1<!--$Id: h_nelem.so,v 10.12 2000/03/18 21:43:08 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 Reference Guide: Hash table size</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<a name="2"><!--meow--></a> 12<table width="100%"><tr valign=top> 13<td><b><dl><dt>Berkeley DB Reference Guide:<dd>Access Methods</dl></b></td> 14<td align=right><a href="../am_conf/h_hash.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../am_conf/recno.html"><img src="../../images/next.gif" alt="Next"></a> 15</td></tr></table> 16<p align=center><b>Hash table size</b></p> 17<p>When setting up the hash database, knowing the expected number of elements 18that will be stored in the hash table is useful. This value can be used 19by the Hash access method implementation to more accurately construct the 20necessary number of buckets that the database will eventually require.</p> 21<p>The anticipated number of elements in the hash table can be specified by 22calling the <a href="../../api_c/db_set_h_nelem.html">DB->set_h_nelem</a> method. If not specified, or set too low, 23hash tables will expand gracefully as keys are entered, although a slight 24performance degradation may be noticed. In order for the estimated number 25of elements to be a useful value to Berkeley DB, the <a href="../../api_c/db_set_h_ffactor.html">DB->set_h_ffactor</a> method 26must also be called to set the page fill factor.</p> 27<table width="100%"><tr><td><br></td><td align=right><a href="../am_conf/h_hash.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../am_conf/recno.html"><img src="../../images/next.gif" alt="Next"></a> 28</td></tr></table> 29<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 30</body> 31</html> 32
