http://git-wip-us.apache.org/repos/asf/qpid-site/blob/7a90fd79/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Flow-To-Disk.html.in ---------------------------------------------------------------------- diff --git a/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Flow-To-Disk.html.in b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Flow-To-Disk.html.in new file mode 100644 index 0000000..1d34c7c --- /dev/null +++ b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Flow-To-Disk.html.in @@ -0,0 +1,32 @@ +<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.7. Consumers</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Flow-To-Disk.html">Prev</a> </td><th align="center" width="60%">Chapter 9. Runtime</th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-Runtime-Background-Recovery.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Flow-To-Disk"></a>9.7. Consumers</h2></div></div></div><p>A Consumer is created when an AMQP connection wishes to receive messages from a message source (such as a + Queue). The standard behaviours of consumers are defined by the respective AMQP specification, however in addition + to the standard behaviours a number of Qpid specific enhancements are available</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Consumers-Prioirty"></a>9.7.1. Priority</h3></div></div></div><p>By default, when there are multiple competing consumers attached to the same message source, the Broker + attempts to distribute messages from the queue in a "fair" manner. Some use cases require allocation of messages + to consumers to be based on the "priority" of the consumer. Where there are multiple consumers having differing + priorities, the Broker will always attempt to deliver a message to a higher priority consumer before attempting + delivery to a lower priority consumer. That is, a lower priority consumer will only receive a message if no + higher priority consumers currently have credit available to consume the message, or those consumers have declined + to accept the message (for instance because it does not meet the criteria of any selectors associated with the + consumer).</p><p>Where a consumer is created with no explicit priority provided, the consumer is given the highest possible + priority.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6268"></a>9.7.1.1. Creating a Consumer with a non-standard priority</h4></div></div></div><p> + In AMQP 0-9 and 0-9-1 the priority of the consumer can be set by adding an entry into the table provided as the + <code class="literal">arguments</code> field (known as the <code class="literal">filter</code> field on AMQP 0-9) of the + <code class="literal">basic.consume</code> method. The key for the entry must be the literal short string + <code class="literal">x-priority</code>, and the value of the entry must be an integral number in the range + -2<sup>31</sup> to 2<sup>31</sup>-1. + </p><p> + In AMQP 0-10 the priority of the consumer can be set in the map provided as the <code class="literal">arguments</code> + field of the <code class="literal">message.subscribe</code> method. The key for the entry must be the literal string + <code class="literal">x-priority</code>, and the value of the entry must be an integral number in the range + -2<sup>31</sup> to 2<sup>31</sup>-1. + </p><p> + In AMQP 1.0 the priority of the consumer is set in the <code class="literal">properties</code> map of the + <code class="literal">attach</code> frame where the broker side of the link represents the sending side of the link. + The key for the entry must be the literal string <code class="literal">priority</code>, and the value of the entry must + be an integral number in the range -2<sup>31</sup> to 2<sup>31</sup>-1. + </p><p> + When using the Qpid JMS client for AMQP 0-9/0-9-1/0-10 the consumer priority can be set in the address being + used for the Destination object. + + </p><div class="table"><a id="d0e6327"></a><p class="title"><strong>Table 9.1. Setting the consumer priority</strong></p><div class="table-contents"><table border="1" summary="Setting the consumer priority"><colgroup><col /><col /></colgroup><thead><tr><th>Syntax</th><th>Example</th></tr></thead><tbody><tr><td>Addressing</td><td>myqueue : { link : { x-subscribe: { arguments : { x-priority : '10' } } } }</td></tr><tr><td>Binding URL</td><td>direct://amq.direct/myqueue/myqueue?x-qpid-replay-priority='10'</td></tr></tbody></table></div></div><p><br class="table-break" /> + </p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Runtime-Flow-To-Disk.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="Java-Broker-Runtime.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-Runtime-Background-Recovery.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.6. Flow to Disk </td><td align="center" width="20%"><a accesskey="h" href="AMQP-Messaging-Broker-Java-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 9.8. Background Recovery</td></tr></table></div></div> \ No newline at end of file
http://git-wip-us.apache.org/repos/asf/qpid-site/blob/7a90fd79/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Handling-Undeliverable-Messages.html.in ---------------------------------------------------------------------- diff --git a/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Handling-Undeliverable-Messages.html.in b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Handling-Undeliverable-Messages.html.in new file mode 100644 index 0000000..b5f0709 --- /dev/null +++ b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Handling-Undeliverable-Messages.html.in @@ -0,0 +1,39 @@ +<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.4. Handing Undeliverable Messages</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Producer-Transaction-Timeout.html">Prev</a> </td><th align="center" width="60%">Chapter 9. Runtime</th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-Runtime-Close-Connection-When-No-Route.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages"></a>9.4. Handing Undeliverable Messages</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages-Introduction"></a>9.4.1. Introduction</h3></div></div></div><p> Messages that cannot be delivered successfully to a c onsumer (for instance, because the + client is using a transacted session and rolls-back the transaction) can be made available on + the queue again and then subsequently be redelivered, depending on the precise session + acknowledgement mode and messaging model used by the application. This is normally desirable + behaviour that contributes to the ability of a system to withstand unexpected errors. However, it + leaves open the possibility for a message to be repeatedly redelivered (potentially indefinitely), + consuming system resources and preventing the delivery of other messages. Such undeliverable + messages are sometimes known as poison messages.</p><p>For an example, consider a stock ticker application that has been designed to consume prices + contained within JMS TextMessages. What if inadvertently a BytesMessage is placed onto the queue? + As the ticker application does not expect the BytesMessage, its processing might fail and cause it + to roll-back the transaction, however the default behavior of the Broker would mean that the + BytesMessage would be delivered over and over again, preventing the delivery of other legitimate + messages, until an operator intervenes and removes the erroneous message from the queue. </p><p>Qpid has maximum delivery count and dead-letter queue (DLQ) features which can be used in + concert to construct a system that automatically handles such a condition. These features are + described in the following sections.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages-Maximum-Delivery-Count"></a>9.4.2. Maximum Delivery Count</h3></div></div></div><p> Maximum delivery count is a property of a queue. If a consumer application is unable to + process a message more than the specified number of times, then the broker will either route the + message to a dead-letter queue (if one has been defined), or will discard the message. </p><p> In order for a maximum delivery count to be enforced, the consuming client + <span class="emphasis"><em>must</em></span> call <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/Session.html#rollback()" target="_top">Session#rollback()</a> (or <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/Session.html#recover()" target="_top">Session#recover()</a> if the session is not transacted). It is during the Broker's + processing of Session#rollback() (or Session#recover()) that if a message has been seen + at least the maximum number of times then it will move the message to the DLQ or discard the + message.</p><p>If the consuming client fails in another manner, for instance, closes the connection, the + message will not be re-routed and consumer application will see the same poison message again + once it reconnects.</p><p> If the consuming application is using AMQP 0-9-1, 0-9, or 0-8 protocols, it is necessary to + set the client system property <code class="varname">qpid.reject.behaviour</code> or connection or binding + URL option <code class="varname">rejectbehaviour</code> to the value <code class="literal">server</code>.</p><p>It is possible to determine the number of times a message has been sent to a consumer via + the Management interfaces, but is not possible to determine this information from a message client. + Specifically, the optional JMS message header <span class="property">JMSXDeliveryCount</span> is not + supported.</p><p>Maximum Delivery Count can be specified when a new queue is created or using the the + queue declare property <span class="property">x-qpid-maximum-delivery-count</span></p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages-Dead-Letter-Queues"></a>9.4.3. Dead Letter Queues (DLQ)</h3></div></div></div><p>A Dead Letter Queue (DLQ) acts as an destination for messages that have somehow exceeded the + normal bounds of processing and is utilised to prevent disruption to flow of other messages. When + a DLQ is enabled for a given queue if a consuming client indicates it no longer wishes the + receive the message (typically by exceeding a Maximum Delivery Count) then the message is moved + onto the DLQ and removed from the original queue. </p><p>The DLQ feature causes generation of a Dead Letter Exchange and a Dead Letter Queue. These + are named convention QueueName<span class="emphasis"><em>_DLE</em></span> and QueueName<span class="emphasis"><em>_DLQ</em></span>.</p><p>DLQs can be enabled when a new queue is created + or using the queue declare property <span class="property">x-qpid-dlq-enabled</span>.</p><div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Avoid excessive queue depth</h3><p>Applications making use of DLQs <span class="emphasis"><em>should</em></span> make provision for the frequent + examination of messages arriving on DLQs so that both corrective actions can be taken to resolve + the underlying cause and organise for their timely removal from the DLQ. Messages on DLQs + consume system resources in the same manner as messages on normal queues so excessive queue + depths should not be permitted to develop.</p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Runtime-Producer-Transaction-Timeout.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="Java-Broker-Runtime.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-Runtime-Close-Connection-When-No-Route.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.3. Producer Transaction Timeout </td><td align="center" width="20%"><a accesskey="h" href="AMQP-Messaging-Broker-Java-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 9.5. Closing client connections on unroutable mandatory messages</td></tr></table></div></div> \ No newline at end of file http://git-wip-us.apache.org/repos/asf/qpid-site/blob/7a90fd79/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Memory.html.in ---------------------------------------------------------------------- diff --git a/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Memory.html.in b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Memory.html.in new file mode 100644 index 0000000..be585d6 --- /dev/null +++ b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Memory.html.in @@ -0,0 +1,127 @@ +<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.11. Memory</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Connection-Limit.html">Prev</a> </td><th align="center" width="60%">Chapter 9. Runtime</th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-High-Availability.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Memory"></a>9.11. Memory</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Memory-Introduction"></a>9.11.1. Introduction</h3></div></div></div><p> + Understanding how the Qpid broker uses memory is essential to running a high performing and reliable service. + A wrongly configured broker can exhibit poor performance or even crash with an <code class="literal">OutOfMemoryError</code>. + Unfortunately, memory usage is not a simple topic and thus requires some in depth explanations. + This page should give the required background information to make informed decisions on how to configure your broker. + </p><p> + <a class="xref" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Types" title="9.11.2. Types of Memory">Section 9.11.2, “Types of Memory”</a> explains the two different kinds of Java memory most relevant to the broker. + <a class="xref" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Usage" title="9.11.3. Memory Usage in the Broker">Section 9.11.3, “Memory Usage in the Broker”</a> goes on to explain which parts of the broker use what kind of memory. + <a class="xref" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Low-Memory" title="9.11.4. Low Memory Conditions">Section 9.11.4, “Low Memory Conditions”</a> explains what happens when the system runs low on memory. + <a class="xref" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Defaults" title="9.11.5. Defaults">Section 9.11.5, “Defaults”</a> lays out the default settings of the Qpid broker. + Finally, <a class="xref" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Tuning" title="9.11.6. Memory Tuning the Broker">Section 9.11.6, “Memory Tuning the Broker”</a> gives some advice on tuning your broker. + </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Memory-Types"></a>9.11.2. Types of Memory</h3></div></div></div><p> + While Java has a couple of different internal memory types we will focus on the two types that are relevant to the Qpid broker. + Both of these memory types are taken from the same physical memory (RAM). + </p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6474"></a>9.11.2.1. Heap</h4></div></div></div><p> + Normally, all objects are allocated from Java's heap memory. + Once, nothing references an object it is cleaned up by the Java Garbage Collector and it's memory returned to the heap. + This works fine for most use cases. + However, when interacting with other parts of the operating system using Java's heap is not ideal. + This is where the so called direct memory comes into play. + </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6479"></a>9.11.2.2. Direct</h4></div></div></div><p> + The world outside of the JVM, in particular the operating system (OS), does not know about Java heap memory and uses other structures like C arrays. + In order to interact with these systems Java needs to copy data between its own heap memory and these native structures. + This can become a bottle neck when there is a lot of exchange between Java and the OS like in I/O (both disk and network) heavy applications. + Java's solution to this is to allow programmers to request <code class="literal">ByteBuffer</code>s from so called direct memory. + This is an opaque structure that <span class="emphasis"><em>might</em></span> have an underlying implementation that makes it efficient to interact with the OS. + Unfortunately, the GC is not good at tracking direct memory and in general it is inadvisable to use direct memory for regular objects. + </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Memory-Usage"></a>9.11.3. Memory Usage in the Broker</h3></div></div></div><p> + This section lists some note worthy users of memory within the broker and where possible lists their usage of heap and direct memory. + Note that to ensure smooth performance some heap memory should remain unused by the application and be reserved for the JVM to do house keeping and garbage collection. + <a class="link" href="https://docs.oracle.com/cd/E17277_02/html/java/com/sleepycat/je/util/DbCacheSize.html"; target="_top">Some guides</a> advise to reserve up to 30% of heap memory for the JVM. + </p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6498"></a>9.11.3.1. Broker</h4></div></div></div><p> + The broker itself uses a moderate amount of heap memory (≈15 MB). + However, each connection and session comes with a heap overhead of about 17 kB and 15 kB respectively. + In addition, each connection reserves 512 kB direct memory for network I/O. + </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6503"></a>9.11.3.2. Virtual Hosts</h4></div></div></div><p> + The amount of memory a Virtual Host uses depends on its type. + For a JSON Virtual Host Node with a BDB Virtual Host the heap memory usage is approximately 2 MB. + However, each BDB Virtual Hosts has a mandatory cache in heap memory which has an impact on performance. + See <a class="link" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Usage-BDB" title="9.11.3.4. Message Store">below</a> for more information. + </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6511"></a>9.11.3.3. Messages</h4></div></div></div><p> + Messages and their headers are kept in direct memory and have an additional overhead of approximately 1 kB heap memory each. + This means that most brokers will want to have more direct memory than heap memory. + When many small messages accumulate on the broker the 1 kB heap memory overhead can become a <a class="link" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Low-Memory-Heap" title="9.11.4.1. Low on Heap Memory">limiting factor</a>. + </p><p> + When the broker is <a class="link" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Low-Memory-Direct" title="9.11.4.2. Low on Direct Memory">running low on direct memory</a> + it will evict messages from memory and <a class="link" href="Java-Broker-Runtime-Flow-To-Disk.html" title="9.6. Flow to Disk">flow them to disk</a>. + For persistent messages this only means freeing the direct memory representation because they always have an on-disk representation to guard against unexpected failure (e.g., a power cut). + For transient messages this implies additional disk I/O. + After being flown to disk messages need to be re-read from disk before delivery. + </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Memory-Usage-BDB"></a>9.11.3.4. Message Store</h4></div></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="d0e6530"></a>Berkeley DB (BDB)</h5></div></div></div><p> + The broker can use Oracle's BDB JE (BDB) as a message store to persist messages by writing them to a database. + BDB uses a mandatory cache for navigating and organising its database structure. + Sizing and tuning this cache is a topic of its own and would go beyond the scope of this guide. + Suffice to say that by default Qpid uses 5% of heap memory for BDB caches (each Virtual Host uses a separate cache) or 10 MB per BDB store, whichever is greater. + See the <a class="link" href="http://www.oracle.com/us/products/database/berkeley-db/je"; target="_top">official webpage</a> especially <a class="link" href="http://docs.oracle.com/cd/E17277_02/html/java/com/sleepycat/je/util/DbCacheSize.html"; target="_top">this page</a> for more information. + For those interested, Qpid uses <a class="link" href="http://docs.oracle.com/cd/E17277_02/html/java/com/sleepycat/je/CacheMode.html#EVICT_LN"; target="_top">EVICT_LN</a> as its default JE cacheMode. + </p><p> + Note that due to licensing concerns Qpid does not ship the BDB JE jar files. + </p></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="d0e6546"></a>Derby</h5></div></div></div><p> + TODO + </p></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6551"></a>9.11.3.5. HTTP Management</h4></div></div></div><p> + Qpid uses Jetty for the HTTP Management (both REST and Web Management Console). + When the management plugin is loaded it will allocate the memory it needs and should not require more memory during operation and can thus be largely ignored. + </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Memory-Low-Memory"></a>9.11.4. Low Memory Conditions</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Memory-Low-Memory-Heap"></a>9.11.4.1. Low on Heap Memory</h4></div></div></div><p> + When the broker runs low on heap memory performance will degrade because the JVM will trigger full garbage collection (GC) events in a struggle to free memory. + These full GC events are also called stop-the-world events as they completely halt the execution of the Java application. + Stop-the-world-events may take any where from a couple of milliseconds up to several minutes. + Should the heap memory demands rise even further the JVM will eventually throw an OutOfMemoryError which will cause the broker to shut down. + </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Memory-Low-Memory-Direct"></a>9.11.4.2. Low on Direct Memory</h4></div></div></div><p> + When the broker detects that it uses 40% of available direct memory it will start flowing incoming transient messages to disk and reading them back before delivery. + This will prevent the broker from running out of direct memory but may degrade performance by requiring disk I/O. + </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Memory-Defaults"></a>9.11.5. Defaults</h3></div></div></div><p> + By default Qpid uses these settings: + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> + 0.5 GB heap memory + </li><li class="listitem"> + 1.5 GB direct memory + </li><li class="listitem"> + 5% of heap reserved for the JE cache. + </li><li class="listitem"> + Start flow-to-disk at 40% direct memory utilisation. + </li></ul></div><p> + As an example, this would accommodate a broker with 50 connections, each serving 5 sessions, and each session having 1000 messages of 1 kB on queues in the broker. + This means a total of 250 concurrent sessions and a total of 250000 messages without flowing messages to disk. + </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Memory-Tuning"></a>9.11.6. Memory Tuning the Broker</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6587"></a>9.11.6.1. Java Tuning</h4></div></div></div><p> + Most of these options are implementation specific. It is assumed you are using Oracle Java 1.7 and Qpid v6. + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> + Heap and direct memory can be configured through the <a class="link" href="Java-Broker-Appendix-Environment-Variables.html#Java-Broker-Appendix-Environment-Variables-Qpid-Java-Mem"><code class="literal">QPID_JAVA_MEM</code> environment variable</a>. + </li></ul></div><p> + </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6601"></a>9.11.6.2. Qpid Tuning</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> + The system property <code class="literal">qpid.broker.bdbTotalCacheSize</code> sets the total amount of heap memory (in bytes) allocated to BDB caches. + </li><li class="listitem"> + The system property <code class="literal">broker.flowToDiskThreshold</code> sets the threshold (in bytes) for flowing transient messages to disk. + Should the broker use more than direct memory it will flow incoming messages to disk. + Should utilisation fall beneath the threshold it will stop flowing messages to disk. + </li></ul></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6615"></a>9.11.6.3. Formulas</h4></div></div></div><p> + We developed a simple formula which estimates the <span class="emphasis"><em>minimum</em></span> memory usage of the broker under certain usage. + These are rough estimate so we strongly recommend testing your configuration extensively. + Also, if your machine has more memory available by all means use more memory as it can only improve the performance and stability of your broker. + However, remember that both heap and direct memory are served from your computer's physical memory so their sum should never exceed the physically available RAM (minus what other processes use). + </p><p> + </p><div class="informalequation"><span class="mathphrase"> + memory<sub>heap</sub> = 15 MB + 15 kB * N<sub>sessions</sub> + 1.5 kB * N<sub>messages</sub> + 17 kB * N<sub>connections</sub> + </span></div><p> + </p><p> + </p><div class="informalequation"><span class="mathphrase"> + memory<sub>direct</sub> = 2 MB + (200 B + averageSize<sub>msg</sub> *2)* N<sub>messages</sub> + 1MB * N<sub>connections</sub> + </span></div><p> + </p><p> + Where <span class="mathphrase">N</span> denotes the total number of connections/sessions/messages on the broker. Furthermore, for direct memory only the messages that have not been flown to disk are relevant. + </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The formulae assume the worst case in terms of memory usage: persistent messages and TLS connections. Transient messages consume less heap memory than peristent and plain connections consume less direct memory than TLS + connections. + </p></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="d0e6667"></a>9.11.6.4. Things to Consider</h4></div></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="d0e6670"></a>Performance</h5></div></div></div><p> + Choosing a smaller direct memory size will lower the threshold for flowing transient messages to disk when messages accumulate on a queue. + This can have impact on performance in the transient case where otherwise no disk I/O would be involved. + </p><p> + Having too little heap memory will result in poor performance due to frequent garbage collection events. See <a class="xref" href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Low-Memory" title="9.11.4. Low Memory Conditions">Section 9.11.4, “Low Memory Conditions”</a> for more details. + </p></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="d0e6679"></a>OutOfMemoryError</h5></div></div></div><p> + Choosing too low heap memory can cause an OutOfMemoryError which will force the broker to shut down. + In this sense the available heap memory puts a hard limit on the number of messages you can have in the broker at the same time. + </p><p> + If the Java runs out of direct memory it also throws a OutOfMemoryError resulting the a broker shutdown. + Under normal circumstances this should not happen but needs to be considered when deviating from the default configuration, especially when changing the flowToDiskThreshold. + </p><p> + If you are sending very large messages you should accommodate for this by making sure you have enough direct memory. + </p></div></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Runtime-Connection-Limit.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="Java-Broker-Runtime.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-High-Availability.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.10. Connection Limits </td><td align="center" width="20%"><a accesskey="h" href="AMQP-Messaging-Broker-Java-Book.html">Home</a></td><td align="right" valign="top" width="40%"> Chapter 10. High Availability</td></tr></table></div></div> \ No newline at end of file http://git-wip-us.apache.org/repos/asf/qpid-site/blob/7a90fd79/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Message-Compression.html.in ---------------------------------------------------------------------- diff --git a/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Message-Compression.html.in b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Message-Compression.html.in new file mode 100644 index 0000000..7add0e1 --- /dev/null +++ b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Message-Compression.html.in @@ -0,0 +1,15 @@ +<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.9. Message Compression</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Background-Recovery.html">Prev</a> </td><th align="center" width="60%">Chapter 9. Runtime</th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-Runtime-Connection-Limit.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Message-Compression"></a>9.9. Message Compression</h2></div></div></div><p>The Apache Qpid Broker for Java supports<a class="footnote" href="#ftn.d0e6382" id="d0e6382"><sup class="footnote">[13]</sup></a> message compression. This feature works in co-operation with Qpid + Clients implementing the same feature.</p><p>Once the feature is enabled (using Broker context variable + <span class="emphasis"><em>broker.messageCompressionEnabled</em></span>), the Broker will advertise support for the + message compression feature to the client at connection time. This allows clients to opt to turn + on message compression, allowing message payload sizes to be reduced.</p><p>If the Broker has connections from clients who have message compression enabled and others who + do not, it will internally, on-the-fly, decompress compressed messages when sending to clients + without support and conversely, compress uncomressed messages when sending to clients who do.</p><p>The Broker has a threshold below which it will not consider compressing a message, this is + controlled by Broker content variable + (<code class="literal">connection.messageCompressionThresholdSize</code>) and expresses a size in bytes.</p><p>This feature <span class="emphasis"><em>may</em></span> have a beneficial effect on performance by:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Reducing the number of bytes transmitted over the wire, both between Client and Broker, and + in the HA case, Broker to Broker, for replication purposes.</p></li><li class="listitem"><p>Reducing storage space when data is at rest within the Broker, both on disk and in + memory.</p></li></ul></div><p>Of course, compression and decompression is computationally expensive. Turning on the feature + may have a negative impact on CPU utilization on Broker and/or Client. Also for small messages + payloads, message compression may increase the message size. It is recommended to test the feature + with representative data.</p><div class="footnotes"><br /><hr style="width:100; text-align:left;margin-left: 0" /><div class="footnote" id="ftn.d0e6382"><p><a class="para" href="#d0e6382"><sup class="para">[13] </sup></a>Message compression is not yet supported for the 1.0 + protocol.</p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Runtime-Background-Recovery.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="Java-Broker-Runtime.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-Runtime-Connection-Limit.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.8. Background Recovery </td><td align="center" width="20%"><a accesskey="h" href="AMQP-Messaging-Broker-Java-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 9.10. Connection Limits</td></tr></table></div></div> \ No newline at end of file http://git-wip-us.apache.org/repos/asf/qpid-site/blob/7a90fd79/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Producer-Transaction-Timeout.html.in ---------------------------------------------------------------------- diff --git a/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Producer-Transaction-Timeout.html.in b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Producer-Transaction-Timeout.html.in new file mode 100644 index 0000000..fb47911 --- /dev/null +++ b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime-Producer-Transaction-Timeout.html.in @@ -0,0 +1,57 @@ +<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.3. Producer Transaction Timeout</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Disk-Space-Management.html">Prev</a> </td><th align="center" width="60%">Chapter 9. Runtime</th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-Runtime-Handling-Undeliverable-Messages.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout"></a>9.3. Producer Transaction Timeout</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-GeneralInformation"></a>9.3.1. General Information</h3></div></div></div><p> The transaction timeout mechanism is used to control bro ker 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 <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/Session.html#commit"; target="_top">Session#commit()</a>.</p><p>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.</p><p>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.</p><p>The following section provide more details on this feature and its use.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Purpose"></a>9.3.2. Purpose</h3></div></div></div><p> 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. </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Scope"></a>9.3.3. Scope</h3></div></div></div><p>Note that only <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/MessageProducer.html"; target="_top">MessageProducer</a> 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.</p><p>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.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Effect"></a>9.3.4. Effect</h3></div></div></div><p>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.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Effect-Broker-Side"></a>9.3.4.1. Broker Logging and Connection Close</h4></div></div></div><p>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.</p><p>When the openClose or idleClose specified threshold value is exceeded, the broker will + throw an exception back to the client connection via the <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/ExceptionListener.html"; target="_top">ExceptionListener</a>, log the + action and then close the connection.</p><p>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.</p><pre class="screen">CHN-1008 : Idle Transaction : 13,116 ms +CHN-1008 : Idle Transaction : 14,116 ms +CHN-1008 : Idle Transaction : 15,118 ms +CHN-1003 : Close + </pre><p>The second example broker log output shown below illustrates the same mechanism operating + on an open transaction.</p><pre class="screen"> +CHN-1007 : Open Transaction : 12,406 ms +CHN-1007 : Open Transaction : 13,406 ms +CHN-1007 : Open Transaction : 14,406 ms +CHN-1003 : Close + </pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Effect-Client-Side"></a>9.3.4.2. Client Side Effect</h4></div></div></div><p>After a Close threshold has been exceeded, the trigger client will receive this exception + on its <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/ExceptionListener.html"; target="_top">exception + listener</a>, prior to being disconnected:</p><code class="computeroutput">org.apache.qpid.AMQConnectionClosedException: Error: Idle transaction timed out + [error code 506: resource error]</code><p>Any later attempt to use the connection will result in this exception being thrown:</p><pre class="screen">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) + </pre><p>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.</p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Configuration"></a>9.3.5. Configuration</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Producer-Transaction-Timeout-Configuration-Overview"></a>9.3.5.1. Configuration</h4></div></div></div><p>The transaction timeouts can be specified when a new virtualhost is created or an exiting + virtualhost is edited.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Runtime-Disk-Space-Management.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="Java-Broker-Runtime.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-Runtime-Handling-Undeliverable-Messages.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.2. Disk Space Management </td><td align="center" width="20%"><a accesskey="h" href="AMQP-Messaging-Broker-Java-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 9.4. Handing Undeliverable Messages</td></tr></table></div></div> \ No newline at end of file http://git-wip-us.apache.org/repos/asf/qpid-site/blob/7a90fd79/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime.html.in ---------------------------------------------------------------------- diff --git a/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime.html.in b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime.html.in new file mode 100644 index 0000000..cbe0013 --- /dev/null +++ b/input/releases/qpid-java-6.1.0/java-broker/book/Java-Broker-Runtime.html.in @@ -0,0 +1,95 @@ +<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">Chapter 9. Runtime</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Security-Configuration-Encryption.html">Prev</a> </td><th align="center" width="60%"> </th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-Runtime-Disk-Space-Management.html">Next</a></td></tr></table><hr /></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a id="Java-Broker-Runtime"></a>Chapter 9. Runtime</h1></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="Java-Broker-Runtime.html#Java-Broker-Runtime-Logging">9.1. Logging</a></span></dt><dd><dl><dt><span class="section"><a href="Java-Broker-Runtime.html#Java-Broker-Runtime-Logging-Concepts">9.1.1. Concepts</a></span></dt><dt><span class="section"><a href=" Java-Broker-Runtime.html#Java-Broker-Runtime-Logging-Default-Configuration">9.1.2. Default Configuration</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime.html#Java-Broker-Runtime-Logging-Loggers">9.1.3. Loggers</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime.html#Java-Broker-Runtime-Logging-InclusionRules">9.1.4. Inclusion Rules</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime.html#Java-Broker-Runtime-Logging-Management">9.1.5. Logging Management</a></span></dt></dl></dd><dt><span class="section"><a href="Java-Broker-Runtime-Disk-Space-Management.html">9.2. Disk Space Management</a></span></dt><dd><dl><dt><span class="section"><a href="Java-Broker-Runtime-Disk-Space-Management.html#Qpid-Producer-Flow-Control">9.2.1. Producer Flow Control</a></span></dt></dl></dd><dt><span class="section"><a href="Java-Broker-Runtime-Producer-Transaction-Timeout.html">9.3. Producer Transaction Timeout</a></span></dt><dd><dl><dt><span cla ss="section"><a href="Java-Broker-Runtime-Producer-Transaction-Timeout.html#Java-Broker-Runtime-Producer-Transaction-Timeout-GeneralInformation">9.3.1. General Information</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Producer-Transaction-Timeout.html#Java-Broker-Runtime-Producer-Transaction-Timeout-Purpose">9.3.2. Purpose</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Producer-Transaction-Timeout.html#Java-Broker-Runtime-Producer-Transaction-Timeout-Scope">9.3.3. Scope</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Producer-Transaction-Timeout.html#Java-Broker-Runtime-Producer-Transaction-Timeout-Effect">9.3.4. Effect</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Producer-Transaction-Timeout.html#Java-Broker-Runtime-Producer-Transaction-Timeout-Configuration">9.3.5. Configuration</a></span></dt></dl></dd><dt><span class="section"><a href="Java-Broker-Runtime-Handling-Undeliverable-Messages .html">9.4. Handing Undeliverable Messages</a></span></dt><dd><dl><dt><span class="section"><a href="Java-Broker-Runtime-Handling-Undeliverable-Messages.html#Java-Broker-Runtime-Handling-Undeliverable-Messages-Introduction">9.4.1. Introduction</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Handling-Undeliverable-Messages.html#Java-Broker-Runtime-Handling-Undeliverable-Messages-Maximum-Delivery-Count">9.4.2. Maximum Delivery Count</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Handling-Undeliverable-Messages.html#Java-Broker-Runtime-Handling-Undeliverable-Messages-Dead-Letter-Queues">9.4.3. Dead Letter Queues (DLQ)</a></span></dt></dl></dd><dt><span class="section"><a href="Java-Broker-Runtime-Close-Connection-When-No-Route.html">9.5. Closing client connections on unroutable mandatory messages</a></span></dt><dd><dl><dt><span class="section"><a href="Java-Broker-Runtime-Close-Connection-When-No-Route.html#Java-Broker-Runtime-Close-Connect ion-When-No-Route-Summary">9.5.1. Summary</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Close-Connection-When-No-Route.html#Java-Broker-Runtime-Close-Connection-When-No-Route-Configuration">9.5.2. Configuring <span class="emphasis"><em>closeWhenNoRoute</em></span></a></span></dt></dl></dd><dt><span class="section"><a href="Java-Broker-Runtime-Flow-To-Disk.html">9.6. Flow to Disk</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Flow-To-Disk.html">9.7. Consumers</a></span></dt><dd><dl><dt><span class="section"><a href="Java-Broker-Runtime-Flow-To-Disk.html#Java-Broker-Runtime-Consumers-Prioirty">9.7.1. Priority</a></span></dt></dl></dd><dt><span class="section"><a href="Java-Broker-Runtime-Background-Recovery.html">9.8. Background Recovery</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Message-Compression.html">9.9. Message Compression</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Connection-Li mit.html">9.10. Connection Limits</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html">9.11. Memory</a></span></dt><dd><dl><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Introduction">9.11.1. Introduction</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Types">9.11.2. Types of Memory</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Usage">9.11.3. Memory Usage in the Broker</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Low-Memory">9.11.4. Low Memory Conditions</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Defaults">9.11.5. Defaults</a></span></dt><dt><span class="section"><a href="Java-Broker-Runtime-Memory.html#Java-Broker-Runtime-Memory-Tuning">9.11.6. Memory Tunin g the Broker</a></span></dt></dl></dd></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Logging"></a>9.1. Logging</h2></div></div></div><p>This section describes the flexible logging capabilities of the Apache Qpid Broker for Java.</p><p> + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>The Broker is capable of sending logging events to a variety of destinations including + plain files, remote syslog daemons, and an in-memory buffer (viewable from Management). + The system is also open for extension meaning it is possible to produce a plugin to log to + a bespoke destination.</p></li><li class="listitem"><p>Logging can be dynamically configured at runtime. For instance, it is possible to + temporarily increase the logging verbosity of the system whilst a problem is investigated + and then revert later, all without the need to restart the Broker.</p></li><li class="listitem"><p>Virtualhosts can be configured to generate their own separate log, and the Broker is + capable of generating a log either inclusive or exclusive of virtualhost events.</p></li><li class="listitem"><p>Logs are accessible over Management, removing the need for those operating the Broker + to have shell level access.</p></li></ul></div><p> + </p><p>In the remainder of this section you will first find a description of the concepts used in + the logging subsystem. Next, you find a description of the default configuration. The section + then concludes with a in-depth description of the loggers themselves and how they may be + configured.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Logging-Concepts"></a>9.1.1. Concepts</h3></div></div></div><p>The logging subsystem uses two concepts:</p><p> + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>A <span class="emphasis"><em>Logger</em></span> is responsible for production of a log. The Broker + ships a variety of loggers, for instance, a file logger, which is capable of writing a + log file to the file system, a Syslog Logger capable of writing to a remote syslog + daemon and console logger capable of writing to stdout or stderr.</p><p>Loggers are attached at two points within the Broker Model; the Broker itself and + the virtualhosts. Loggers attached at the Broker can capture log events for the system + as a whole, or can exclude events related to virtualhosts.</p><p>Loggers attached to a virtualhost capture log events relating to that virtualhost + only.</p><p>The Broker and virtualhosts can have zero or more Loggers. If no loggers are + configured, no logging is generated at all.</p></li><li class="listitem"><p><span class="emphasis"><em>Inclusion rules</em></span> govern what appears within a log. Inclusion + rules are associated with Loggers. This means it is possible for different Loggers to + have different contents.</p><p>A Logger with no inclusion rules will produce an empty log.</p></li></ul></div><p> + </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Logging-Default-Configuration"></a>9.1.2. Default Configuration</h3></div></div></div><p>The default configuration is designed to be suitable for use without change in small + production environments. It has the following characteristics:</p><p> + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>The Broker generates a single log file <code class="literal">qpid.log</code>. This logfile is + rolled automatically when the file reaches 100MB. A maximum history of one file is + retained. On restart the the log will be appended to.</p><p>The log contains: </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>All operational logging events. See <a class="xref" href="Java-Broker-Appendix-Operation-Logging.html" title="Appendix C. Operational Logging">Appendix C, <em>Operational Logging</em></a>.</p></li><li class="listitem"><p>Log events from Qpid itself deemed informational or + higher.</p></li><li class="listitem"><p>Log events from Qpid's dependencies (such as Derby or Jetty) that are + deemed warning or higher.</p></li></ul></div><p> + </p><p>The default location for the log file is + <code class="literal">${QPID_WORK}/log/qpid.log</code>.</p></li><li class="listitem"><p>The Broker also caches the last 4096 log events in a memory cache. By default, the + memory logger logs the same things the file logger does.</p></li></ul></div><p> + </p><p>The configuration can be customised at runtime using Management. This makes it possible to + investigate unusual conditions <span class="emphasis"><em>without</em></span> the need to restart the Broker. + For instance, you may alter the logging level so that a verbose log is produced whilst an + investigation is in progress and revert the setting later, all without the need to restart the + Broker.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Logging-Loggers"></a>9.1.3. Loggers</h3></div></div></div><p>Loggers are responsible for the writing of a log. The log includes log events that match a + Logger's inclusion rules.</p><p>Loggers are associated with either the Broker or a virtualhost. Virtualhost loggers write + only log events related to that virtualhost. Broker Loggers write log events from the Broker + as a whole. Optionally a Broker Logger can be configured to exclude log events coming from + virtualhosts. These abilities can be usefully exploited together in managed service scenarios + to produce separate logs for separate user groups.</p><p>Loggers can be added or removed at runtime, without restarting the Broker. However changes + to a Logger's configuration such as filenames and rolling options don't take effect until the + next restart. Changes to a Logger's inclusion rules take effect immediately.</p><p>All loggers allow the log event layout to be customised. Loggers understand <a class="link" href="http://logback.qos.ch/manual/layouts.html#ClassicPatternLayout"; target="_top"> Logback Classic + Pattern Layouts</a>. </p><p>The following sections describes each Logger implementation in detail.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Logging-Loggers-FileLogger"></a>9.1.3.1. FileLogger</h4></div></div></div><p>A <span class="emphasis"><em>FileLogger</em></span> - writes a log file to the filesystem. The name and + location of the log file, the rolling configuration, and compression options can be + configured.</p><p>The <span class="emphasis"><em>roll daily</em></span> option, if enabled, will cause the log file will be + rolled at midnight local time. The rolled over file will have a suffix in the form + <code class="literal">yyyy-mm-dd</code>. In roll daily mode, <span class="emphasis"><em>maximum number of rolled + files</em></span> controls the maximum number of <span class="emphasis"><em>days</em></span> to be retained. + Older files will be deleted.</p><p>The <span class="emphasis"><em>maximum file size</em></span> option limits the size of any one log file. + Once a log file reaches the given size, it will be rolled. The rolled over file will have + the numeric suffix, beginning at <code class="literal">1</code>. If the log file rolls again, first + the existing file with the suffix <code class="literal">.1</code> is renamed to <code class="literal">.2</code> + and so forth. If roll daily is not in use, <span class="emphasis"><em>maximum number of rolled + files</em></span> governs the number of rolled <span class="emphasis"><em>files</em></span> that will be + retained.</p><p><span class="emphasis"><em>Roll on restart</em></span> governs whether the log file is rolled when the + Broker is restarted. If not ticked, the Broker will append to the existing log file until it + needs to be rolled.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Logging-Loggers-ConsoleLogger"></a>9.1.3.2. ConsoleLogger</h4></div></div></div><p><span class="emphasis"><em>ConsoleLogger</em></span> - writes a log file standard out or standard + error.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Logging-Loggers-SyslogLogger"></a>9.1.3.3. SyslogLogger</h4></div></div></div><p><span class="emphasis"><em>SyslogLogger</em></span> - writes a log file to a syslog daemon using the + <code class="literal">USER</code> facility. The hostname and port number of the syslog daemon can be + configured.</p><p>Log entries can be prefixed with a string. This string defaults to include the word + <code class="literal">Qpid</code> and the name of the Broker or virtualhost. This serves to + distinguish the logging generated by this Qpid instance, from other Qpid instances, or other + applications using the <code class="literal">USER</code>.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="Java-Broker-Runtime-Logging-Loggers-MemoryLogger"></a>9.1.3.4. MemoryLogger</h4></div></div></div><p><span class="emphasis"><em>MemoryLogger</em></span> - writes a log file to a circular in-memory buffer. By + default the circular buffer holds the last 4096 log events. The contents of the buffer can + be viewed via Management. See <a class="xref" href="Java-Broker-Runtime.html#Java-Broker-Runtime-Logging-Management-MemoryLogger" title="Figure 9.3. Viewing a memory logger">Figure 9.3, “Viewing a memory logger”</a></p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Logging-InclusionRules"></a>9.1.4. Inclusion Rules</h3></div></div></div><p>A <span class="emphasis"><em>Logger</em></span> has one or more <span class="emphasis"><em>inclusion rules</em></span>. These + govern what appears in the log. A Logger with no inclusion rules will log nothing.</p><p>Inclusion rules can be added, removed or changed at runtime. Changes take place + immediately.</p><p> + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>The <span class="emphasis"><em>Name And Level</em></span> inclusion rule accepts log events that match + a given <span class="emphasis"><em>log event source name</em></span> and have a level that equals or + exceeds the specified value.</p><p>The log event source name refers to the fully qualified class name from which the + event originates. These names permit a trailing wild card <code class="literal">.*</code>. For + instance a source name of <code class="literal">org.apache.qpid.*</code> will match all events + from classes in the package <code class="literal">org.apache.qpid</code> and any sub packages + beneath.</p><p>The <span class="emphasis"><em>Level</em></span> governs the level of the events that will be included + in the log. It may take one of the following values: ERROR, WARN, INFO, DEBUG, TRACE + where ERROR is considered the highest and TRACE the lowest. In addition, there are two + special values: OFF and ALL, the former excludes all log events whereas the latter will + include everything. When considering whether a logging event should be included in the + log, the logging event must have a level that matches that of the inclusion rule or be + higher, otherwise the log event will not appear in the log.</p></li></ul></div><p> + </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Logging-Management"></a>9.1.5. Logging Management</h3></div></div></div><p>The logging subsystem can be completely managed from the Web Management Console or the + REST API. You can: </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Add, remove, or change the configuration of Loggers.</p></li><li class="listitem"><p>Add, remove, or change the Inclusion Rules.</p></li><li class="listitem"><p>For FileLoggers, download the log file and rolled log files associated with + the Logger.</p></li><li class="listitem"><p>For MemoryLoggers, view the last <code class="literal">n</code> log + events</p></li></ul></div><p> + </p><p> The figure that follows shows a FileLogger. The attributes area shows the configuration + of the Logger. The inclusion rule table shows the rules that are associated with the Logger. + The area towards the bottom of the tab allows the log files to be downloaded to the browser. + </p><div class="figure"><a id="Java-Broker-Runtime-Logging-Management-FileLogger"></a><p class="title"><strong>Figure 9.1. Viewing a file logger</strong></p><div class="figure-contents"><div class="mediaobject"><table border="0" style="cellpadding: 0; cellspacing: 0;" summary="manufactured viewport for HTML img" width="900"><tr><td><img alt="Viewing a file logger" src="images/Management-Web-Logging-FileLogger.png" width="900" /></td></tr></table></div></div></div><p><br class="figure-break" /> + </p><p> The figure below shows the editing of the level of an inclusion rule. </p><div class="figure"><a id="Java-Broker-Runtime-Logging-Management-InclusionRule"></a><p class="title"><strong>Figure 9.2. Editing an inclusion rule</strong></p><div class="figure-contents"><div class="mediaobject"><table border="0" style="cellpadding: 0; cellspacing: 0;" summary="manufactured viewport for HTML img" width="900"><tr><td><img alt="Editing an inclusion rule" src="images/Management-Web-Logging-InclusionRule.png" width="900" /></td></tr></table></div></div></div><p><br class="figure-break" /> + </p><p> The figure below shows a Memory Logger. Note that the Memory Logger provides access to + the cached message via the viewer towards the bottom on the tab. </p><div class="figure"><a id="Java-Broker-Runtime-Logging-Management-MemoryLogger"></a><p class="title"><strong>Figure 9.3. Viewing a memory logger</strong></p><div class="figure-contents"><div class="mediaobject"><table border="0" style="cellpadding: 0; cellspacing: 0;" summary="manufactured viewport for HTML img" width="900"><tr><td><img alt="Viewing a memory logger" src="images/Management-Web-Logging-MemoryLogger.png" width="900" /></td></tr></table></div></div></div><p><br class="figure-break" /> + </p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Security-Configuration-Encryption.html">Prev</a> </td><td align="center" width="20%"> </td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-Runtime-Disk-Space-Management.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">8.4. Configuration Encryption </td><td align="center" width="20%"><a accesskey="h" href="AMQP-Messaging-Broker-Java-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 9.2. Disk Space Management</td></tr></table></div></div> \ No newline at end of file --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
