<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="zh-CN" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="zh-CN" > <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>tt — Arthas 3.1.0 文档</title>
<link rel="shortcut icon" href="_static/favicon.ico"/>
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="_static/overrides.css" type="text/css" />
<link rel="index" title="索引" href="genindex.html" />
<link rel="search" title="搜索" href="search.html" />
<link rel="next" title="cat" href="cat.html" />
<link rel="prev" title="stack" href="stack.html" />
<script src="_static/center_page.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.13.1/styles/github.min.css">
<script src="_static/js/modernizr.min.js"></script>
</head>
<body class="wy-body-for-nav">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-scroll">
<div class="wy-side-nav-search">
<a href="index.html" class="icon icon-home"> Arthas
</a>
<div class="version">
3.1.0
</div>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
<input type="text" name="q" placeholder="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
<ul class="current">
<li class="toctree-l1"><a class="reference external" href="https://alibaba.github.io/arthas/en/">English Docs</a></li>
<li class="toctree-l1"><a class="reference external" href="https://alibaba.github.io/arthas/arthas-tutorials?language=cn">在线教程(推荐)</a></li>
<li class="toctree-l1"><a class="reference internal" href="install-detail.html">安装</a></li>
<li class="toctree-l1"><a class="reference internal" href="quick-start.html">快速入门</a></li>
<li class="toctree-l1"><a class="reference internal" href="advanced-use.html">进阶使用</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="commands.html">命令列表</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="dashboard.html">dashboard</a></li>
<li class="toctree-l2"><a class="reference internal" href="thread.html">thread</a></li>
<li class="toctree-l2"><a class="reference internal" href="jvm.html">jvm</a></li>
<li class="toctree-l2"><a class="reference internal" href="sysprop.html">sysprop</a></li>
<li class="toctree-l2"><a class="reference internal" href="sysenv.html">sysenv</a></li>
<li class="toctree-l2"><a class="reference internal" href="getstatic.html">getstatic</a></li>
<li class="toctree-l2"><a class="reference internal" href="ognl.html">ognl</a></li>
<li class="toctree-l2"><a class="reference internal" href="sc.html">sc</a></li>
<li class="toctree-l2"><a class="reference internal" href="sm.html">sm</a></li>
<li class="toctree-l2"><a class="reference internal" href="dump.html">dump</a></li>
<li class="toctree-l2"><a class="reference internal" href="jad.html">jad</a></li>
<li class="toctree-l2"><a class="reference internal" href="classloader.html">classloader</a></li>
<li class="toctree-l2"><a class="reference internal" href="mc.html">mc</a></li>
<li class="toctree-l2"><a class="reference internal" href="redefine.html">redefine</a></li>
<li class="toctree-l2"><a class="reference internal" href="monitor.html">monitor</a></li>
<li class="toctree-l2"><a class="reference internal" href="watch.html">watch</a></li>
<li class="toctree-l2"><a class="reference internal" href="trace.html">trace</a></li>
<li class="toctree-l2"><a class="reference internal" href="stack.html">stack</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">tt</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#">使用参考</a><ul>
<li class="toctree-l4"><a class="reference internal" href="#demo">启动 Demo</a></li>
<li class="toctree-l4"><a class="reference internal" href="#">记录调用</a></li>
<li class="toctree-l4"><a class="reference internal" href="#">检索调用记录</a></li>
<li class="toctree-l4"><a class="reference internal" href="#">查看调用信息</a></li>
<li class="toctree-l4"><a class="reference internal" href="#">重做一次调用</a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="cat.html">cat</a></li>
<li class="toctree-l2"><a class="reference internal" href="pwd.html">pwd</a></li>
<li class="toctree-l2"><a class="reference internal" href="options.html">options</a></li>
<li class="toctree-l2"><a class="reference internal" href="commands.html#arthas">Arthas 基础命令</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="docker.html">Docker</a></li>
<li class="toctree-l1"><a class="reference external" href="https://github.com/alibaba/arthas/issues?q=label%3Auser-case">用户案例</a></li>
<li class="toctree-l1"><a class="reference external" href="https://github.com/alibaba/arthas/issues?q=label%3Aquestion-answered">常见问题</a></li>
<li class="toctree-l1"><a class="reference external" href="https://github.com/alibaba/arthas">Fork me at GitHub</a></li>
<li class="toctree-l1"><a class="reference external" href="https://github.com/alibaba/arthas/blob/master/CONTRIBUTING.md">参与贡献</a></li>
<li class="toctree-l1"><a class="reference internal" href="release-notes.html">Release Notes</a></li>
<li class="toctree-l1"><a class="reference internal" href="contact-us.html">QQ群/钉钉群</a></li>
</ul>
</div>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
<nav class="wy-nav-top" aria-label="top navigation">
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="index.html">Arthas</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="breadcrumbs navigation">
<ul class="wy-breadcrumbs">
<li><a href="index.html">Docs</a> »</li>
<li><a href="commands.html">命令列表</a> »</li>
<li>tt</li>
<li class="wy-breadcrumbs-aside">
<a href="https://github.com/alibaba/arthas/blob/master/site/src/site/sphinx/tt.md" class="fa fa-github"> Edit on GitHub</a>
</li>
</ul>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<div class="section" id="tt">
<span id="tt"></span><h1>tt<a class="headerlink" href="#tt" title="永久链接至标题">¶</a></h1>
<blockquote>
<div>方法执行数据的时空隧道，记录下指定方法每次调用的入参和返回信息，并能对这些不同的时间下调用进行观测</div></blockquote>
<p><tt class="docutils literal">watch</tt> 虽然很方便和灵活，但需要提前想清楚观察表达式的拼写，这对排查问题而言要求太高，因为很多时候我们并不清楚问题出自于何方，只能靠蛛丝马迹进行猜测。</p>
<p>这个时候如果能记录下当时方法调用的所有入参和返回值、抛出的异常会对整个问题的思考与判断非常有帮助。</p>
<p>于是乎，TimeTunnel 命令就诞生了。</p>
<div class="section" id="">
<span id="id1"></span><h2>使用参考<a class="headerlink" href="#" title="永久链接至标题">¶</a></h2>
<div class="section" id="demo">
<span id="demo"></span><h3>启动 Demo<a class="headerlink" href="#demo" title="永久链接至标题">¶</a></h3>
<p>启动<a class="reference internal" href="quick-start.html"><span class="doc">快速入门</span></a>里的<tt class="docutils literal">arthas-demo</tt>。</p>
</div>
<div class="section" id="">
<span id="id2"></span><h3>记录调用<a class="headerlink" href="#" title="永久链接至标题">¶</a></h3>
<p>对于一个最基本的使用来说，就是记录下当前方法的每次调用环境现场。</p>
<div class="highlight-bash notranslate"><div class="highlight hljs"><pre class="bash">$ tt -t demo.MathGame primeFactors
Press Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 66 ms.
INDEX TIMESTAMP COST(ms) IS-RET IS-EXP OBJECT CLASS METHOD
-------------------------------------------------------------------------------------------------------------------------------------
1000 2018-12-04 11:15:38 1.096236 false true 0x4b67cf4d MathGame primeFactors
1001 2018-12-04 11:15:39 0.191848 false true 0x4b67cf4d MathGame primeFactors
1002 2018-12-04 11:15:40 0.069523 false true 0x4b67cf4d MathGame primeFactors
1003 2018-12-04 11:15:41 0.186073 false true 0x4b67cf4d MathGame primeFactors
1004 2018-12-04 11:15:42 17.76437 true false 0x4b67cf4d MathGame primeFactors
</pre></div>
</div>
<ul>
<li><p class="first">命令参数解析</p>
<ul>
<li><p class="first"><tt class="docutils literal">-t</tt></p>
<p>tt 命令有很多个主参数，<tt class="docutils literal">-t</tt> 就是其中之一。这个参数的表明希望记录下类 <tt class="docutils literal">*Test</tt> 的 <tt class="docutils literal">print</tt> 方法的每次执行情况。</p>
</li>
<li><p class="first"><tt class="docutils literal">-n 3</tt></p>
<p>当你执行一个调用量不高的方法时可能你还能有足够的时间用 <tt class="docutils literal">CTRL+C</tt> 中断 tt 命令记录的过程，但如果遇到调用量非常大的方法，瞬间就能将你的 JVM 内存撑爆。</p>
<p>此时你可以通过 <tt class="docutils literal">-n</tt> 参数指定你需要记录的次数，当达到记录次数时 Arthas 会主动中断tt命令的记录过程，避免人工操作无法停止的情况。</p>
</li>
</ul>
</li>
<li><p class="first">表格字段说明</p>
</li>
</ul>
<table border="1" class="docutils">
<thead>
<tr>
<th>表格字段</th>
<th>字段解释</th>
</tr>
</thead>
<tbody>
<tr>
<td>INDEX</td>
<td>时间片段记录编号，每一个编号代表着一次调用，后续tt还有很多命令都是基于此编号指定记录操作，非常重要。</td>
</tr>
<tr>
<td>TIMESTAMP</td>
<td>方法执行的本机时间，记录了这个时间片段所发生的本机时间</td>
</tr>
<tr>
<td>COST(ms)</td>
<td>方法执行的耗时</td>
</tr>
<tr>
<td>IS-RET</td>
<td>方法是否以正常返回的形式结束</td>
</tr>
<tr>
<td>IS-EXP</td>
<td>方法是否以抛异常的形式结束</td>
</tr>
<tr>
<td>OBJECT</td>
<td>执行对象的<code>hashCode()</code>，注意，曾经有人误认为是对象在JVM中的内存地址，但很遗憾他不是。但他能帮助你简单的标记当前执行方法的类实体</td>
</tr>
<tr>
<td>CLASS</td>
<td>执行的类名</td>
</tr>
<tr>
<td>METHOD</td>
<td>执行的方法名</td>
</tr>
</tbody>
</table><ul>
<li><p class="first">条件表达式</p>
<p>不知道大家是否有在使用过程中遇到以下困惑</p>
<ul class="simple">
<li>Arthas 似乎很难区分出重载的方法</li>
<li>我只需要观察特定参数，但是 tt 却全部都给我记录了下来</li>
</ul>
<p>条件表达式也是用 <tt class="docutils literal">OGNL</tt> 来编写，核心的判断对象依然是 <tt class="docutils literal">Advice</tt> 对象。除了 <tt class="docutils literal">tt</tt> 命令之外，<tt class="docutils literal">watch</tt>、<tt class="docutils literal">trace</tt>、<tt class="docutils literal">stack</tt> 命令也都支持条件表达式。</p>
</li>
<li><p class="first">解决方法重载</p>
<p><tt class="docutils literal">tt -t *Test print params.length==1</tt></p>
<p>通过制定参数个数的形式解决不同的方法签名，如果参数个数一样，你还可以这样写</p>
<p><tt class="docutils literal">tt -t *Test print 'params[1] instanceof Integer'</tt></p>
</li>
<li><p class="first">解决指定参数</p>
<p><tt class="docutils literal">tt -t *Test print params[0].mobile=="13989838402"</tt></p>
</li>
<li><p class="first">构成条件表达式的 <tt class="docutils literal">Advice</tt> 对象</p>
<p>前边看到了很多条件表达式中，都使用了 <tt class="docutils literal">params[0]</tt>，有关这个变量的介绍，请参考<a class="reference internal" href="advice-class.html"><span class="doc">表达式核心变量</span></a></p>
</li>
</ul>
</div>
<div class="section" id="">
<span id="id3"></span><h3>检索调用记录<a class="headerlink" href="#" title="永久链接至标题">¶</a></h3>
<p>当你用 <tt class="docutils literal">tt</tt> 记录了一大片的时间片段之后，你希望能从中筛选出自己需要的时间片段，这个时候你就需要对现有记录进行检索。</p>
<p>假设我们有这些记录</p>
<div class="highlight-bash notranslate"><div class="highlight hljs"><pre class="bash">$ tt -l
INDEX TIMESTAMP COST(ms) IS-RET IS-EXP OBJECT CLASS METHOD
-------------------------------------------------------------------------------------------------------------------------------------
1000 2018-12-04 11:15:38 1.096236 false true 0x4b67cf4d MathGame primeFactors
1001 2018-12-04 11:15:39 0.191848 false true 0x4b67cf4d MathGame primeFactors
1002 2018-12-04 11:15:40 0.069523 false true 0x4b67cf4d MathGame primeFactors
1003 2018-12-04 11:15:41 0.186073 false true 0x4b67cf4d MathGame primeFactors
1004 2018-12-04 11:15:42 17.76437 true false 0x4b67cf4d MathGame primeFactors
9
1005 2018-12-04 11:15:43 0.4776 false true 0x4b67cf4d MathGame primeFactors
Affect(row-cnt:6) cost in 4 ms.
</pre></div>
</div>
<p>我需要筛选出 <tt class="docutils literal">primeFactors</tt> 方法的调用信息</p>
<div class="highlight-bash notranslate"><div class="highlight hljs"><pre class="bash">$ tt -s 'method.name=="primeFactors"'
INDEX TIMESTAMP COST(ms) IS-RET IS-EXP OBJECT CLASS METHOD
-------------------------------------------------------------------------------------------------------------------------------------
1000 2018-12-04 11:15:38 1.096236 false true 0x4b67cf4d MathGame primeFactors
1001 2018-12-04 11:15:39 0.191848 false true 0x4b67cf4d MathGame primeFactors
1002 2018-12-04 11:15:40 0.069523 false true 0x4b67cf4d MathGame primeFactors
1003 2018-12-04 11:15:41 0.186073 false true 0x4b67cf4d MathGame primeFactors
1004 2018-12-04 11:15:42 17.76437 true false 0x4b67cf4d MathGame primeFactors
9
1005 2018-12-04 11:15:43 0.4776 false true 0x4b67cf4d MathGame primeFactors
Affect(row-cnt:6) cost in 607 ms.
</pre></div>
</div>
<p>你需要一个 <tt class="docutils literal">-s</tt> 参数。<span style="color:red;">同样的，搜索表达式的核心对象依旧是 <tt class="docutils literal">Advice</tt> 对象。</span></p>
</div>
<div class="section" id="">
<span id="id4"></span><h3>查看调用信息<a class="headerlink" href="#" title="永久链接至标题">¶</a></h3>
<p>对于具体一个时间片的信息而言，你可以通过 <tt class="docutils literal">-i</tt> 参数后边跟着对应的 <tt class="docutils literal">INDEX</tt> 编号查看到他的详细信息。</p>
<div class="highlight-bash notranslate"><div class="highlight hljs"><pre class="bash">$ tt -i 1003
INDEX 1003
GMT-CREATE 2018-12-04 11:15:41
COST(ms) 0.186073
OBJECT 0x4b67cf4d
CLASS demo.MathGame
METHOD primeFactors
IS-RETURN false
IS-EXCEPTION true
PARAMETERS[0] @Integer[-564322413]
THROW-EXCEPTION java.lang.IllegalArgumentException: number is: -564322413, need >= 2
at demo.MathGame.primeFactors(MathGame.java:46)
at demo.MathGame.run(MathGame.java:24)
at demo.MathGame.main(MathGame.java:16)
Affect(row-cnt:1) cost in 11 ms.
</pre></div>
</div>
</div>
<div class="section" id="">
<span id="id5"></span><h3>重做一次调用<a class="headerlink" href="#" title="永久链接至标题">¶</a></h3>
<p>当你稍稍做了一些调整之后，你可能需要前端系统重新触发一次你的调用，此时得求爷爷告奶奶的需要前端配合联调的同学再次发起一次调用。而有些场景下，这个调用不是这么好触发的。</p>
<p><tt class="docutils literal">tt</tt> 命令由于保存了当时调用的所有现场信息，所以我们可以自己主动对一个 <tt class="docutils literal">INDEX</tt> 编号的时间片自主发起一次调用，从而解放你的沟通成本。此时你需要 <tt class="docutils literal">-p</tt> 参数。通过 <tt class="docutils literal">--replay-times</tt> 指定
调用次数，通过 <tt class="docutils literal">--replay-interval</tt> 指定多次调用间隔(单位ms, 默认1000ms)</p>
<div class="highlight-bash notranslate"><div class="highlight hljs"><pre class="bash">$ tt -i 1004 -p
RE-INDEX 1004
GMT-REPLAY 2018-12-04 11:26:00
OBJECT 0x4b67cf4d
CLASS demo.MathGame
METHOD primeFactors
PARAMETERS[0] @Integer[946738738]
IS-RETURN true
IS-EXCEPTION false
COST(ms) 0.186073
RETURN-OBJ @ArrayList[
@Integer[2],
@Integer[11],
@Integer[17],
@Integer[2531387],
]
Time fragment[1004] successfully replayed.
Affect(row-cnt:1) cost in 14 ms.
</pre></div>
</div>
<p>你会发现结果虽然一样，但调用的路径发生了变化，有原来的程序发起变成了 Arthas 自己的内部线程发起的调用了。</p>
<ul>
<li><p class="first">需要强调的点</p>
<ol>
<li><p class="first"><strong>ThreadLocal 信息丢失</strong></p>
<p>很多框架偷偷的将一些环境变量信息塞到了发起调用线程的 ThreadLocal 中，由于调用线程发生了变化，这些 ThreadLocal 线程信息无法通过 Arthas 保存，所以这些信息将会丢失。</p>
<p>一些常见的 CASE 比如：鹰眼的 TraceId 等。</p>
</li>
<li><p class="first"><strong>引用的对象</strong></p>
<p>需要强调的是，<tt class="docutils literal">tt</tt> 命令是将当前环境的对象引用保存起来，但仅仅也只能保存一个引用而已。如果方法内部对入参进行了变更，或者返回的对象经过了后续的处理，那么在 <tt class="docutils literal">tt</tt> 查看的时候将无法看到当时最准确的值。这也是为什么 <tt class="docutils literal">watch</tt> 命令存在的意义。</p>
</li>
</ol>
</li>
</ul>
</div>
</div>
</div>
</div>
</div>
<footer>
<div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
<a href="cat.html" class="btn btn-neutral float-right" title="cat" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right"></span></a>
<a href="stack.html" class="btn btn-neutral" title="stack" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left"></span> Previous</a>
</div>
<hr/>
<div role="contentinfo">
<p>
© Copyright 2018, Alibaba Middleware Group, and contributors.
</p>
</div>
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/rtfd/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT:'./',
VERSION:'3.1.0',
LANGUAGE:'zh_CN',
COLLAPSE_INDEX:false,
FILE_SUFFIX:'.html',
HAS_SOURCE: true,
SOURCELINK_SUFFIX: '.txt'
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script type="text/javascript" src="_static/translations.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script type="text/javascript" src="_static/js/theme.js"></script>
<script type="text/javascript">
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
</script>
<div class="github-fork-ribbon-wrapper right">
<div class="github-fork-ribbon">
<a href="https://github.com/alibaba/arthas" target="_blank">Fork me at GitHub</a>
</div>
</div>
<script type="text/javascript" src="_static/add_badges.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.13.1/highlight.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/highlightjs-line-numbers.js/2.5.0/highlightjs-line-numbers.min.js"></script>
<script>
document.querySelectorAll('div.hljs > pre').forEach(function(block) {
hljs.highlightBlock(block);
hljs.lineNumbersBlock(block);
});
</script>
<script>
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "https://hm.baidu.com/hm.js?d5c5e25b100f0eb51a4c35c8a86ea9b4";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
</script>
</body>
</html>