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151 lines
5.7 KiB
HTML
151 lines
5.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>Garbage collects unfinished XA transactions after severe errors</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.mysqlnd-ms-xa-gc" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">mysqlnd_ms_xa_gc</h1>
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<p class="verinfo">(PECL mysqlnd_ms < 1.6.0)</p><p class="refpurpose"><span class="refname">mysqlnd_ms_xa_gc</span> — <span class="dc-title">Garbage collects unfinished XA transactions after severe errors</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.mysqlnd-ms-xa-gc-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>mysqlnd_ms_xa_gc</strong></span>
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( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$connection</code></span>
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[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$gtrid</code></span>
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[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$ignore_max_retries</code></span>
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]] ) : <span class="type">int</span></div>
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<p class="para rdfs-comment">
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Garbage collects unfinished XA transactions.
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</p>
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<p class="para">
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The XA protocol is a blocking protocol. There exist cases when servers
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participating in a global transaction cannot make progress when the transaction
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coordinator crashes or disconnects. In such a case, the MySQL servers
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keep waiting for instructions to finish the XA transaction in question.
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Because transactions occupy resources, transactions should always be
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terminated properly.
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</p>
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<p class="para">
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Garbage collection requires configuring a state store to track global
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transactions. Should a PHP client crash in the middle of a transaction
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and a new PHP client be started, then the built-in garbage collection
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can learn about the aborted global transaction and terminate it. If you
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do not configure a state store, the garbage collection cannot perform
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any cleanup tasks.
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</p>
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<p class="para">
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The state store should be crash-safe and be highly available to survive
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its own crash. Currently, only MySQL is supported as a state store.
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</p>
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<p class="para">
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Garbage collection can also be performed automatically in the background.
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See the plugin configuration directive <em>garbage_collection</em>
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for details.
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</p>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<strong>Experimental</strong><br />
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<p class="para">
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The feature is currently under development. There may be issues and/or
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feature limitations. Do not use in production environments.
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</p>
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</p></blockquote>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.mysqlnd-ms-xa-gc-parameters">
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<h3 class="title">参数</h3>
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<dl>
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<dt>
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<code class="parameter">connection</code></dt>
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<dd>
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<p class="para">
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A MySQL connection handle obtained from any of the
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connect functions of the <a href="ref.mysqli.html" class="link">mysqli</a>,
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<a href="ref.mysql.html" class="link">mysql</a> or
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<a href="ref.pdo_mysql.html" class="link">PDO_MYSQL</a> extensions.
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</p>
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</dd>
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<dt>
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<code class="parameter">gtrid</code></dt>
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<dd>
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<p class="para">
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Global transaction identifier (gtrid). If given, the garbage
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collection considers the transaction only. Otherwise,
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the state store is scanned for any unfinished transaction.
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</p>
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</dd>
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<dt>
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<code class="parameter">ignore_max_retries</code></dt>
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<dd>
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<p class="para">
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Whether to ignore the plugin configuration <em>max_retries</em> setting.
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If garbage collection continuously fails and the <em>max_retries</em>
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limit is reached prior to finishing the failed global transaction,
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you can attempt further runs prior to investigating the cause
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and solving the issue manually by issuing appropriate SQL statements
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on the participants. Setting the parameter has the same effect
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as temporarily setting <em>max_retries = 0</em>.
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</p>
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</dd>
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</dl>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.mysqlnd-ms-xa-gc-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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Returns <strong><code>TRUE</code></strong> if garbage collection was successful. Otherwise, returns <strong><code>FALSE</code></strong>
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.mysqlnd-ms-xa-gc-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member">
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<a href="mysqlnd_ms.quickstart.xa_transactions.html" class="link">Quickstart XA/Distributed transactions</a>
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</li>
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<li class="member">
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<a href="mysqlnd_ms.configuration.html" class="link">Runtime configuration</a>
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</li>
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<li class="member">
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<a href="mysqlnd-ms.plugin-ini-json.html#ini.mysqlnd-ms-plugin-config-v2.xa" class="link">State store configuration</a>
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</li>
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<li class="member">
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<span class="function"><a href="mysqlnd_ms_get_stats.html" class="function" rel="rdfs-seeAlso">mysqlnd_ms_get_stats()</a> - Returns query distribution and connection statistics</span>
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</li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |