The issue: It's hard to find the bottleneck
- Even best designed and coded apps maybe slow
- Finding the bottleneck is sometimes really hard
- Trial and error is time consuming
The solution: Profile your code
- A profiler shows you, which parts of your code consumes how many time
- The Xdebug debugger already contains a profiler
- Profiling shows you the bottlenecks in overview
Recommendation: Profiler
- Xdebug (open source) http://xdebug.org
- APD (open source) http://pecl.php.net/package/apd