Understanding MySQL Internals

Chapter 3. Core Classes, Structures, Variables, and APIs

The MySQL source code contains several hundred thousand lines and continues to grow. Finding your way in it is quite a challenge. However, the task is not as difficult and daunting as it appears initially, if you are familiar with the core elements of the code and their respective roles. The purpose of this chapter is to give you a foundation that will enable you to read most sections of the code with some degree of ease.

This chapter is meant to be a literacy crash course. We will focus on the core elements of the code that are critical to understanding what is generally going on. The more specific details of various modules will be discussed in later chapters dedicated to them.

In the discussion of the various code elements, I will inevitably have to leave out a number of less significant class members, API calls, and global variables due to space constraints. Additionally, by the time this book is printed, a number of new code elements might appear, and a few might change names or functions to some extent. However, it is reasonable to expect that such cases will be minimal. The major part of the code we will discuss in this chapter has already stabilized and will not change significantly.

I must also note that again for reasons of space constraints we will have to leave out a large number of vital classes, structures, and macros. However, I hope that once you become familiar with what we have covered, you will have sufficient ...