1<!--$Id: db_set_priority.so,v 1.1 2007/05/22 18:06:05 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: DB->set_priority</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>DB->set_priority</b> 14</td> 15<td align=right> 16<a href="/api_c/api_core.html"><img src="/images/api.gif" alt="API"></a> 17<a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db.h> 23<p> 24int 25DB->set_priority(DB *db, DB_CACHE_PRIORITY priority); 26<p> 27int 28DB->get_priority(DB *db, DB_CACHE_PRIORITY *priorityp); 29</pre></b> 30<hr size=1 noshade> 31<b>Description: DB->set_priority</b> 32<!--$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_c/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 44returns a non-zero error value on failure 45and 0 on success. 46</p> 47<b>Parameters</b> <br> 48 <b>priority</b><ul compact><li>The <b>priority</b> parameter must be set to one of the following 49values: 50<br> 51<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> 52<b><a name="DB_PRIORITY_LOW">DB_PRIORITY_LOW</a></b><ul compact><li>The next lowest priority.</ul> 53<b><a name="DB_PRIORITY_DEFAULT">DB_PRIORITY_DEFAULT</a></b><ul compact><li>The default priority.</ul> 54<b><a name="DB_PRIORITY_HIGH">DB_PRIORITY_HIGH</a></b><ul compact><li>The next highest priority.</ul> 55<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> 56<br></ul> 57<br> 58<hr size=1 noshade> 59<b>Description: DB->get_priority</b> 60<p>The DB->get_priority method returns the cache priority for pages referenced by the 61<a href="/api_c/db_class.html">DB</a> 62handle.</p> 63<p>The DB->get_priority method may be called at any time during the life of the 64application.</p> 65<p>The DB->get_priority method 66returns a non-zero error value on failure 67and 0 on success. 68</p> 69<b>Parameters</b> <br> 70 <b>priorityp</b><ul compact><li>The DB->get_priority method returns a reference to the 71cache priority for pages referenced by the 72<a href="/api_c/db_class.html">DB</a> 73handle in <b>priorityp</b>.</ul> 74<br> 75<hr size=1 noshade> 76<br><b>Class</b> 77<a href="/api_c/db_class.html">DB</a> 78<br><b>See Also</b> 79<a href="/api_c/db_list.html">Databases and Related Methods</a> 80</tt> 81<table width="100%"><tr><td><br></td><td align=right> 82<a href="/api_c/api_core.html"><img src="/images/api.gif" alt="API"></a><a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a> 83</td></tr></table> 84<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 85</body> 86</html> 87
