mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 01:26:25 +00:00
119 lines
5.3 KiB
HTML
119 lines
5.3 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 close</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 TCL API Reference" />
|
|||
|
|
<link rel="up" href="tclapi.html" title="Chapter 1. Berkeley DB Tcl APIs" />
|
|||
|
|
<link rel="prev" href="tclapi.html" title="Chapter 1. Berkeley DB Tcl APIs" />
|
|||
|
|
<link rel="next" href="db_count.html" title="db count" />
|
|||
|
|
</head>
|
|||
|
|
<body>
|
|||
|
|
<div xmlns="" class="navheader">
|
|||
|
|
<div class="libver">
|
|||
|
|
<p>Library Version 11.2.5.2</p>
|
|||
|
|
</div>
|
|||
|
|
<table width="100%" summary="Navigation header">
|
|||
|
|
<tr>
|
|||
|
|
<th colspan="3" align="center"><span xmlns="http://www.w3.org/1999/xhtml" class="emphasis"><em>db</em></span> close</th>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="20%" align="left"><a accesskey="p" href="tclapi.html">Prev</a> </td>
|
|||
|
|
<th width="60%" align="center">Chapter 1.
|
|||
|
|
Berkeley DB Tcl APIs
|
|||
|
|
</th>
|
|||
|
|
<td width="20%" align="right"> <a accesskey="n" href="db_count.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="db_close"></a><span class="emphasis"><em>db</em></span> close</h2>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<pre class="programlisting">db close
|
|||
|
|
[-nosync] </pre>
|
|||
|
|
<p>
|
|||
|
|
The <span class="emphasis"><em>db</em></span> <span class="bold"><strong>close</strong></span>
|
|||
|
|
command 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 <span class="emphasis"><em>db</em></span> <span class="bold"><strong>close</strong></span> or <span class="emphasis"><em>db</em></span> <span class="bold"><strong>sync</strong></span> command may result in inconsistent or lost
|
|||
|
|
information.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The options are as follows:
|
|||
|
|
</p>
|
|||
|
|
<div class="itemizedlist">
|
|||
|
|
<ul type="disc">
|
|||
|
|
<li>
|
|||
|
|
<p>
|
|||
|
|
<span class="bold"><strong>-nosync</strong></span>
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
Do not flush cached information to disk.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The <code class="literal">-nosync</code> flag is a dangerous option. It should only be set 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>
|
|||
|
|
<p>
|
|||
|
|
It is important to understand that flushing cached information to disk
|
|||
|
|
only minimizes the window of opportunity for corrupted data. 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
|
|||
|
|
after all applications using the database have successfully called
|
|||
|
|
<span class="emphasis"><em>db</em></span> <span class="bold"><strong>close</strong></span>,
|
|||
|
|
atomically replace the original database with the updated copy.
|
|||
|
|
</p>
|
|||
|
|
</li>
|
|||
|
|
</ul>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
After <span class="emphasis"><em>db</em></span> <span class="bold"><strong>close</strong></span>
|
|||
|
|
has been called, regardless of its return, the DB handle may not be
|
|||
|
|
accessed again.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The <span class="emphasis"><em>db</em></span> <span class="bold"><strong>close</strong></span>
|
|||
|
|
command returns 0 on success, and in the case of error, a Tcl error is
|
|||
|
|
thrown.
|
|||
|
|
</p>
|
|||
|
|
</div>
|
|||
|
|
<div class="navfooter">
|
|||
|
|
<hr />
|
|||
|
|
<table width="100%" summary="Navigation footer">
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left"><a accesskey="p" href="tclapi.html">Prev</a> </td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="u" href="tclapi.html">Up</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right"> <a accesskey="n" href="db_count.html">Next</a></td>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left" valign="top">Chapter 1.
|
|||
|
|
Berkeley DB Tcl APIs
|
|||
|
|
</td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="h" href="index.html">Home</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right" valign="top"> <span class="emphasis"><em>db</em></span> count</td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
</div>
|
|||
|
|
</body>
|
|||
|
|
</html>
|