SQL Tuning (Paperback)
A poorly performing database application not only costs users time, but also has an impact on other applications running on the same computer or the same network. SQL Tuning provides an essential next step for SQL developers and database administrators who want to extend their SQL tuning expertise and get the most from their database applications.
There are two basic issues to focus on when tuning SQL: how to find and interpret the execution plan of an SQL statement and how to change SQL to get a specific alternate execution plan. SQL Tuning provides answers to these questions and addresses a third issue that's even more important: how to find the optimal execution plan for the query to use.
Author Dan Tow outlines a timesaving method he's developed for finding the optimum execution plan--rapidly and systematically--regardless of the complexity of the SQL or the database platform being used. You'll learn how to understand and control SQL execution plans and how to diagram SQL queries to deduce the best execution plan for a query. Key chapters in the book include exercises to reinforce the concepts you've learned. SQL Tuning concludes by addressing special concerns and unique solutions to "unsolvable problems."
Whether you are a programmer who develops SQL-based applications or a database administrator or other who troubleshoots poorly tuned applications, SQL Tuning will arm you with a reliable and deterministic method for tuning your SQL queries to gain optimal performance.
Table of Contents
Why Tune SQL?
Who Should Tune SQL?
How This Book Can Help
2. Data-Access Basics
Caching in the Database
Uncommon Database Objects
Single-Table Access Paths
3. Viewing and Interpreting Execution Plans
Reading Oracle Execution Plans
Reading DB2 Execution Plans
Reading SQL Server Execution Plans
4. Controlling Execution Plans
Universal Techniques for Controlling Plans
Controlling Plans on Oracle
Controlling Plans on DB2
Controlling Plans on SQL Server
5. Diagramming Simple SQL Queries
Why a New Method?
Full Query Diagrams
Interpreting Query Diagrams
Simplified Query Diagrams
6. Deducing the Best Execution Plan
Robust Execution Plans
Standard Heuristic Join Order
A Special Case
A Complex Example
Special Rules for Special Cases
7. Diagramming and Tuning Complex SQL Queries
Abnormal Join Diagrams
Queries with Subqueries
Queries with Views
Queries with Set Operations
8. Why the Diagramming Method Works
The Case for Nested Loops
Choosing the Driving Table
Choosing the Next Table to Join
9. Special Cases
Merged Join and Filter Indexes
10. Outside-the-Box Solutions to Seemingly Unsolvable Problems
When Very Fast Is Not Fast Enough
Queries that Return Data from Too Many Rows
Tuned Queries that Return Few Rows, Slowly
A. Exercise Solutions
B. The Full Process, End to End