High Performance MySQL [Electronic resources] نسخه متنی

Chapter 5. Query Performance

This chapter deals with an issue
faced by every MySQL user sooner or later: speeding up slow queries.
MySQL is a very fast database server, but its innate speed can carry
your applications only so far. Eventually you need to roll up your
sleeves, get your hands dirty, and figure out why your queries are
slowand ultimately figure out what needs to be done to get a
response quickly.

We're frequently asked how we
"figure this stuff out."
It's really quite simple. Once you start to
understand how MySQL does what it does, you'll begin
to have an intuitive feeling for it, and query optimization will
start to seem really easy. It's not always that
easy, but with the proper background, you should end up able to
figure out most optimization problems.

This chapter aims to provide a framework for understanding how MySQL
works to resolve queries. With this foundation, you can continue
through this chapter to the next, where the knowledge is applied to
application design and server performance tuning.

We'll begin with an overview of how MySQL handles
query processing. After that, we'll look at the
optimizer's built-in features. Then
we'll discuss identifying slow queries and finish up
with a look at some of the hints you can provide to
MySQL's query optimizer.