76 lines
4.7 KiB
HTML
76 lines
4.7 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.Type" content="concept" />
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<meta name="DC.Title" content="MAINT parameter comparison" />
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<meta name="abstract" content="This topic compares the influences of the immediate, rebuild, and delayed maintenances on opening and processing files." />
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<meta name="description" content="This topic compares the influences of the immediate, rebuild, and delayed maintenances on opening and processing files." />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>MAINT parameter comparison</title>
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</head>
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<body id="rbafonoid16"><a name="rbafonoid16"><!-- --></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">MAINT parameter comparison</h1>
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<div><p>This topic compares the influences of the immediate, rebuild, and
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delayed maintenances on opening and processing files.</p>
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<div class="tablenoborder"><a name="rbafonoid16__rbafomtcomp"><!-- --></a><table cellpadding="4" cellspacing="0" summary="" id="rbafonoid16__rbafomtcomp" width="100%" frame="border" border="1" rules="rows"><caption>Table 1. MAINT
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values</caption><thead align="left"><tr><th align="left" valign="bottom" width="25%" class="firstcol" id="d0e22">Function</th>
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<th align="left" valign="bottom" width="25%" id="d0e24">Immediate maintenance</th>
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<th align="left" valign="bottom" width="25%" id="d0e26">Rebuild maintenance</th>
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<th align="left" valign="bottom" width="25%" id="d0e28">Delayed maintenance</th>
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</tr>
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</thead>
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<tbody><tr><th align="left" valign="top" width="25%" class="firstcol" id="d0e32" headers="d0e22 ">Open</th>
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<td align="left" valign="top" width="25%" headers="d0e32 d0e24 ">Fast open because the access path is current.</td>
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<td align="left" valign="top" width="25%" headers="d0e32 d0e26 ">Slow open because access path must be rebuilt.</td>
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<td align="left" valign="top" width="25%" headers="d0e32 d0e28 ">Moderately fast open because the access path
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does not have to be rebuilt, but it must still be changed. Slow open if extensive
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changes are needed.</td>
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</tr>
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<tr><th align="left" valign="top" width="25%" class="firstcol" id="d0e41" headers="d0e22 ">Process</th>
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<td align="left" valign="top" width="25%" headers="d0e41 d0e24 ">Slower update/output operations when many
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access paths with immediate maintenance are built over changing data (the
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system must maintain the access paths).</td>
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<td align="left" valign="top" width="25%" headers="d0e41 d0e26 ">Faster update/output operations when many
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access paths with rebuild maintenance are built over changing data and are
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not open (the system does not have to maintain the access paths).</td>
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<td align="left" valign="top" width="25%" headers="d0e41 d0e28 ">Moderately fast update/output operations
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when many access paths with delayed maintenance are built over
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changing data and are not open, (the system records the changes, but the access
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path itself is not maintained).</td>
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</tr>
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</tbody>
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</table>
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</div>
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<div class="note"><span class="notetitle">Notes:</span> <ol><li>Delayed or rebuild maintenance cannot be specified for a file that has
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unique keys.</li>
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<li>Rebuild maintenance cannot be specified for a file if its access path
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is being journaled.</li>
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</ol>
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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="rbafoapcurr.htm" title="You can specify how access paths are maintained for closed files with the MAINT parameter.">Specify the current access path maintenance (MAINT) parameter</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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