<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>Db::verify()</title> <link rel="stylesheet" href="apiReference.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Berkeley DB C++ API Reference" /> <link rel="up" href="db.html" title="Chapter 2. The Db Handle" /> <link rel="prev" href="dbupgrade.html" title="Db::upgrade()" /> <link rel="next" href="db_heap_rid.html" title="DbHeapRecordId" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">Db::verify()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="dbupgrade.html">Prev</a> </td> <th width="60%" align="center">Chapter 2. The Db Handle </th> <td width="20%" align="right"> <a accesskey="n" href="db_heap_rid.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="dbverify"></a>Db::verify()</h2> </div> </div> </div> <pre class="programlisting">#include <db_cxx.h> int Db::verify(const char *file, const char *database, ostream *outfile, u_int32_t flags);</pre> <p> The <code class="methodname">Db::verify()</code> method verifies the integrity of all databases in the file specified by the <span class="bold"><strong>file</strong></span> parameter, and optionally outputs the databases' key/data pairs to the file stream specified by the <span class="bold"><strong>outfile</strong></span> parameter. </p> <p> <span class="bold"><strong>The <code class="methodname">Db::verify()</code> 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.</strong></span> </p> <p> The <code class="methodname">Db::verify()</code> method may not be called after the <a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a> method is called. </p> <p> The <a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a> handle may not be accessed again after <code class="methodname">Db::verify()</code> is called, regardless of its return. </p> <p> The <code class="methodname">Db::verify()</code> method will return DB_VERIFY_BAD if a database is corrupted. When the DB_SALVAGE flag is specified, the DB_VERIFY_BAD return means that all key/data pairs in the file may not have been successfully output. Unless otherwise specified, the <code class="methodname">Db::verify()</code> <span> <span> method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </span> </span> </p> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp6019632"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp6015864"></a>file</h4> </div> </div> </div> <p> The <span class="bold"><strong>file</strong></span> parameter is the physical file in which the databases to be verified are found. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp6010504"></a>database</h4> </div> </div> </div> <p> The <span class="bold"><strong>database</strong></span> parameter is the database in <span class="bold"><strong>file</strong></span> on which the database checks for btree and duplicate sort order and for hashing are to be performed. See the DB_ORDERCHKONLY flag for more information. </p> <p> The database parameter must be set to NULL except when the DB_ORDERCHKONLY flag is set. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp6018016"></a>outfile</h4> </div> </div> </div> <p> The <span class="bold"><strong>outfile</strong></span> parameter is an optional file stream to which the databases' key/data pairs are written. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp6008272"></a>flags</h4> </div> </div> </div> <p> The <span class="bold"><strong>flags</strong></span> parameter must be set to 0 or the following value: </p> <div class="itemizedlist"> <ul type="disc"> <li> <p><a id="verify_DB_SALVAGE"></a> <code class="literal">DB_SALVAGE</code> </p> <p> Write the key/data pairs from all databases in the file to the file stream named in the <span class="bold"><strong>outfile</strong></span> parameter. Key values are written for Btree, Hash and Queue databases, but not for Recno databases. </p> <p> The output format is the same as that specified for the <a class="link" href="db_dump.html" title="db_dump">db_dump</a> utility, and can be used as input for the <a class="link" href="db_load.html" title="db_load">db_load</a> utility. </p> <p> Because the key/data pairs are output in page order as opposed to the sort order used by <a class="link" href="db_dump.html" title="db_dump">db_dump</a>, using <code class="methodname">Db::verify()</code> to dump key/data pairs normally produces less than optimal loads for Btree databases. </p> </li> </ul> </div> <p> In addition, the following flags may be set by bitwise inclusively <span class="bold"><strong>OR</strong></span>'ing them into the <span class="bold"><strong>flags</strong></span> parameter: </p> <div class="itemizedlist"> <ul type="disc"> <li> <p><a id="verify_DB_AGGRESSIVE"></a> <code class="literal">DB_AGGRESSIVE</code> </p> <p> Output <span class="bold"><strong>all</strong></span> the key/data pairs in the file that can be found. By default, <code class="methodname">Db::verify()</code> 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_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> </li> <li> <p><a id="verify_DB_PRINTABLE"></a> <code class="literal">DB_PRINTABLE</code> </p> <p> When using the DB_SALVAGE flag, if characters in either the key or data items are printing characters (as defined by <span class="bold"><strong>isprint</strong></span>(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> <p> Note: different systems may have different notions about what characters are considered <span class="emphasis"><em>printing characters</em></span>, and databases dumped in this manner may be less portable to external systems. </p> </li> <li> <p><a id="verify_DB_NOORDERCHK"></a> <code class="literal">DB_NOORDERCHK</code> </p> <p> Skip the database checks for btree and duplicate sort order and for hashing. </p> <p> The <code class="methodname">Db::verify()</code> 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 <code class="methodname">Db::verify()</code> 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_NOORDERCHK flag, and then individually verify the sort order and hashing function for each database in the file using the DB_ORDERCHKONLY flag. </p> </li> <li> <p><a id="verify_DB_ORDERCHKONLY"></a> <code class="literal">DB_ORDERCHKONLY</code> </p> <p> Perform the database checks for btree and duplicate sort order and for hashing, skipped by DB_NOORDERCHK. </p> <p> When this flag is specified, a <span class="bold"><strong>database</strong></span> parameter 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 <code class="methodname">Db::verify()</code> with the DB_NOORDERCHK flag set. </p> </li> </ul> </div> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp6050672"></a>Environment Variables</h3> </div> </div> </div> <p> If the database was opened within a database environment, the environment variable <code class="literal">DB_HOME</code> may be used as the path of the database environment home. </p> <p> <code class="methodname">Db::verify()</code> is affected by any database directory specified using the <a class="xref" href="envset_data_dir.html" title="DbEnv::set_data_dir()">DbEnv::set_data_dir()</a> method, or by setting the "set_data_dir" string in the environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp6026400"></a>Errors</h3> </div> </div> </div> <p> The <code class="methodname">Db::verify()</code> <span> <span> method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a> exception, encapsulating one of the following non-zero errors, or return one of the following non-zero errors: </span> </span> </p> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp6048960"></a>EINVAL</h4> </div> </div> </div> <p> If the method was called after <a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a> was called; or if an invalid flag value or parameter was specified. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp6045240"></a>ENOENT</h4> </div> </div> </div> <p> The file or directory does not exist. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp6055376"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp6050888"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="dbupgrade.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="db.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="db_heap_rid.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Db::upgrade() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DbHeapRecordId</td> </tr> </table> </div> </body> </html>