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Lesson 3Tuning with database design
ObjectiveDescribe how database design effects performance

Database Design Tuning

Good design prevents Performance Problems

Design is the most important area of tuning. A good database design is critical for a well-tuned database and should be considered the first step in the tuning process. In fact, it is very difficult, if not impossible, to tune a database that does not have an efficient database design. Essentially, by database design we are referring to the logical and physical design of the Oracle tables, the presence of table indexes, and the design of the application that accesses the database. For an overview, we can separate Oracle database design into logical design, physical design, and application design.

SQL Tuning and efficient Database Design

Question: Why is the ability to tune a database and dependent upon efficient database design?
The ability to tune a database is inherently dependent upon efficient database design because the underlying structure and organization of a database play a crucial role in determining its performance, maintainability, and scalability. In this context, tuning refers to optimizing the database to improve its overall performance and efficiency. A well-designed database enables efficient data retrieval, minimizes redundancy, ensures data integrity, and provides a solid foundation for future growth.
  1. Data retrieval efficiency: A key factor in the performance of a database is the speed at which data can be accessed and retrieved. Efficient database design involves carefully selecting appropriate data types, indexing strategies, and normalization levels to ensure that queries run quickly and efficiently. Proper indexing, for example, enables the database to locate and retrieve the desired data much faster, which, in turn, leads to improved performance.
  2. Minimizing redundancy: Efficient database design seeks to minimize data redundancy by organizing the data in such a way that it is stored only once. This is typically achieved through normalization, a process that eliminates redundant data and ensures that each piece of information is stored in the most appropriate table. Reducing redundancy not only conserves storage space, but also helps prevent data inconsistencies, as updating redundant data in multiple locations can lead to inconsistencies if not properly managed.
  3. Data integrity: Ensuring data integrity is a crucial aspect of efficient database design. This involves implementing constraints, relationships, and validation rules that maintain the accuracy and consistency of the data. By establishing referential integrity, for example, a well-designed database enforces consistency between related tables, preventing orphaned records and maintaining data integrity. This, in turn, promotes a reliable and stable database environment.
  4. Scalability and maintainability: As an organization grows and evolves, its database must be able to accommodate new requirements and increased amounts of data. An efficient database design provides a solid foundation that can be easily extended and adapted to meet these changing needs. By adhering to best practices and designing the database with future growth in mind, developers can minimize the need for extensive modifications or rework later on, saving both time and resources.
  5. Performance monitoring and optimization: A well-designed database facilitates performance monitoring and optimization by providing a clear and organized structure, which simplifies the process of identifying and addressing performance bottlenecks. With a solid database design in place, administrators can more easily monitor performance metrics, identify areas for improvement, and apply tuning techniques to optimize the database's performance.

The ability to tune a database is highly dependent on efficient database design. A well-designed database not only provides a strong foundation for optimal performance but also enables easier identification and resolution of performance issues. By focusing on efficient database design, organizations can ensure that their databases remain performant, scalable, and maintainable over time, ultimately contributing to the overall success of the organization.

Application design

The design of the application also has a great impact on Oracle performance. The proper use of PL/SQL stored procedures and database constraints, as well as the parallel processing demands of the application will have a great impact on the performance of the database. In this module, we will focus on the first two, logical and physical design.

Logical design

This refers to the logical structure of the tables and the number of SQL join operations that are required to service a request. As a general rule, the more we pre-join tables together in design, the faster the tables will perform at run time. Also, good logical design will greatly minimize disk I/O, since less work is required to retrieve the desired information.
Note: Disk I/O tuning is the single largest component of Oracle response time. Anything that can be done to reduce disk I/O will make your Oracle database run faster.

Physical design

Physical design is the implementation detail behind the database structure. This refers to the sizing of the table parameters, the placement of indexes, and the physical configuration of the Oracle instance.
In the next few lessons, we'll focus our attention on logical design.