<!--$Id: db_close.html,v 1.1 2003/02/15 04:55:50 zarzycki Exp $--> <!--$Id: db_close.html,v 1.1 2003/02/15 04:55:50 zarzycki Exp $--> <!--Copyright 1997-2002 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: Db.close</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++"> </head> <body bgcolor=white> <a name="2"><!--meow--></a> <table width="100%"><tr valign=top> <td> <h1>Db.close</h1> </td> <td align=right> <a href="../api_java/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <hr size=1 noshade> <tt> <h3><pre> import com.sleepycat.db.*; <p> public int close(int flags) throws DbException; </pre></h3> <h1>Description</h1> <p>The Db.close method flushes any cached database information to disk, closes any open cursors, frees any allocated resources, and closes any underlying files. Because key/data pairs are cached in memory, failing to sync the file with the Db.close or <a href="../api_java/db_sync.html">Db.sync</a> method may result in inconsistent or lost information. <p>The <b>flags</b> value must be set to 0 or by bitwise inclusively <b>OR</b>'ing together one or more of the following values: <p><dl compact> <p><dt><a name="Db.DB_NOSYNC">Db.DB_NOSYNC</a><dd>Do not flush cached information to disk. The <a href="../api_java/db_close.html#DB_NOSYNC">Db.DB_NOSYNC</a> flag is a dangerous option. It should be set only if the application is doing logging (with transactions) so that the database is recoverable after a system or application crash, or if the database is always generated from scratch after any system or application crash. <p><b>It is important to understand that flushing cached information to disk only minimizes the window of opportunity for corrupted data.</b> Although unlikely, it is possible for database corruption to happen if a system or application crash occurs while writing data to the database. To ensure that database corruption never occurs, applications must either: use transactions and logging with automatic recovery; use logging and application-specific recovery; or edit a copy of the database, and once all applications using the database have successfully called Db.close, atomically replace the original database with the updated copy. </dl> <p>When multiple threads are using the <a href="../api_java/db_class.html">Db</a> concurrently, only a single thread may call the Db.close method. <p>The <a href="../api_java/db_class.html">Db</a> handle may not be accessed again after Db.close is called, regardless of its return. <p>The Db.close method throws an exception that encapsulates a non-zero error value on failure. <h1>Errors</h1> <p>The Db.close method may fail and throw an exception encapsulating a non-zero error for the following conditions: <p><dl compact> <p><dt>EINVAL<dd>An invalid flag value or parameter was specified. </dl> <p>The Db.close method may fail and throw an exception for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the Db.close method may fail and throw a <a href="../api_java/runrec_class.html">DbRunRecoveryException</a>, in which case all subsequent Berkeley DB calls will fail in the same way. <h1>Class</h1> <a href="../api_java/db_class.html">Db</a> <h1>See Also</h1> <a href="../api_java/db_list.html">Databases and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_java/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> </body> </html>