestions for SMP Parameter Settings</h1>
|
|
|
|
<div id="body0000001100991256"><p id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_p8060118">Starting from this version, SMP auto adaptation is enabled. For newly deployed clusters, the default value of <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b1287017219010">query_dop</strong> is <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b178762211012">0</strong>, and SMP parameters have been adjusted. To ensure forward compatibility, the value of <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b2490194511566">query_dop</strong> should remain unchanged after an existing cluster is upgraded.</p>
|
|
<p id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_p144261042145911">For an upgraded cluster, if you want to set <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b18307916596">query_dop</strong> to <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b1794716317594">0</strong> and enable SMP parallel processing, modify the following parameters to obtain better dop options:</p>
|
|
<ul id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_ul540441719011"><li id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_li19404617605">comm_usable_memory<p id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_p1678013529291"><a name="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_li19404617605"></a><a name="en-us_topic_0000001145694501_li19404617605"></a>If the system memory is large, the value of <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b162457131659">max_process_memory</strong> is large. In this case, you are advised to set the value of this parameter to 5% of <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b16777200962">max_process_memory</strong>, that is, 4 GB by default.</p>
|
|
</li><li id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_li9550424709">comm_max_stream<p id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_p884213531438"><a name="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_li9550424709"></a><a name="en-us_topic_0000001145694501_li9550424709"></a>The recommended value for this parameter is calculated as follows: comm_max_stream = Min(dop_limit x dop_limit x 20 x 2, max_process_memory (bytes) x 0.025/Number of DNs/260). The value must be within the value range of <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b731329171419">comm_max_stream</strong>.</p>
|
|
</li><li id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_li349920291409">max_connections<p id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_p286713341669"><a name="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_li349920291409"></a><a name="en-us_topic_0000001145694501_li349920291409"></a>The recommended value for this parameter is calculated as follows: max_connections = dop_limit x 20 x 6 + 24. The value must be within the value range of <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b4705121771819">max_connections</strong>.</p>
|
|
<div class="caution" id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_note99110550251"><span class="cautiontitle"><img src="public_sys-resources/caution_3.0-en-us.png"> </span><div class="cautionbody"><p id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_p59111555202514">In the preceding formulas, <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b7979546121820">dop_limit</strong> indicates the number of CPUs corresponding to each DN in the cluster. It is calculated as follows: <strong id="EN-US_TOPIC_0000001100991256__en-us_topic_0000001145694501_b2657181716191">dop_limit</strong> = Number of logical CPU cores of a single server/Number of DNs of a single server.</p>
|
|
</div></div>
|
|
</li></ul>
|
|
</div>
|
|
|
|
<div>
|
|
<div class="familylinks">
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0468.html">Configuring the SMP</a></div>
|
|
</div>
|
|
</div>
|
|
|