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5.6 KiB
HTML
97 lines
5.6 KiB
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<title>CPI4322 - Access path built from keyed file &1</title>
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<body id="cpi4322"><a name="cpi4322"><!-- --></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">CPI4322 - Access path built from keyed file &1</h1>
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<div>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="border" border="1" rules="all"><thead align="left"><tr><th colspan="2" align="center" valign="middle" id="d0e16">CPI4322</th>
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</tr>
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</thead>
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<tbody><tr valign="middle"><td valign="middle" width="26.02040816326531%" headers="d0e16 ">Message Text:</td>
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<td valign="middle" width="73.9795918367347%" headers="d0e16 ">Access path built from keyed file &1.</td>
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</tr>
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<tr valign="middle"><td valign="middle" width="26.02040816326531%" headers="d0e16 ">Cause Text:</td>
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<td valign="middle" width="73.9795918367347%" headers="d0e16 ">A temporary access path was built using the access path from member &3
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of keyed file &1 in library &2 to access records from member &6
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of file &4 in library &5 for reason code &10. This process took &11
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minutes and &12 seconds. The access path built contains &15 entries.
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The reason codes and their meanings follow: <ol><li>Perform specified ordering/grouping criteria.</li>
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<li>Perform specified join criteria.</li>
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<li>Perform specified record selection to minimize I/O wait time</li>
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</ol>
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The access path was built using the following key fields. The key fields
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and their corresponding sequence (ASCEND or DESCEND) will be shown: <p></p>
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&17.
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<p></p>
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A key field of *MAP indicates the key field is an expression
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(derived field). <p></p>
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The temporary access path was built using
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sequence table &13 in library &14. <p></p>
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A sequence table
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of *N indicates the access path was built without a sequence table. A sequence
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table of *I indicates the table was an internally derived table that is not
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available to the user. <p></p>
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If file &4 in library &5 is
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a logical file then the temporary access path is built over member &9
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of physical file &7 in library &8. Creating an access path from a
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keyed file generally results in improved performance.</td>
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</tr>
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<tr valign="middle"><td valign="middle" width="26.02040816326531%" headers="d0e16 ">Recovery Text:</td>
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<td valign="middle" width="73.9795918367347%" headers="d0e16 ">If this query is run frequently, you may want to create an access path
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(index) similar to this definition for performance reasons. Create the access
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path using sequence table &13 in library &14, unless the sequence
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table is *N. If an access path is created, it is possible the query optimizer
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may still choose to create a temporary access path to process the query.
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<p></p>
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If *MAP is returned for one of the key fields or *I is returned
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for the sequence table, then a permanent access path cannot be created. A
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permanent access path cannot be built with these specifications. <p></p>
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A
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temporary access path can only be created using index only access if all of
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the fields that were used by this temporary access path are also key fields
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for the access path from the keyed file. </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="section"><p>This message indicates that a temporary index was created from
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the access path of an existing keyed table or index.</p>
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</div>
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<div class="section"><p>Generally, this action should not take a significant amount of
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time or resource because only a subset of the data in the table needs to be
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read. This is normally done to allow the optimizer to use an existing index
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for selection while creating one for ordering, grouping, or join criteria.
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Sometimes even faster performance can be achieved by creating a logical file
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or SQL index that satisfies the index requirement stated in the message help.</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="pimes.htm" title="You can evaluate the structure and performance of the given SQL statements in a program using informational messages put in the job log by the database manager.">Query optimization performance information messages</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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