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diff --git a/qpid/doc/book/src/java-broker/Java-Broker-Runtime-Producer-Transaction-Timeout.xml b/qpid/doc/book/src/java-broker/Java-Broker-Runtime-Producer-Transaction-Timeout.xml deleted file mode 100644 index 2813274c61..0000000000 --- a/qpid/doc/book/src/java-broker/Java-Broker-Runtime-Producer-Transaction-Timeout.xml +++ /dev/null @@ -1,137 +0,0 @@ -<?xml version="1.0" encoding="utf-8"?> -<!DOCTYPE entities [ -<!ENTITY % entities SYSTEM "commonEntities.xml"> -%entities; -]> -<!-- - - Licensed to the Apache Software Foundation (ASF) under one - or more contributor license agreements. See the NOTICE file - distributed with this work for additional information - regarding copyright ownership. The ASF licenses this file - to you under the Apache License, Version 2.0 (the - "License"); you may not use this file except in compliance - with the License. You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, - software distributed under the License is distributed on an - "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY - KIND, either express or implied. See the License for the - specific language governing permissions and limitations - under the License. - ---> - -<section id="Java-Broker-Runtime-Producer-Transaction-Timeout"> - <title>Producer Transaction Timeout</title> - <section role="h2" id="Java-Broker-Runtime-Producer-Transaction-Timeout-GeneralInformation"> - <title>General Information</title> - <para> The transaction timeout mechanism is used to control broker resources when clients - producing messages using transactional sessions hang or otherwise become unresponsive, or simply - begin a transaction and keep using it without ever calling <ulink - url="&oracleJeeDocUrl;javax/jms/Session.html#commit">Session#commit()</ulink>.</para> - <para>Users can choose to configure an idleWarn or openWarn threshold, after which the identified - transaction should be logged as a WARN level alert as well as (more importantly) an idleClose or - openClose threshold after which the transaction and the connection it applies to will be - closed.</para> - <para>This feature is particularly useful in environments where the owner of the broker does not - have full control over the implementation of clients, such as in a shared services - deployment.</para> - <para>The following section provide more details on this feature and its use.</para> - </section> - <section role="h2" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Purpose"> - <title>Purpose</title> - <para> This feature has been introduced to address the scenario where an open transaction on the - broker holds an open transaction on the persistent store. This can have undesirable consequences - if the store does not time out or close long-running transactions, such as with BDB. This can can - result in a rapid increase in disk usage size, bounded only by available space, due to growth of - the transaction log. </para> - </section> - <section role="h2" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Scope"> - <title>Scope</title> - <para>Note that only <ulink url="&oracleJeeDocUrl;javax/jms/MessageProducer.html" - >MessageProducer</ulink> clients will be affected by a transaction timeout, since store - transaction lifespan on a consumer only spans the execution of the call to Session#commit() and - there is no scope for a long-lived transaction to arise.</para> - <para>It is also important to note that the transaction timeout mechanism is purely a JMS - transaction timeout, and unrelated to any other timeouts in the Qpid client library and will have - no impact on any RDBMS your application may utilise.</para> - </section> - <section role="h2" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Effect"> - <title>Effect</title> - <para>Full details of configuration options are provided in the sections that follow. This section - gives a brief overview of what the Transaction Timeout feature can do.</para> - <section role="h3" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Effect-Broker-Side"> - <title>Broker Logging and Connection Close</title> - <para>When the openWarn or idleWarn specified threshold is exceeded, the broker will log a WARN - level alert with details of the connection and channel on which the threshold has been exceeded, - along with the age of the transaction.</para> - <para>When the openClose or idleClose specified threshold value is exceeded, the broker will - throw an exception back to the client connection via the <ulink - url="&oracleJeeDocUrl;javax/jms/ExceptionListener.html">ExceptionListener</ulink>, log the - action and then close the connection.</para> - <para>The example broker log output shown below is where the idleWarn threshold specified is - lower than the idleClose threshold and the broker therefore logs the idle transaction 3 times - before the close threshold is triggered and the connection closed out.</para> - <screen><![CDATA[CHN-1008 : Idle Transaction : 13,116 ms -CHN-1008 : Idle Transaction : 14,116 ms -CHN-1008 : Idle Transaction : 15,118 ms -CHN-1003 : Close]]> - </screen> - <para>The second example broker log output shown below illustrates the same mechanism operating - on an open transaction.</para> - <screen><![CDATA[ -CHN-1007 : Open Transaction : 12,406 ms -CHN-1007 : Open Transaction : 13,406 ms -CHN-1007 : Open Transaction : 14,406 ms -CHN-1003 : Close]]> - </screen> - </section> - <section role="h3" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Effect-Client-Side"> - <title>Client Side Effect</title> - <para>After a Close threshold has been exceeded, the trigger client will receive this exception - on its <ulink url="&oracleJeeDocUrl;javax/jms/ExceptionListener.html">exception - listener</ulink>, prior to being disconnected:</para> - <computeroutput>org.apache.qpid.AMQConnectionClosedException: Error: Idle transaction timed out - [error code 506: resource error]</computeroutput> - <para>Any later attempt to use the connection will result in this exception being thrown:</para> - <screen><![CDATA[Producer: Caught an Exception: javax.jms.IllegalStateException: Object org.apache.qpid.client.AMQSession_0_8@129b0e1 has been closed - javax.jms.IllegalStateException: Object org.apache.qpid.client.AMQSession_0_8@129b0e1 has been closed - at org.apache.qpid.client.Closeable.checkNotClosed(Closeable.java:70) - at org.apache.qpid.client.AMQSession.checkNotClosed(AMQSession.java:555) - at org.apache.qpid.client.AMQSession.createBytesMessage(AMQSession.java:573)]]> - </screen> - <para>Thus clients must be able to handle this case successfully, reconnecting where required and - registering an exception listener on all connections. This is critical, and must be communicated - to client applications by any broker owner switching on transaction timeouts.</para> - </section> - - </section> - <section role="h2" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Configuration"> - <title>Configuration</title> - <section role="h3" id="Java-Broker-Runtime-Producer-Transaction-Timeout-Configuration-Overview"> - <title>Configuration</title> - <para>The transaction timeouts can be specified when a new virtualhost is created or an exiting - virtualhost is edited.</para> - <para>We would recommend that only warnings are configured at first, which should allow broker - administrators to obtain an idea of the distribution of transaction lengths on their systems, - and configure production settings appropriately for both warning and closure. Ideally - establishing thresholds should be achieved in a representative UAT environment, with clients and - broker running, prior to any production deployment.</para> - <para>It is impossible to give suggested values, due to the large variation in usage depending on - the applications using a broker. However, clearly transactions should not span the expected - lifetime of any client application as this would indicate a hung client.</para> - <para>When configuring warning and closure timeouts, it should be noted that these only apply to - message producers that are connected to the broker, but that a timeout will cause the connection - to be closed - this disconnecting all producers and consumers created on that connection.</para> - <para>This should not be an issue for environments using Mule or Spring, where connection - factories can be configured appropriately to manage a single MessageProducer object per JMS - Session and Connection. Clients that use the JMS API directly should be aware that sessions - managing both consumers and producers, or multiple producers, will be affected by a single - producer hanging or leaving a transaction idle or open, and closed, and must take appropriate - action to handle that scenario.</para> - </section> - </section> -</section> |