mirror of
https://github.com/yasuhirokimura/db18
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Yasuhiro KIMURA
128 lines
5.5 KiB
HTML
128 lines
5.5 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>What other services does Berkeley DB provide?</title>
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<link rel="stylesheet" href="gettingStarted.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 Programmer's Reference Guide" />
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<link rel="up" href="intro.html" title="Chapter 1. Introduction" />
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<link rel="prev" href="intro_need.html" title="Do you need Berkeley DB?" />
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<link rel="next" href="intro_distrib.html" title="What does the Berkeley DB distribution include?" />
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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 18.1.40</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">What other services does Berkeley DB provide?</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="intro_need.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 1. Introduction </th>
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<td width="20%" align="right"> <a accesskey="n" href="intro_distrib.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="intro_what"></a>What other services does Berkeley DB provide?</h2>
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</div>
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</div>
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</div>
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<p>
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Berkeley DB also provides core database services to
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developers. These services include:
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</p>
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<div class="variablelist">
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<dl>
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<dt>
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<span class="term">Page cache management:</span>
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</dt>
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<dd>
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The page cache provides fast access to a cache
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of database pages, handling the I/O associated with
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the cache to ensure that dirty pages are written back
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to the file system and that new pages are allocated on
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demand. Applications may use the Berkeley DB shared
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memory buffer manager to serve their own files and
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pages.
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</dd>
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<dt>
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<span class="term">Transactions and logging:</span>
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</dt>
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<dd>
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The transaction and logging systems provide
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recoverability and atomicity for multiple database
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operations. The transaction system uses two-phase
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locking and write-ahead logging protocols to ensure
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that database operations may be undone or redone in
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the case of application or system failure.
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Applications may use Berkeley DB transaction and
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logging subsystems to protect their own data
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structures and operations from application or system
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failure.
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</dd>
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<dt>
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<span class="term">Locking:</span>
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</dt>
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<dd>
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The locking system provides multiple reader or
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single writer access to objects. The Berkeley DB
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access methods use the locking system to acquire the
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right to read or write database pages. Applications
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may use the Berkeley DB locking subsystem to support
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their own locking needs.
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</dd>
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</dl>
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</div>
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<p>
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By combining the page cache, transaction, locking, and
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logging systems, Berkeley DB provides the same services found
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in much larger, more complex and more expensive database
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systems. Berkeley DB supports multiple simultaneous readers
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and writers and guarantees that all changes are recoverable,
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even in the case of a catastrophic hardware failure during a
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database update.
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</p>
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<p>
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Developers may select some or all of the core database
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services for any access method or database. Therefore, it is
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possible to choose the appropriate storage structure and the
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right degrees of concurrency and recoverability for any
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application. In addition, some of the subsystems (for example,
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the Locking subsystem) can be called separately from the
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Berkeley DB access method. As a result, developers can
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integrate non-database objects into their transactional
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applications using Berkeley DB.
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</p>
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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="intro_need.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="intro.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="intro_distrib.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">Do you need Berkeley DB? </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"> What does the Berkeley DB
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distribution include?</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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