73 lines
4.9 KiB
HTML
73 lines
4.9 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="Rebuild access paths" />
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<meta name="abstract" content="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." />
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<meta name="description" content="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." />
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<meta name="DC.Relation" scheme="URI" content="rbaforzahfpri.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbaforzahfprp.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbaforzahfprq.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbaforzahfprr.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="rbaforzahfpro" />
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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>Rebuild access paths</title>
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</head>
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<body id="rbaforzahfpro"><a name="rbaforzahfpro"><!-- --></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">Rebuild access paths</h1>
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<div><p>Rebuilding a database access path might take as much as one minute
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for every 10 000 records. But some factors might affect the time estimate
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for rebuilding access paths.</p>
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<p>The following factors affect the time estimate for rebuilding
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access paths:</p>
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<ul><li>Storage pool size. You can improve the rebuild time by running the job
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in a larger storage pool.</li>
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<li>The system model. The speed of the processing unit is a key factor.</li>
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<li>Key length. A large key length slows rebuilding the access path because
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the access path constructs and stores more key information. </li>
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<li>Select/omit values. Select/omit processing slows the rebuilding of an
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access path because the system compares each record to see if it meets the
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select/omit values.</li>
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<li>Record length. A large record length slows the rebuilding of an access
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path because the system looks at more data. </li>
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<li>Storage device that contains the data. The relative speed of the storage
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device that contains the actual data and the device that stores the access
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path affects the time needed to rebuild an access path.</li>
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<li>The order of the records in the file. The system tries to rebuild an access
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path so that it can find information quickly when using that access path.
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The order of the records in a file has a small affect on how fast the system
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builds the access path while trying to maintain an efficient access path.</li>
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</ul>
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</div>
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<div>
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<ul class="ullinks">
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<li class="ulchildlink"><strong><a href="rbaforzahfprp.htm">Control when access paths are rebuilt</a></strong><br />
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If the system ends abnormally, during the next initial program load (IPL), the system automatically lists those files that require access path recovery. You can control when access paths are rebuilt.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfprq.htm">Design files to reduce access path rebuilding time</a></strong><br />
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File design can help reduce access path recovery time.</li>
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<li class="ulchildlink"><strong><a href="rbaforzahfprr.htm">Other methods to avoid rebuilding access paths</a></strong><br />
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If you do not journal your access paths or do not take advantage of system-managed access-path protection (SMAPP), consider other system functions that reduce the chances of rebuilding access paths.</li>
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</ul>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbaforzahfpri.htm" title="The system ensures the integrity of an access path before you can use it. If the system determines that the access path is unusable, the system attempts to recover it. You can control when to have the access path recovered.">Reduce time in access path recovery</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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