12 PHP optimization tips

Ilia Alshanetsky’s PHP performance talk given last week at the Zend conference is pretty useful as far as getting small tips for tweaking PHP code.

1. If a method can be static, declare it static. Speed improvement is by a factor of 4.
2. Avoid magic like __get, __set, __autoload
3. require_once() is expensive
4. Use full paths in includes and requires, less time spent on resolving the OS paths.
5. If you need to find out the time when the script started executing, $_SERVER['REQUEST_TIME'] is preferred to time()
6. See if you can use strncasecmp, strpbrk and stripos instead of regex
7. str_replace is faster than preg_replace, but strtr is faster than str_replace by a factor of 4
8. If the function, such as string replacement function, accepts both arrays and single characters as arguments, and if your argument list is not too long, consider writing a few redundant replacement statements, passing one character at a time, instead of one line of code that accepts arrays as search and replace arguments.
9. Error suppression with @ is very slow.
10. $row['id'] is 7 times faster than $row[id]
11. Error messages are expensive
12. Do not use functions inside of for loop, such as for ($x=0; $x <>each time.

For templating, are you using Smarty? This is probably the fastest way to ensure the frequently viewed pages of the site are cached. Also, check out this list of high-availability and scalability presentations. There’s also a great article on references in PHP.