Abstract: An apparatus and method allow analyzing the performance of a computer program. The computer program is initially executed according to a predefined set of program execution conditions. As the computer program executes, information for each code segment is logged. Using the logged performance data, a graphical representation of the executed computer program is constructed. A user can then formulate ad hoc queries to analyze any desired performance parameters for the computer program by replaying how the computer program ran using the graphical representation of the executed computer program. The present invention thus allows a user to detect via queries complex performance bottlenecks that are caused by interactions between multiple code segments.