Install memcached with PHP memcache Extension

“MemCached” is a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.
If you are on a cPanel based server, you can install the PHP Extension by running the script /scrips/easyapache and enable memcache during the process. Once completed, you need to install memcached daemon by following the step 1 listed below. If you are not on cPanel based server follow the two steps listed below.

1. Steps to Install memcached

You have to activate the RPMForge custom repository to install latest memcached rpm.

rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.i386.rpm

or

rpm -Uhv http://apt.sw.be/redhat/el5/en/x86_64/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm

You can now use yum to install memcached

yum -y install memcached

Once the installation is completed, you will be able to locate the config file at the location /etc/sysconfig/memcached . Edit the file according to your requirement. It will be something like below.

PORT=”11211″                #define on which port to urn
USER=”nobody”           #same as apache user
MAXCONN=”2048″     #maximum number of connections allowed
CACHESIZE=”32″         #memory used for caching
OPTIONS=””                   #use for any custom options

Always specify a user for memcached when you start it from the shell. You can use nobody user or a user named memcached.

Now you can test it with the following command.

memcached -u memcached -d -m 1048 -l 127.0.0.1 -p 11211

or

memcached -d -u nobody -m 1048 -p 11211 127.0.0.1

Check if memcached is listening on port 11211

netstat -plan | grep “:11211″

Done.

Now you can go to step 2 to perform the installation of php extension.
2. Steps to Install PHP Memcache

Download and install the latest version of PHP extension from PECL.

cd /usr/share

wget http://pecl.php.net/get/memcache-2.2.7.tgz

tar -xvf memcache-2.2.7.tgz

cd memcache-2.2.7.tgz

phpize
./configure
make
make install

After successful installation check if memcache.so is added to php.ini. If its not there add it manually to php.ini, restart apache and create a phpinfo page and check for memcache.

To locate php.ini

php -i | grep php.ini

vi /usr/local/lib/php.ini

Add the following

extension=”memcache.so”

Restart httpd

/etc/rc.d/init.d/httpd restart

Check if its loaded in command line by using the following.

php -i | grep memcache

It will show something like below.

memcache
memcache support => enabled

You can also test memcache by creating memcachetest.php file with the following code and see the results.

<?php
//memcached simple test
$memcache = new Memcache;
$memcache->connect(‘localhost’, 11211) or die (“Could not connect”);
$key = md5(’42data’);  //something unique
for ($k=0; $k<5; $k++) {
$data = $memcache->get($key);
if ($data == NULL) {
$data = array();
//generate an array of random shit
echo “expensive query”;
for ($i=0; $i<100; $i++) {
for ($j=0; $j<10; $j++) {
$data[$i][$j] = 42;  //who cares
}
}
$memcache->set($key,$data,0,3600);
} else {
echo “cached”;
}
}