mirror of
https://github.com/sigmasternchen/php-doc-en
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57236796d1
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@310337 c90b9560-bf6c-de11-be94-00142212c4b1
139 lines
4.1 KiB
XML
Executable file
139 lines
4.1 KiB
XML
Executable file
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="function.mysqlnd-ms-query-is-select" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<refnamediv>
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<refname>mysqlnd_ms_query_is_select</refname>
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<refpurpose>Find whether to send the query to the master, the slave or the last used MySQL server</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>int</type>
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<methodname>mysqlnd_ms_query_is_select</methodname>
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<methodparam><type>string</type><parameter>query</parameter></methodparam>
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</methodsynopsis>
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<para>
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Finds whether to send the query to the master, the slave or the
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last used MySQL server.
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</para>
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<para>
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The plugins built-in read/write split mechanism
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will be used to analyze the query string to make a recommendation where
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to send the query. The built-in read/write split mechanism is very
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basic and simple. The plugin will recommend sending all queries to the
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MySQL replication master server but those which begin with
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<literal>SELECT</literal>, or begin with a SQL hint which
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enforces sending the query to a slave server. Due to the basic
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but fast algorithm the plugin may propose to run some read-only
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statements such as <literal>SHOW TABLES</literal> on the replication master.
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<variablelist>
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<varlistentry>
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<term><parameter>query</parameter></term>
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<listitem>
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<para>
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Query string to test.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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A return value of <constant>MYSQLND_MS_QUERY_USE_MASTER</constant>
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indicates that the query should be send to the MySQL replication
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master server. The function returns a value of
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<constant>MYSQLND_MS_QUERY_USE_SLAVE</constant> if the query can be run
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on a slave because it is considered read-only. A value of
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<constant>MYSQLND_MS_QUERY_USE_LAST_USED</constant> is returned to recommend
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running the query on the last used server. This can either be a MySQL
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replication master server or a MySQL replication slave server.
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title><function>mysqlnd_ms_query_is_select</function> example</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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function is_select($query)
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{
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switch (mysqlnd_ms_query_is_select($query))
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{
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case MYSQLND_MS_QUERY_USE_MASTER:
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printf("'%s' should be run on the master.\n", $query);
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break;
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case MYSQLND_MS_QUERY_USE_SLAVE:
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printf("'%s' should be run on a slave.\n", $query);
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break;
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case MYSQLND_MS_QUERY_USE_LAST_USED:
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printf("'%s' should be run on the server that has run the previous query\n", $query);
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break;
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default:
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printf("No suggestion where to run the '%s', fallback to master recommended\n", $query);
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break;
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}
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}
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is_select("INSERT INTO test(id) VALUES (1)");
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is_select("SELECT 1 FROM DUAL");
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is_select("/*" . MYSQLND_MS_LAST_USED_SWITCH . "*/SELECT 2 FROM DUAL");
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?>
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]]>
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</programlisting>
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&example.outputs;
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<screen>
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<![CDATA[
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INSERT INTO test(id) VALUES (1) should be run on the master.
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SELECT 1 FROM DUAL should be run on a slave.
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/*ms=last_used*/SELECT 2 FROM DUAL should be run on the server that has run the previous query
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]]>
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</screen>
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</example>
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member>
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<link linkend="mysqlnd-ms.constants">Predefined Constants</link>
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</member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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