1<!--$Id: env_set_lk_max_locks.so,v 10.23 2004/09/28 15:04:20 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: DbEnv::set_lk_max_locks</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>DbEnv::set_lk_max_locks</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 25DbEnv::set_lk_max_locks(u_int32_t max); 26<p> 27int 28DbEnv::get_lk_max_locks(u_int32_t *lk_maxp); 29</pre></b> 30<hr size=1 noshade> 31<b>Description: DbEnv::set_lk_max_locks</b> 32<p>Set the maximum number of locks supported by the Berkeley DB environment. 33This value is used by <a href="../api_cxx/env_open.html">DbEnv::open</a> to estimate how much space to 34allocate for various lock-table data structures. The default value is 351000 locks. For specific information on configuring the size of the lock 36subsystem, see <a href="../ref/lock/max.html">Configuring locking: 37sizing the system</a>.</p> 38<p>The database environment's maximum number of locks may also be configured using the 39environment's <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file. The syntax of the entry in that 40file is a single line with the string "set_lk_max_locks", one or more whitespace 41characters, and the number of locks. 42Because the <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file is read when the database environment 43is opened, it will silently overrule configuration done before that 44time.</p> 45<p>The DbEnv::set_lk_max_locks method configures a database environment, not only operations 46performed using the specified <a href="../api_cxx/env_class.html">DbEnv</a> handle.</p> 47<p>The DbEnv::set_lk_max_locks method may not be called after the <a href="../api_cxx/env_open.html">DbEnv::open</a> method is 48called. 49If the database environment already exists when 50<a href="../api_cxx/env_open.html">DbEnv::open</a> is called, the information specified to DbEnv::set_lk_max_locks 51will be ignored. 52</p> 53<p>The DbEnv::set_lk_max_locks method 54either returns a non-zero error value 55or throws an exception that encapsulates a non-zero error value on 56failure, and returns 0 on success. 57</p> 58<b>Parameters</b> <br> 59 <b>max</b><ul compact><li>The <b>max</b> parameter is the maximum number of locks supported by 60the Berkeley DB environment.</ul> 61<br> 62<br><b>Errors</b> 63<p>The DbEnv::set_lk_max_locks method 64may fail and throw 65<a href="../api_cxx/except_class.html">DbException</a>, 66encapsulating one of the following non-zero errors, or return one of 67the following non-zero errors:</p> 68<br> 69<b>EINVAL</b><ul compact><li>If the method was called after <a href="../api_cxx/env_open.html">DbEnv::open</a> was called; or if an 70invalid flag value or parameter was specified.</ul> 71<br> 72<hr size=1 noshade> 73<b>Description: DbEnv::get_lk_max_locks</b> 74<p>The DbEnv::get_lk_max_locks method returns the maximum number of locks.</p> 75<p>The DbEnv::get_lk_max_locks method may be called at any time during the life of the 76application.</p> 77<p>The DbEnv::get_lk_max_locks method 78either returns a non-zero error value 79or throws an exception that encapsulates a non-zero error value on 80failure, and returns 0 on success. 81</p> 82<b>Parameters</b> <br> 83 <b>lk_maxp</b><ul compact><li>The DbEnv::get_lk_max_locks method returns the 84maximum number of locks in <b>lk_maxp</b>.</ul> 85<br> 86<hr size=1 noshade> 87<br><b>Class</b> 88<a href="../api_cxx/env_class.html">DbEnv</a>, <a href="../api_cxx/lock_class.html">DbLock</a> 89<br><b>See Also</b> 90<a href="../api_cxx/lock_list.html">Locking Subsystem and Related Methods</a> 91</tt> 92<table width="100%"><tr><td><br></td><td align=right> 93<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> 94</td></tr></table> 95<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 96</body> 97</html> 98
