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Yasuhiro KIMURA
168 lines
8.4 KiB
HTML
168 lines
8.4 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>XA: Frequently Asked Questions</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 Programmer's Reference Guide" />
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<link rel="up" href="xa.html" title="Chapter 14. Distributed Transactions" />
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<link rel="prev" href="xa_xa_restrict.html" title="Restrictions on XA Transactions" />
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<link rel="next" href="apprec.html" title="Chapter 15. Application Specific Logging and Recovery" />
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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 18.1.40</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">XA: Frequently Asked Questions</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="xa_xa_restrict.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 14. Distributed Transactions </th>
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<td width="20%" align="right"> <a accesskey="n" href="apprec.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="xa_faq"></a>XA: Frequently Asked Questions</h2>
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</div>
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</div>
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</div>
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<div class="orderedlist">
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<ol type="1">
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<li>
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<span class="bold">
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<strong>Is it possible to mix XA and non-XA
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transactions?</strong>
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</span>
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<p>
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Yes. It is also possible for XA and non-XA
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transactions to coexist in the same Berkeley DB
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environment. To do this, specify the same environment
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to the non-XA <a href="../api_reference/C/envopen.html" class="olink">DB_ENV->open()</a> calls as was specified in the
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Tuxedo configuration file.
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</p>
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</li>
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<li>
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<span class="bold">
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<strong>Does converting an application to
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run within XA change any of the already existing C/C++
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API calls it does?</strong>
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</span>
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<p>
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When converting an application to run under XA, the
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application's Berkeley DB calls are unchanged, with
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three exceptions:
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</p>
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<div class="orderedlist">
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<ol type="a">
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<li>
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The application must specify the
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<a href="../api_reference/C/dbcreate.html#dbcreate_DB_XA_CREATE" class="olink">DB_XA_CREATE</a> flag to the <a href="../api_reference/C/dbcreate.html" class="olink">db_create()</a>
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function.
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</li>
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<li>
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Unless the application is performing an
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operation for a non-XA transaction, the
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application should never explicitly call
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<a href="../api_reference/C/txncommit.html" class="olink">DB_TXN->commit()</a>, <a href="../api_reference/C/txnabort.html" class="olink">DB_TXN->abort()</a>, and <a href="../api_reference/C/txnbegin.html" class="olink">DB_ENV->txn_begin()</a>, and those
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calls should be replaced by calls into the Tuxedo
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transaction manager.
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</li>
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<li>
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Unless the application is performing an
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operation for a non-XA transaction, the
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application should specify a transaction argument
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of NULL to Berkeley DB methods taking transaction
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arguments (for example, <a href="../api_reference/C/dbput.html" class="olink">DB->put()</a> or
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<a href="../api_reference/C/dbcursor.html" class="olink">DB->cursor()</a>).
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</li>
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</ol>
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</div>
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<p>
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Otherwise, the application should be
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unchanged.
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</p>
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</li>
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<li>
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<span class="bold">
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<strong>How does Berkeley DB recovery
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interact with recovery by the Tuxedo transaction
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manager?</strong>
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</span>
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<p>
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Recovery is completed in two steps. First, each
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resource manager should recover its environment(s).
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This can be done via a program that calls <a href="../api_reference/C/envopen.html" class="olink">DB_ENV->open()</a> or
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by calling the <a href="../api_reference/C/db_recover.html" class="olink">db_recover</a> utility. If using the
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<a href="../api_reference/C/db_recover.html" class="olink">db_recover</a> utility, then the
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teoption should be specified so that
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the regions that are recovered persist after the
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utility exits. Any transactions that were prepared,
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but neither completed nor aborted, are restored to
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their prepared state so that they may be aborted or
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committed via the Tuxedo recovery mechanisms. After
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each resource manager has recovered, then Tuxedo
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recovery may begin. Tuxedo will interact with each
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resource manager via the __db_xa_recover function
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which returns the list of prepared, but not yet
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completed transactions. It should issue a commit or
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abort for each one, and only after having completed
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each transaction will normal processing resume.
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</p>
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<p>
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Finally, standard log file archival and catastrophic
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recovery procedures should occur independently of XA
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operation.
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</p>
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</li>
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<li>
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<span class="bold">
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<strong>Does Berkeley DB provide
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multi-threaded support for XA transactions?</strong>
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</span>
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<p>
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Yes. For information on how to build multi-threaded
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servers for XA transactions, see <a class="ulink" href="http://download.oracle.com/docs/cd/E13161_01/tuxedo/docs10gr3/pgc/pgthr.html" target="_top">http://download.oracle.com/docs/cd/E13161_01/tuxedo/docs10gr3/pgc/pgthr.html</a>.
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All databases used by servers should be opened
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with handles created with the <a href="../api_reference/C/dbcreate.html#dbcreate_DB_XA_CREATE" class="olink">DB_XA_CREATE</a> flag in
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the <a href="../api_reference/C/dbcreate.html" class="olink">db_create()</a> method and must be opened in the
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tpsvrinit routine. Note that the environment parameter
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of the <a href="../api_reference/C/dbcreate.html" class="olink">db_create()</a> method must be assigned NULL. For
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more information on the tpsvrinit routine, see <a class="ulink" href="http://download.oracle.com/docs/cd/E13161_01/tuxedo/docs10gr3/pgc/pgthr.html" target="_top">http://download.oracle.com/docs/cd/E13161_01/tuxedo/docs10gr3/pgc/pgthr.html</a>.
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</p>
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</li>
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</ol>
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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="xa_xa_restrict.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="xa.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="apprec.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">Restrictions on XA Transactions </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 15. Application Specific Logging and
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Recovery </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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