<!--$Id: db_verify.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.verify</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.verify</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 void verify(String file, String database, java.io.OutputStream outfile, int flags) throws DbException; </pre></h3> <h1>Description</h1> <p>The Db.verify method verifies the integrity of all databases in the file specified by the <b>file</b> argument, and optionally outputs the databases' key/data pairs to the file stream specified by the <b>outfile</b> argument. <p>The <b>flags</b> value must be set to 0 or the following value: <p><dl compact> <p><dt><a name="Db.DB_SALVAGE">Db.DB_SALVAGE</a><dd>Write the key/data pairs from all databases in the file to the file stream named in the <b>outfile</b> argument. The output format is the same as that specified for the <a href="../utility/db_dump.html">db_dump</a> utility, and can be used as input for the <a href="../utility/db_load.html">db_load</a> utility. <p>Because the key/data pairs are output in page order as opposed to the sort order used by <a href="../utility/db_dump.html">db_dump</a>, using Db.verify to dump key/data pairs normally produces less than optimal loads for Btree databases. </dl> <p>In addition, the following flags may be set by bitwise inclusively <b>OR</b>'ing them into the <b>flags</b> parameter: <p><dl compact> <p><dt><a name="Db.DB_AGGRESSIVE">Db.DB_AGGRESSIVE</a><dd>Output <b>all</b> the key/data pairs in the file that can be found. By default, Db.verify does not assume corruption. For example, if a key/data pair on a page is marked as deleted, it is not then written to the output file. When Db.DB_AGGRESSIVE is specified, corruption is assumed, and any key/data pair that can be found is written. In this case, key/data pairs that are corrupted or have been deleted may appear in the output (even if the file being salvaged is in no way corrupt), and the output will almost certainly require editing before being loaded into a database. <p><dt><a name="Db.DB_PRINTABLE">Db.DB_PRINTABLE</a><dd>When using the Db.DB_SALVAGE flag, if characters in either the key or data items are printing characters (as defined by <b>isprint</b>(3)), use printing characters to represent them. This flag permits users to use standard text editors and tools to modify the contents of databases or selectively remove data from salvager output. <p>Note: different systems may have different notions about what characters are considered <i>printing characters</i>, and databases dumped in this manner may be less portable to external systems. <p><dt><a name="Db.DB_NOORDERCHK">Db.DB_NOORDERCHK</a><dd>Skip the database checks for btree and duplicate sort order and for hashing. <p>The Db.verify method normally verifies that btree keys and duplicate items are correctly sorted, and hash keys are correctly hashed. If the file being verified contains multiple databases using differing sorting or hashing algorithms, some of them must necessarily fail database verification because only one sort order or hash function can be specified before Db.verify is called. To verify files with multiple databases having differing sorting orders or hashing functions, first perform verification of the file as a whole by using the Db.DB_NOORDERCHK flag, and then individually verify the sort order and hashing function for each database in the file using the Db.DB_ORDERCHKONLY flag. <p><dt><a name="Db.DB_ORDERCHKONLY">Db.DB_ORDERCHKONLY</a><dd>Perform the database checks for btree and duplicate sort order and for hashing, skipped by Db.DB_NOORDERCHK. <p>When this flag is specified, a <b>database</b> argument should also be specified, indicating the database in the physical file which is to be checked. This flag is only safe to use on databases that have already successfully been verified using Db.verify with the Db.DB_NOORDERCHK flag set. </dl> <p>The database argument must be set to null except when the Db.DB_ORDERCHKONLY flag is set. <p><b>The Db.verify method does not perform any locking, even in Berkeley DB environments that are configured with a locking subsystem. As such, it should only be used on files that are not being modified by another thread of control.</b> <p>The Db.verify interface may not be called after the <a href="../api_java/db_open.html">Db.open</a> interface is called. <a name="3"><!--meow--></a> <p>The Db.verify method throws an exception that encapsulates a non-zero error value on failure, and <a href="../ref/program/errorret.html#DB_VERIFY_BAD">Db.DB_VERIFY_BAD</a> if a database is corrupted. When the Db.DB_SALVAGE flag is specified, the <a href="../ref/program/errorret.html#DB_VERIFY_BAD">Db.DB_VERIFY_BAD</a> return means that all key/data pairs in the file may not have been successfully output. <h1>Environment Variables</h1> <p><dl compact> <p><dt>DB_HOME<dd>If a <b>dbenv</b> argument to <a href="../api_c/db_create.html">db_create</a> was specified, the environment variable <b>DB_HOME</b> may be used as the path of the database environment home. <p>Db.verify is affected by any database directory specified using the <a href="../api_java/env_set_data_dir.html">DbEnv.set_data_dir</a> method, or by setting the "set_data_dir" string in the environment's <b>DB_CONFIG</b> file. </dl> <h1>Errors</h1> <p>The Db.verify 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. <p>Db.verify was called after <a href="../api_java/db_open.html">Db.open</a>. </dl> <p>The Db.verify 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.verify 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>