Professional LAMP: Linux®, Apache, MySQL®, and PHP5 Web Development

Chapter 9. Code Efficiency

The faster you can serve pages, the busier your site can be without users experiencing delays. This chapter covers methods for improving the performance of your sites, and also for identifying which methods are likely to be most effective.

"More pages in less time" is the rationale, but just as there are car enthusiasts who spend every free moment elbow-deep in their car's innards trying to shave another tenth of a second off the quarter mile, there are site developers who want to shave another millisecond off displaying the login page. You can take things too far!

You don't want to waste your time on improvements that no one will notice, so the first section of this chapter will present a couple of cameos that illustrate just how little difference even large improvements can sometimes make, how much difference small improvements can make, and how valuable it is to understand your entire system before messing with it.

Your program runs on PHP, which runs on your web server and communicates with your DBMS, which both run on your operating system, which runs on the physical hardware. Subsequent sections look at all of these for opportunities for improvement and techniques for deciding what needs improving.

Finally, there will be a few tiny miscellaneous coding tweaks that might shave a millisecond off the login page, which are presented here because if you know and use them from the beginning, you won't later be tempted to spend time better spent elsewhere ...