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101 lines
4.2 KiB
HTML
101 lines
4.2 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>Enabling Transaction Snapshots in the SQL Layer</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 Installation and Build Guide" />
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<link rel="up" href="upgrade_52_toc.html" title="Chapter 9. Upgrading Berkeley DB 11.2.5.1 applications to Berkeley DB 11.2.5.2" />
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<link rel="prev" href="upgrade_11gr2_52_heap.html" title="Heap Access Method" />
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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">Enabling Transaction Snapshots in the SQL Layer</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="upgrade_11gr2_52_heap.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 9.
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Upgrading Berkeley DB 11.2.5.1 applications to Berkeley DB 11.2.5.2
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="upgrade_11gr2_52_rep_2site_strict.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="upgrade_11gr2_52_mvcc_sql"></a>Enabling Transaction Snapshots in the SQL Layer</h2>
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</div>
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</div>
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</div>
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<div class="toc">
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<dl>
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<dt>
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<span class="sect2">
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<a href="upgrade_11gr2_52_mvcc_sql.html#id3375960">New Pragmas</a>
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</span>
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</dt>
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</dl>
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</div>
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<p>
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Read/write concurrency can now be enabled in the SQL API by using
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<code class="literal">PRAGMA multiversion=on</code> before accessing any
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tables in the database. After multiversion has been enabled, it
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can be temporarily disabled using the
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<code class="literal">PRAGMA transaction_snapshots=on/off</code>.
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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="id3375960"></a>New Pragmas</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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For more details on pragmas concerning Transaction Snapshots
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read <a href="../bdb-sql/mvcc.html" class="olink">Using Multiversion Concurrency Control</a> in the <em class="citetitle">Berkeley DB Getting Started with the SQL APIs</em> guide.
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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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<code class="literal">PRAGMA multiversion=ON|OFF;</code>
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</li>
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<li>
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<code class="literal">PRAGMA snapshot_isolation=ON|OFF</code>
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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="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="upgrade_11gr2_52_heap.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="upgrade_52_toc.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="upgrade_11gr2_52_rep_2site_strict.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">Heap Access Method </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"> 2SITE_STRICT Enabled by Default in Replication</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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