Chapter 24 - Advanced application development. This chapter covers advanced issues in application development, including performance tuning, performance benchmarks, database-application testing, and standardization. | Chapter 24: Advanced Application Development Database System Concepts, 6th Ed. ©Silberschatz, Korth and Sudarshan See for conditions on re-use Chapter 24: Advanced Application Development Performance Tuning Performance Benchmarks Standardization E-Commerce Legacy Systems Database System Concepts - 6th Edition ©Silberschatz, Korth and Sudarshan Performance Tuning Adjusting various parameters and design choices to improve system performance for a specific application. Tuning is best done by 1. identifying bottlenecks, and 2. eliminating them. Can tune a database system at 3 levels: Hardware -- ., add disks to speed up I/O, add memory to increase buffer hits, move to a faster processor. Database system parameters -- ., set buffer size to avoid paging of buffer, set checkpointing intervals to limit log size. System may have automatic tuning. Higher level database design, such as the schema, indices and transactions (more later) Database System Concepts - 6th Edition ©Silberschatz, Korth and Sudarshan Bottlenecks Performance of most systems (at least before they are tuned) usually limited by performance of one or a few components: these are called bottlenecks ., 80% of the code may take up 20% of time and 20% of code takes up 80% of time Worth spending most time on 20% of code that take 80% of time Bottlenecks may be in hardware (., disks are very busy, CPU is idle), or in software Removing one bottleneck often exposes another De-bottlenecking consists of repeatedly finding bottlenecks, and removing them This is a heuristic Database System Concepts - 6th Edition ©Silberschatz, Korth and Sudarshan Identifying Bottlenecks Transactions request a sequence of services ., CPU, Disk I/O, locks With concurrent transactions, transactions may have to wait for a requested service while other transactions are being served Can model database as a queueing
