PHP: APC Configuration and Usage Tips and Tricks
This PHP APC guide is divided on four different section:
1. PHP APC Configuration
2. Enable PHP APC Statistics
3. Howto Use PHP APC User Cache
4. PHP APC Performance Testing
2. Enable PHP APC Statistics
This is important part, if you want to see some statistics how APC Cache is working.
2.1 Find apc.php File
updatedb locate apc.php |
Example location on Fedora/CentOS/RHEL /usr/share/doc/php-pecl-apc-3.1.10/apc.php.
2.2 Make apc.php File Public
Here you can use create new virtual host for APC statictics or just copy apc.php file under some existing virtual host.
2.3 Configure apc.php File
Modify at least following settings:
defaults('USE_AUTHENTICATION',1); defaults('ADMIN_USERNAME','your-user-name'); // Admin Username defaults('ADMIN_PASSWORD','your-password'); // Admin Password - CHANGE THIS TO ENABLE!!! |
2.4 Check APC Statistics
Open apc.php on your browser to see statistics. Your statisticss url could be example http://stats.your-domain.com/apc.php.
PHP APC Statictics Screenshot (APC 3.1.10, PHP 5.3.14, Nginx 1.2.2)
This PHP APC guide is divided on four different section:
1. PHP APC Configuration
2. Enable PHP APC Statistics
3. Howto Use PHP APC User Cache
4. PHP APC Performance Testing
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The best thing with learning PHP programming is having a lot of people who are always willing to share their knowledge. One of the best tips on APC configuration is this one that you have made.
I disagree with this:
“Normally it’s wise cache only “small” files and this value is good to set example to default 1 Mb.”
Why did you say that? Caching large files is also good because you are avoiding parsing these files.
Anyway thanks for the tips :)
Hi Luis,
Some cases it might be good increase apc.max_file_size value. But…
Let’s think very normal example, VPS servers (512Mb, 1Gb, 2Gb) where you have to limit amount of APC memory (e.g. 32Mb, 64Mb 128Mb, 256Mb), and you have hundreds of files, a lot of small files (less than 1Mb) and a few large files (like 25Mb).
Okay, you cache all files ignoring the size (set very high apc.max_file_size value), then the cache will reach maximum capacity almost constantly and it clean forcefully any entries that haven’t been accessed in the last apc.ttl seconds. This is situation where you use APC, but finally your scripts are loading much slower than without any cache, because you end up the situation where load files from disk, add files to cache and delete files from cache. Which is much heavier than just load files from disk.
The optimal situation is a situation where your cache is almost fully used, but newer reach maximum capacity (Cache full count number is always zero) and almost all incoming requests are hits (not misses).
But, if you have enough memory to get all your files cached, then it’s okay to set very high apc.max_file_size and cache everything. :)
I installed APC on a Debian server using apt-get.
I can’t find the apc.php file in the location you mentioned where else is this file located ?
Hi A.Jesin,
On Debian check /usr/share/doc/php-apc/ path or try following (as root):
Hello JR,
I tried everything and still I couldn’t find apc.php. I even tried
find / -name apc.phpSo finally I downloaded the APC archive from PECL’s website and used the apc.php from it.
I have uploaded a copy of it to my blog at http://jesin.tk/apc-php-download/ for people who have installed it from the repository.
Hi again A.Jesin,
Strange that Debian doesn’t include apc.php at all, but nice to hear that you got it working and even write helpful post to other Debian users who can’t get apc.php file from Debian’s on pakcages. Thanks!
It’s in /etc/php5/conf.d/20-apc.ini
Thanks Henrik!
Hi. I am coming from windows and am on fedora 18. What do I use for domain-name here? domainname command states there is no domain name set. i.e. none
Hi Chandan Pednekar,
Do you mean APC statistics url?