39 lines
3.0 KiB
HTML
39 lines
3.0 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<META http-equiv="Content-Type" content="text/html; charset=utf-8">
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<LINK rel="stylesheet" type="text/css" href="../../../rzahg/ic.css">
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<title>Queuing network</title>
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</head>
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<BODY>
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<!-- Java sync-link -->
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<SCRIPT LANGUAGE="Javascript" SRC="../../../rzahg/synch.js" TYPE="text/javascript"></SCRIPT>
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<h4><a name="prftuneqnet"></a>Queuing network</h4>
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<p>WebSphere Application Server - Express contains interrelated components that must be tuned to support the custom needs of your e-business application. These adjustments help the system achieve maximum throughput while maintaining the overall stability of the system. This group of interconnected components is known as a queuing network. These queues or components include the network, Web server, Web container, data source, and possibly a connection manager to a custom back-end system. Each of these resources represents a queue of requests waiting to use that resource. Various queue settings include:</p>
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<ul>
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<li><a href="prftunehttp.htm">IBM HTTP Server</a>: ThreadsPerChild</li>
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<li><a href="prftuneappsvr.htm#webcont">Web container</a>: Thread pool maximum size, HTTP transports MaxKeepAliveConnections, and MaxKeepAliveRequests</li>
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<li><a href="prftuneappsvr.htm#data">Data source</a>: Connection pooling and Statement cache size</li>
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</ul>
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<p><img src="rzaiz616.gif" width="550" height="211" alt="Queuing network example" border="0"></p>
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<p>Most of the queues that make up the queuing network are closed queues. A closed queue places a limit on the maximum number of requests present in the queue, while an open queue has no limit. A closed queue supports strict management of system resources. For example, the Web container thread pool setting controls the size of the Web container queue. If the average servlet running in a Web container creates 10MB of objects during each request, a value of 100 for thread pools limits the memory consumed by the Web container to 1GB.</p>
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<p>In a closed queue, requests can be active or waiting. An active request is doing work or waiting for a response from a downstream queue. For example, an active request in the Web server is doing work, such as retrieving static HTML, or waiting for a request to be processed in the Web container. A waiting request is waiting to become active. The request remains in the waiting state until one of the active requests leaves the queue.</p>
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<p>All of the Web servers that WebSphere Application Server - Express supports are closed queues, as are WebSphere Application Server - Express data sources. You can configure Web containers as open or closed queues. In general, it is recommended that you use closed queues. If there are no threads available in the pool, a new thread is created for the duration of the request.</p>
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<blockquote>
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<p><strong><a href="prftuneqtip.htm">Queue configuration tips</a></strong>
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<br>This topic provides tips to help you tune the queuing network configuration.</p>
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</blockquote>
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</body>
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</html>
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