63 lines
3.7 KiB
HTML
63 lines
3.7 KiB
HTML
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<title>SQL402A - Hashing algorithm used to process join</title>
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</head>
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<body id="sql402a"><a name="sql402a"><!-- --></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">SQL402A - Hashing algorithm used to process join</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">SQL402A</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 ">Hashing algorithm used to process join</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 ">The hash join algorithm is typically used for longer running join queries.
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The original query will be subdivided into hash join steps. <p></p>
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Each
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hash join step will be optimized and processed separately. Access plan implementation
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information for each of the hash join steps is not available because access
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plans are not saved for the individual hash join dials. Debug messages detailing
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the implementation of each hash dial can be found in the joblog if the query
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is run in debug mode using the <span class="cmdname">STRDBG</span> CL command.</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 ">The hash join method is usually a good implementation choice, however,
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if you want to disallow the use of this method specify ALWCPYDTA(*YES).
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<p></p>
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Refer to <a href="rzajqdta.htm#rzajqdta">Data access on DB2 UDB for iSeries: data access paths and methods</a> for more
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information about hashing algorithm for join processing.</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>
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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="prtsqlinfmsg.htm" title="The following are the messages returned from PRTSQLINF.">PRTSQLINF message reference</a></div>
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