63 lines
4.4 KiB
HTML
63 lines
4.4 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 name="DC.Type" content="reference" />
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<meta name="DC.Title" content="Temporary list" />
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<meta name="abstract" content="The temporary list is a temporary object that allows the optimizer to store intermediate results of a query. The list is an unsorted data structure that is used to simplify the operation of the query. Since the list does not have any keys, the rows within the list can only be retrieved by a sequential scan operation." />
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<meta name="description" content="The temporary list is a temporary object that allows the optimizer to store intermediate results of a query. The list is an unsorted data structure that is used to simplify the operation of the query. Since the list does not have any keys, the rows within the list can only be retrieved by a sequential scan operation." />
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<meta name="DC.subject" content="definitions, temporary list access method, temporary list, access method, temporary list scan" />
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<meta name="keywords" content="definitions, temporary list access method, temporary list, access method, temporary list scan" />
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<meta name="DC.Relation" scheme="URI" content="rzajqtempobj.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzajqlistscan.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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<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>Temporary list</title>
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</head>
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<body id="rzajqtemplist"><a name="rzajqtemplist"><!-- --></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">Temporary list</h1>
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<div><p>The temporary list is a temporary object that allows the optimizer
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to store intermediate results of a query. The list is an unsorted data structure
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that is used to simplify the operation of the query. Since the list does not
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have any keys, the rows within the list can only be retrieved by a sequential
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scan operation.</p>
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<div class="section"><p>The temporary list can be used for a variety of reasons, some
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of which include an overly complex view or derived table, Symmetric Multiprocessing
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(SMP) or simply to prevent a portion of the query from being processed multiple
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times.</p>
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</div>
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<div class="section"><p>A temporary list is an internal data structure and can only be
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created by the database manager.</p>
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</div>
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<div class="section"><p>Visual explain icon:</p>
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</div>
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<div class="section"><p><img src="rzajq521.gif" alt="Temporary list icon" /></p>
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</div>
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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="rzajqlistscan.htm">List scan</a></strong><br />
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The list scan operation is used when a portion of the query will be processed multiple times, but no key columns can be identified. In these cases, that portion of the query is processed once and its results are stored within the temporary list. The list can then be scanned for only those rows that satisfy any selection or processing contained within the temporary object.</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="rzajqtempobj.htm" title="Temporary objects are created by the optimizer in order to process a query. In general, these temporary objects are internal objects and cannot be accessed by a user.">Temporary objects and access methods</a></div>
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</div>
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</div>
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</body>
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</html> |