90 lines
4.5 KiB
HTML
90 lines
4.5 KiB
HTML
<!--$Id: env_failchk.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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<!--See the file LICENSE for redistribution information.-->
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<html>
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<head>
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<title>Berkeley DB: DB_ENV->failchk</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->failchk</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->failchk(DB_ENV *dbenv, u_int32_t flags);
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</pre></b>
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<hr size=1 noshade>
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<b>Description: DB_ENV->failchk</b>
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<p>The DB_ENV->failchk method checks for threads of control (either a true
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thread or a process) that have exited while manipulating Berkeley DB library
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data structures, while holding a logical database lock, or with an
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unresolved transaction (that is, a transaction that was never aborted
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or committed). For more information, see <a href="../ref/cam/app.html">Architecting Data Store and Concurrent Data Store applications</a>, and
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<a href="../ref/transapp/app.html">Architecting Transactional Data Store
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applications</a>.</p>
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<p>The DB_ENV->failchk method is based on the "thread_id" and "is_alive"
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functions specified to the <a href="../api_c/env_set_thread_id.html">DB_ENV->set_thread_id</a> method. Applications
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calling the DB_ENV->failchk method must have already called the
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<a href="../api_c/env_set_isalive.html">DB_ENV->set_isalive</a> method, on the same <a href="../api_c/env_class.html">DB_ENV</a>, and must have
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configured their database environment using the
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<a href="../api_c/env_set_thread_count.html">DB_ENV->set_thread_count</a> method.</p>
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<p>If DB_ENV->failchk determines a thread of control exited while
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holding database read locks, it will release those locks. If
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DB_ENV->failchk determines a thread of control exited with an
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unresolved transaction, the transaction will be aborted. In either of
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these cases, DB_ENV->failchk will return 0 and the application may
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continue to use the database environment.</p>
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<p>In either of these cases, the DB_ENV->failchk method will also report
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the process and thread IDs associated with any released locks or
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aborted transactions. The information is printed to a specified output
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channel (see the <a href="../api_c/env_set_msgfile.html">DB_ENV->set_msgfile</a> method for more information), or
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passed to an application callback function (see the
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<a href="../api_c/env_set_msgcall.html">DB_ENV->set_msgcall</a> method for more information).</p>
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<p>If DB_ENV->failchk determines a thread of control has exited such
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that database environment recovery is required, it will return
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<a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>. In this case, the application should not
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continue to use the database environment. For a further description as
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to the actions the application should take when this failure occurs, see
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<a href="../ref/cam/fail.html">Handling failure in Data Store and
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Concurrent Data Store applications</a>, and
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<a href="../ref/transapp/fail.html">Handling failure in Transactional
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Data Store applications</a>.</p>
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<p>The DB_ENV->failchk method may not be called before the <a href="../api_c/env_open.html">DB_ENV->open</a> method is called.</p>
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<p>The DB_ENV->failchk 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>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul>
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<br>
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<br><b>Errors</b>
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<p>The DB_ENV->failchk 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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<br><b>Class</b>
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<a href="../api_c/env_class.html">DB_ENV</a>
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<br><b>See Also</b>
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<a href="../api_c/env_list.html">Database Environments 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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</body>
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</html>
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