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146 lines
5.9 KiB
HTML
146 lines
5.9 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>Configuring the Transaction Subsystem</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="Getting Started with Berkeley DB, Java Edition Transaction Processing" />
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<link rel="up" href="usingtxns.html" title="Chapter 3. Transaction Basics" />
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<link rel="prev" href="txnindices.html" title="Secondary Indices with Transaction Applications" />
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<link rel="next" href="txnconcurrency.html" title="Chapter 4. Concurrency" />
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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 12.2.7.5</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">Configuring the Transaction Subsystem</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="txnindices.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 3. Transaction Basics</th>
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<td width="20%" align="right"> <a accesskey="n" href="txnconcurrency.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="maxtxns"></a>Configuring the Transaction Subsystem</h2>
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</div>
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</div>
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</div>
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<span>
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<span>
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<p>
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<span>
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When you configure your transaction subsystem, you need to consider your transaction timeout
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value.
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</span>
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This value represents the longest period of time a
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transaction can be active. Note, however, that
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transaction timeouts are checked only when JE
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examines its lock tables for blocked locks
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(see <a class="xref" href="blocking_deadlocks.html" title="Locks, Blocks, and Deadlocks">Locks, Blocks, and Deadlocks</a>
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for more information). Therefore, a transaction's timeout can
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have expired, but the application will not be notified until JE
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has a reason to examine its lock tables.
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</p>
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<p>
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Be aware that some transactions may be
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inappropriately timed out before the transaction has a
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chance to complete. You should therefore use this
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mechanism only if you know your application
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might have unacceptably long transactions and
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you want to make sure your application will
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not stall during their execution.
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(This might happen if, for example, your
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transaction blocks or requests too much
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data.)
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</p>
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<p>
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Note that by default transaction timeouts are set to 0 seconds, which means that they never time
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out.
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</p>
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<p>
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To set the maximum timeout value for your transactions,
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use the
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<span><code class="methodname">EnvironmentConfig.setTxnTimeout()</code></span>
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method. This method configures the entire
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environment; not just the handle used to set the
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configuration. Further, this value may
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be set at any time during the application's
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lifetime.
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</p>
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<p>
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This value can also be set using the <code class="literal">je.txn.timeout</code> property in your JE
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properties file.
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</p>
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</span>
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</span>
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<p>
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For example:
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</p>
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<pre class="programlisting">package je.txn;
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import com.sleepycat.je.Environment;
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import com.sleepycat.je.EnvironmentConfig;
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import java.io.File;
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...
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Environment myEnv = null;
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try {
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EnvironmentConfig myEnvConfig = new EnvironmentConfig();
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myEnvConfig.setTransactional(true);
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// Configure a maximum transaction timeout of 1 second.
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myEnvConfig.setTxnTimeout(1000000);
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myEnv = new Environment(new File("/my/env/home"),
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myEnvConfig);
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// From here, you open your databases (or store), proceed with your
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// database or store operations, and respond to deadlocks as is
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// normal (omitted for brevity).
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...</pre>
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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="txnindices.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="usingtxns.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="txnconcurrency.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">Secondary Indices with Transaction Applications </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"> Chapter 4. Concurrency</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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