103 lines
5.1 KiB
HTML
103 lines
5.1 KiB
HTML
<!--$Id: env_set_lk_detect.html 63573 2008-05-23 21:43:21Z trent.nelson $-->
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<!--Copyright (c) 1997,2008 Oracle. All rights reserved.-->
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<html>
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<head>
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<title>Berkeley DB: DB_ENV->set_lk_detect</title>
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<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
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<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++">
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</head>
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<body bgcolor=white>
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<table width="100%"><tr valign=top>
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<td>
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<b>DB_ENV->set_lk_detect</b>
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</td>
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<td align=right>
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<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a>
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<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td>
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</tr></table>
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<hr size=1 noshade>
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<tt>
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<b><pre>
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#include <db.h>
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<p>
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int
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DB_ENV->set_lk_detect(DB_ENV *dbenv, u_int32_t detect);
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<p>
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int
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DB_ENV->get_lk_detect(DB_ENV *dbenv, u_int32_t *lk_detectp);
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</pre></b>
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<hr size=1 noshade>
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<b>Description: DB_ENV->set_lk_detect</b>
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<p>Set if the deadlock detector is to be run whenever a lock conflict
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occurs, and specify what lock request(s) should be rejected. As
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transactions acquire locks on behalf of a single locker ID, rejecting a
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lock request associated with a transaction normally requires the
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transaction be aborted.</p>
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<p>The database environment's deadlock detector configuration may also be configured using the
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environment's <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file. The syntax of the entry in that
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file is a single line with the string "set_lk_detect", one or more whitespace
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characters, and the method <b>detect</b> parameter as a string; for example,
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"set_lk_detect DB_LOCK_OLDEST".
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Because the <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file is read when the database environment
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is opened, it will silently overrule configuration done before that
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time.</p>
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<p>The DB_ENV->set_lk_detect method configures a database environment, not only operations
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performed using the specified <a href="../api_c/env_class.html">DB_ENV</a> handle.</p>
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<p>The DB_ENV->set_lk_detect method may be called at any time during the life of the
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application.</p>
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<p>The DB_ENV->set_lk_detect method
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returns a non-zero error value on failure
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and 0 on success.
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</p>
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<b>Parameters</b> <br>
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<b>detect</b><ul compact><li>The <b>detect</b> parameter configures the deadlock detector. The
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specified value must be one of the following list:
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<br>
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<b><a name="DB_LOCK_DEFAULT">DB_LOCK_DEFAULT</a></b><ul compact><li>Use whatever lock policy was specified when the database environment
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was created. If no lock policy has yet been specified, set the lock
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policy to DB_LOCK_RANDOM.</ul>
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<b><a name="DB_LOCK_EXPIRE">DB_LOCK_EXPIRE</a></b><ul compact><li>Reject lock requests which have timed out. No other deadlock detection
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is performed.</ul>
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<b><a name="DB_LOCK_MAXLOCKS">DB_LOCK_MAXLOCKS</a></b><ul compact><li>Reject the lock request for the locker ID with the most locks.</ul>
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<b><a name="DB_LOCK_MAXWRITE">DB_LOCK_MAXWRITE</a></b><ul compact><li>Reject the lock request for the locker ID with the most write locks.</ul>
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<b><a name="DB_LOCK_MINLOCKS">DB_LOCK_MINLOCKS</a></b><ul compact><li>Reject the lock request for the locker ID with the fewest locks.</ul>
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<b><a name="DB_LOCK_MINWRITE">DB_LOCK_MINWRITE</a></b><ul compact><li>Reject the lock request for the locker ID with the fewest write locks.</ul>
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<b><a name="DB_LOCK_OLDEST">DB_LOCK_OLDEST</a></b><ul compact><li>Reject the lock request for the locker ID with the oldest lock.</ul>
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<b><a name="DB_LOCK_RANDOM">DB_LOCK_RANDOM</a></b><ul compact><li>Reject the lock request for a random locker ID.</ul>
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<b><a name="DB_LOCK_YOUNGEST">DB_LOCK_YOUNGEST</a></b><ul compact><li>Reject the lock request for the locker ID with the youngest lock.</ul>
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<br></ul>
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<br>
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<br><b>Errors</b>
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<p>The DB_ENV->set_lk_detect method
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may fail and return one of the following non-zero errors:</p>
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<br>
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<b>EINVAL</b><ul compact><li>An
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invalid flag value or parameter was specified.</ul>
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<br>
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<hr size=1 noshade>
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<b>Description: DB_ENV->get_lk_detect</b>
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<p>The DB_ENV->get_lk_detect method returns the deadlock detector configuration.</p>
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<p>The DB_ENV->get_lk_detect method may be called at any time during the life of the
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application.</p>
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<p>The DB_ENV->get_lk_detect method
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returns a non-zero error value on failure
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and 0 on success.
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</p>
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<b>Parameters</b> <br>
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<b>lk_detectp</b><ul compact><li>The DB_ENV->get_lk_detect method returns the
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deadlock detector configuration in <b>lk_detectp</b>.</ul>
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<br>
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<hr size=1 noshade>
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<br><b>Class</b>
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<a href="../api_c/env_class.html">DB_ENV</a>, <a href="../api_c/lock_class.html">DB_LOCK</a>
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<br><b>See Also</b>
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<a href="../api_c/lock_list.html">Locking Subsystem and Related Methods</a>
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</tt>
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<table width="100%"><tr><td><br></td><td align=right>
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<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>
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</td></tr></table>
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<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font>
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