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<refentry xml:id="function.mysqlnd-memcache-set" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>mysqlnd_memcache_set</refname>
  <refpurpose>Associate a MySQL connection with a Memcache connection</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type>
   <methodname>mysqlnd_memcache_set</methodname>
   <methodparam><type>mixed</type><parameter>mysql_connection</parameter></methodparam>
   <methodparam choice="opt"><type>Memcached</type><parameter>memcache_connection</parameter></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>pattern</parameter></methodparam>
   <methodparam choice="opt"><type>callback</type><parameter>callback</parameter></methodparam>
  </methodsynopsis>
  <para>
   Associate <parameter>mysql_connection</parameter> with
   <parameter>memcache_connection</parameter> using <parameter>pattern</parameter>
   as a PCRE regular expression, and <parameter>callback</parameter> as a notification
   callback or to unset the association of <parameter>mysql_connection</parameter>.
  </para>
  <para>
   While associating a MySQL connection with a Memcache connection, this function
   will query the MySQL Server for its configuration. It will automatically
   detect whether the server is configured to use the InnoDB Memcache Daemon
   Plugin or MySQL Cluster NDB Memcache support. It will also query the server
   to automatically identify exported tables and other configuration options.
   The results of this automatic configuration can be retrieved using
   <function>mysqlnd_memcache_get_config</function>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <variablelist>
   <varlistentry>
    <term><parameter>mysql_connection</parameter></term>
    <listitem>
     <para>
      A handle to a MySQL Server using one of the MySQL API extensions for PHP, which are
      <link linkend="ref.pdo-mysql">PDO_MYSQL</link>, <link linkend="book.mysqli">mysqli</link> or
      <link linkend="book.mysql">ext/mysql</link>.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>memcache_connection</parameter></term>
    <listitem>
     <para>
      A <link linkend="book.memcached">Memcached</link> instance with a 
      connection to the MySQL Memcache Daemon plugin. If this parameter
      is omitted, then <parameter>mysql_connection</parameter> will be unassociated
      from any memcache connection. And if a previous association exists, then it will be
      replaced.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>pattern</parameter></term>
    <listitem>
     <para>
      A regular expression in <link linkend="book.pcre">Perl Compatible
      Regular Expression</link> syntax used to identify potential
      Memcache-queries. The query should have three sub patterns. The
      first subpattern contains the requested field list, the second the name
      of the ID column from the query and the third the requested value. If
      this parameter is omitted or os set to &null;, then a default
      pattern will be used.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>callback</parameter></term>
    <listitem>
     <para>
      A callback which will be used whenever a query is being sent to 
      MySQL. The callback will receive a single &boolean; parameter
      telling if a query was sent via Memcache.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &true; if the association or disassociation is successful, otherwise &false; if there
   is an error.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>
     <function>mysqlnd_memcache_set</function> example with
     <function>var_dump</function> as a simple debugging callback.</title>

    <programlisting role="php">
<![CDATA[
<?php
$mysqli = new mysqli("host", "user", "passwd", "database");
$memc = new Memcached();
$memc->addServer("host", 11211);
mysqlnd_memcache_set($mysqli, $memc, NULL, 'var_dump');

/* This query will be intercepted and executed via Memcache protocol */
echo "Sending query for id via Memcache: ";
$mysqli->query("SELECT f1, f2, f3 FROM test WHERE id = 1");

/* f1 is not configured as valid key field, this won't be sent via Memcache */
echo "Sending query for f1 via Memcache: ";
$mysqli->query("SELECT id FROM test WHERE f1 = 1");

mysqlnd_memcache_set($mysqli);

/* Now the regular MySQL protocol will be used */
echo "var_dump won't be invoked: ";
$mysqli->query("SELECT f1, f2, f3 WHERE id = 1");

?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
Sending query for id via Memcache: bool(true)
Sending query for f1 via Memcache: bool(false)
var_dump won't be invoked: 
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member>
     <function>mysqlnd_memcache_get_config</function>
    </member>
   </simplelist>
  </para>
 </refsect1>

</refentry>

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