What is Debugging?

The term debugging is a holdover from the earliest days of computing. According to popular lore, one of the early systems crashed and nobody could find the source of the problem until someone found that an insect had immolated itself inside one of the crude switches in the system. From then on, the process of fixing software problems became known as debugging. For the purposes of this book, we will be using a very broad definition of debugging Informix applications.

Debugging Informix Applications: The process of identifying and correcting portions of Informix applications that are either not working at all, not working according to specifications, or not working at optimal efficiency.

This definition can cover:

• Coding errors in ESQL/C, 4GL, NewEra, or other Informix application development tools

• Coding errors in SQL statements

• Tuning problems with Informix engines

• Database design errors

• Physical database layout problems

• Design problems with custom applications

Most of the coding examples will utilize ESQL/C, not because of any inherent superiority of the language, but because of the fact that it is the language with which I am most familiar. For specific debugging techniques for 4GL or NewEra, the reader is directed to the other Informix Press titles on these subjects.

This chapter will take a global approach to the process of debugging. These principles can be applied to any type of troubleshooting or debugging and is most definitely not limited to Informix issues. We'll cover the Informix-specific material later in the book. For now, we need to develop an overall strategy and mindset that will put us in a position to later apply these techniques to debugging Informix systems.