56 lines
3.5 KiB
HTML
56 lines
3.5 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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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Design files to reduce access path rebuilding time" />
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<meta name="abstract" content="File design can help reduce access path recovery time." />
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<meta name="description" content="File design can help reduce access path recovery time." />
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<meta name="DC.Relation" scheme="URI" content="rbaforzahfpro.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="rbaforzahfprq" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Design files to reduce access path rebuilding time</title>
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</head>
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<body id="rbaforzahfprq"><a name="rbaforzahfprq"><!-- --></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">Design files to reduce access path rebuilding time</h1>
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<div><p>File design can help reduce access path recovery time.</p>
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<p>For example, you might divide a large master file into a
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history file and a transaction file. The system uses the transaction file
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for adding new data. The system uses the history file for inquiry only. On
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a daily basis, you might merge the transaction data into the history file,
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then clear the transaction file for the next day's data. With this design,
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you shorten the time to rebuild access paths. </p>
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<p>However, if the system abnormally ended during the day, the access path
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to the smaller transaction file might need to be rebuilt. Still, the access
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path to the large history file, being read-only for most of the day, would
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rarely be unsynchronized with its data. Therefore, you reduce the chance of
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rebuilding this access path.</p>
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<p>Consider the trade-off between using a file design to reduce access path
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rebuilding time and using system-supplied functions like access path journaling.
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The above file design might require a more complex application design. After
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evaluating your situation, you might decide to use system-supplied functions
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like journaling your access paths rather than design applications that are
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more complex.</p>
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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="rbaforzahfpro.htm" title="Rebuilding a database access path might take as much as one minute for every 10 000 records. But some factors might affect the time estimate for rebuilding access paths.">Rebuild access paths</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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