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https://github.com/sigmasternchen/php-doc-en
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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@321499 c90b9560-bf6c-de11-be94-00142212c4b1
69 lines
2.3 KiB
XML
69 lines
2.3 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<chapter xml:id="mysqlnd.persist" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<title>Persistent Connections</title>
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<para>
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<emphasis role="bold">Using Persistent Connections</emphasis>
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</para>
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<para>
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If <literal>mysqli</literal> is used with <literal>mysqlnd</literal>,
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when a persistent connection is created it generates a
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<literal>COM_CHANGE_USER</literal>
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(<literal>mysql_change_user()</literal>) call on the server. This
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ensures that re-authentication of the connection takes place.
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</para>
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<para>
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As there is some overhead associated with the
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<literal>COM_CHANGE_USER</literal> call, it is possible to switch this
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off at compile time. Reusing a persistent connection will then
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generate a <literal>COM_PING</literal> (<literal>mysql_ping</literal>)
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call to simply test the connection is reusable.
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</para>
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<para>
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Generation of <literal>COM_CHANGE_USER</literal> can be switched off
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with the compile flag
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<literal>MYSQLI_NO_CHANGE_USER_ON_PCONNECT</literal>. For example:
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</para>
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<programlisting>
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<![CDATA[
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shell# CFLAGS="-DMYSQLI_NO_CHANGE_USER_ON_PCONNECT" ./configure --with-mysql=/usr/local/mysql/ --with-mysqli=/usr/local/mysql/bin/mysql_config --with-pdo-mysql=/usr/local/mysql/bin/mysql_config --enable-debug && make clean && make -j6
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]]>
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</programlisting>
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<para>
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Or alternatively:
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</para>
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<programlisting>
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<![CDATA[
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shell# export CFLAGS="-DMYSQLI_NO_CHANGE_USER_ON_PCONNECT"
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shell# configure --whatever-option
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shell# make clean
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shell# make
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]]>
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</programlisting>
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<para>
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Note that only <literal>mysqli</literal> on <literal>mysqlnd</literal>
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uses <literal>COM_CHANGE_USER</literal>. Other extension-driver
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combinations use <literal>COM_PING</literal> on initial use of a
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persistent connection.
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</para>
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</chapter>
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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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