60 lines
3.9 KiB
HTML
60 lines
3.9 KiB
HTML
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<meta name="DC.Title" content="Querying database monitor view 3020 - Index advised" />
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<meta name="abstract" content="The index advisor information can be found in the Database Monitor view 3020 - Index advised (SQE)." />
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<meta name="description" content="The index advisor information can be found in the Database Monitor view 3020 - Index advised (SQE)." />
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<title>Querying database monitor view 3020 - Index advised</title>
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</head>
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<body id="rzajqadvise3020"><a name="rzajqadvise3020"><!-- --></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">Querying database monitor view 3020 - Index advised</h1>
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<div><p>The index advisor information can be found in the Database Monitor
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view 3020 - Index advised (SQE).</p>
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<div class="section"><p>The advisor information is stored in columns QQIDXA, QQIDXK and
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QQIDXD. When the QQIDXA column contains a value of 'Y' the optimizer is advising
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you to create an index using the key columns shown in column QQIDXD. The intention
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of creating this index is to improve the performance of the query.</p>
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</div>
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<div class="section"><p>In the list of key columns contained in column QQIDXD the optimizer
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has listed what it considers the suggested primary and secondary key columns.
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Primary key columns are columns that should significantly reduce the number
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of keys selected based on the corresponding query selection. Secondary key
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columns are columns that may or may not significantly reduce the number of
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keys selected.</p>
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</div>
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<div class="section"><p>Column QQIDXK contains the number of suggested primary key columns
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that are listed in column QQIDXD. These are the left-most suggested key columns.
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The remaining key columns are considered secondary key columns and are listed
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in order of expected selectivity based on the query. For example, assuming
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QQIDXK contains the value of 4 and QQIDXD specifies 7 key columns, then the
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first 4 key columns specified in QQIDXK is the primary key columns. The remaining
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3 key columns are the suggested secondary key columns.</p>
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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="idxadvisor.htm" title="The query optimizer analyzes the row selection in the query and determines, based on default values, if creation of a permanent index improves performance. If the optimizer determines that a permanent index might be beneficial, it returns the key columns necessary to create the suggested index.">Query optimizer index advisor</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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