Performance information for SQL application programming
Efficient applications are an important first step to good system and application performance. As you code applications that access data in DB2®, consider performance objectives in your application design.
The following topics can help you understand how application programmers can consider performance as they write applications that access data in DB2 for z/OS®.
Concurrency and programming
- Protects the integrity of the data that is being read or updated from being changed by other applications.
- Minimizes the length of time that other access to the data is prevented.
Writing efficient queries
The predicates, subqueries, and other structures in SQL statements affect the access paths that DB2 uses to access the data.
Analyzing access paths
By analyzing the access path that DB2 uses to access the data for an SQL statement, you can discover potential problems. You can use this information to modify your statement to perform better.
- Investigating access path problems
- 00C200A4
- Investigating SQL performance by using EXPLAIN
- Interpreting data access by using EXPLAIN
- EXPLAIN tables
- EXPLAIN
- Tuning SQL with Optim Query Tuner, Part 1: Understanding access paths (IBM developerWorks)
- Generating visual representations of access plans (IBM Data Studio)
Distributed data access performance
The goal is to reduce the amount of network traffic that is required to access the distributed data, and to manage the use of system resources such as distributed database access threads and connections.