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228 lines
9.5 KiB
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<?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>DbEnv::txn_recover()</title>
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<link rel="stylesheet" href="apiReference.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 C++ API Reference" />
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<link rel="up" href="txn.html" title="Chapter 13. The DbTxn Handle" />
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<link rel="prev" href="envset_tx_timestamp.html" title="DbEnv::set_tx_timestamp()" />
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<link rel="next" href="txnbegin.html" title="DbEnv::txn_begin()" />
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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">DbEnv::txn_recover()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="envset_tx_timestamp.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 13.
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The DbTxn Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="txnbegin.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="txnrecover"></a>DbEnv::txn_recover()</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db_cxx.h>
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int
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DbEnv::txn_recover(DB_PREPLIST preplist[],
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long count, long *retp, u_int32_t flags);</pre>
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<p>
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Database environment recovery restores transactions that were
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prepared, but not yet resolved at the time of the system shut down or
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crash, to their state prior to the shut down or crash, including any
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locks previously held. The <code class="methodname">DbEnv::txn_recover()</code> method returns a
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list of those prepared transactions.
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</p>
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<p>
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The <code class="methodname">DbEnv::txn_recover()</code> method should only be called after the
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environment has been recovered.
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</p>
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<p>
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Multiple threads of control may call <code class="methodname">DbEnv::txn_recover()</code>, but only
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one thread of control may resolve each returned transaction, that is,
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only one thread of control may call <a class="xref" href="txncommit.html" title="DbTxn::commit()">DbTxn::commit()</a>
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or <a class="xref" href="txnabort.html" title="DbTxn::abort()">DbTxn::abort()</a> on each
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returned transaction. Callers of <code class="methodname">DbEnv::txn_recover()</code> must call
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<a class="xref" href="txndiscard.html" title="DbTxn::discard()">DbTxn::discard()</a> to
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discard each transaction they do not resolve.
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</p>
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<p>
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On return from <code class="methodname">DbEnv::txn_recover()</code>, the <span class="bold"><strong>preplist</strong></span> parameter will be filled in with a list of transactions
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that must be resolved by the application (committed, aborted or discarded). The <span class="bold"><strong>preplist</strong></span> parameter is a structure of type
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<code class="literal">DB_PREPLIST</code>; the following <code class="literal">DB_PREPLIST</code> fields will be
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filled in:
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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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<p>
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<span class="bold"><strong>DB_TXN * txn;</strong></span>
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</p>
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<p>
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The transaction handle for the transaction.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int8_t gid[DB_GID_SIZE];</strong></span>
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</p>
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<p>
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The global transaction ID for the transaction. The global transaction
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ID is the one specified when the transaction was prepared. The
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application is responsible for ensuring uniqueness among global
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transaction IDs.
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</p>
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</li>
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</ul>
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</div>
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<p>
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The <code class="methodname">DbEnv::txn_recover()</code> <span>
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<span>
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method either returns a non-zero error value or throws an
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exception that encapsulates a non-zero error value on
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failure, and returns 0 on success.
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</span>
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</span>
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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="id3671451"></a>Parameters</h3>
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</div>
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</div>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3671462"></a>preplist</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>preplist</strong></span> parameter references
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memory into which the list of transactions to be resolved by the
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application is copied.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3671442"></a>count</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>count</strong></span> parameter specifies the
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number of available entries in the passed-in <span class="bold"><strong>preplist</strong></span> array. The <span class="bold"><strong>retp</strong></span> parameter returns the number of entries
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<code class="methodname">DbEnv::txn_recover()</code> has filled in, in the array.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3671474"></a>flags</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>flags</strong></span> parameter must be set to
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one of the following values:
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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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<p>
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<code class="literal">DB_FIRST</code>
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</p>
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<p>
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Begin returning a list of prepared, but not yet resolved transactions.
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Specifying this flag begins a new pass over all prepared, but not yet
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completed transactions, regardless of whether they have already been
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returned in previous calls to <code class="methodname">DbEnv::txn_recover.()</code> Calls to
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<code class="methodname">DbEnv::txn_recover()</code> from different threads of control should not be
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intermixed in the same environment.
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</p>
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</li>
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<li>
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<p>
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<code class="literal">DB_NEXT</code>
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</p>
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<p>
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Continue returning a list of prepared, but not yet resolved
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transactions, starting where the last call to
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<code class="methodname">DbEnv::txn_recover()</code>
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left off.
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</p>
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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="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="id3671577"></a>Class</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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<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>, <a class="link" href="txn.html" title="Chapter 13. The DbTxn Handle">DbTxn</a>
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</p>
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</div>
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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="id3671486"></a>See Also</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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<a class="xref" href="txn.html#txnlist" title="Transaction Subsystem and Related Methods">Transaction Subsystem and Related Methods</a>
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</p>
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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="envset_tx_timestamp.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="txn.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="txnbegin.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">DbEnv::set_tx_timestamp() </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"> DbEnv::txn_begin()</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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