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| Introduction |
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| <b>1.</b> |
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| <b>2.</b> |
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| Preface |
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| <b>4.</b> |
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| Messaging Concepts |
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| <b>5.</b> |
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| Architecture |
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| <b>6.</b> |
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| Using the Server |
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| <b>7.</b> |
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| Using JMS |
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| <a href="./using-core.html"> |
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| <b>8.</b> |
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| Using Core |
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| <li class="chapter " data-level="9" data-path="jms-core-mapping.html"> |
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| <a href="./jms-core-mapping.html"> |
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| <b>9.</b> |
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| Mapping JMS Concepts to the Core API |
| </a> |
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| </li> |
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| <li class="chapter " data-level="10" data-path="client-classpath.html"> |
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| <a href="./client-classpath.html"> |
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| <b>10.</b> |
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| The Client Classpath |
| </a> |
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| <b>11.</b> |
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| Examples |
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| <li class="chapter " data-level="12" data-path="wildcard-routing.html"> |
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| <a href="./wildcard-routing.html"> |
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| <b>12.</b> |
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| Routing Messages With Wild Cards |
| </a> |
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| </li> |
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| <li class="chapter " data-level="13" data-path="wildcard-syntax.html"> |
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| <a href="./wildcard-syntax.html"> |
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| <b>13.</b> |
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| Understanding the Apache ActiveMQ Artemis Wildcard Syntax |
| </a> |
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| </li> |
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| <li class="chapter " data-level="14" data-path="filter-expressions.html"> |
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| <a href="./filter-expressions.html"> |
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| <b>14.</b> |
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| Filter Expressions |
| </a> |
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| </li> |
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| <li class="chapter " data-level="15" data-path="persistence.html"> |
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| <a href="./persistence.html"> |
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| <b>15.</b> |
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| Persistence |
| </a> |
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| <li class="chapter " data-level="16" data-path="configuring-transports.html"> |
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| <a href="./configuring-transports.html"> |
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| <b>16.</b> |
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| Configuring Transports |
| </a> |
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| </li> |
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| <li class="chapter active" data-level="17" data-path="connection-ttl.html"> |
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| <a href="./connection-ttl.html"> |
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| <b>17.</b> |
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| Detecting Dead Connections |
| </a> |
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| </li> |
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| <li class="chapter " data-level="18" data-path="slow-consumers.html"> |
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| <a href="./slow-consumers.html"> |
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| <b>18.</b> |
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| Detecting Slow Consumers |
| </a> |
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| </li> |
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| <li class="chapter " data-level="19" data-path="transaction-config.html"> |
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| <a href="./transaction-config.html"> |
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| <b>19.</b> |
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| Resource Manager Configuration |
| </a> |
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| </li> |
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| <li class="chapter " data-level="20" data-path="flow-control.html"> |
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| <a href="./flow-control.html"> |
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| <b>20.</b> |
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| Flow Control |
| </a> |
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| </li> |
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| <li class="chapter " data-level="21" data-path="send-guarantees.html"> |
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| <a href="./send-guarantees.html"> |
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| <b>21.</b> |
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| Guarantees of sends and commits |
| </a> |
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| </li> |
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| <li class="chapter " data-level="22" data-path="undelivered-messages.html"> |
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| <a href="./undelivered-messages.html"> |
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| <b>22.</b> |
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| Message Redelivery and Undelivered Messages |
| </a> |
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| </li> |
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| <li class="chapter " data-level="23" data-path="message-expiry.html"> |
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| <a href="./message-expiry.html"> |
| <i class="fa fa-check"></i> |
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| <b>23.</b> |
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| Message Expiry |
| </a> |
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| </li> |
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| <li class="chapter " data-level="24" data-path="large-messages.html"> |
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| <a href="./large-messages.html"> |
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| <b>24.</b> |
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| Large Messages |
| </a> |
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| </li> |
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| <li class="chapter " data-level="25" data-path="paging.html"> |
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| <a href="./paging.html"> |
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| <b>25.</b> |
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| Paging |
| </a> |
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| </li> |
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| <li class="chapter " data-level="26" data-path="queue-attributes.html"> |
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| <a href="./queue-attributes.html"> |
| <i class="fa fa-check"></i> |
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| <b>26.</b> |
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| Queue Attributes |
| </a> |
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| </li> |
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| <li class="chapter " data-level="27" data-path="scheduled-messages.html"> |
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| <a href="./scheduled-messages.html"> |
| <i class="fa fa-check"></i> |
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| <b>27.</b> |
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| Scheduled Messages |
| </a> |
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| </li> |
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| <li class="chapter " data-level="28" data-path="last-value-queues.html"> |
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| <a href="./last-value-queues.html"> |
| <i class="fa fa-check"></i> |
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| <b>28.</b> |
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| Last-Value Queues |
| </a> |
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| </li> |
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| <li class="chapter " data-level="29" data-path="message-grouping.html"> |
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| <a href="./message-grouping.html"> |
| <i class="fa fa-check"></i> |
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| <b>29.</b> |
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| Message Grouping |
| </a> |
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| </li> |
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| <li class="chapter " data-level="30" data-path="pre-acknowledge.html"> |
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| <a href="./pre-acknowledge.html"> |
| <i class="fa fa-check"></i> |
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| <b>30.</b> |
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| Extra Acknowledge Modes |
| </a> |
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| </li> |
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| <li class="chapter " data-level="31" data-path="management.html"> |
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| <a href="./management.html"> |
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| <b>31.</b> |
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| Management |
| </a> |
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| </li> |
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| <li class="chapter " data-level="32" data-path="security.html"> |
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| <a href="./security.html"> |
| <i class="fa fa-check"></i> |
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| <b>32.</b> |
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| Security |
| </a> |
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| </li> |
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| <li class="chapter " data-level="33" data-path="resource-limits.html"> |
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| <a href="./resource-limits.html"> |
| <i class="fa fa-check"></i> |
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| <b>33.</b> |
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| Resource Limits |
| </a> |
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| </li> |
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| <li class="chapter " data-level="34" data-path="jms-bridge.html"> |
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| <a href="./jms-bridge.html"> |
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| <b>34.</b> |
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| The JMS Bridge |
| </a> |
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| </li> |
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| <li class="chapter " data-level="35" data-path="client-reconnection.html"> |
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| <a href="./client-reconnection.html"> |
| <i class="fa fa-check"></i> |
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| <b>35.</b> |
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| Client Reconnection and Session Reattachment |
| </a> |
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| </li> |
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| <li class="chapter " data-level="36" data-path="diverts.html"> |
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| <a href="./diverts.html"> |
| <i class="fa fa-check"></i> |
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| <b>36.</b> |
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| Diverting and Splitting Message Flows |
| </a> |
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| </li> |
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| <li class="chapter " data-level="37" data-path="core-bridges.html"> |
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| <a href="./core-bridges.html"> |
| <i class="fa fa-check"></i> |
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| <b>37.</b> |
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| Core Bridges |
| </a> |
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| </li> |
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| <li class="chapter " data-level="38" data-path="duplicate-detection.html"> |
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| <a href="./duplicate-detection.html"> |
| <i class="fa fa-check"></i> |
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| <b>38.</b> |
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| Duplicate Message Detection |
| </a> |
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| </li> |
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| <li class="chapter " data-level="39" data-path="clusters.html"> |
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| <a href="./clusters.html"> |
| <i class="fa fa-check"></i> |
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| <b>39.</b> |
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| Clusters |
| </a> |
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| </li> |
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| <li class="chapter " data-level="40" data-path="ha.html"> |
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| <a href="./ha.html"> |
| <i class="fa fa-check"></i> |
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| <b>40.</b> |
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| High Availability and Failover |
| </a> |
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| </li> |
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| <li class="chapter " data-level="41" data-path="graceful-shutdown.html"> |
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| <a href="./graceful-shutdown.html"> |
| <i class="fa fa-check"></i> |
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| <b>41.</b> |
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| Graceful Server Shutdown |
| </a> |
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| </li> |
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| <li class="chapter " data-level="42" data-path="libaio.html"> |
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| <a href="./libaio.html"> |
| <i class="fa fa-check"></i> |
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| <b>42.</b> |
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| Libaio Native Libraries |
| </a> |
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| </li> |
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| <li class="chapter " data-level="43" data-path="thread-pooling.html"> |
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| <a href="./thread-pooling.html"> |
| <i class="fa fa-check"></i> |
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| <b>43.</b> |
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| Thread management |
| </a> |
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| </li> |
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| <li class="chapter " data-level="44" data-path="logging.html"> |
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| <a href="./logging.html"> |
| <i class="fa fa-check"></i> |
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| <b>44.</b> |
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| Logging |
| </a> |
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| </li> |
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| <li class="chapter " data-level="45" data-path="rest.html"> |
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| <a href="./rest.html"> |
| <i class="fa fa-check"></i> |
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| <b>45.</b> |
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| REST Interface |
| </a> |
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| </li> |
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| <li class="chapter " data-level="46" data-path="embedding-activemq.html"> |
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| <a href="./embedding-activemq.html"> |
| <i class="fa fa-check"></i> |
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| <b>46.</b> |
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| Embedding Apache ActiveMQ Artemis |
| </a> |
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| </li> |
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| <li class="chapter " data-level="47" data-path="spring-integration.html"> |
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| <a href="./spring-integration.html"> |
| <i class="fa fa-check"></i> |
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| <b>47.</b> |
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| Spring Integration |
| </a> |
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| </li> |
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| <li class="chapter " data-level="48" data-path="aerogear-integration.html"> |
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| <a href="./aerogear-integration.html"> |
| <i class="fa fa-check"></i> |
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| <b>48.</b> |
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| AeroGear Integration |
| </a> |
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| </li> |
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| <li class="chapter " data-level="49" data-path="vertx-integration.html"> |
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| <a href="./vertx-integration.html"> |
| <i class="fa fa-check"></i> |
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| <b>49.</b> |
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| VertX Integration |
| </a> |
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| </li> |
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| <li class="chapter " data-level="50" data-path="intercepting-operations.html"> |
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| <a href="./intercepting-operations.html"> |
| <i class="fa fa-check"></i> |
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| <b>50.</b> |
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| Intercepting Operations |
| </a> |
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| </li> |
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| <li class="chapter " data-level="51" data-path="protocols-interoperability.html"> |
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| <a href="./protocols-interoperability.html"> |
| <i class="fa fa-check"></i> |
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| <b>51.</b> |
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| Protocols and Interoperability |
| </a> |
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| </li> |
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| <li class="chapter " data-level="52" data-path="tools.html"> |
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| <a href="./tools.html"> |
| <i class="fa fa-check"></i> |
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| <b>52.</b> |
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| Tools |
| </a> |
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| </li> |
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| <li class="chapter " data-level="53" data-path="maven-plugin.html"> |
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| <a href="./maven-plugin.html"> |
| <i class="fa fa-check"></i> |
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| <b>53.</b> |
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| Maven Plugin |
| </a> |
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| |
| </li> |
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| <li class="chapter " data-level="54" data-path="perf-tuning.html"> |
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| <a href="./perf-tuning.html"> |
| <i class="fa fa-check"></i> |
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| <b>54.</b> |
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| Troubleshooting and Performance Tuning |
| </a> |
| |
| |
| |
| </li> |
| |
| <li class="chapter " data-level="55" data-path="configuration-index.html"> |
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| |
| <a href="./configuration-index.html"> |
| <i class="fa fa-check"></i> |
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| <b>55.</b> |
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| Configuration Reference |
| </a> |
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| </li> |
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| Published with GitBook |
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| <!-- Title --> |
| <h1> |
| <i class="fa fa-circle-o-notch fa-spin"></i> |
| <a href="./" >ActiveMQ Artemis Documentation</a> |
| </h1> |
| </div> |
| |
| <div class="page-wrapper" tabindex="-1"> |
| <div class="page-inner"> |
| |
| |
| <section class="normal" id="section-"> |
| |
| <h1 id="detecting-dead-connections">Detecting Dead Connections</h1> |
| <p>In this section we will discuss connection time-to-live (TTL) and |
| explain how Apache ActiveMQ Artemis deals with crashed clients and clients which have |
| exited without cleanly closing their resources.</p> |
| <h2 id="cleaning-up-dead-connection-resources-on-the-server">Cleaning up Dead Connection Resources on the Server</h2> |
| <p>Before an Apache ActiveMQ Artemis client application exits it is considered good |
| practice that it should close its resources in a controlled manner, |
| using a <code>finally</code> block.</p> |
| <p>Here's an example of a well behaved core client application closing its |
| session and session factory in a finally block:</p> |
| <pre><code class="lang-java">ServerLocator locator = <span class="hljs-keyword">null</span>; |
| ClientSessionFactory sf = <span class="hljs-keyword">null</span>; |
| ClientSession session = <span class="hljs-keyword">null</span>; |
| |
| <span class="hljs-keyword">try</span> |
| { |
| locator = ActiveMQClient.createServerLocatorWithoutHA(..); |
| |
| sf = locator.createClientSessionFactory();; |
| |
| session = sf.createSession(...); |
| |
| ... do some stuff with the session... |
| } |
| <span class="hljs-keyword">finally</span> |
| { |
| <span class="hljs-keyword">if</span> (session != <span class="hljs-keyword">null</span>) |
| { |
| session.close(); |
| } |
| |
| <span class="hljs-keyword">if</span> (sf != <span class="hljs-keyword">null</span>) |
| { |
| sf.close(); |
| } |
| |
| <span class="hljs-keyword">if</span>(locator != <span class="hljs-keyword">null</span>) |
| { |
| locator.close(); |
| } |
| } |
| </code></pre> |
| <p>And here's an example of a well behaved JMS client application:</p> |
| <pre><code class="lang-java">Connection jmsConnection = <span class="hljs-keyword">null</span>; |
| |
| <span class="hljs-keyword">try</span> |
| { |
| ConnectionFactory jmsConnectionFactory = ActiveMQJMSClient.createConnectionFactoryWithoutHA(...); |
| |
| jmsConnection = jmsConnectionFactory.createConnection(); |
| |
| ... do some stuff with the connection... |
| } |
| <span class="hljs-keyword">finally</span> |
| { |
| <span class="hljs-keyword">if</span> (connection != <span class="hljs-keyword">null</span>) |
| { |
| connection.close(); |
| } |
| } |
| </code></pre> |
| <p>Unfortunately users don't always write well behaved applications, and |
| sometimes clients just crash so they don't have a chance to clean up |
| their resources!</p> |
| <p>If this occurs then it can leave server side resources, like sessions, |
| hanging on the server. If these were not removed they would cause a |
| resource leak on the server and over time this result in the server |
| running out of memory or other resources.</p> |
| <p>We have to balance the requirement for cleaning up dead client resources |
| with the fact that sometimes the network between the client and the |
| server can fail and then come back, allowing the client to reconnect. |
| Apache ActiveMQ Artemis supports client reconnection, so we don't want to clean up |
| "dead" server side resources too soon or this will prevent any client |
| from reconnecting, as it won't be able to find its old sessions on the |
| server.</p> |
| <p>Apache ActiveMQ Artemis makes all of this configurable. For each <code>ClientSessionFactory</code> |
| we define a <em>connection TTL</em>. Basically, the TTL determines how long the |
| server will keep a connection alive in the absence of any data arriving |
| from the client. The client will automatically send "ping" packets |
| periodically to prevent the server from closing it down. If the server |
| doesn't receive any packets on a connection for the connection TTL time, |
| then it will automatically close all the sessions on the server that |
| relate to that connection.</p> |
| <p>If you're using JMS, the connection TTL is defined by the |
| <code>ConnectionTTL</code> attribute on a <code>ActiveMQConnectionFactory</code> instance, or |
| if you're deploying JMS connection factory instances direct into JNDI on |
| the server side, you can specify it in the xml config, using the |
| parameter <code>connectionTtl</code>.</p> |
| <p>The default value for connection ttl on an "unreliable" connection (e.g. |
| a Netty connection) is <code>60000</code>ms, i.e. 1 minute. The default value for |
| connection ttl on a "reliable" connection (e.g. an in-vm connection) is |
| <code>-1</code>. A value of <code>-1</code> for <code>ConnectionTTL</code> means the server will never |
| time out the connection on the server side.</p> |
| <p>If you do not wish clients to be able to specify their own connection |
| TTL, you can override all values used by a global value set on the |
| server side. This can be done by specifying the |
| <code>connection-ttl-override</code> attribute in the server side configuration. |
| The default value for <code>connection-ttl-override</code> is <code>-1</code> which means "do |
| not override" (i.e. let clients use their own values).</p> |
| <h2 id="closing-core-sessions-or-jms-connections-that-you-have-failed-to-close">Closing core sessions or JMS connections that you have failed to close</h2> |
| <p>As previously discussed, it's important that all core client sessions |
| and JMS connections are always closed explicitly in a <code>finally</code> block |
| when you are finished using them.</p> |
| <p>If you fail to do so, Apache ActiveMQ Artemis will detect this at garbage collection |
| time, and log a warning similar to the following in the logs (If you are |
| using JMS the warning will involve a JMS connection not a client |
| session):</p> |
| <pre><code>[Finalizer] 20:14:43,244 WARNING [org.apache.activemq.artemis.core.client.impl.DelegatingSession] I'm closing a ClientSession you left open. Please make sure you close all ClientSessions explicitly before let |
| ting them go out of scope! |
| [Finalizer] 20:14:43,244 WARNING [org.apache.activemq.artemis.core.client.impl.DelegatingSession] The session you didn't close was created here: |
| java.lang.Exception |
| at org.apache.activemq.artemis.core.client.impl.DelegatingSession.<init>(DelegatingSession.java:83) |
| at org.acme.yourproject.YourClass (YourClass.java:666) |
| </code></pre><p>Apache ActiveMQ Artemis will then close the connection / client session for you.</p> |
| <p>Note that the log will also tell you the exact line of your user code |
| where you created the JMS connection / client session that you later did |
| not close. This will enable you to pinpoint the error in your code and |
| correct it appropriately.</p> |
| <h2 id="detecting-failure-from-the-client-side">Detecting failure from the client side.</h2> |
| <p>In the previous section we discussed how the client sends pings to the |
| server and how "dead" connection resources are cleaned up by the server. |
| There's also another reason for pinging, and that's for the <em>client</em> to |
| be able to detect that the server or network has failed.</p> |
| <p>As long as the client is receiving data from the server it will consider |
| the connection to be still alive.</p> |
| <p>If the client does not receive any packets for |
| <code>client-failure-check-period</code> milliseconds then it will consider the |
| connection failed and will either initiate failover, or call any |
| <code>FailureListener</code> instances (or <code>ExceptionListener</code> instances if you are |
| using JMS) depending on how it has been configured.</p> |
| <p>If you're using JMS it's defined by the <code>ClientFailureCheckPeriod</code> |
| attribute on a <code>ActiveMQConnectionFactory</code> instance..</p> |
| <p>The default value for client failure check period on an "unreliable" |
| connection (e.g. a Netty connection) is <code>30000</code>ms, i.e. 30 seconds. The |
| default value for client failure check period on a "reliable" connection |
| (e.g. an in-vm connection) is <code>-1</code>. A value of <code>-1</code> means the client |
| will never fail the connection on the client side if no data is received |
| from the server. Typically this is much lower than connection TTL to |
| allow clients to reconnect in case of transitory failure.</p> |
| <h2 id="configuring-asynchronous-connection-execution">Configuring Asynchronous Connection Execution</h2> |
| <p>Most packets received on the server side are executed on the remoting |
| thread. These packets represent short-running operations and are always |
| executed on the remoting thread for performance reasons.</p> |
| <p>However, by default some kinds of packets are executed using a thread |
| from a thread pool so that the remoting thread is not tied up for too |
| long. Please note that processing operations asynchronously on another |
| thread adds a little more latency. These packets are:</p> |
| <ul> |
| <li><p><code>org.apache.activemq.artemis.core.protocol.core.impl.wireformat.RollbackMessage</code></p> |
| </li> |
| <li><p><code>org.apache.activemq.artemis.core.protocol.core.impl.wireformat.SessionCloseMessage</code></p> |
| </li> |
| <li><p><code>org.apache.activemq.artemis.core.protocol.core.impl.wireformat.SessionCommitMessage</code></p> |
| </li> |
| <li><p><code>org.apache.activemq.artemis.core.protocol.core.impl.wireformat.SessionXACommitMessage</code></p> |
| </li> |
| <li><p><code>org.apache.activemq.artemis.core.protocol.core.impl.wireformat.SessionXAPrepareMessage</code></p> |
| </li> |
| <li><p><code>org.apache.activemq.artemis.core.protocol.core.impl.wireformat.SessionXARollbackMessage</code></p> |
| </li> |
| </ul> |
| <p>To disable asynchronous connection execution, set the parameter |
| <code>async-connection-execution-enabled</code> in <code>broker.xml</code> to |
| <code>false</code> (default value is <code>true</code>).</p> |
| |
| |
| </section> |
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