86 lines
5.2 KiB
HTML
86 lines
5.2 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<meta name="DC.Title" content="How commitment control works" />
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<meta name="abstract" content="Commitment control is a function that allows you to define and process a group of changes to resources, such as database files or tables, as a transaction." />
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<meta name="description" content="Commitment control is a function that allows you to define and process a group of changes to resources, such as database files or tables, as a transaction." />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2004, 2006" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>How commitment control works</title>
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</head>
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<body id="rzakjhowworks"><a name="rzakjhowworks"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">How commitment control works</h1>
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<div><p>Commitment control is a function that allows you to define and
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process a group of changes to resources, such as database files or tables,
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as a transaction.</p>
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<p>Commitment control ensures that either the entire group of individual changes
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occur on all systems that participate or that none of the changes occur. For
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example, when you transfer funds from a savings to a checking account, more
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than one change occurs as a group. To you, this transfer seems like a single
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change. However, more than one change occurs to the database because both
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savings and checking accounts are updated. To keep both accounts accurate,
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either all the changes or none of the changes must occur to the checking and
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savings account.</p>
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<p>Commitment control allows you to:</p>
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<ul><li>Ensure that all changes within a transaction are completed for all resources
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that are affected.</li>
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<li>Ensure that all changes within a transaction are removed if processing
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is interrupted.</li>
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<li>Remove changes that are made during a transaction when the application
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determines that a transaction is in error.</li>
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</ul>
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<p>You can also design an application so that commitment control can restart
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the application if a job, an activation group within a job, or the system
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ends abnormally. With commitment control, you can have assurance that when
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the application starts again, no partial updates are in the database due to
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incomplete transactions from a prior failure.</p>
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<div class="section"><h4 class="sectiontitle">Transaction</h4><p>A transaction is a group of individual
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changes to objects on the system that appears as a single atomic change to
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the user.</p>
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<div class="note"><span class="notetitle">Note:</span> iSeries™ navigator uses the term<em> transaction</em>,
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whereas the character-based interface uses the term<em> Logical Unit of Work
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(LUW)</em>. The two terms are interchangeable. This topic, unless specifically
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referring to the character-based interface, uses the term transaction.</div>
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<p>A transaction can be any of the following situations:</p>
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<ul><li>Inquiries in which no database file changes occur.</li>
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<li>Simple transactions that change one database file.</li>
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<li>Complex transactions that changes one or more database files.</li>
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<li>Complex transactions that change one or more database files, but these
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changes represent only a part of a logical group of transactions.</li>
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<li>Simple or complex transactions that involve database files at more than
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one location. The database files can be: <ul><li>On a single remote system.</li>
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<li>On the local system and one or more remote systems.</li>
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<li>Assigned to more than one journal on the local system. Each journal can
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be thought of as a <dfn class="term">local location</dfn>.</li>
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</ul>
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</li>
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<li>Simple or complex transactions on the local system that involve objects
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other than database files.</li>
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</ul>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzakjconcepts.htm" title="This topic provides information to help you understand how commitment control works, how it interacts with your system, and how it interacts with other systems in your network.">Commitment control concepts</a></div>
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</div>
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</div>
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</body>
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</html>
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