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<h2 class="title" style="clear: both"><a id="dbset_priority"></a>Db::set_priority()</h2>
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<pre class="programlisting">#include <db_cxx.h>
int
Db::set_priority(DB_CACHE_PRIORITY priority); </pre>
<p>
Set the cache priority for pages referenced by the
<a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a> handle.
</p>
<p>
The priority of a page biases the replacement algorithm to be more or
less likely to discard a page when space is needed in the buffer pool.
The bias is temporary, and pages will eventually be discarded if they
are not referenced again. The <code class="methodname">Db::set_priority()</code> method is only
advisory, and does not guarantee pages will be treated in a specific
way.
</p>
<p>
The <code class="methodname">Db::set_priority()</code> method may be called at any time during the
life of the application.
</p>
<p>
The <code class="methodname">Db::set_priority()</code> <span>
<span>
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</span>
</span>
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<div class="sect2" lang="en" xml:lang="en">
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<h3 class="title"><a id="id1650414"></a>Parameters</h3>
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<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id1650270"></a>priority</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>priority</strong></span> parameter must be set to
one of the following values:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p><a id="set_priority_DB_PRIORITY_VERY_LOW"></a>
<code class="literal">DB_PRIORITY_VERY_LOW</code>
</p>
<p>
The lowest priority: pages are the most likely to be discarded.
</p>
</li>
<li>
<p><a id="set_priority_DB_PRIORITY_LOW"></a>
<code class="literal">DB_PRIORITY_LOW</code>
</p>
<p>
The next lowest priority.
</p>
</li>
<li>
<p><a id="set_priority_DB_PRIORITY_DEFAULT"></a>
<code class="literal">DB_PRIORITY_DEFAULT</code>
</p>
<p>
The default priority.
</p>
</li>
<li>
<p><a id="set_priority_DB_PRIORITY_HIGH"></a>
<code class="literal">DB_PRIORITY_HIGH</code>
</p>
<p>
The next highest priority.
</p>
</li>
<li>
<p><a id="set_priority_DB_PRIORITY_VERY_HIGH"></a>
<code class="literal">DB_PRIORITY_VERY_HIGH</code>
</p>
<p>
The highest priority: pages are the least likely to be discarded.
</p>
</li>
</ul>
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<h3 class="title"><a id="id1650558"></a>Class</h3>
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<a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a>
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<h3 class="title"><a id="id1650268"></a>See Also</h3>
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