How do I know if any PHP caching is enabled?

Question

I used to think caching was very hard to install so I've never done it... After reading about APC, it seems pretty easy to install. I always thought I would have to modify lots of PHP code inside my application to use it lol.

Anyways, I am wanting to install APC. I can use phpinfo() and notice it's not listed on the page, so it's not installed. Does this also show for the various other cache systems out there? I don't want to install APC if I have another caching system already installed since I'm not sure if it'll cause conflicts. Do hosts automatically install these for you?

What are the steps to check for to see if I have any sort of caching enabled?

Solution 1

Any installed caching extensions will be listed in your phpinfo() file; They should be listed as one of the arguments in the "Configure Command" box (e.g. -enable-apc) and should have their own sections somewhere down the page.

Two of the most popular PHP caching modules are APC and Memcache.

Solution 2

To check it programmatically:

if(extension_loaded('apc') && ini_get('apc.enabled'))
{
    echo "APC enabled!";
}

Note: As of version 5.5 PHP now has an Opcode cache/optimizer included (though disabled by default). If you still want to run APC there is the APCu extension as @alcohol mentions in a comment. If you are using that extension you would need to replace extension_loaded('apc') with extension_loaded('apcu'). Or you could verify it from the command line:

phpX.Y -i | grep apcu

Make sure though that you are using the same PHP binary that is used by your web server.

Solution 3

For those, who are using APCU (wich is replacement for APC)

Just run in command line:

php -r "var_dump(function_exists('apcu_enabled') && apcu_enabled());"

Comments

[Joker]

Thanks for the info. Looks like I don't have any installed.

[alcohol]

There is also ext-apcu, specifically tailored because of the changes in PHP 5.5