# mysqlnd_memcache_set

(PECL mysqlnd_memcache >= 1.0.0)

mysqlnd_memcache_set — Associate a MySQL connection with a Memcache connection

### Description

mysqlnd_memcache_set ( mixed `$mysql_connection` [, Memcached `$memcache_connection` [, string `$pattern` [, callable `$callback` ]]] ) : bool

Associate `mysql_connection` with `memcache_connection` using `pattern` as a PCRE regular expression, and `callback` as a notification callback or to unset the association of `mysql_connection`.

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 mysqlnd_memcache_get_config().

### Parameters

`mysql_connection`

  A handle to a MySQL Server using one of the MySQL API extensions for PHP, which are PDO_MYSQL, mysqli or ext/mysql.

`memcache_connection`

  A Memcached instance with a connection to the MySQL Memcache Daemon plugin. If this parameter is omitted, then `mysql_connection` will be unassociated from any memcache connection. And if a previous association exists, then it will be replaced.

`pattern`

  A regular expression in Perl Compatible Regular Expression 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.

`callback`

  A callback which will be used whenever a query is being sent to MySQL. The callback will receive a single bool parameter telling if a query was sent via Memcache.

### Return Values

`TRUE` if the association or disassociation is successful, otherwise `FALSE` if there is an error.

### Examples

Example #1 mysqlnd_memcache_set() example with var_dump() as a simple debugging callback.

`<?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");
?>`

The above example will output:

    Sending query for id via Memcache: bool(true)
    Sending query for f1 via Memcache: bool(false)
    var_dump won't be invoked:

### See Also

- mysqlnd_memcache_get_config() - Returns information about the plugin configuration