<!DOCTYPE html SYSTEM "about:legacy-compat"> <html lang="en"><head><META http-equiv="Content-Type" content="text/html; charset=UTF-8"><link href="../images/docs-stylesheet.css" rel="stylesheet" type="text/css"><title>Apache Tomcat 8 Configuration Reference (8.0.53) - The Executor (thread pool)</title><meta name="author" content="Filip Hanik"><script type="application/javascript" data-comments-identifier="tomcat-8.0-doc/config/executor"> "use strict"; // Enable strict mode (function() { var thisScript = document.currentScript; if (!thisScript) { // Workaround for IE <= 11 var scripts = document.getElementsByTagName("script"); thisScript = scripts[scripts.length - 1]; } document.addEventListener("DOMContentLoaded", (function() { var commentsDiv = document.getElementById("comments_thread"); var commentsShortname = "tomcat"; var commentsIdentifier = "https://tomcat.apache.org/" + thisScript.getAttribute("data-comments-identifier") + ".html"; (function(w, d) { if (w.location.hostname.toLowerCase() == "tomcat.apache.org") { var s = d.createElement("script"); s.type = "application/javascript"; s.async = true; s.src = "https://comments.apache.org/show_comments.lua?site=" + encodeURIComponent(commentsShortname) + "&page=" + encodeURIComponent(commentsIdentifier); d.head.appendChild(s); } else { commentsDiv.appendChild(d.createTextNode("Comments are disabled for this page at the moment.")); } })(window, document); }), false); })(); </script></head><body><div id="wrapper"><header><div id="header"><div><div><div class="logo noPrint"><a href="https://tomcat.apache.org/"><img alt="Tomcat Home" src="../images/tomcat.png"></a></div><div style="height: 1px;"></div><div class="asfLogo noPrint"><a href="https://www.apache.org/" target="_blank"><img src="../images/asf-logo.svg" alt="The Apache Software Foundation" style="width: 266px; height: 83px;"></a></div><h1>Apache Tomcat 8 Configuration Reference</h1><div class="versionInfo"> Version 8.0.53, <time datetime="2018-06-29">Jun 29 2018</time></div><div style="height: 1px;"></div><div style="clear: left;"></div></div></div></div></header><div id="middle"><div><div id="mainLeft" class="noprint"><div><nav><div><h2>Links</h2><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Config Ref. Home</a></li><li><a href="https://wiki.apache.org/tomcat/FAQ">FAQ</a></li><li><a href="#comments_section">User Comments</a></li></ul></div><div><h2>Top Level Elements</h2><ul><li><a href="server.html">Server</a></li><li><a href="service.html">Service</a></li></ul></div><div><h2>Executors</h2><ul><li><a href="executor.html">Executor</a></li></ul></div><div><h2>Connectors</h2><ul><li><a href="http.html">HTTP</a></li><li><a href="ajp.html">AJP</a></li></ul></div><div><h2>Containers</h2><ul><li><a href="context.html">Context</a></li><li><a href="engine.html">Engine</a></li><li><a href="host.html">Host</a></li><li><a href="cluster.html">Cluster</a></li></ul></div><div><h2>Nested Components</h2><ul><li><a href="cookie-processor.html">CookieProcessor</a></li><li><a href="credentialhandler.html">CredentialHandler</a></li><li><a href="globalresources.html">Global Resources</a></li><li><a href="jar-scanner.html">JarScanner</a></li><li><a href="jar-scan-filter.html">JarScanFilter</a></li><li><a href="listeners.html">Listeners</a></li><li><a href="loader.html">Loader</a></li><li><a href="manager.html">Manager</a></li><li><a href="realm.html">Realm</a></li><li><a href="resources.html">Resources</a></li><li><a href="sessionidgenerator.html">SessionIdGenerator</a></li><li><a href="valve.html">Valve</a></li></ul></div><div><h2>Cluster Elements</h2><ul><li><a href="cluster.html">Cluster</a></li><li><a href="cluster-manager.html">Manager</a></li><li><a href="cluster-channel.html">Channel</a></li><li><a href="cluster-membership.html">Channel/Membership</a></li><li><a href="cluster-sender.html">Channel/Sender</a></li><li><a href="cluster-receiver.html">Channel/Receiver</a></li><li><a href="cluster-interceptor.html">Channel/Interceptor</a></li><li><a href="cluster-valve.html">Valve</a></li><li><a href="cluster-deployer.html">Deployer</a></li><li><a href="cluster-listener.html">ClusterListener</a></li></ul></div><div><h2>web.xml</h2><ul><li><a href="filter.html">Filter</a></li></ul></div><div><h2>Other</h2><ul><li><a href="systemprops.html">System properties</a></li></ul></div></nav></div></div><div id="mainRight"><div id="content"><h2>The Executor (thread pool)</h2><h3 id="Table_of_Contents">Table of Contents</h3><div class="text"> <ul><li><a href="#Introduction">Introduction</a></li><li><a href="#Attributes">Attributes</a><ol><li><a href="#Common_Attributes">Common Attributes</a></li><li><a href="#Standard_Implementation">Standard Implementation</a></li></ol></li></ul> </div><h3 id="Introduction">Introduction</h3><div class="text"> <p>The <strong>Executor</strong> represents a thread pool that can be shared between components in Tomcat. Historically there has been a thread pool per connector created but this allows you to share a thread pool, between (primarily) connector but also other components when those get configured to support executors</p> <p>The executor has to implement the <code>org.apache.catalina.Executor</code> interface.</p> <p>The executor is a nested element to the <a href="service.html">Service</a> element. And in order for it to be picked up by the connectors, the Executor element has to appear prior to the Connector element in server.xml</p> </div><h3 id="Attributes">Attributes</h3><div class="text"> <div class="subsection"><h4 id="Common_Attributes">Common Attributes</h4><div class="text"> <p>All implementations of <strong>Executor</strong> support the following attributes:</p> <table class="defaultTable"><tr><th style="width: 15%;"> Attribute </th><th style="width: 85%;"> Description </th></tr><tr><td><code class="attributeName">className</code></td><td> <p>The class of the implementation. The implementation has to implement the <code>org.apache.catalina.Executor</code> interface. This interface ensures that the object can be referenced through its <code>name</code> attribute and that implements Lifecycle, so that it can be started and stopped with the container. The default value for the className is <code>org.apache.catalina.core.StandardThreadExecutor</code></p> </td></tr><tr><td><strong><code class="attributeName">name</code></strong></td><td> <p>The name used to reference this pool in other places in server.xml. The name is required and must be unique.</p> </td></tr></table> </div></div> <div class="subsection"><h4 id="Standard_Implementation">Standard Implementation</h4><div class="text"> <p> The default implementation supports the following attributes:</p> <table class="defaultTable"><tr><th style="width: 15%;"> Attribute </th><th style="width: 85%;"> Description </th></tr><tr><td><code class="attributeName">threadPriority</code></td><td> <p>(int) The thread priority for threads in the executor, the default is <code>5</code> (the value of the <code>Thread.NORM_PRIORITY</code> constant)</p> </td></tr><tr><td><code class="attributeName">daemon</code></td><td> <p>(boolean) Whether the threads should be daemon threads or not, the default is <code>true</code></p> </td></tr><tr><td><code class="attributeName">namePrefix</code></td><td> <p>(String) The name prefix for each thread created by the executor. The thread name for an individual thread will be <code>namePrefix+threadNumber</code></p> </td></tr><tr><td><code class="attributeName">maxThreads</code></td><td> <p>(int) The max number of active threads in this pool, default is <code>200</code></p> </td></tr><tr><td><code class="attributeName">minSpareThreads</code></td><td> <p>(int) The minimum number of threads (idle and active) always kept alive, default is <code>25</code></p> </td></tr><tr><td><code class="attributeName">maxIdleTime</code></td><td> <p>(int) The number of milliseconds before an idle thread shutsdown, unless the number of active threads are less or equal to minSpareThreads. Default value is <code>60000</code>(1 minute)</p> </td></tr><tr><td><code class="attributeName">maxQueueSize</code></td><td> <p>(int) The maximum number of runnable tasks that can queue up awaiting execution before we reject them. Default value is <code>Integer.MAX_VALUE</code></p> </td></tr><tr><td><code class="attributeName">prestartminSpareThreads</code></td><td> <p>(boolean) Whether minSpareThreads should be started when starting the Executor or not, the default is <code>false</code></p> </td></tr><tr><td><code class="attributeName">threadRenewalDelay</code></td><td> <p>(long) If a <a href="listeners.html">ThreadLocalLeakPreventionListener</a> is configured, it will notify this executor about stopped contexts. After a context is stopped, threads in the pool are renewed. To avoid renewing all threads at the same time, this option sets a delay between renewal of any 2 threads. The value is in ms, default value is <code>1000</code> ms. If value is negative, threads are not renewed.</p> </td></tr></table> </div></div> </div><div class="noprint"><h3 id="comments_section"> Comments </h3><div class="text"><p class="notice"><strong>Notice: </strong>This comments section collects your suggestions on improving documentation for Apache Tomcat.<br><br> If you have trouble and need help, read <a href="https://tomcat.apache.org/findhelp.html">Find Help</a> page and ask your question on the tomcat-users <a href="https://tomcat.apache.org/lists.html">mailing list</a>. Do not ask such questions here. This is not a Q&A section.<br><br> The Apache Comments System is explained <a href="../comments.html">here</a>. Comments may be removed by our moderators if they are either implemented or considered invalid/off-topic. </p><div id="comments_thread"></div></div></div></div></div></div></div><footer><div id="footer"> Copyright © 1999-2018, The Apache Software Foundation </div></footer></div></body></html>