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How to Install the PHP APCu Extension

In the examples shown, replace "X.Y" with your app's PHP version (for example, "5.6" or "7.1").

The APCu extension adds object caching functions to PHP.

APCu is the official replacement for the outdated APC extension. APC provided both opcode caching (opcache) and object caching. As PHP versions 5.5 and above include their own opcache, APC was no longer compatible, and its opcache functionality became useless. The developers of APC then created APCu, which offers only the object caching functionality (they removed the outdated opcache).

Installing APCu on PHP 7.0, 7.1, and 7.2

To install this extension on PHP 7.X, SSH in to your server as root and run these commands:

sudo apt-get -y install gcc make autoconf libc-dev pkg-config
sudo pecl7.X-sp install apcu

When asked the following question, press Enter.

Enable internal debugging in APCu [no] :

Once installed, create a configuration file for the extension and restart PHP by running the following commands as root

sudo bash -c "echo extension=apcu.so > /etc/php7.X-sp/conf.d/apcu.ini"
sudo service php7.X-fpm-sp restart
APCu for PHP 7+ does not support an option for full backwards compatibility with APC. If you require full backwards compatibility with APC and you're using PHP 7+, you'll also need to install the APCu Backwards Compatibility (apcu-bc) extension.

Installing APCu on PHP 5.4, 5.5, and 5.6

To install this extension on PHP 5.X, SSH in to your server as root and run these commands:

sudo apt-get -y install gcc make autoconf libc-dev pkg-config
sudo pecl5.X-sp install apcu-4.0.11

When asked the following questions, press Enter.

Enable full APC compatibility [yes] :
Enable internal debugging in APCu [no] :

Once installed, create a configuration file for the extension and restart PHP by running the following command as root:

sudo bash -c "echo extension=apcu.so > /etc/php5.X-sp/conf.d/apcu.ini"
sudo service php5.X-fpm-sp restart

Verifying the Installation

You can verify APCu is installed correctly by running the command:

phpX.Y-sp -i | grep apcu

You should see output like the following:

Additional .ini files parsed => /etc/phpX.Y-sp/conf.d/apcu.ini,
apcu

Last updated: August 31, 2017