86 lines
5.5 KiB
HTML
86 lines
5.5 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 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="Control when access paths are rebuilt" />
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<meta name="abstract" content="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." />
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<meta name="description" content="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." />
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<meta name="DC.Relation" scheme="URI" content="rbaforzahfpro.htm" />
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<meta name="DC.Relation" scheme="URI" content="../cl/edtrbdap.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="rbaforzahfprp" />
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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>Control when access paths are rebuilt</title>
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</head>
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<body id="rbaforzahfprp"><a name="rbaforzahfprp"><!-- --></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">Control when access paths are rebuilt</h1>
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<div><p>If the system ends abnormally, during the next initial program
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load (IPL), the system automatically lists those files that require
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access path recovery. You can control when access paths are rebuilt.</p>
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<p>You can decide whether to rebuild the access path:</p>
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<div class="p"> <ul><li>During the IPL</li>
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<li>After the IPL</li>
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<li>When you first use the file. </li>
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</ul>
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</div>
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<div class="p">You can also: <ul><li>Change the scheduling order in which the access paths are rebuilt</li>
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<li>Hold rebuilding of an access path indefinitely</li>
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<li>Continue the IPL process while access paths with a sequence value that
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is less than or equal to the <em>*IPL threshold</em> value are rebuilding.</li>
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<li>Control the rebuilding of access paths after the system has completed
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the IPL process by using the Edit Rebuild of Access Paths (EDTRBDAP) command.</li>
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</ul>
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</div>
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<p>The IPL threshold value determines which access paths to rebuild during
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the IPL. All access paths with a sequence value that is less than or equal
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to the IPL threshold value rebuild during the IPL. Changing the IPL threshold
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value to 99 means that all access paths with a sequence value of 1 through
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99 rebuild during the IPL. Changing the IPL threshold value to 0 means that
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no access paths rebuild until after the system completes its IPL, except those
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access paths that were being journaled and those access paths for system files.</p>
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<p>The access path recovery value for a file is determined by the value you
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specified for the RECOVER parameter on the create and change file commands.
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The default recovery value for *IPL (rebuild during IPL) is 25 and the default
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value for AFTIPL (rebuild after IPL) is 75; therefore, RECOVER(*IPL) will
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show as 25. The initial IPL threshold value is 50; this allows the parameters
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to affect when the access path is rebuilt. You can override this value on
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the Edit Rebuild of Access Paths display.</p>
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<p>If a file is not needed immediately after IPL time, specify that the file
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can be rebuilt at a later time. This should reduce the number of access paths
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that need to be rebuilt at IPL, allowing the system to complete its IPL much
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faster.</p>
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<p>For example, you can specify that all files that must have their access
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paths rebuilt should rebuild the access paths when the file is first used.
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In this case, no access paths are rebuilt at IPL. You can control the order
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in which the access paths are rebuilt by running only those programs that
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use the files you want to rebuild first. This method shortens the IPL time
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and can make the first of several applications available faster. However,
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the overall time to rebuild access paths probably is longer. (Other work might
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be running when the access paths are being rebuilt, and there might be less
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main storage available to rebuild the access paths).</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 class="relref"><strong>Related reference</strong><br />
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<div><a href="../cl/edtrbdap.htm">Edit Rebuild of Access Paths (EDTRBDAP) command</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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