What is Code Tracing?

Think of a black box flight recorder; when something goes wrong with an airplane, the problem is not actually reproduced. Instead, the flight recorder captures the complete data that flight analysts may need in order to understand why the problem occurred. Zend Server does the same for PHP applications. Rather than spending time on trying to set up the environment and reproduce all the steps that led up to the failure, Zend Server captures the full execution of the application in real-time – in production or in the test lab – so root cause can quickly be identified. Code tracing can be activated automatically to capture problems when they occur in real time, or manually by the user for specific requests. Code tracing captures the following data:

* Function calls: every function called as part of a request, represented as a time-synchronized tree based function execution flow.
* Arguments and return values: all arguments and return values passed into and returned from functions in the traced request
* Duration: breakdown of execution time at the function level – particularly useful for identification of performance problems
* Memory usage: for every executed function, the memory it consumes – allowing easy identification of functions with abnormal memory consumption or memory leaks
* File name and line of code: for each function call, the file name and exact line of code from which the function was called

The trace displayed in the Zend Server web console functions like a DVD player, showing the recorded execution history of the application. Users can follow the footsteps of a single problematic request in order to quickly pinpoint the root cause of the problem.