1<!--$Id: db_set_priority.so,v 1.1 2007/05/22 18:06:05 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: Db::set_priority</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>Db::set_priority</b> 14</td> 15<td align=right> 16<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a> 17<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db_cxx.h> 23<p> 24int 25Db::set_priority(DB_CACHE_PRIORITY priority); 26<p> 27int 28Db::get_priority(DB_CACHE_PRIORITY *priorityp); 29</pre></b> 30<hr size=1 noshade> 31<b>Description: Db::set_priority</b> 32<!--$Id: dbc_set_priority.so,v 1.3 2007/05/22 18:06:05 bostic Exp $--> 33<p>Set the cache priority for pages referenced by the 34<a href="../api_cxx/db_class.html">Db</a> 35handle.</p> 36<p>The priority of a page biases the replacement algorithm to be more or 37less likely to discard a page when space is needed in the buffer pool. 38The bias is temporary, and pages will eventually be discarded if they 39are not referenced again. The Db::set_priority method is only advisory, and does 40not guarantee pages will be treated in a specific way.</p> 41<p>The Db::set_priority method may be called at any time during the life of the 42application.</p> 43<p>The Db::set_priority method 44either returns a non-zero error value 45or throws an exception that encapsulates a non-zero error value on 46failure, and returns 0 on success. 47</p> 48<b>Parameters</b> <br> 49 <b>priority</b><ul compact><li>The <b>priority</b> parameter must be set to one of the following 50values: 51<br> 52<b><a name="DB_PRIORITY_VERY_LOW">DB_PRIORITY_VERY_LOW</a></b><ul compact><li>The lowest priority: pages are the most likely to be discarded.</ul> 53<b><a name="DB_PRIORITY_LOW">DB_PRIORITY_LOW</a></b><ul compact><li>The next lowest priority.</ul> 54<b><a name="DB_PRIORITY_DEFAULT">DB_PRIORITY_DEFAULT</a></b><ul compact><li>The default priority.</ul> 55<b><a name="DB_PRIORITY_HIGH">DB_PRIORITY_HIGH</a></b><ul compact><li>The next highest priority.</ul> 56<b><a name="DB_PRIORITY_VERY_HIGH">DB_PRIORITY_VERY_HIGH</a></b><ul compact><li>The highest priority: pages are the least likely to be discarded.</ul> 57<br></ul> 58<br> 59<hr size=1 noshade> 60<br><b>Class</b> 61<a href="../api_cxx/db_class.html">Db</a> 62<br><b>See Also</b> 63<a href="../api_cxx/db_list.html">Databases and Related Methods</a> 64</tt> 65<table width="100%"><tr><td><br></td><td align=right> 66<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 67</td></tr></table> 68<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 69</body> 70</html> 71