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283 lines
12 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>DB_TXN->commit()</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 12. The DB_TXN Handle" />
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<link rel="prev" href="txnabort.html" title="DB_TXN->abort()" />
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<link rel="next" href="txndiscard.html" title="DB_TXN->discard()" />
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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 11.2.5.3</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">DB_TXN->commit()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="txnabort.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 12.
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The DB_TXN Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="txndiscard.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="txncommit"></a>DB_TXN->commit()</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.h>
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int
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DB_TXN->commit(DB_TXN *tid, u_int32_t flags); </pre>
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<p>
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The <code class="methodname">DB_TXN->commit()</code> method ends the transaction.
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</p>
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<p>
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In the case of nested transactions, if the transaction is a parent
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transaction, committing the parent transaction causes all unresolved
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children of the parent to be committed. In the case of nested
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transactions, if the transaction is a child transaction, its locks are
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not released, but are acquired by its parent. Although the commit of
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the child transaction will succeed, the actual resolution of the child
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transaction is postponed until the parent transaction is committed or
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aborted; that is, if its parent transaction commits, it will be
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committed; and if its parent transaction aborts, it will be aborted.
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</p>
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<p>
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All cursors opened within the transaction must be closed
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before the transaction is committed. If they are not closed,
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they will be closed by this function. When the close
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operation for a cursor fails, the method returns a non-zero
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error value for the first instance of such an error, closes
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the rest of the cursors, and then aborts the transaction.
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</p>
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<p>
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After <code class="methodname">DB_TXN->commit()</code> has been called, regardless of its return, the
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<a class="link" href="txn.html" title="Chapter 12. The DB_TXN Handle">DB_TXN</a> handle may not be
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accessed again. If <code class="methodname">DB_TXN->commit()</code> encounters an error, the
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transaction and all child transactions of the transaction are aborted.
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</p>
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<p>
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The <code class="methodname">DB_TXN->commit()</code> <span>
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<span>
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method returns a non-zero error value on failure and 0 on success.
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</span>
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</span>
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The errors values that this method returns include the error values of the
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<code class="methodname">DBcursor->close()</code> method and the following:
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</p>
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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="idp62825784"></a>DB_LOCK_DEADLOCK</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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A transactional database environment operation was selected to resolve
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a deadlock.
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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="idp62880848"></a>DB_LOCK_NOTGRANTED</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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A Berkeley DB Concurrent Data Store database environment configured
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for lock timeouts was unable to grant a lock in the allowed time.
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</p>
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<p>
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You attempted to open a database handle that is configured
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for no waiting exclusive locking, but the exclusive lock could not be
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immediately obtained. See
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<a class="xref" href="dbset_lk_exclusive.html" title="DB->set_lk_exclusive()">DB->set_lk_exclusive()</a>
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for more information.
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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="idp62887632"></a>DB_REP_LEASE_EXPIRED</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 operation failed because the site's replication master lease has expired.
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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="idp62862488"></a>EINVAL</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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If the cursor is already closed; or if an invalid flag value or parameter was specified.
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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="idp62904680"></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="idp62904872"></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 0
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or 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_TXN_NOSYNC</code>
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</p>
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<p>
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Do not synchronously flush the log. This means the transaction will
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exhibit the ACI (atomicity, consistency, and isolation) properties,
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but not D (durability); that is, database integrity will be
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maintained, but it is possible that this transaction may be undone
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during recovery.
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</p>
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<p>
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This behavior may be set for a Berkeley DB environment using the
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<a class="xref" href="envset_flags.html" title="DB_ENV->set_flags()">DB_ENV->set_flags()</a>
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method or for a single transaction using the
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<a class="xref" href="txnbegin.html" title="DB_ENV->txn_begin()">DB_ENV->txn_begin()</a> method.
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Any value specified to this method overrides both of those settings.
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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_TXN_SYNC</code>
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</p>
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<p>
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Synchronously flush the log. This means the transaction will exhibit
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all of the ACID (atomicity, consistency, isolation, and durability)
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properties.
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</p>
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<p>
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This behavior is the default for Berkeley DB environments unless the
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<a class="link" href="envset_flags.html#envset_flags_DB_TXN_NOSYNC">DB_TXN_NOSYNC</a>
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flag was specified to the
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<a class="xref" href="envset_flags.html" title="DB_ENV->set_flags()">DB_ENV->set_flags()</a> method.
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This behavior may also be set for a single transaction using the
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<a class="xref" href="txnbegin.html" title="DB_ENV->txn_begin()">DB_ENV->txn_begin()</a>
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method. Any value specified to this method overrides both of those
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settings.
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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_TXN_WRITE_NOSYNC</code>
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</p>
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<p>
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Write but do not synchronously flush the log on
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transaction commit. This means that transactions
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exhibit the ACI (atomicity, consistency, and
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isolation) properties, but not D (durability); that
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is, database integrity will be maintained, but if the
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system fails, it is possible some number of the most
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recently committed transactions may be undone during
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recovery. The number of transactions at risk is
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governed by how often the system flushes dirty
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buffers to disk and how often the log is
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checkpointed.
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</p>
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<p>
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This form of commit protects you against application
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crashes, but not against OS crashes. This method
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offers less room for the possiblity of data loss than
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does <code class="literal">DB_TXN_NOSYNC</code>.
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</p>
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<p>
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This behavior may be set for a Berkeley DB environment using the
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<a class="xref" href="envset_flags.html" title="DB_ENV->set_flags()">DB_ENV->set_flags()</a>
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method or for a single transaction using the
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<a class="xref" href="txnbegin.html" title="DB_ENV->txn_begin()">DB_ENV->txn_begin()</a> method.
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Any value specified to this method overrides both of those settings.
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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="idp62908824"></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 DB_ENV Handle">DB_ENV</a>, <a class="link" href="txn.html" title="Chapter 12. The DB_TXN Handle">DB_TXN</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="idp62888280"></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="txnabort.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="txndiscard.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">DB_TXN->abort() </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"> DB_TXN->discard()</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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