mirror of
https://github.com/yasuhirokimura/db18
synced 2026-06-08 18:29:23 +00:00
Yasuhiro KIMURA
245 lines
9.5 KiB
HTML
245 lines
9.5 KiB
HTML
<?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_ENV->log_get_config()</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="lsn.html" title="Chapter 7. The DB_LSN Handle" />
|
||
<link rel="prev" href="logflush.html" title="DB_ENV->log_flush()" />
|
||
<link rel="next" href="logprintf.html" title="DB_ENV->log_printf()" />
|
||
</head>
|
||
<body>
|
||
<div xmlns="" class="navheader">
|
||
<div class="libver">
|
||
<p>Library Version 18.1.40</p>
|
||
</div>
|
||
<table width="100%" summary="Navigation header">
|
||
<tr>
|
||
<th colspan="3" align="center">
|
||
<span xmlns="http://www.w3.org/1999/xhtml">DB_ENV->log_get_config()</span>
|
||
|
||
</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="logflush.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 7.
|
||
The DB_LSN Handle
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="logprintf.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="envlog_get_config"></a>
|
||
<span>DB_ENV->log_get_config()</span>
|
||
|
||
</h2>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<pre class="programlisting">#include <db.h>
|
||
|
||
int
|
||
DB_ENV->log_get_config(DB_ENV *dbenv, u_int32_t which, int *onoffp); </pre>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->log_get_config()</code> method returns whether the specified
|
||
<span class="bold"><strong>which</strong></span> parameter is currently set or
|
||
not. You can manage this value using the
|
||
<a class="xref" href="envlog_set_config.html" title="DB_ENV->log_set_config()">
|
||
<span>DB_ENV->log_set_config()</span>
|
||
|
||
</a>
|
||
method.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->log_get_config()</code> method may be called at any time during
|
||
the life of the application.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->log_get_config()</code> <span>
|
||
<span>
|
||
method returns a non-zero error value on failure and 0 on success.
|
||
</span>
|
||
|
||
</span>
|
||
</p>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm139753799851584"></a>Parameters</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="idm139753799818080"></a>which</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>which</strong></span> parameter is
|
||
the message value for which configuration is being
|
||
checked. Must be set to one of the following values:
|
||
</p>
|
||
<div class="itemizedlist">
|
||
<ul type="disc">
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_BLOB"></a>
|
||
<code class="literal">DB_LOG_EXT_FILE</code>
|
||
</p>
|
||
<p>
|
||
Enables full logging of
|
||
<a class="link" href="blob.html" title="Chapter 13. External Files">external file</a> data.
|
||
</p>
|
||
</li>
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_DIRECT"></a>
|
||
<code class="literal">DB_LOG_DIRECT</code>
|
||
</p>
|
||
<p>
|
||
System buffering is turned off for Berkeley DB log
|
||
files to avoid double caching.
|
||
</p>
|
||
</li>
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_DSYNC"></a>
|
||
<code class="literal">DB_LOG_DSYNC</code>
|
||
</p>
|
||
<p>
|
||
Berkeley DB is configured to flush log writes to the backing disk before
|
||
returning from the write system call, rather than flushing log writes
|
||
explicitly in a separate system call, as necessary.
|
||
</p>
|
||
</li>
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_AUTO_REMOVE"></a>
|
||
<code class="literal">DB_LOG_AUTO_REMOVE</code>
|
||
</p>
|
||
<p>
|
||
Berkeley DB automatically removes log files that
|
||
are no longer needed.
|
||
</p>
|
||
</li>
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_IN_MEMORY"></a>
|
||
<code class="literal">DB_LOG_IN_MEMORY</code>
|
||
</p>
|
||
<p>
|
||
Transaction logs are maintained in memory rather than on disk. This
|
||
means that transactions exhibit the ACI (atomicity, consistency, and
|
||
isolation) properties, but not D (durability).
|
||
</p>
|
||
</li>
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_NOSYNC"></a>
|
||
<code class="literal">DB_LOG_NOSYNC</code>
|
||
</p>
|
||
<p>
|
||
The transaction log is not flushed from from the operating system cache to
|
||
stable storage when the logging system switches log files or a durable
|
||
transaction commits. This means that transactions exhibit the ACI
|
||
(atomicity, consistency, and isolation) properties, but only partially
|
||
support D (durability); that is, database integrity will be maintained if
|
||
the application fails and the environment is recovered, but not if the
|
||
system fails. All database files must be verified and/or restored from a
|
||
replication group master or archival backup after system failure.
|
||
</p>
|
||
</li>
|
||
<li>
|
||
<p><a id="log_get_config_DB_LOG_ZERO"></a>
|
||
<code class="literal">DB_LOG_ZERO</code>
|
||
</p>
|
||
<p>
|
||
All pages of a log file are zeroed when that log file is created.
|
||
</p>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="idm139753799778528"></a>onoffp</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>onoffp</strong></span> parameter
|
||
references memory into which the configuration of the
|
||
specified <span class="bold"><strong>which</strong></span> parameter
|
||
is copied.
|
||
</p>
|
||
<p>
|
||
If the returned <span class="bold"><strong>onoff</strong></span>
|
||
value is zero, the parameter is off; otherwise, on.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm139753799827120"></a>Class</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm139753799786736"></a>See Also</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="xref" href="lsn.html#loglist" title="Logging Subsystem and Related Methods">Logging Subsystem and Related Methods</a>,
|
||
<a class="xref" href="envlog_set_config.html" title="DB_ENV->log_set_config()">
|
||
<span>DB_ENV->log_set_config()</span>
|
||
|
||
</a>
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="navfooter">
|
||
<hr />
|
||
<table width="100%" summary="Navigation footer">
|
||
<tr>
|
||
<td width="40%" align="left"><a accesskey="p" href="logflush.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="lsn.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="logprintf.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">
|
||
<span>DB_ENV->log_flush()</span>
|
||
|
||
</td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top">
|
||
<span>DB_ENV->log_printf()</span>
|
||
|
||
</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|