1. PHP Op&miza&on & Scalability
Techniques
Fo&s Alexandrou
Web Developer
(e‐skafos.gr, iheartshops.com & many more)
Disclaimer: Highly Technical Presenta&on, might cause brain
injuries
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

2. When is op&miza&on needed
• Web Applica&ons
• Websites with lots of traffic
– E‐Skafos case study
• Websites that are promising high traffic
– iHeartShops case study
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

3. Easy Stuff
• Opcode Caching – Boot and forget – Pre‐
compiled code loaded in memory (runs a lot
faster)
– APC
– Xcache
• Pecl Extensions
• Minimum Configura&on
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

4. Advanced Stuff ‐ Memcache
• Storage engine using keys
• Re‐seXng aYer data update
• Memcache became really popular aYer
Facebook started using it
• Cheat: Write a class that extends it ;)
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

5. Advanced Stuff – Code Tweaks
• “echo“ func&on faster than print
• Single quotes (‘) faster than double quotes (“)
• Using short tags “<?” is more expensive than
“<?php”
• The shut up equator (@)
• Leave Magic to David Coperfield (__get(),
__set(), __autoload())
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

6. Code Tweaks – String replacement
• str_replace faster than preg_replace (not
always)
– str_replace faster for templa&ng
– preg_replace faster for large data sets
• str_replace($array1, $array2, $subject) a lot
faster than loops
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

7. Code Tweaks – String replacement
(preg_replace vs str_replace)
• Data sets Templa&ng
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

8. Code Tweaking ‐ Loops
• NEVER use func&ons inside a for – they’re
called upon each loop!
• Bad:
for ($i = 0; $i<count($array); $i++){
…….
}
• Good:
$count = count($array) //Called once
for ($i = 0; $i<$count; $i++){
…….
}
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

9. Code Tweaks – Constants & Sta&c
• Constants are your friends
$foo = array(‘bar’=>0);
$foo[‘bar’] = 1;
Is 700% slower than
$foo[‘bar’] = 1;
• Sta&cs are also your friends
– Declaring sta&c func&ons is 4 &mes faster!
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

10. Code Tweaks – Proper coding
• Go with the flow:
– Ini&alize your variables
– Use singleton classes
– Study SQL & avoid PHP juggling when SQL can do
the hard work
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

11. Use a second web server for sta&c
stuff
• Install a second web server on second IP (eg.
Ligh{pd) and replace images, css, js, mov, flv
paths
• Avoid main webserver overhead
• Tune up your main web server
• Use mod_compress on ligh{pd
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

12. SQL op&miza&on
• Replica&on
– Use master server for inserts, updates, deletes
– Use slave server for selects
• Use memcache for database stuff (selects or
stored procedures)
• Mul&ple Databases
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

13. Deploy to the Cloud
• Windows Azure
– Available on Monday 12/4/10 (for Greece)
– Programmer != Sysadmin
– Add instances easily
• Amazon EC2
– You need an experienced administrator
• Other par&es
• Cheaters (Selling dedicated servers as cloud)
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr

14. Thank you!
• Ques&ons
• Contact Informa&on
– fo&s@redmark.gr
– twi{er.com/falexandrou
– facebook.com/falexandrou
– www.redmark.gr ‐ www.e‐skafos.gr ‐
www.iheartshops.com
‐ Thnx to @HumanWorks for the &ps 
Fo&s Alexandrou ‐ @falexandrou ‐
www.redmark.gr