You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@activemq.apache.org by cl...@apache.org on 2017/09/14 19:48:13 UTC
svn commit: r1018163 [38/45] - in
/websites/production/activemq/content/artemis/docs: 2.2.0/ latest/
latest/diagrams/ latest/gitbook/ latest/gitbook/fonts/
latest/gitbook/fonts/fontawesome/
latest/gitbook/gitbook-plugin-fontsettings/ latest/gitbook/git...
Added: websites/production/activemq/content/artemis/docs/latest/send-guarantees.html
==============================================================================
--- websites/production/activemq/content/artemis/docs/latest/send-guarantees.html (added)
+++ websites/production/activemq/content/artemis/docs/latest/send-guarantees.html Thu Sep 14 19:48:11 2017
@@ -0,0 +1,1174 @@
+
+<!DOCTYPE HTML>
+<html lang="" >
+ <head>
+ <title>Guarantees of sends and commits · ActiveMQ Artemis Documentation</title>
+ <meta charset="UTF-8">
+ <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+ <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
+ <meta name="description" content="">
+ <meta name="generator" content="GitBook 3.1.1">
+
+
+
+
+ <link rel="stylesheet" href="gitbook/style.css">
+
+
+
+
+ <link rel="stylesheet" href="gitbook/gitbook-plugin-highlight/website.css">
+
+
+
+ <link rel="stylesheet" href="gitbook/gitbook-plugin-search/search.css">
+
+
+
+ <link rel="stylesheet" href="gitbook/gitbook-plugin-fontsettings/website.css">
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ <meta name="HandheldFriendly" content="true"/>
+ <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
+ <meta name="apple-mobile-web-app-capable" content="yes">
+ <meta name="apple-mobile-web-app-status-bar-style" content="black">
+ <link rel="apple-touch-icon-precomposed" sizes="152x152" href="gitbook/images/apple-touch-icon-precomposed-152.png">
+ <link rel="shortcut icon" href="gitbook/images/favicon.ico" type="image/x-icon">
+
+
+ <link rel="next" href="undelivered-messages.html" />
+
+
+ <link rel="prev" href="flow-control.html" />
+
+
+ </head>
+ <body>
+
+<div class="book">
+ <div class="book-summary">
+
+
+<div id="book-search-input" role="search">
+ <input type="text" placeholder="Type to search" />
+</div>
+
+
+ <nav role="navigation">
+
+
+
+<ul class="summary">
+
+
+
+
+
+
+
+
+
+ <li class="chapter " data-level="1.1" data-path="./">
+
+ <a href="./">
+
+
+ Introduction
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.2" data-path="notice.html">
+
+ <a href="notice.html">
+
+
+ Legal Notice
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.3" data-path="preface.html">
+
+ <a href="preface.html">
+
+
+ Preface
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.4" data-path="project-info.html">
+
+ <a href="project-info.html">
+
+
+ Project Info
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.5" data-path="messaging-concepts.html">
+
+ <a href="messaging-concepts.html">
+
+
+ Messaging Concepts
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.6" data-path="architecture.html">
+
+ <a href="architecture.html">
+
+
+ Architecture
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.7" data-path="using-server.html">
+
+ <a href="using-server.html">
+
+
+ Using the Server
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.8" data-path="address-model.html">
+
+ <a href="address-model.html">
+
+
+ Address Model
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.9" data-path="using-jms.html">
+
+ <a href="using-jms.html">
+
+
+ Using JMS
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.10" data-path="using-core.html">
+
+ <a href="using-core.html">
+
+
+ Using Core
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.11" data-path="using-AMQP.html">
+
+ <a href="using-AMQP.html">
+
+
+ Using AMQP
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.12" data-path="jms-core-mapping.html">
+
+ <a href="jms-core-mapping.html">
+
+
+ Mapping JMS Concepts to the Core API
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.13" data-path="client-classpath.html">
+
+ <a href="client-classpath.html">
+
+
+ The Client Classpath
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.14" data-path="examples.html">
+
+ <a href="examples.html">
+
+
+ Examples
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.15" data-path="wildcard-routing.html">
+
+ <a href="wildcard-routing.html">
+
+
+ Routing Messages With Wild Cards
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.16" data-path="wildcard-syntax.html">
+
+ <a href="wildcard-syntax.html">
+
+
+ Understanding the Apache ActiveMQ Artemis Wildcard Syntax
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.17" data-path="filter-expressions.html">
+
+ <a href="filter-expressions.html">
+
+
+ Filter Expressions
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.18" data-path="persistence.html">
+
+ <a href="persistence.html">
+
+
+ Persistence
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.19" data-path="configuring-transports.html">
+
+ <a href="configuring-transports.html">
+
+
+ Configuring Transports
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.20" data-path="config-reload.html">
+
+ <a href="config-reload.html">
+
+
+ Configuration Reload
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.21" data-path="connection-ttl.html">
+
+ <a href="connection-ttl.html">
+
+
+ Detecting Dead Connections
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.22" data-path="slow-consumers.html">
+
+ <a href="slow-consumers.html">
+
+
+ Detecting Slow Consumers
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.23" data-path="network-isolation.html">
+
+ <a href="network-isolation.html">
+
+
+ Avoiding Network Isolation
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.24" data-path="critical-analysis.html">
+
+ <a href="critical-analysis.html">
+
+
+ Detecting Broker Issues (Critical Analysis)
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.25" data-path="transaction-config.html">
+
+ <a href="transaction-config.html">
+
+
+ Resource Manager Configuration
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.26" data-path="flow-control.html">
+
+ <a href="flow-control.html">
+
+
+ Flow Control
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter active" data-level="1.27" data-path="send-guarantees.html">
+
+ <a href="send-guarantees.html">
+
+
+ Guarantees of sends and commits
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.28" data-path="undelivered-messages.html">
+
+ <a href="undelivered-messages.html">
+
+
+ Message Redelivery and Undelivered Messages
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.29" data-path="message-expiry.html">
+
+ <a href="message-expiry.html">
+
+
+ Message Expiry
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.30" data-path="large-messages.html">
+
+ <a href="large-messages.html">
+
+
+ Large Messages
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.31" data-path="paging.html">
+
+ <a href="paging.html">
+
+
+ Paging
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.32" data-path="queue-attributes.html">
+
+ <a href="queue-attributes.html">
+
+
+ Queue Attributes
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.33" data-path="scheduled-messages.html">
+
+ <a href="scheduled-messages.html">
+
+
+ Scheduled Messages
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.34" data-path="last-value-queues.html">
+
+ <a href="last-value-queues.html">
+
+
+ Last-Value Queues
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.35" data-path="message-grouping.html">
+
+ <a href="message-grouping.html">
+
+
+ Message Grouping
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.36" data-path="pre-acknowledge.html">
+
+ <a href="pre-acknowledge.html">
+
+
+ Extra Acknowledge Modes
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.37" data-path="management.html">
+
+ <a href="management.html">
+
+
+ Management
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.38" data-path="management-console.html">
+
+ <a href="management-console.html">
+
+
+ Management Console
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.39" data-path="security.html">
+
+ <a href="security.html">
+
+
+ Security
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.40" data-path="broker-plugins.html">
+
+ <a href="broker-plugins.html">
+
+
+ Broker Plugins
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.41" data-path="resource-limits.html">
+
+ <a href="resource-limits.html">
+
+
+ Resource Limits
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.42" data-path="jms-bridge.html">
+
+ <a href="jms-bridge.html">
+
+
+ The JMS Bridge
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.43" data-path="client-reconnection.html">
+
+ <a href="client-reconnection.html">
+
+
+ Client Reconnection and Session Reattachment
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.44" data-path="diverts.html">
+
+ <a href="diverts.html">
+
+
+ Diverting and Splitting Message Flows
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.45" data-path="core-bridges.html">
+
+ <a href="core-bridges.html">
+
+
+ Core Bridges
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.46" data-path="duplicate-detection.html">
+
+ <a href="duplicate-detection.html">
+
+
+ Duplicate Message Detection
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.47" data-path="clusters.html">
+
+ <a href="clusters.html">
+
+
+ Clusters
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.48" data-path="ha.html">
+
+ <a href="ha.html">
+
+
+ High Availability and Failover
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.49" data-path="graceful-shutdown.html">
+
+ <a href="graceful-shutdown.html">
+
+
+ Graceful Server Shutdown
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.50" data-path="libaio.html">
+
+ <a href="libaio.html">
+
+
+ Libaio Native Libraries
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.51" data-path="thread-pooling.html">
+
+ <a href="thread-pooling.html">
+
+
+ Thread management
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.52" data-path="logging.html">
+
+ <a href="logging.html">
+
+
+ Logging
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.53" data-path="rest.html">
+
+ <a href="rest.html">
+
+
+ REST Interface
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.54" data-path="embedding-activemq.html">
+
+ <a href="embedding-activemq.html">
+
+
+ Embedding Apache ActiveMQ Artemis
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.55" data-path="karaf.html">
+
+ <a href="karaf.html">
+
+
+ Apache Karaf
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.56" data-path="spring-integration.html">
+
+ <a href="spring-integration.html">
+
+
+ Spring Integration
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.57" data-path="cdi-integration.html">
+
+ <a href="cdi-integration.html">
+
+
+ CDI Integration
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.58" data-path="intercepting-operations.html">
+
+ <a href="intercepting-operations.html">
+
+
+ Intercepting Operations
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.59" data-path="protocols-interoperability.html">
+
+ <a href="protocols-interoperability.html">
+
+
+ Protocols and Interoperability
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.60" data-path="tools.html">
+
+ <a href="tools.html">
+
+
+ Tools
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.61" data-path="maven-plugin.html">
+
+ <a href="maven-plugin.html">
+
+
+ Maven Plugin
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.62" data-path="unit-testing.html">
+
+ <a href="unit-testing.html">
+
+
+ Unit Testing
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.63" data-path="perf-tuning.html">
+
+ <a href="perf-tuning.html">
+
+
+ Troubleshooting and Performance Tuning
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.64" data-path="configuration-index.html">
+
+ <a href="configuration-index.html">
+
+
+ Configuration Reference
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.65" data-path="updating-artemis.html">
+
+ <a href="updating-artemis.html">
+
+
+ Updating Artemis
+
+ </a>
+
+
+
+ </li>
+
+
+
+
+ <li class="divider"></li>
+
+ <li>
+ <a href="https://www.gitbook.com" target="blank" class="gitbook-link">
+ Published with GitBook
+ </a>
+ </li>
+</ul>
+
+
+ </nav>
+
+
+ </div>
+
+ <div class="book-body">
+
+ <div class="body-inner">
+
+
+
+<div class="book-header" role="navigation">
+
+
+ <!-- Title -->
+ <h1>
+ <i class="fa fa-circle-o-notch fa-spin"></i>
+ <a href="." >Guarantees of sends and commits</a>
+ </h1>
+</div>
+
+
+
+
+ <div class="page-wrapper" tabindex="-1" role="main">
+ <div class="page-inner">
+
+<div id="book-search-results">
+ <div class="search-noresults">
+
+ <section class="normal markdown-section">
+
+ <h1 id="guarantees-of-sends-and-commits">Guarantees of sends and commits</h1>
+<h2 id="guarantees-of-transaction-completion">Guarantees of Transaction Completion</h2>
+<p>When committing or rolling back a transaction with Apache ActiveMQ Artemis, the request
+to commit or rollback is sent to the server, and the call will block on
+the client side until a response has been received from the server that
+the commit or rollback was executed.</p>
+<p>When the commit or rollback is received on the server, it will be
+committed to the journal, and depending on the value of the parameter
+<code>journal-sync-transactional</code> the server will ensure that the commit or
+rollback is durably persisted to storage before sending the response
+back to the client. If this parameter has the value <code>false</code> then commit
+or rollback may not actually get persisted to storage until some time
+after the response has been sent to the client. In event of server
+failure this may mean the commit or rollback never gets persisted to
+storage. The default value of this parameter is <code>true</code> so the client can
+be sure all transaction commits or rollbacks have been persisted to
+storage by the time the call to commit or rollback returns.</p>
+<p>Setting this parameter to <code>false</code> can improve performance at the expense
+of some loss of transaction durability.</p>
+<p>This parameter is set in <code>broker.xml</code></p>
+<h2 id="guarantees-of-non-transactional-message-sends">Guarantees of Non Transactional Message Sends</h2>
+<p>If you are sending messages to a server using a non transacted session,
+Apache ActiveMQ Artemis can be configured to block the call to send until the message
+has definitely reached the server, and a response has been sent back to
+the client. This can be configured individually for durable and
+non-durable messages, and is determined by the following two URL parameters:</p>
+<ul>
+<li><p><code>blockOnDurableSend</code>. If this is set to <code>true</code> then all calls to
+send for durable messages on non transacted sessions will block
+until the message has reached the server, and a response has been
+sent back. The default value is <code>true</code>.</p>
+</li>
+<li><p><code>blockOnNonDurableSend</code>. If this is set to <code>true</code> then all calls to
+send for non-durable messages on non transacted sessions will block
+until the message has reached the server, and a response has been
+sent back. The default value is <code>false</code>.</p>
+</li>
+</ul>
+<p>Setting block on sends to <code>true</code> can reduce performance since each send
+requires a network round trip before the next send can be performed.
+This means the performance of sending messages will be limited by the
+network round trip time (RTT) of your network, rather than the bandwidth
+of your network. For better performance we recommend either batching
+many messages sends together in a transaction since with a transactional
+session, only the commit / rollback blocks not every send, or, using
+Apache ActiveMQ Artemis's advanced <em>asynchronous send acknowledgements feature</em>
+described in Asynchronous Send Acknowledgements.</p>
+<p>When the server receives a message sent from a non transactional
+session, and that message is durable and the message is routed to at
+least one durable queue, then the server will persist the message in
+permanent storage. If the journal parameter
+<code>journal-sync-non-transactional</code> is set to <code>true</code> the server will not
+send a response back to the client until the message has been persisted
+and the server has a guarantee that the data has been persisted to disk.
+The default value for this parameter is <code>true</code>.</p>
+<h2 id="guarantees-of-non-transactional-acknowledgements">Guarantees of Non Transactional Acknowledgements</h2>
+<p>If you are acknowledging the delivery of a message at the client side
+using a non transacted session, Apache ActiveMQ Artemis can be configured to block the
+call to acknowledge until the acknowledge has definitely reached the
+server, and a response has been sent back to the client. This is
+configured with the parameter <code>BlockOnAcknowledge</code>. If this is set to
+<code>true</code> then all calls to acknowledge on non transacted sessions will
+block until the acknowledge has reached the server, and a response has
+been sent back. You might want to set this to <code>true</code> if you want to
+implement a strict <em>at most once</em> delivery policy. The default value is
+<code>false</code></p>
+<h2 id="asynchronous-send-acknowledgements">Asynchronous Send Acknowledgements</h2>
+<p>If you are using a non transacted session but want a guarantee that
+every message sent to the server has reached it, then, as discussed in
+Guarantees of Non Transactional Message Sends, you can configure Apache ActiveMQ Artemis to block the call to send until the server
+has received the message, persisted it and sent back a response. This
+works well but has a severe performance penalty - each call to send
+needs to block for at least the time of a network round trip (RTT) - the
+performance of sending is thus limited by the latency of the network,
+<em>not</em> limited by the network bandwidth.</p>
+<p>Let's do a little bit of maths to see how severe that is. We'll consider
+a standard 1Gib ethernet network with a network round trip between the
+server and the client of 0.25 ms.</p>
+<p>With a RTT of 0.25 ms, the client can send <em>at most</em> 1000/ 0.25 = 4000
+messages per second if it blocks on each message send.</p>
+<p>If each message is < 1500 bytes and a standard 1500 bytes MTU (Maximum Transmission Unit) size is
+used on the network, then a 1GiB network has a <em>theoretical</em> upper limit
+of (1024 * 1024 * 1024 / 8) / 1500 = 89478 messages per second if
+messages are sent without blocking! These figures aren't an exact
+science but you can clearly see that being limited by network RTT can
+have serious effect on performance.</p>
+<p>To remedy this, Apache ActiveMQ Artemis provides an advanced new feature called
+<em>asynchronous send acknowledgements</em>. With this feature, Apache ActiveMQ Artemis can be
+configured to send messages without blocking in one direction and
+asynchronously getting acknowledgement from the server that the messages
+were received in a separate stream. By de-coupling the send from the
+acknowledgement of the send, the system is not limited by the network
+RTT, but is limited by the network bandwidth. Consequently better
+throughput can be achieved than is possible using a blocking approach,
+while at the same time having absolute guarantees that messages have
+successfully reached the server.</p>
+<p>The window size for send acknowledgements is determined by the
+confirmation-window-size parameter on the connection factory or client
+session factory. Please see <a href="client-reconnection.html">Client Reconnection and Session Reattachment</a> for more info on this.</p>
+<h1 id="asynchronous-send-acknowledgements">Asynchronous Send Acknowledgements</h1>
+<p>To use the feature using the core API, you implement the interface
+<code>org.apache.activemq.artemis.api.core.client.SendAcknowledgementHandler</code> and set
+a handler instance on your <code>ClientSession</code>.</p>
+<p>Then, you just send messages as normal using your <code>ClientSession</code>, and
+as messages reach the server, the server will send back an
+acknowledgement of the send asynchronously, and some time later you are
+informed at the client side by Apache ActiveMQ Artemis calling your handler's
+<code>sendAcknowledged(ClientMessage message)</code> method, passing in a reference
+to the message that was sent.</p>
+<p>To enable asynchronous send acknowledgements you must make sure
+<code>confirmationWindowSize</code> is set to a positive integer value, e.g.
+10MiB</p>
+<p>Please see <a href="examples.html">the examples chapter</a> for a full working example.</p>
+
+
+ </section>
+
+ </div>
+ <div class="search-results">
+ <div class="has-results">
+
+ <h1 class="search-results-title"><span class='search-results-count'></span> results matching "<span class='search-query'></span>"</h1>
+ <ul class="search-results-list"></ul>
+
+ </div>
+ <div class="no-results">
+
+ <h1 class="search-results-title">No results matching "<span class='search-query'></span>"</h1>
+
+ </div>
+ </div>
+</div>
+
+ </div>
+ </div>
+
+ </div>
+
+
+
+ <a href="flow-control.html" class="navigation navigation-prev " aria-label="Previous page: Flow Control">
+ <i class="fa fa-angle-left"></i>
+ </a>
+
+
+ <a href="undelivered-messages.html" class="navigation navigation-next " aria-label="Next page: Message Redelivery and Undelivered Messages">
+ <i class="fa fa-angle-right"></i>
+ </a>
+
+
+
+ </div>
+
+ <script>
+ var gitbook = gitbook || [];
+ gitbook.push(function() {
+ gitbook.page.hasChanged({"page":{"title":"Guarantees of sends and commits","level":"1.27","depth":1,"next":{"title":"Message Redelivery and Undelivered Messages","level":"1.28","depth":1,"path":"undelivered-messages.md","ref":"undelivered-messages.md","articles":[]},"previous":{"title":"Flow Control","level":"1.26","depth":1,"path":"flow-control.md","ref":"flow-control.md","articles":[]},"dir":"ltr"},"config":{"plugins":[],"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"highlight":{},"search":{},"lunr":{"maxIndexSize":1000000},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"fontsettings":{"theme":"white","family":"sans","size":2},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"style
s/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false}},"github":"apache/activemq-artemis","theme":"default","githubHost":"https://github.com/","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"README.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"title":"ActiveMQ Artemis Documentation","links":{"home":"http://activemq.apache.org/artemis","issues":"https://issues.apache.org/jira/browse/ARTEMIS","contribute":"http://activemq.apache.org/contributing.html"},"gitbook":"3.x.x","description":"ActiveMQ Artemis User Guide and Reference Documentation"},"file":{"path":"send-guarantees.md","mtime":"2017-09-08T01:26:53.000Z","type":"markdown"},"gitbook":{"version":"3.1.1","time":"2017-09-14T19:42:32.953Z"},"basePath":".","book":{"language":""}});
+ });
+ </script>
+</div>
+
+
+ <script src="gitbook/gitbook.js"></script>
+ <script src="gitbook/theme.js"></script>
+
+
+ <script src="gitbook/gitbook-plugin-search/search-engine.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-search/search.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-lunr/lunr.min.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-lunr/search-lunr.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-sharing/buttons.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-fontsettings/fontsettings.js"></script>
+
+
+
+ </body>
+</html>
+
Added: websites/production/activemq/content/artemis/docs/latest/slow-consumers.html
==============================================================================
--- websites/production/activemq/content/artemis/docs/latest/slow-consumers.html (added)
+++ websites/production/activemq/content/artemis/docs/latest/slow-consumers.html Thu Sep 14 19:48:11 2017
@@ -0,0 +1,1091 @@
+
+<!DOCTYPE HTML>
+<html lang="" >
+ <head>
+ <title>Detecting Slow Consumers · ActiveMQ Artemis Documentation</title>
+ <meta charset="UTF-8">
+ <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+ <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
+ <meta name="description" content="">
+ <meta name="generator" content="GitBook 3.1.1">
+
+
+
+
+ <link rel="stylesheet" href="gitbook/style.css">
+
+
+
+
+ <link rel="stylesheet" href="gitbook/gitbook-plugin-highlight/website.css">
+
+
+
+ <link rel="stylesheet" href="gitbook/gitbook-plugin-search/search.css">
+
+
+
+ <link rel="stylesheet" href="gitbook/gitbook-plugin-fontsettings/website.css">
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ <meta name="HandheldFriendly" content="true"/>
+ <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
+ <meta name="apple-mobile-web-app-capable" content="yes">
+ <meta name="apple-mobile-web-app-status-bar-style" content="black">
+ <link rel="apple-touch-icon-precomposed" sizes="152x152" href="gitbook/images/apple-touch-icon-precomposed-152.png">
+ <link rel="shortcut icon" href="gitbook/images/favicon.ico" type="image/x-icon">
+
+
+ <link rel="next" href="network-isolation.html" />
+
+
+ <link rel="prev" href="connection-ttl.html" />
+
+
+ </head>
+ <body>
+
+<div class="book">
+ <div class="book-summary">
+
+
+<div id="book-search-input" role="search">
+ <input type="text" placeholder="Type to search" />
+</div>
+
+
+ <nav role="navigation">
+
+
+
+<ul class="summary">
+
+
+
+
+
+
+
+
+
+ <li class="chapter " data-level="1.1" data-path="./">
+
+ <a href="./">
+
+
+ Introduction
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.2" data-path="notice.html">
+
+ <a href="notice.html">
+
+
+ Legal Notice
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.3" data-path="preface.html">
+
+ <a href="preface.html">
+
+
+ Preface
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.4" data-path="project-info.html">
+
+ <a href="project-info.html">
+
+
+ Project Info
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.5" data-path="messaging-concepts.html">
+
+ <a href="messaging-concepts.html">
+
+
+ Messaging Concepts
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.6" data-path="architecture.html">
+
+ <a href="architecture.html">
+
+
+ Architecture
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.7" data-path="using-server.html">
+
+ <a href="using-server.html">
+
+
+ Using the Server
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.8" data-path="address-model.html">
+
+ <a href="address-model.html">
+
+
+ Address Model
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.9" data-path="using-jms.html">
+
+ <a href="using-jms.html">
+
+
+ Using JMS
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.10" data-path="using-core.html">
+
+ <a href="using-core.html">
+
+
+ Using Core
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.11" data-path="using-AMQP.html">
+
+ <a href="using-AMQP.html">
+
+
+ Using AMQP
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.12" data-path="jms-core-mapping.html">
+
+ <a href="jms-core-mapping.html">
+
+
+ Mapping JMS Concepts to the Core API
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.13" data-path="client-classpath.html">
+
+ <a href="client-classpath.html">
+
+
+ The Client Classpath
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.14" data-path="examples.html">
+
+ <a href="examples.html">
+
+
+ Examples
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.15" data-path="wildcard-routing.html">
+
+ <a href="wildcard-routing.html">
+
+
+ Routing Messages With Wild Cards
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.16" data-path="wildcard-syntax.html">
+
+ <a href="wildcard-syntax.html">
+
+
+ Understanding the Apache ActiveMQ Artemis Wildcard Syntax
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.17" data-path="filter-expressions.html">
+
+ <a href="filter-expressions.html">
+
+
+ Filter Expressions
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.18" data-path="persistence.html">
+
+ <a href="persistence.html">
+
+
+ Persistence
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.19" data-path="configuring-transports.html">
+
+ <a href="configuring-transports.html">
+
+
+ Configuring Transports
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.20" data-path="config-reload.html">
+
+ <a href="config-reload.html">
+
+
+ Configuration Reload
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.21" data-path="connection-ttl.html">
+
+ <a href="connection-ttl.html">
+
+
+ Detecting Dead Connections
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter active" data-level="1.22" data-path="slow-consumers.html">
+
+ <a href="slow-consumers.html">
+
+
+ Detecting Slow Consumers
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.23" data-path="network-isolation.html">
+
+ <a href="network-isolation.html">
+
+
+ Avoiding Network Isolation
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.24" data-path="critical-analysis.html">
+
+ <a href="critical-analysis.html">
+
+
+ Detecting Broker Issues (Critical Analysis)
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.25" data-path="transaction-config.html">
+
+ <a href="transaction-config.html">
+
+
+ Resource Manager Configuration
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.26" data-path="flow-control.html">
+
+ <a href="flow-control.html">
+
+
+ Flow Control
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.27" data-path="send-guarantees.html">
+
+ <a href="send-guarantees.html">
+
+
+ Guarantees of sends and commits
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.28" data-path="undelivered-messages.html">
+
+ <a href="undelivered-messages.html">
+
+
+ Message Redelivery and Undelivered Messages
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.29" data-path="message-expiry.html">
+
+ <a href="message-expiry.html">
+
+
+ Message Expiry
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.30" data-path="large-messages.html">
+
+ <a href="large-messages.html">
+
+
+ Large Messages
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.31" data-path="paging.html">
+
+ <a href="paging.html">
+
+
+ Paging
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.32" data-path="queue-attributes.html">
+
+ <a href="queue-attributes.html">
+
+
+ Queue Attributes
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.33" data-path="scheduled-messages.html">
+
+ <a href="scheduled-messages.html">
+
+
+ Scheduled Messages
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.34" data-path="last-value-queues.html">
+
+ <a href="last-value-queues.html">
+
+
+ Last-Value Queues
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.35" data-path="message-grouping.html">
+
+ <a href="message-grouping.html">
+
+
+ Message Grouping
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.36" data-path="pre-acknowledge.html">
+
+ <a href="pre-acknowledge.html">
+
+
+ Extra Acknowledge Modes
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.37" data-path="management.html">
+
+ <a href="management.html">
+
+
+ Management
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.38" data-path="management-console.html">
+
+ <a href="management-console.html">
+
+
+ Management Console
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.39" data-path="security.html">
+
+ <a href="security.html">
+
+
+ Security
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.40" data-path="broker-plugins.html">
+
+ <a href="broker-plugins.html">
+
+
+ Broker Plugins
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.41" data-path="resource-limits.html">
+
+ <a href="resource-limits.html">
+
+
+ Resource Limits
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.42" data-path="jms-bridge.html">
+
+ <a href="jms-bridge.html">
+
+
+ The JMS Bridge
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.43" data-path="client-reconnection.html">
+
+ <a href="client-reconnection.html">
+
+
+ Client Reconnection and Session Reattachment
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.44" data-path="diverts.html">
+
+ <a href="diverts.html">
+
+
+ Diverting and Splitting Message Flows
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.45" data-path="core-bridges.html">
+
+ <a href="core-bridges.html">
+
+
+ Core Bridges
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.46" data-path="duplicate-detection.html">
+
+ <a href="duplicate-detection.html">
+
+
+ Duplicate Message Detection
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.47" data-path="clusters.html">
+
+ <a href="clusters.html">
+
+
+ Clusters
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.48" data-path="ha.html">
+
+ <a href="ha.html">
+
+
+ High Availability and Failover
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.49" data-path="graceful-shutdown.html">
+
+ <a href="graceful-shutdown.html">
+
+
+ Graceful Server Shutdown
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.50" data-path="libaio.html">
+
+ <a href="libaio.html">
+
+
+ Libaio Native Libraries
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.51" data-path="thread-pooling.html">
+
+ <a href="thread-pooling.html">
+
+
+ Thread management
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.52" data-path="logging.html">
+
+ <a href="logging.html">
+
+
+ Logging
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.53" data-path="rest.html">
+
+ <a href="rest.html">
+
+
+ REST Interface
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.54" data-path="embedding-activemq.html">
+
+ <a href="embedding-activemq.html">
+
+
+ Embedding Apache ActiveMQ Artemis
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.55" data-path="karaf.html">
+
+ <a href="karaf.html">
+
+
+ Apache Karaf
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.56" data-path="spring-integration.html">
+
+ <a href="spring-integration.html">
+
+
+ Spring Integration
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.57" data-path="cdi-integration.html">
+
+ <a href="cdi-integration.html">
+
+
+ CDI Integration
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.58" data-path="intercepting-operations.html">
+
+ <a href="intercepting-operations.html">
+
+
+ Intercepting Operations
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.59" data-path="protocols-interoperability.html">
+
+ <a href="protocols-interoperability.html">
+
+
+ Protocols and Interoperability
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.60" data-path="tools.html">
+
+ <a href="tools.html">
+
+
+ Tools
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.61" data-path="maven-plugin.html">
+
+ <a href="maven-plugin.html">
+
+
+ Maven Plugin
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.62" data-path="unit-testing.html">
+
+ <a href="unit-testing.html">
+
+
+ Unit Testing
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.63" data-path="perf-tuning.html">
+
+ <a href="perf-tuning.html">
+
+
+ Troubleshooting and Performance Tuning
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.64" data-path="configuration-index.html">
+
+ <a href="configuration-index.html">
+
+
+ Configuration Reference
+
+ </a>
+
+
+
+ </li>
+
+ <li class="chapter " data-level="1.65" data-path="updating-artemis.html">
+
+ <a href="updating-artemis.html">
+
+
+ Updating Artemis
+
+ </a>
+
+
+
+ </li>
+
+
+
+
+ <li class="divider"></li>
+
+ <li>
+ <a href="https://www.gitbook.com" target="blank" class="gitbook-link">
+ Published with GitBook
+ </a>
+ </li>
+</ul>
+
+
+ </nav>
+
+
+ </div>
+
+ <div class="book-body">
+
+ <div class="body-inner">
+
+
+
+<div class="book-header" role="navigation">
+
+
+ <!-- Title -->
+ <h1>
+ <i class="fa fa-circle-o-notch fa-spin"></i>
+ <a href="." >Detecting Slow Consumers</a>
+ </h1>
+</div>
+
+
+
+
+ <div class="page-wrapper" tabindex="-1" role="main">
+ <div class="page-inner">
+
+<div id="book-search-results">
+ <div class="search-noresults">
+
+ <section class="normal markdown-section">
+
+ <h1 id="detecting-slow-consumers">Detecting Slow Consumers</h1>
+<p>In this section we will discuss how Apache ActiveMQ Artemis can be configured to deal
+with slow consumers. A slow consumer with a server-side queue (e.g. JMS
+topic subscriber) can pose a significant problem for broker performance.
+If messages build up in the consumer's server-side queue then memory
+will begin filling up and the broker may enter paging mode which would
+impact performance negatively. However, criteria can be set so that
+consumers which don't acknowledge messages quickly enough can
+potentially be disconnected from the broker which in the case of a
+non-durable JMS subscriber would allow the broker to remove the
+subscription and all of its messages freeing up valuable server
+resources.</p>
+<h2 id="configuration-required-for-detecting-slow-consumers">Configuration required for detecting slow consumers</h2>
+<p>By default the server will not detect slow consumers. If slow consumer
+detection is desired then see <a href="queue-attributes.html">queue attributes chapter</a>
+for more details.</p>
+<p>The calculation to determine whether or not a consumer is slow only
+inspects the number of messages a particular consumer has
+<em>acknowledged</em>. It doesn't take into account whether or not flow control
+has been enabled on the consumer, whether or not the consumer is
+streaming a large message, etc. Keep this in mind when configuring slow
+consumer detection.</p>
+<p>Please note that slow consumer checks are performed using the scheduled
+thread pool and that each queue on the broker with slow consumer
+detection enabled will cause a new entry in the internal
+<code>java.util.concurrent.ScheduledThreadPoolExecutor</code> instance. If there
+are a high number of queues and the <code>slow-consumer-check-period</code> is
+relatively low then there may be delays in executing some of the checks.
+However, this will not impact the accuracy of the calculations used by
+the detection algorithm. See <a href="thread-pooling.html">thread pooling</a> for more details about this pool.</p>
+
+
+ </section>
+
+ </div>
+ <div class="search-results">
+ <div class="has-results">
+
+ <h1 class="search-results-title"><span class='search-results-count'></span> results matching "<span class='search-query'></span>"</h1>
+ <ul class="search-results-list"></ul>
+
+ </div>
+ <div class="no-results">
+
+ <h1 class="search-results-title">No results matching "<span class='search-query'></span>"</h1>
+
+ </div>
+ </div>
+</div>
+
+ </div>
+ </div>
+
+ </div>
+
+
+
+ <a href="connection-ttl.html" class="navigation navigation-prev " aria-label="Previous page: Detecting Dead Connections">
+ <i class="fa fa-angle-left"></i>
+ </a>
+
+
+ <a href="network-isolation.html" class="navigation navigation-next " aria-label="Next page: Avoiding Network Isolation">
+ <i class="fa fa-angle-right"></i>
+ </a>
+
+
+
+ </div>
+
+ <script>
+ var gitbook = gitbook || [];
+ gitbook.push(function() {
+ gitbook.page.hasChanged({"page":{"title":"Detecting Slow Consumers","level":"1.22","depth":1,"next":{"title":"Avoiding Network Isolation","level":"1.23","depth":1,"path":"network-isolation.md","ref":"network-isolation.md","articles":[]},"previous":{"title":"Detecting Dead Connections","level":"1.21","depth":1,"path":"connection-ttl.md","ref":"connection-ttl.md","articles":[]},"dir":"ltr"},"config":{"plugins":[],"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"highlight":{},"search":{},"lunr":{"maxIndexSize":1000000},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"fontsettings":{"theme":"white","family":"sans","size":2},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css",
"mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false}},"github":"apache/activemq-artemis","theme":"default","githubHost":"https://github.com/","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"README.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"title":"ActiveMQ Artemis Documentation","links":{"home":"http://activemq.apache.org/artemis","issues":"https://issues.apache.org/jira/browse/ARTEMIS","contribute":"http://activemq.apache.org/contributing.html"},"gitbook":"3.x.x","description":"ActiveMQ Artemis User Guide and Reference Documentation"},"file":{"path":"slow-consumers.md","mtime":"2017-09-08T01:26:53.000Z","type":"markdown"},"gitbook":{"version":"3.1.1","time":"2017-09-14T19:42:32.953Z"},"basePath":".","book":{"language":""}});
+ });
+ </script>
+</div>
+
+
+ <script src="gitbook/gitbook.js"></script>
+ <script src="gitbook/theme.js"></script>
+
+
+ <script src="gitbook/gitbook-plugin-search/search-engine.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-search/search.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-lunr/lunr.min.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-lunr/search-lunr.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-sharing/buttons.js"></script>
+
+
+
+ <script src="gitbook/gitbook-plugin-fontsettings/fontsettings.js"></script>
+
+
+
+ </body>
+</html>
+