mirror of
https://github.com/MariaDB/server.git
synced 2025-11-09 11:41:36 +03:00
57 lines
3.7 KiB
HTML
57 lines
3.7 KiB
HTML
<!--$Id: intro.so,v 10.25 2000/03/18 21:43:12 bostic Exp $-->
|
|
<!--Copyright 1997, 1998, 1999, 2000 by Sleepycat Software, Inc.-->
|
|
<!--All rights reserved.-->
|
|
<html>
|
|
<head>
|
|
<title>Berkeley DB Reference Guide: Introduction</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>
|
|
<table><tr valign=top>
|
|
<td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Environment</dl></h3></td>
|
|
<td width="1%"><a href="../../ref/arch/utilities.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../ref/toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/env/create.html"><img src="../../images/next.gif" alt="Next"></a>
|
|
</td></tr></table>
|
|
<p>
|
|
<h1 align=center>Introduction</h1>
|
|
<p>A Berkeley DB environment is an encapsulation of one or more databases, log
|
|
files and shared information about the database environment such as shared
|
|
memory buffer cache pages.
|
|
<p>The simplest way to administer a Berkeley DB application environment is to
|
|
create a single <b>home</b> directory that stores the files for the
|
|
applications that will share the environment. The environment home
|
|
directory must be created before any Berkeley DB applications are run. Berkeley DB
|
|
itself never creates the environment home directory. The environment can
|
|
then be identified by the name of that directory.
|
|
<p>An environment may be shared by any number of applications as well as by
|
|
any number of threads within the applications. It is possible for an
|
|
environment to include resources from other directories on the system,
|
|
and applications often choose to distribute resources to other directories
|
|
or disks for performance or other reasons. However, by default, the
|
|
databases, shared regions (the locking, logging, memory pool, and
|
|
transaction shared memory areas) and log files will be stored in a single
|
|
directory hierarchy.
|
|
<p>It is important to realize that all applications sharing a database
|
|
environment implicitly trust each other. They have access to each other's
|
|
data as it resides in the shared regions and they will share resources
|
|
such as buffer space and locks. At the same time, any applications using
|
|
the same databases <b>must</b> share an environment if consistency is
|
|
to be maintained between them.
|
|
<p>The Berkeley DB environment is created and described by the <a href="../../api_c/env_create.html">db_env_create</a>
|
|
and <a href="../../api_c/env_open.html">DBENV->open</a> interfaces. In situations where customization is
|
|
desired, such as storing log files on a separate disk drive, applications
|
|
must describe the customization by either creating an environment
|
|
configuration file in the environment home directory or by arguments
|
|
passed to the <a href="../../api_c/env_open.html">DBENV->open</a> interface. See the documentation on that
|
|
function for details on this procedure.
|
|
<p>Once an environment has been created, database files specified using
|
|
relative pathnames will be named relative to the home directory. Using
|
|
pathnames relative to the home directory allows the entire environment
|
|
to be easily moved to facilitate restoring and recovering a database in
|
|
a different directory or on a different system.
|
|
<table><tr><td><br></td><td width="1%"><a href="../../ref/arch/utilities.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../ref/toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/env/create.html"><img src="../../images/next.gif" alt="Next"></a>
|
|
</td></tr></table>
|
|
<p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font>
|
|
</body>
|
|
</html>
|