You Know that Even Good Tools Work Better in Skilled Hands ...

You Know that Even Good Tools Work Better in Skilled Hands

Everybody has heard of sluggish SQL queries, or even whole systems, that a heroic someone improved with small effort. Usually the improvement is small too, so we will avoid extravagant promises. But we will make you the following guarantees .

• You will be able to follow our arguments without deep thinking or hard work. All we assume is that you have basic knowledge of programming and standard SQL syntax. In fact, you can read this book on a plane or at the beach .

• All of our observations have been confirmed by tests on real DBMSs within the last several months.

• We know that "optimizing" is very different from "over-clocking," and we only discuss safe, rational, relational techniques.

One accusation that could be leveled, and to which we plead guilty, is that some of our material is ad hoc advice instead of general principles. Of course! There are only a few general principles in DBMS optimization.

• First, do no harm. (Actually that's from Hippocrates' ancient manual on medical treatments . It applies to anybody fixing what ain't really broke.)

• Get more memory, add indexes, re-cable the network. (If you can influence the environment like that, then do so.)

• Design right in the first place.

• Understand the query.

Instead of general principals, we will be looking at what can be done with what's likely to be at hand. If we descend sometimes to mere tips and warnings about traps, that's because we've seen over the years that examples of real situations can help people realize what the general rules are. As has often been observed , tips should be based on principles.

The DBMSs that we looked at while preparing this book include IBM DB2, Informix, Ingres II, InterBase, Microsoft SQL Server, MySQL, Oracle, and Sybase (MS Windows NT versions). Each was installed and tested using the default switches recommended in the vendors ' instructions. To avoid favoring any vendor's idiosyncrasies, all SQL examples in this book are written in ANSI/ISO Standard SQL:1999. Host-language examples are written in C plus ODBC, or Java plus JDBC.

Your DBMS is your pal. We won't counsel you to subvert it, be paranoid about it, or insult it by assuming it's stupid. Rather, as you would with a pal, you should try to get to know it better, and help it to help you.