55 lines
3.2 KiB
HTML
55 lines
3.2 KiB
HTML
<?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="Materialization" />
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<meta name="abstract" content="When running Classic Query Engine (CQE), a partitioned table is materialized under some conditions." />
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<meta name="description" content="When running Classic Query Engine (CQE), a partitioned table is materialized under some conditions." />
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<meta name="DC.Relation" scheme="URI" content="cqe.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="sqematerialize" />
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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>Materialization</title>
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</head>
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<body id="sqematerialize"><a name="sqematerialize"><!-- --></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">Materialization</h1>
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<div><p>When running Classic Query Engine (CQE), a partitioned table is
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materialized under some conditions.</p>
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<p>These conditions are:</p>
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<ul><li>It is a part of a join query.</li>
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<li>It has a GROUP BY clause.</li>
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<li>It has a column built-in function.</li>
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</ul>
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<div class="p">In order to reduce the size of the temporary table and reduce the run time
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involved for the query, any selection in the query that can be used during
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the creation of the temporary table to eliminate rows is processed to decrease
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the size of the temporary table and reduce processing time during materialization
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cases. <div class="note"><span class="notetitle">Note:</span> When the partitioned table is materialized, the size of the
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temporary table cannot exceed 4 294 967 288 rows. Pushdown of selection processing
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is performed to limit the number of rows in the temporary table. If the number
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of rows exceeds 4 294 967 288, a resource limit error is issued
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and the query ends.</div>
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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="cqe.htm" title="When queries are implemented using Classic Query Engine (CQE), you need to be aware of how the query is optimized including materialization and index usage.">Queries using Classic Query Engine</a></div>
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</div>
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</div>
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</body>
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</html> |