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273 lines
12 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>DB_ENV->log_archive()</title>
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<link rel="stylesheet" href="apiReference.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB C API Reference" />
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<link rel="up" href="lsn.html" title="Chapter 7. The DB_LSN Handle" />
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<link rel="prev" href="envget_lg_regionmax.html" title="DB_ENV->get_lg_regionmax()" />
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<link rel="next" href="logcursor.html" title="DB_ENV->log_cursor()" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 11.2.5.2</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">DB_ENV->log_archive()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="envget_lg_regionmax.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 7.
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The DB_LSN Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="logcursor.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="logarchive"></a>DB_ENV->log_archive()</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db.h>
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int
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DB_ENV->log_archive(DB_ENV *env, char *(*listp)[], u_int32_t flags); </pre>
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<p>
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The <code class="methodname">DB_ENV->log_archive()</code> method returns an array of log or database
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filenames.
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</p>
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<p>
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By default, <code class="methodname">DB_ENV->log_archive()</code> returns the names of all of the
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log files that are no longer in use (for example, that are no longer involved in active
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transactions), and that may safely be archived for catastrophic recovery and then removed
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from the system. If there are no filenames to return, the memory location to which
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<span class="bold"><strong>listp</strong></span> refers will be set to NULL.
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</p>
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<p>
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When Replication Manager is in use, log archiving is
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performed in a replication group-aware manner such that the
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log file status of other sites in the group is considered to
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determine if a log file is in use.
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</p>
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<p>
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Arrays of log filenames are stored in allocated memory. If application-specific allocation
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routines have been declared (see <a class="xref" href="envset_alloc.html" title="DB_ENV->set_alloc()">DB_ENV->set_alloc()</a>
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for more information), they are used to allocate the memory; otherwise, the standard
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C library <span class="bold"><strong>malloc</strong></span>(3) is used. The caller is responsible
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for deallocating the memory. To deallocate the memory, free the memory reference;
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references inside the returned memory need not be individually freed.
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</p>
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<p>
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Log cursor handles (returned by the <a class="xref" href="logcursor.html" title="DB_ENV->log_cursor()">DB_ENV->log_cursor()</a>
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method) may have open file descriptors for log files in the database environment. Also,
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the Berkeley DB interfaces to the database environment logging subsystem (for example,
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<a class="xref" href="logput.html" title="DB_ENV->log_put()">DB_ENV->log_put()</a> and <a class="xref" href="txnabort.html" title="DB_TXN->abort()">DB_TXN->abort()</a> ) may allocate log cursors and have open file descriptors
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for log files as well. On operating systems where filesystem related system calls (for
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example, rename and unlink on Windows/NT) can fail if a process has an open file descriptor
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for the affected file, attempting to move or remove the log files listed by
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<code class="methodname">DB_ENV->log_archive()</code> may fail. All Berkeley DB internal use of log
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cursors operates on active log files only and furthermore, is short-lived in nature. So,
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an application seeing such a failure should be restructured to close any open log cursors
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it may have, and otherwise to retry the operation until it succeeds. (Although the latter
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is not likely to be necessary; it is hard to imagine a reason to move or rename a log file
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in which transactions are being logged or aborted.)
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</p>
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<p>
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See <a class="link" href="db_archive.html" title="db_archive">db_archive</a> for more information on
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database archival procedures.
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</p>
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<p>
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The <code class="methodname">DB_ENV->log_archive()</code> method is the underlying method used by the
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<a class="link" href="db_archive.html" title="db_archive">db_archive</a> utility.
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See the <a class="link" href="db_archive.html" title="db_archive">db_archive</a>
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utility source code for an example of using <code class="methodname">DB_ENV->log_archive()</code> in
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a IEEE/ANSI Std 1003.1 (POSIX) environment.
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</p>
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<p>
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The <code class="methodname">DB_ENV->log_archive()</code> <span>
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<span>
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method returns a non-zero error value on failure and 0 on success.
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</span>
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</span>
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</p>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3907344"></a>Parameters</h3>
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</div>
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</div>
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</div>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3907333"></a>listp</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>listp</strong></span> parameter references memory
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into which the allocated array of log or database filenames is copied.
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If there are no filenames to return, the memory location to which
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<span class="bold"><strong>listp</strong></span> refers will be set to NULL.
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</p>
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</div>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3907031"></a>flags</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>flags</strong></span> parameter must be set to 0
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or by bitwise inclusively <span class="bold"><strong>OR</strong></span>'ing
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together one or more of the following values:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p><a id="archive_DB_ARCH_ABS"></a>
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<code class="literal">DB_ARCH_ABS</code>
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</p>
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<p>
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All pathnames are returned as absolute pathnames, instead of relative
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to the database home directory.
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</p>
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</li>
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<li>
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<p><a id="archive_DB_ARCH_DATA"></a>
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<code class="literal">DB_ARCH_DATA</code>
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</p>
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<p>
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Return the database files that need to be archived in order to recover
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the database from catastrophic failure. If any of the database files
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have not been accessed during the lifetime of the current log files,
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<code class="methodname">DB_ENV->log_archive()</code> will not include them in this list. It is also
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possible that some of the files referred to by the log have since been
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deleted from the system.
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</p>
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<p>
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The <code class="literal">DB_ARCH_DATA</code> and <code class="literal">DB_ARCH_LOG flags</code> are mutually exclusive.
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</p>
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</li>
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<li>
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<p><a id="archive_DB_ARCH_LOG"></a>
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<code class="literal">DB_ARCH_LOG</code>
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</p>
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<p>
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Return all the log filenames, regardless of whether or not they are in
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use.
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</p>
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<p>
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The <code class="literal">DB_ARCH_DATA</code> and <code class="literal">DB_ARCH_LOG flags</code> are mutually exclusive.
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</p>
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</li>
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<li>
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<p><a id="archive_DB_ARCH_REMOVE"></a>
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<code class="literal">DB_ARCH_REMOVE</code>
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</p>
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<p>
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Remove log files that are no longer needed; no filenames are returned.
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Automatic log file removal is likely to make catastrophic recovery
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impossible.
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</p>
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<p>
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The <code class="literal">DB_ARCH_REMOVE</code> flag may not be specified with any other flag.
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</p>
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</li>
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</ul>
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</div>
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</div>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3907680"></a>Errors</h3>
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</div>
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</div>
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</div>
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<p>
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The <code class="methodname">DB_ENV->log_archive()</code> <span>
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<span>
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method may fail and return one of the following non-zero errors:
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</span>
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</span>
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</p>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3907696"></a>EINVAL</h4>
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</div>
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</div>
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</div>
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<p>
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An invalid flag value or parameter was specified.
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</p>
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</div>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3907724"></a>Class</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>,
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<a class="link" href="logc.html" title="The DB_LOGC Handle">DB_LOGC</a>,
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<a class="link" href="lsn.html" title="Chapter 7. The DB_LSN Handle">DB_LSN</a>
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</p>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3907774"></a>See Also</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="xref" href="lsn.html#loglist" title="Logging Subsystem and Related Methods">Logging Subsystem and Related Methods</a>
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</p>
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</div>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="envget_lg_regionmax.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="lsn.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="logcursor.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">DB_ENV->get_lg_regionmax() </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top"> DB_ENV->log_cursor()</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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