Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 771 | blopes | 1 | <!DOCTYPE html SYSTEM "about:legacy-compat"> |
| 2 | <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 9 Configuration Reference (9.0.112) - The Cluster Receiver object</title></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 9 Configuration Reference</h1><div class="versionInfo"> |
||
| 3 | Version 9.0.112, |
||
| 4 | <time datetime="2025-11-06">Nov 6 2025</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://cwiki.apache.org/confluence/display/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/1.1</a></li><li><a href="http2.html">HTTP/2</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="runtime-attributes.html">Runtime attributes</a></li><li><a href="systemprops.html">System properties</a></li><li><a href="jaspic.html">JASPIC</a></li></ul></div></nav></div></div><div id="mainRight"><div id="content"><h2>The Cluster Receiver object</h2><h3 id="Table_of_Contents">Table of Contents</h3><div class="text"> |
||
| 5 | <ul><li><a href="#Introduction">Introduction</a></li><li><a href="#Blocking_vs_Non-Blocking_Receiver">Blocking vs Non-Blocking Receiver</a></li><li><a href="#Attributes">Attributes</a><ol><li><a href="#Common_Attributes">Common Attributes</a></li><li><a href="#NioReceiver">NioReceiver</a></li><li><a href="#BioReceiver">BioReceiver</a></li></ol></li></ul> |
||
| 6 | </div><h3 id="Introduction">Introduction</h3><div class="text"> |
||
| 7 | <p> |
||
| 8 | The receiver component is responsible for receiving cluster messages. |
||
| 9 | As you might notice through the configuration, is that the receiving of messages |
||
| 10 | and sending of messages are two different components, this is different from many other |
||
| 11 | frameworks, but there is a good reason for it, to decouple the logic for how messages are sent from |
||
| 12 | how messages are received.<br> |
||
| 13 | The receiver is very much like the Tomcat Connector, its the base of the thread pool |
||
| 14 | for incoming cluster messages. The receiver is straight forward, but all the socket settings |
||
| 15 | for incoming traffic are managed here. |
||
| 16 | </p> |
||
| 17 | </div><h3 id="Blocking_vs_Non-Blocking_Receiver">Blocking vs Non-Blocking Receiver</h3><div class="text"> |
||
| 18 | <p> |
||
| 19 | The receiver supports both a non blocking, <code>org.apache.catalina.tribes.transport.nio.NioReceiver</code>, and a |
||
| 20 | blocking, <code>org.apache.catalina.tribes.transport.bio.BioReceiver</code>. It is preferred to use the non blocking receiver |
||
| 21 | to be able to grow your cluster without running into thread starvation.<br> |
||
| 22 | Using the non blocking receiver allows you to with a very limited thread count to serve a large number of messages. |
||
| 23 | Usually the rule is to use 1 thread per node in the cluster for small clusters, and then depending on your message frequency |
||
| 24 | and your hardware, you'll find an optimal number of threads peak out at a certain number. |
||
| 25 | </p> |
||
| 26 | </div><h3 id="Attributes">Attributes</h3><div class="text"> |
||
| 27 | <div class="subsection"><h4 id="Common_Attributes">Common Attributes</h4><div class="text"> |
||
| 28 | <table class="defaultTable"><tr><th style="width: 15%;"> |
||
| 29 | Attribute |
||
| 30 | </th><th style="width: 85%;"> |
||
| 31 | Description |
||
| 32 | </th></tr><tr id="Attributes_Common Attributes_className"><td><strong><code class="attributeName">className</code></strong></td><td> |
||
| 33 | The implementation of the receiver component. Two implementations available, |
||
| 34 | <code>org.apache.catalina.tribes.transport.nio.NioReceiver</code> and |
||
| 35 | <code>org.apache.catalina.tribes.transport.bio.BioReceiver</code>.<br> |
||
| 36 | The <code>org.apache.catalina.tribes.transport.nio.NioReceiver</code> is the |
||
| 37 | preferred implementation |
||
| 38 | </td></tr><tr id="Attributes_Common Attributes_address"><td><code class="attributeName">address</code></td><td> |
||
| 39 | The address (network interface) to listen for incoming traffic. |
||
| 40 | Same as the bind address. The default value is <code>auto</code> and translates to |
||
| 41 | <code>java.net.InetAddress.getLocalHost().getHostAddress()</code>. |
||
| 42 | </td></tr><tr id="Attributes_Common Attributes_direct"><td><code class="attributeName">direct</code></td><td> |
||
| 43 | Possible values are <code>true</code> or <code>false</code>. |
||
| 44 | Set to true if you want the receiver to use direct bytebuffers when reading data |
||
| 45 | from the sockets. |
||
| 46 | </td></tr><tr id="Attributes_Common Attributes_port"><td><code class="attributeName">port</code></td><td> |
||
| 47 | The listen port for incoming data. The default value is <code>4000</code>. |
||
| 48 | To avoid port conflicts the receiver will automatically bind to a free port within the range of |
||
| 49 | <code> port <= bindPort < port+autoBind</code> |
||
| 50 | So for example, if port is 4000, and autoBind is set to 10, then the receiver will open up |
||
| 51 | a server socket on the first available port in the range 4000-4009. |
||
| 52 | </td></tr><tr id="Attributes_Common Attributes_autoBind"><td><code class="attributeName">autoBind</code></td><td> |
||
| 53 | Default value is <code>100</code>. |
||
| 54 | Use this value if you wish to automatically avoid port conflicts the cluster receiver will try to open a |
||
| 55 | server socket on the <code>port</code> attribute port, and then work up <code>autoBind</code> number of times. |
||
| 56 | </td></tr><tr id="Attributes_Common Attributes_securePort"><td><code class="attributeName">securePort</code></td><td> |
||
| 57 | The secure listen port. This port is SSL enabled. If this attribute is omitted no SSL port is opened up. |
||
| 58 | There default value is unset, meaning there is no SSL socket available. |
||
| 59 | </td></tr><tr id="Attributes_Common Attributes_udpPort"><td><code class="attributeName">udpPort</code></td><td> |
||
| 60 | The UDP listen port. If this attribute is omitted no UDP port is opened up. |
||
| 61 | There default value is unset, meaning there is no UDP listener available. |
||
| 62 | </td></tr><tr id="Attributes_Common Attributes_selectorTimeout"><td><code class="attributeName">selectorTimeout</code></td><td> |
||
| 63 | The value in milliseconds for the polling timeout in the <code>NioReceiver</code>. On older versions of the JDK |
||
| 64 | there have been bugs, that should all now be cleared out where the selector never woke up. |
||
| 65 | The default value is a very high <code>5000</code> milliseconds. |
||
| 66 | </td></tr><tr id="Attributes_Common Attributes_maxThreads"><td><code class="attributeName">maxThreads</code></td><td> |
||
| 67 | The maximum number of threads in the receiver thread pool. The default value is <code>15</code> |
||
| 68 | Adjust this value relative to the number of nodes in the cluster, the number of messages being exchanged and |
||
| 69 | the hardware you are running on. A higher value doesn't mean more efficiency, tune this value according to your |
||
| 70 | own test results. |
||
| 71 | </td></tr><tr id="Attributes_Common Attributes_minThreads"><td><code class="attributeName">minThreads</code></td><td> |
||
| 72 | Minimum number of threads to be created when the receiver is started up. Default value is <code>6</code> |
||
| 73 | </td></tr><tr id="Attributes_Common Attributes_maxIdleTime"><td><code class="attributeName">maxIdleTime</code></td><td> |
||
| 74 | Maximum number of milliseconds of until Idle thread terminates. Default value is <code>60000</code> milliseconds. |
||
| 75 | </td></tr><tr id="Attributes_Common Attributes_ooBInline"><td><code class="attributeName">ooBInline</code></td><td> |
||
| 76 | Boolean value for the socket OOBINLINE option. Possible values are <code>true</code> or <code>false</code>. |
||
| 77 | </td></tr><tr id="Attributes_Common Attributes_rxBufSize"><td><code class="attributeName">rxBufSize</code></td><td> |
||
| 78 | The receiver buffer size on the receiving sockets. Value is in bytes, the default value is <code>65536</code> bytes. |
||
| 79 | </td></tr><tr id="Attributes_Common Attributes_txBufSize"><td><code class="attributeName">txBufSize</code></td><td> |
||
| 80 | The sending buffer size on the receiving sockets. Value is in bytes, the default value is <code>25188</code> bytes. |
||
| 81 | </td></tr><tr id="Attributes_Common Attributes_udpRxBufSize"><td><code class="attributeName">udpRxBufSize</code></td><td> |
||
| 82 | The receive buffer size on the datagram socket. |
||
| 83 | Default value is <code>25188</code> bytes. |
||
| 84 | </td></tr><tr id="Attributes_Common Attributes_udpTxBufSize"><td><code class="attributeName">udpTxBufSize</code></td><td> |
||
| 85 | The send buffer size on the datagram socket. |
||
| 86 | Default value is <code>65536</code> bytes. |
||
| 87 | </td></tr><tr id="Attributes_Common Attributes_soKeepAlive"><td><code class="attributeName">soKeepAlive</code></td><td> |
||
| 88 | Boolean value for the socket SO_KEEPALIVE option. Possible values are <code>true</code> or <code>false</code>. |
||
| 89 | </td></tr><tr id="Attributes_Common Attributes_soLingerOn"><td><code class="attributeName">soLingerOn</code></td><td> |
||
| 90 | Boolean value to determine whether to use the SO_LINGER socket option. |
||
| 91 | Possible values are <code>true</code> or <code>false</code>. Default value is <code>true</code>. |
||
| 92 | </td></tr><tr id="Attributes_Common Attributes_soLingerTime"><td><code class="attributeName">soLingerTime</code></td><td> |
||
| 93 | Sets the SO_LINGER socket option time value. The value is in seconds. |
||
| 94 | The default value is <code>3</code> seconds. |
||
| 95 | </td></tr><tr id="Attributes_Common Attributes_soReuseAddress"><td><code class="attributeName">soReuseAddress</code></td><td> |
||
| 96 | Boolean value for the socket SO_REUSEADDR option. Possible values are <code>true</code> or <code>false</code>. |
||
| 97 | </td></tr><tr id="Attributes_Common Attributes_tcpNoDelay"><td><code class="attributeName">tcpNoDelay</code></td><td> |
||
| 98 | Boolean value for the socket TCP_NODELAY option. Possible values are <code>true</code> or <code>false</code>. |
||
| 99 | The default value is <code>true</code> |
||
| 100 | </td></tr><tr id="Attributes_Common Attributes_timeout"><td><code class="attributeName">timeout</code></td><td> |
||
| 101 | Sets the SO_TIMEOUT option on the socket. The value is in milliseconds and the default value is <code>3000</code> |
||
| 102 | milliseconds. |
||
| 103 | </td></tr><tr id="Attributes_Common Attributes_useBufferPool"><td><code class="attributeName">useBufferPool</code></td><td> |
||
| 104 | Boolean value whether to use a shared buffer pool of cached <code>org.apache.catalina.tribes.io.XByteBuffer</code> |
||
| 105 | objects. If set to true, the XByteBuffer that is used to pass a message up the channel, will be recycled at the end |
||
| 106 | of the requests. This means that interceptors in the channel must not maintain a reference to the object |
||
| 107 | after the <code>org.apache.catalina.tribes.ChannelInterceptor#messageReceived</code> method has exited. |
||
| 108 | </td></tr></table> |
||
| 109 | </div></div> |
||
| 110 | <div class="subsection"><h4 id="NioReceiver">NioReceiver</h4><div class="text"> |
||
| 111 | </div></div> |
||
| 112 | <div class="subsection"><h4 id="BioReceiver">BioReceiver</h4><div class="text"> |
||
| 113 | </div></div> |
||
| 114 | |||
| 115 | </div></div></div></div></div><footer><div id="footer"> |
||
| 116 | Copyright © 1999-2025, The Apache Software Foundation |
||
| 117 | <br> |
||
| 118 | Apache Tomcat, Tomcat, Apache, the Apache Tomcat logo and the Apache logo |
||
| 119 | are either registered trademarks or trademarks of the Apache Software |
||
| 120 | Foundation. |
||
| 121 | </div></footer></div></body></html> |