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            <title><![CDATA[Kylin V10 SP3 auditd 无法启动问题解决]]></title>
            <link>https://www.msezi.com/article/272e730e-da16-804d-aaae-ce7327bafa79</link>
            <guid>https://www.msezi.com/article/272e730e-da16-804d-aaae-ce7327bafa79</guid>
            <pubDate>Thu, 18 Sep 2025 00:00:00 GMT</pubDate>
            <description><![CDATA[Kylin V10 SP3 auditd 无法启动问题解决]]></description>
            <content:encoded><![CDATA[<div id="notion-article" class="mx-auto overflow-hidden "><main class="notion light-mode notion-page notion-block-272e730eda16804daaaece7327bafa79"><div class="notion-viewport"></div><div class="notion-collection-page-properties"></div><h2 class="notion-h notion-h1 notion-h-indent-0 notion-block-272e730eda16808faea7e47c0ff492fa" data-id="272e730eda16808faea7e47c0ff492fa"><span><div id="272e730eda16808faea7e47c0ff492fa" class="notion-header-anchor"></div><a class="notion-hash-link" href="#272e730eda16808faea7e47c0ff492fa" title="Kylin V10 SP3 auditd 无法启动问题解决"><svg viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M7.775 3.275a.75.75 0 001.06 1.06l1.25-1.25a2 2 0 112.83 2.83l-2.5 2.5a2 2 0 01-2.83 0 .75.75 0 00-1.06 1.06 3.5 3.5 0 004.95 0l2.5-2.5a3.5 3.5 0 00-4.95-4.95l-1.25 1.25zm-4.69 9.64a2 2 0 010-2.83l2.5-2.5a2 2 0 012.83 0 .75.75 0 001.06-1.06 3.5 3.5 0 00-4.95 0l-2.5 2.5a3.5 3.5 0 004.95 4.95l1.25-1.25a.75.75 0 00-1.06-1.06l-1.25 1.25a2 2 0 01-2.83 0z"></path></svg></a><span class="notion-h-title">Kylin V10 SP3 auditd 无法启动问题解决</span></span></h2><h3 class="notion-h notion-h2 notion-h-indent-1 notion-block-272e730eda16807cb25fe8de02dda25c" data-id="272e730eda16807cb25fe8de02dda25c"><span><div id="272e730eda16807cb25fe8de02dda25c" class="notion-header-anchor"></div><a class="notion-hash-link" href="#272e730eda16807cb25fe8de02dda25c" title="问题发现"><svg viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M7.775 3.275a.75.75 0 001.06 1.06l1.25-1.25a2 2 0 112.83 2.83l-2.5 2.5a2 2 0 01-2.83 0 .75.75 0 00-1.06 1.06 3.5 3.5 0 004.95 0l2.5-2.5a3.5 3.5 0 00-4.95-4.95l-1.25 1.25zm-4.69 9.64a2 2 0 010-2.83l2.5-2.5a2 2 0 012.83 0 .75.75 0 001.06-1.06 3.5 3.5 0 00-4.95 0l-2.5 2.5a3.5 3.5 0 004.95 4.95l1.25-1.25a.75.75 0 00-1.06-1.06l-1.25 1.25a2 2 0 01-2.83 0z"></path></svg></a><span class="notion-h-title">问题发现</span></span></h3><div class="notion-text notion-block-272e730eda1680d49a68f635c0c1360f">通过systemctl status auditd.service查看audit服务，未正常运行，重启也无法启动。</div><div class="notion-text notion-block-272e730eda168074b5cecdb2f2125c27">并报错：Condition check resulted in securityAuditing Service being skipped</div><h3 class="notion-h notion-h2 notion-h-indent-1 notion-block-272e730eda1680e48fb6ffc4be9ad0a8" data-id="272e730eda1680e48fb6ffc4be9ad0a8"><span><div id="272e730eda1680e48fb6ffc4be9ad0a8" class="notion-header-anchor"></div><a class="notion-hash-link" href="#272e730eda1680e48fb6ffc4be9ad0a8" title="原因分析"><svg viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M7.775 3.275a.75.75 0 001.06 1.06l1.25-1.25a2 2 0 112.83 2.83l-2.5 2.5a2 2 0 01-2.83 0 .75.75 0 00-1.06 1.06 3.5 3.5 0 004.95 0l2.5-2.5a3.5 3.5 0 00-4.95-4.95l-1.25 1.25zm-4.69 9.64a2 2 0 010-2.83l2.5-2.5a2 2 0 012.83 0 .75.75 0 001.06-1.06 3.5 3.5 0 00-4.95 0l-2.5 2.5a3.5 3.5 0 004.95 4.95l1.25-1.25a.75.75 0 00-1.06-1.06l-1.25 1.25a2 2 0 01-2.83 0z"></path></svg></a><span class="notion-h-title">原因分析</span></span></h3><div class="notion-text notion-block-272e730eda1680838139d35130aaddf5">由于系统内核未开启审计功能导致，官方解释为容易产生较多数据造成磁盘不足引起，系统崩溃，不建议启用。</div><div class="notion-text notion-block-272e730eda1680798112f0703c15dc75">有兴趣可以自行查看：<a class="notion-link" href="https://kb.kylinos.cn/qywx/zsk_view_kb/view/faq/8853" target="_blank" rel="noopener noreferrer">https://kb.kylinos.cn/qywx/zsk_view_kb/view/faq/8853</a></div><h3 class="notion-h notion-h2 notion-h-indent-1 notion-block-272e730eda16803b813bfaba2226e152" data-id="272e730eda16803b813bfaba2226e152"><span><div id="272e730eda16803b813bfaba2226e152" class="notion-header-anchor"></div><a class="notion-hash-link" href="#272e730eda16803b813bfaba2226e152" title="解决办法"><svg viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M7.775 3.275a.75.75 0 001.06 1.06l1.25-1.25a2 2 0 112.83 2.83l-2.5 2.5a2 2 0 01-2.83 0 .75.75 0 00-1.06 1.06 3.5 3.5 0 004.95 0l2.5-2.5a3.5 3.5 0 00-4.95-4.95l-1.25 1.25zm-4.69 9.64a2 2 0 010-2.83l2.5-2.5a2 2 0 012.83 0 .75.75 0 001.06-1.06 3.5 3.5 0 00-4.95 0l-2.5 2.5a3.5 3.5 0 004.95 4.95l1.25-1.25a.75.75 0 00-1.06-1.06l-1.25 1.25a2 2 0 01-2.83 0z"></path></svg></a><span class="notion-h-title">解决办法</span></span></h3><div class="notion-text notion-block-272e730eda168088a991f0a697b48229">手动修改内核参数，启用audit审计功能。</div><h3 class="notion-h notion-h2 notion-h-indent-1 notion-block-272e730eda16802f87c1fda5f03096c1" data-id="272e730eda16802f87c1fda5f03096c1"><span><div id="272e730eda16802f87c1fda5f03096c1" class="notion-header-anchor"></div><a class="notion-hash-link" href="#272e730eda16802f87c1fda5f03096c1" title="解决步骤"><svg viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M7.775 3.275a.75.75 0 001.06 1.06l1.25-1.25a2 2 0 112.83 2.83l-2.5 2.5a2 2 0 01-2.83 0 .75.75 0 00-1.06 1.06 3.5 3.5 0 004.95 0l2.5-2.5a3.5 3.5 0 00-4.95-4.95l-1.25 1.25zm-4.69 9.64a2 2 0 010-2.83l2.5-2.5a2 2 0 012.83 0 .75.75 0 001.06-1.06 3.5 3.5 0 00-4.95 0l-2.5 2.5a3.5 3.5 0 004.95 4.95l1.25-1.25a.75.75 0 00-1.06-1.06l-1.25 1.25a2 2 0 01-2.83 0z"></path></svg></a><span class="notion-h-title">解决步骤</span></span></h3><div class="notion-text notion-block-272e730eda168003ac98c601d83690c4">三个步骤就可以走完。</div><div class="notion-text notion-block-272e730eda1680639c51c342f0150701">1、在/etc/default/grub中启用</div><div class="notion-text notion-block-272e730eda168016bd5ce5151e13077d">2、更新grub配置</div><div class="notion-text notion-block-272e730eda16801a9af6f4966a153f60">3、修改内核后重启</div><div class="notion-callout notion-gray_background_co notion-block-272e730eda1680999d42e5fdf2bcbf62"><div class="notion-page-icon-inline notion-page-icon-span"><span class="notion-page-icon" role="img" aria-label="💡">💡</span></div><div class="notion-callout-text">有关Notion安装或者使用上的问题，欢迎您在底部评论区留言，一起交流~</div></div></main></div>]]></content:encoded>
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            <title><![CDATA[Navicat数据库软件免费了！推出Navicat Premium Lite]]></title>
            <link>https://www.msezi.com/article/49bfee34-14d9-4a2a-b99e-dda0125dbec6</link>
            <guid>https://www.msezi.com/article/49bfee34-14d9-4a2a-b99e-dda0125dbec6</guid>
            <pubDate>Fri, 28 Jun 2024 00:00:00 GMT</pubDate>
            <description><![CDATA[Navicat数据库软件免费了！推出Navicat Premium Lite]]></description>
            <content:encoded><![CDATA[<div id="notion-article" class="mx-auto overflow-hidden "><main class="notion light-mode notion-page notion-block-49bfee3414d94a2ab99edda0125dbec6"><div class="notion-viewport"></div><div class="notion-collection-page-properties"></div><h2 class="notion-h notion-h1 notion-h-indent-0 notion-block-76815c88368a4655b23b824c23cdea3e" data-id="76815c88368a4655b23b824c23cdea3e"><span><div id="76815c88368a4655b23b824c23cdea3e" class="notion-header-anchor"></div><a class="notion-hash-link" href="#76815c88368a4655b23b824c23cdea3e" title="Navicat数据库软件免费了！推出Navicat Premium Lite"><svg viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M7.775 3.275a.75.75 0 001.06 1.06l1.25-1.25a2 2 0 112.83 2.83l-2.5 2.5a2 2 0 01-2.83 0 .75.75 0 00-1.06 1.06 3.5 3.5 0 004.95 0l2.5-2.5a3.5 3.5 0 00-4.95-4.95l-1.25 1.25zm-4.69 9.64a2 2 0 010-2.83l2.5-2.5a2 2 0 012.83 0 .75.75 0 001.06-1.06 3.5 3.5 0 00-4.95 0l-2.5 2.5a3.5 3.5 0 004.95 4.95l1.25-1.25a.75.75 0 00-1.06-1.06l-1.25 1.25a2 2 0 01-2.83 0z"></path></svg></a><span class="notion-h-title">Navicat数据库软件免费了！推出Navicat Premium Lite</span></span></h2><div class="notion-text notion-block-4a360033e43b428cb9393bd772d5462f">2024年6月26日，数据库管理工具领域的知名品牌Navicat，推出其免费版本——Navicat Premium Lite，用户可从Navicat官网下载体验这款软件。</div><div class="notion-text notion-block-1dcea13742d641149a16bc87c6aa7922">这款针对入门级用户的数据库管理开发工具，支持基础的数据库管理和协同合作功能，是Navicat Premium的精简版，同时继承了其强大的数据库连接和管理能力。</div><div class="notion-text notion-block-01cb1580db904341a486d738ffd10133">Navicat Premium Lite支持创建连接多种数据库，包括MySQL、Redis、PostgreSQL、SQL Server、Oracle、MariaDB、SQLite 和 MongoDB，覆盖了当前市场上主流的数据库平台，对于个人用户来说完全足够了。</div><div class="notion-text notion-block-cf1ab052c60744b69e0de7282dd7a3be">英文官网下载地址：<a class="notion-link" href="https://www.navicat.com/en/download/navicat-premium-lite" target="_blank" rel="noopener noreferrer">https://www.navicat.com/en/download/navicat-premium-lite</a></div><div class="notion-text notion-block-a5210ae713b2417dbc3abf0a80dc3a9f">中文官网下载地址：<a class="notion-link" href="https://www.navicat.com.cn/download/navicat-premium-lite" target="_blank" rel="noopener noreferrer">https://www.navicat.com.cn/download/navicat-premium-lite</a></div><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-0430dd227b1746dd85314b0233e1985f"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/image-20240627231159016.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=0430dd22-7b17-46dd-8531-4b0233e1985f" alt="notion image" loading="lazy" decoding="async"/></div></figure><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-9538ced367e544c39a7100096757502b"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/image-20240627231505293.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=9538ced3-67e5-44c3-9a71-00096757502b" alt="notion image" loading="lazy" decoding="async"/></div></figure><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-38b183bbb2cb40028283ac849c8bd81d"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/image-20240627231357805.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=38b183bb-b2cb-4002-8283-ac849c8bd81d" alt="notion image" loading="lazy" decoding="async"/></div></figure></main></div>]]></content:encoded>
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            <title><![CDATA[VMware Workstation Pro 面向个人免费了]]></title>
            <link>https://www.msezi.com/article/437eb80c-03f8-42f2-a47b-21ad24329926</link>
            <guid>https://www.msezi.com/article/437eb80c-03f8-42f2-a47b-21ad24329926</guid>
            <pubDate>Thu, 16 May 2024 00:00:00 GMT</pubDate>
            <description><![CDATA[VMware Workstation Pro 面向个人免费了]]></description>
            <content:encoded><![CDATA[<div id="notion-article" class="mx-auto overflow-hidden "><main class="notion light-mode notion-page notion-block-437eb80c03f842f2a47b21ad24329926"><div class="notion-viewport"></div><div class="notion-collection-page-properties"></div><div class="notion-blank notion-block-a8872baf25694592a77680d614330235"> </div><div class="notion-text notion-block-3b9d5725f6734391bf393fd86bdf4e14">博通收购 VMware Workstation Pro 后，五月中旬面向个人免费了，赶紧下载一个。</div><div class="notion-text notion-block-c2e3d678f1e94b2090b1e0663fee73f1">不能通过原来的方式下载了，在原来的vmware网站是下载不了的。</div><div class="notion-text notion-block-576fbf6b55ab44f99b0b4e5b05419e0a">打开博通官网地址 <a class="notion-link" href="https://support.broadcom.com/" target="_blank" rel="noopener noreferrer">https://support.broadcom.com</a>，使用邮箱和密并注册一个账号。</div><div class="notion-text notion-block-06e27af86dba4071abad3328e4c5bb5b">登录后打开官网：<a class="notion-link" href="https://support.broadcom.com/" target="_blank" rel="noopener noreferrer">https://support.broadcom.com</a>，选择右上角的 VMware Cloud Foundation，然后点击 My Download。</div><div class="notion-text notion-block-a8bdfee3e18f45bcbc0a1609b42a3d8c">在总多产品里面找，Windows 和 Linux 系统的找 VMware Workstation Pro，MAC 的找 VMware Fusion</div><div class="notion-text notion-block-a14d59edfc714468954221dbc9dd67c8">我的是Windows，下面都是 Windows 为例。</div><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-45b05748a62e406da00ee8b8dbef03fb"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/202405161431963.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=45b05748-a62e-406d-a00e-e8b8dbef03fb" alt="notion image" loading="lazy" decoding="async"/></div></figure><div class="notion-text notion-block-0346e0c10ef944a0a2f67df95f2e8641">选择 VMware Workstation Pro 17.0 for Personal Use (Windows)，linux的就选择下面的linux版本</div><div class="notion-text notion-block-9cf2e88221954f24a2ecd33d142ee0e1">当然可以直接打开链接：<a class="notion-link" href="https://support.broadcom.com/group/ecx/productdownloads?subfamily=VMware%20Workstation%20Pro" target="_blank" rel="noopener noreferrer">https://support.broadcom.com/group/ecx/productdownloads?subfamily=VMware Workstation Pro</a></div><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-ba46b89401364a2da6e1f8e766a3a61b"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/202405161432730.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=ba46b894-0136-4a2d-a6e1-f8e766a3a61b" alt="notion image" loading="lazy" decoding="async"/></div></figure><div class="notion-text notion-block-fc11d7c436f14d27af8ae3ce25c9fde8">勾选确认证书后就可以直接下载了</div><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-59f8214362984082b12aed3818816243"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/202405161431378.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=59f82143-6298-4082-b12a-ed3818816243" alt="notion image" loading="lazy" decoding="async"/></div></figure><div class="notion-text notion-block-8496909460264e42a03b2b069ecf85e5">安装过程就正常就行。</div><div class="notion-text notion-block-2a0dc0176b364cf386e7ea8c38cb8bd9">安装完成后选择个人用途</div><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-67be51c582dc4d9fbb6c645748f7c9ad"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/202405161431387.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=67be51c5-82dc-4d9f-bb6c-645748f7c9ad" alt="notion image" loading="lazy" decoding="async"/></div></figure><div class="notion-text notion-block-f518a76a76f4469baf1aefa3cd3b50a0">进入后查看license，是个人永久的了。</div><figure class="notion-asset-wrapper notion-asset-wrapper-image notion-block-e6468f8d2c0f44f59f89357c6dc92b23"><div style="position:relative;display:flex;justify-content:center;align-self:center;width:100%;max-width:100%;flex-direction:column"><img src="https://msezi.oss-cn-hangzhou.aliyuncs.com/markdown/202405161432288.png?spaceId=35d3ddd1-3397-4325-822b-1aea45ab34b2&amp;t=e6468f8d-2c0f-44f5-9f89-357c6dc92b23" alt="notion image" loading="lazy" decoding="async"/></div></figure><div class="notion-text notion-block-435fe859e41446a0a94e1a31c8f20372">这对于个人用户来说太友好了。</div></main></div>]]></content:encoded>
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            <title><![CDATA[Ubuntu 12.04更新源]]></title>
            <link>https://www.msezi.com/article/70ad36e5-2f9c-4394-ae01-7a7d99a47955</link>
            <guid>https://www.msezi.com/article/70ad36e5-2f9c-4394-ae01-7a7d99a47955</guid>
            <pubDate>Tue, 08 Oct 2019 00:00:00 GMT</pubDate>
            <description><![CDATA[Ubuntu 12.04更新源，提供官方源、以及国内的高校源和商业源]]></description>
            <content:encoded><![CDATA[<div id="notion-article" class="mx-auto overflow-hidden "><main class="notion light-mode notion-page notion-block-70ad36e52f9c4394ae017a7d99a47955"><div class="notion-viewport"></div><div class="notion-collection-page-properties"></div><div class="notion-blank notion-block-ce72b4d5d9aa45f5b12fc4781511def6"> </div><div class="notion-text notion-block-7c8f9f7d2ac2414b9838ba05b8a4d55d">1、首先备份Ubuntu12.04源列表</div><div class="notion-text notion-block-09d533bd69cc44ffa087fd4d003a46ff">2、修改更新源</div><div class="notion-text notion-block-de9564c7c4ad4dde952128e0308e667b">3、把里面的列表替换成下面的列表其中一个</div><div class="notion-text notion-block-85494662a517405ebcde48d6010cb04a">4、更新源</div></main></div>]]></content:encoded>
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            <title><![CDATA[shell 实现并发，并控制并发数量]]></title>
            <link>https://www.msezi.com/article/10306f29-90d8-4981-8ae5-440f6f2e5a83</link>
            <guid>https://www.msezi.com/article/10306f29-90d8-4981-8ae5-440f6f2e5a83</guid>
            <pubDate>Wed, 03 Nov 2021 00:00:00 GMT</pubDate>
            <description><![CDATA[shell 实现并发，并控制并发数量]]></description>
            <content:encoded><![CDATA[<div id="notion-article" class="mx-auto overflow-hidden "><main class="notion light-mode notion-page notion-block-10306f2990d849818ae5440f6f2e5a83"><div class="notion-viewport"></div><div class="notion-collection-page-properties"></div><hr class="notion-hr notion-block-2eb8a042e0e34d26828ef6fc6febd783"/><div class="notion-text notion-block-f43569eba83e40199746e40dd851efa0">为了方便理解，一步步的来
首先先看一下串行的：</div><div class="notion-text notion-block-2588f017e376440bb7f8af866bc8206d">输出结果：</div><div class="notion-text notion-block-6f44e282f9244c52b246326ccd404979">1
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time: 10</div><div class="notion-text notion-block-c29916227e7b4134a63f44dd65c27da0">这就最原始的进程运行模拟，串行方式，无法有效利用计算机的资源，很浪费切耗时。</div><div class="notion-text notion-block-26996519eb8447bca11446eb5e41bc7c">我们可以把进程放入后台运行，这样的可以达到并发执行的效果：</div><div class="notion-text notion-block-840e69dbc9d244d59a93519a0032b300">执行的结果：</div><div class="notion-text notion-block-acdce3c01b914c99bc3f56686b96ae0b">1
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time: 1</div><div class="notion-text notion-block-499294c0b7a34ff08045e85e056f8560">有次可见，执行后时间由原来的10缩短到了1秒，这是很大的改进</div><div class="notion-text notion-block-f86f2e3f798a4ba3b46105e1571879ce">但是有个问题就是，这里我的总任务才是10个，那如果我的任务是1000个，那么计算机资源就不足了，就容易造成宕机。</div><div class="notion-text notion-block-4a1fb94c0a124cfe81b6f2d65421cfe2">所以需要控制并发数据量，之前我想过很多方法，比如切割任务，和控制循环的时间等等，都不太优雅，查阅资料，找到一个可行方案：使用管道和文件描述符。</div><div class="notion-text notion-block-f62efcbcb2d04e6c9b80ef9a5750b69d">管道：</div><div class="notion-text notion-block-5bd376243a204cb0b763a53a7995b073">因为我对这方面也是新知识，所以一开始就看代码，有点懵，先看点理论知识。
首先说是管道，有无名管道和有名管道
无名管道，在日常使用频率超高，比如：</div><div class="notion-text notion-block-075d5fd0eaa34a95abcd5475bb000865">这里面的“|”就是管道，它将前一个命令的结果输出到后一个进程中，作为两个进程的数据通道，不过他是无名的。</div><div class="notion-text notion-block-835463147f094b1a80d1217bc5000d4f">使用mkfifo命令创建的管道即为有名管，例如，mkfifo pipefile, pipefile即为有名管道
有名管道有一个显著的特点：
如果管道里没有数据，那么去取管道数据时，程序会阻塞住，直到管道内进入数据，然后读取才会终止这个操作，反之，管道在执行写入操作时，如果没有读取操作，同样会阻塞</div><div class="notion-text notion-block-3c29bfc811764435879e19ceaa976b92">由此可以得到的有用内容就是：利用有名管道的特性就可以实现一个队列的控制。</div><div class="notion-text notion-block-e03287a006a944f98794e6033178227f">验证就不做了，网上验证资料很多。</div><div class="notion-text notion-block-f1859e1621fe457397506a4cc17cbbe7">文件描述符：
这个就不过多说了，网上资料也很多。
但是值得注意的是，文件描述符的值不能乱取，取值范围是3-(ulimit -n)-1
ulinit -n是 系统的open files
默认一般就是1024， 直接输入ulimit -n就可以查看</div><div class="notion-text notion-block-cb9a3b7239f346dea297e7e73249e54b">所以代码</div><div class="notion-text notion-block-adb71e174a334921bc5b6ff32897d0fa">运行：</div><div class="notion-text notion-block-5c248b19fbed4493aaf08e8949b81692">mshing@remtor:~/code$ ./Concurrent.sh 20
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time: 5</div><div class="notion-text notion-block-e47b6d5bd5f146f2b76262340086cc87">代码分析
举个例子吧，就拿以前我们学车来说，我们学车的时候就是车少人多，假如有20人练车，但是只有5辆教练车，车钥匙放在教练那里，每个人去练车要去和教练取钥匙练完放回教练那里。那么运行就是每次只能5人同时练习，等有人把车钥匙放回教练那里，下一个才能得到钥匙去练车。只到20个人练完。任务就算完成</div><div class="notion-text notion-block-c4de948271a2439e8a0e991061e1c7e9">该并发是可用的可行的
把里面的循环范围和命令改一下就可批量并发执行了</div><blockquote class="notion-quote notion-block-80348b68b7dc4b5d891e4a3ad9a937c2"><div>最开始产生的需求源于自己的工作，因为工作中需要对数据库的700多张表同时truncate，然是我们的工具很不好使用，而且工具里面操作的也是串行的，有时候truncate表重建表速度更快一些，但是这样是不规范的操作，我们不应该去动表结构。所以产生了使用shell去操作数据库的想法，所以就来做个小脚本。</div></blockquote></main></div>]]></content:encoded>
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            <title><![CDATA[R语言使用merge合并数据框中相同的列元素]]></title>
            <link>https://www.msezi.com/article/2bacf99b-0849-451c-af02-0bf563bbff2b</link>
            <guid>https://www.msezi.com/article/2bacf99b-0849-451c-af02-0bf563bbff2b</guid>
            <pubDate>Thu, 04 Nov 2021 00:00:00 GMT</pubDate>
            <description><![CDATA[R语言使用merge合并数据框中相同的列元素]]></description>
            <content:encoded><![CDATA[<div id="notion-article" class="mx-auto overflow-hidden "><main class="notion light-mode notion-page notion-block-2bacf99b0849451caf020bf563bbff2b"><div class="notion-viewport"></div><div class="notion-collection-page-properties"></div><div class="notion-blank notion-block-aacc24fd284d4d1f9b888b055338cb5b"> </div><div class="notion-text notion-block-7971c4faf4df413bb57e35751b6f084f">合并两个向量是使用<code class="notion-inline-code">merge()</code>函数</div><div class="notion-text notion-block-61387fb25a8c4d038031bdea6aa0b569">若是因子对应的元素不完整，则想要的是全部完整去掉缺失的的时候加上参数<code class="notion-inline-code">all = TRUE</code></div><div class="notion-text notion-block-94c5ffb55a4843a4aa1dc80f147fb5bc">例如：
ID 是共同因子</div><div class="notion-text notion-block-da0aa52d7c0f4d0f8a401be9dfdf4ac9">如果想要因子完整，元素不足自动填充NA的话</div><div class="notion-text notion-block-53bd54eedfad450fb44050edaa3fc791">如果合成的不是数据框，是两个向量矩阵的话，假如data1的元素少于data2的话想要data1不足的填充NA，来一起则：</div><div class="notion-text notion-block-40126d3c95954d2d8dd781e9e21ee0fc">更多讲解请看官网</div><div class="notion-blank notion-block-15c018f9add744faab7d2b342d80cb0b"> </div></main></div>]]></content:encoded>
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