mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 01:26:25 +00:00
201 lines
8.1 KiB
HTML
201 lines
8.1 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
|
||
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
<html xmlns="http://www.w3.org/1999/xhtml">
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
||
<title>DbTxn::prepare()</title>
|
||
<link rel="stylesheet" href="apiReference.css" type="text/css" />
|
||
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
|
||
<link rel="start" href="index.html" title="Berkeley DB C++ API Reference" />
|
||
<link rel="up" href="txn.html" title="Chapter 13. The DbTxn Handle" />
|
||
<link rel="prev" href="txnid.html" title="DbTxn::id()" />
|
||
<link rel="next" href="txnset_name.html" title="DbTxn::set_name()" />
|
||
</head>
|
||
<body>
|
||
<div xmlns="" class="navheader">
|
||
<div class="libver">
|
||
<p>Library Version 11.2.5.2</p>
|
||
</div>
|
||
<table width="100%" summary="Navigation header">
|
||
<tr>
|
||
<th colspan="3" align="center">DbTxn::prepare()</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="txnid.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 13.
|
||
The DbTxn Handle
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="txnset_name.html">Next</a></td>
|
||
</tr>
|
||
</table>
|
||
<hr />
|
||
</div>
|
||
<div class="sect1" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h2 class="title" style="clear: both"><a id="txnprepare"></a>DbTxn::prepare()</h2>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<pre class="programlisting">#include <db_cxx.h>
|
||
|
||
int
|
||
DbTxn::prepare(u_int8_t gid[DB_GID_SIZE]);</pre>
|
||
<p>
|
||
The <code class="methodname">DbTxn::prepare()</code> method initiates the beginning of a two-phase
|
||
commit.
|
||
</p>
|
||
<p>
|
||
In a distributed transaction environment, Berkeley DB can be used as a
|
||
local transaction manager. In this case, the distributed transaction
|
||
manager must send <span class="emphasis"><em>prepare</em></span> messages to each local
|
||
manager. The local manager must then issue a <code class="methodname">DbTxn::prepare()</code> and
|
||
await its successful return before responding to the distributed
|
||
transaction manager. Only after the distributed transaction manager
|
||
receives successful responses from all of its
|
||
<span class="emphasis"><em>prepare</em></span> messages should it issue any
|
||
<span class="emphasis"><em>commit</em></span> messages.
|
||
</p>
|
||
<p>
|
||
In the case of nested transactions, preparing the parent causes all
|
||
unresolved children of the parent transaction to be committed. Child
|
||
transactions should never be explicitly prepared. Their fate will be
|
||
resolved along with their parent's during global recovery.
|
||
</p>
|
||
<p>
|
||
All open cursors in the transaction are closed and the
|
||
first cursor close error will be returned.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">DbTxn::prepare()</code> <span>
|
||
|
||
<span>
|
||
method either returns a non-zero error value or throws an
|
||
exception that encapsulates a non-zero error value on
|
||
failure, and returns 0 on success.
|
||
</span>
|
||
</span>
|
||
|
||
The errors that this method returns include the error values of <code class="methodname">Dbc::close()</code> and the following:
|
||
|
||
</p>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3674496"></a><span>DbDeadlockException or </span>DB_LOCK_DEADLOCK</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
A transactional database environment operation was selected to resolve
|
||
a deadlock.
|
||
</p>
|
||
<p>
|
||
<a class="xref" href="dbdeadlock.html" title="DbDeadlockException">DbDeadlockException</a> is thrown if
|
||
your Berkeley DB API is configured to throw exceptions.
|
||
Otherwise, <code class="literal">DB_LOCK_DEADLOCK</code> is returned.
|
||
</p>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3674364"></a><span>DbLockNotGrantedException or </span>DB_LOCK_NOTGRANTED</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
A Berkeley DB Concurrent Data Store database environment configured
|
||
for lock timeouts was unable to grant a lock in the allowed time.
|
||
</p>
|
||
<p>
|
||
<a class="xref" href="dblocknotgranted.html" title="DbLockNotGrantedException">DbLockNotGrantedException</a> is thrown if
|
||
your Berkeley DB API is configured to throw exceptions.
|
||
Otherwise, <code class="literal">DB_LOCK_NOTGRANTED</code> is returned.
|
||
</p>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3674328"></a>EINVAL</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
If the cursor is already closed; or if an invalid flag value or parameter was specified.
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3674812"></a>Parameters</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3674815"></a>gid</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>gid</strong></span> parameter specifies the
|
||
global transaction ID by which this transaction will be known. This
|
||
global transaction ID will be returned in calls
|
||
to <a class="xref" href="txnrecover.html" title="DbEnv::txn_recover()">DbEnv::txn_recover()</a>
|
||
telling the application which global transactions must be resolved.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3674694"></a>Class</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<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>
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3674714"></a>See Also</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="xref" href="txn.html#txnlist" title="Transaction Subsystem and Related Methods">Transaction Subsystem and Related Methods</a>
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="navfooter">
|
||
<hr />
|
||
<table width="100%" summary="Navigation footer">
|
||
<tr>
|
||
<td width="40%" align="left"><a accesskey="p" href="txnid.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="txn.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="txnset_name.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">DbTxn::id() </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top"> DbTxn::set_name()</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|