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DbMpoolFile::set_priority
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#include &lt;db_cxx.h&gt;

int
DbMpoolFile::set_priority(DB_CACHE_PRIORITY priority);

int
DbMpoolFile::get_priority(DB_CACHE_PRIORITY *priorityp);
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Description: DbMpoolFile::set_priority

Set the cache priority for pages referenced by the
<a href="../../db4-devel-4.7.25/api_cxx/mempfile_class.html">DbMpoolFile</a>
handle.
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 DbMpoolFile::set_priority method is only advisory, and does
not guarantee pages will be treated in a specific way.
To set the priority for the pages belonging to a particular database,
call the DbMpoolFile::set_priority method using the <a href="../../db4-devel-4.7.25/api_cxx/mempfile_class.html">DbMpoolFile</a> handle
returned by the <a href="../../db4-devel-4.7.25/api_cxx/db_get_mpf.html">Db::get_mpf</a> method.
The DbMpoolFile::set_priority method configures a file in the memory pool, not only
operations performed using the specified <a href="../../db4-devel-4.7.25/api_cxx/mempfile_class.html">DbMpoolFile</a> handle.
The DbMpoolFile::set_priority method may be called at any time during the life of the
application.
The DbMpoolFile::set_priority 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.

Parameters 
 priority<ul compact><li>The priority parameter must be set to one of the following
values:
 
<a name="DB_PRIORITY_VERY_LOW">DB_PRIORITY_VERY_LOW</a><ul compact><li>The lowest priority: pages are the most likely to be discarded.</ul>
<a name="DB_PRIORITY_LOW">DB_PRIORITY_LOW</a><ul compact><li>The next lowest priority.</ul>
<a name="DB_PRIORITY_DEFAULT">DB_PRIORITY_DEFAULT</a><ul compact><li>The default priority.</ul>
<a name="DB_PRIORITY_HIGH">DB_PRIORITY_HIGH</a><ul compact><li>The next highest priority.</ul>
<a name="DB_PRIORITY_VERY_HIGH">DB_PRIORITY_VERY_HIGH</a><ul compact><li>The highest priority: pages are the least likely to be discarded.</ul>
 </ul>
 
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Description: DbMpoolFile::get_priority
The DbMpoolFile::get_priority method returns the cache priority for the file referenced by the <a href="../../db4-devel-4.7.25/api_cxx/mempfile_class.html">DbMpoolFile</a> handle.
The DbMpoolFile::get_priority method may be called at any time during the life of the
application.
The DbMpoolFile::get_priority method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure
<hr size=1 noshade>
 Class
<a href="../../db4-devel-4.7.25/api_cxx/env_class.html">DbEnv</a>, <a href="../../db4-devel-4.7.25/api_cxx/mempfile_class.html">DbMpoolFile</a>
 See Also
<a href="../../db4-devel-4.7.25/api_cxx/memp_list.html">Memory Pools and Related Methods</a>
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