1. 1 CS 5226: Database Administration and Performance Tuning

2. 2 Course Structure Continuous Assessment: 50% –Assignments: 25% –Lab Sessions: 25% Lecturers: –Prof. Ooi Beng Chin (ooibc) –DBAs: Sze Eng Koon and Phillip Lim

3. 3 Text/Reference Books: Dennis Shasha and Phillipe Bonnet: Database Tuning : Principles Experiments and Troubleshooting Techniques. Morgan Kaufmann Publishers. 2002 (released in June 2002). TEXT. Dennis Shasha: Database tuning : a principled approach. Prentice Hall, 1992. REFERENCE (a good reference if cannot get the text book) Database Management Systems, 3 rd edition. Raghu Ramakrishnan & Johannes Gehrke, McGraw-Hill, 2002. Hector Garcia-Molina, Jeffrey D. Ullman, and Jennifer Widom: Database Systems -- The Complete Book. Prentice Hall, 2001. G. J. Vaidyanatha, K. Deshpande and J. Kostelac: Oracle Performance Tuning 101. Osborne/Mc-Graw-Hill. 2001. REFERENCE. Jim Gray (ed): The Benchmark handbook : for database and transaction processing systems. M. Kaufmann Publishers, 1991. REFERENCE.

4. 4 Copyright: Many slides belong to the tutorial: Database Tuning Principles, Experiments and Troubleshooting Techniques Dennis Shasha (shasha@cs.nyu.edu) Philippe Bonnet (bonnet@diku.dk) And lecture notes provided by Database Management Systems, 3 rd edition. Raghu Ramakrishnan & Johannes Gehrke McGraw-Hill, 2002. and some from the web …bonnet@diku.dk

5. 5 Database Tuning Database Tuning is the activity of making a database application run more quickly. More quickly usually means higher throughput, though it may mean lower response time for time-critical applications.

6. 6 Application Programmer (e.g., business analyst, Data architect) Sophisticated Application Programmer (e.g., SAP admin) DBA, Tuner Hardware [Processor(s), Disk(s), Memory] Operating System Concurrency ControlRecovery Storage Subsystem Indexes Query Processor Application

7. 7 Goals of the Course Appreciation of DBMS architecture Study the effect of various components on the performance of the systems Tuning principles Troubleshooting techniques for chasing down performance problems Hands-on experience in Tuning

8. 8 Contents 1.Basic Principles 2.Tuning the guts 3.Indexes 4.Relational Systems 5.Application Interface 6.E-commerce Applications 7.Data warehouse Applications 8.Distributed Applications 9.Troubleshooting

9. 9 Tuning Principles Think globally, fix locally –Localizing the problems Partitioning breaks bottlenecks (temporal and spatial) –ONE part of the system limits the the overall performance –Two approaches: Fix locally Partitioning the LOAD –eg. Free list, lock contention due to long transactions Partitioning in space/logical resources/time

10. 10 Tuning Principles Start-up costs are high; running costs are low –Start-up costs include Disk access Data transfer Query processing System calls –Reduce the number of start-ups

11. 11 An example: Time = Seek Time + Rotational Delay + Transfer Time + Other Rule ofRandom I/O: Expensive Thumb Sequential I/O: Much less Ex:1 KB Block »Random I/O: 20 ms. »Sequential I/O: 1 ms.

12. 12 Tuning Principles Render onto server what is due onto Server –Task allocation between the server and the application programs –Factors: Relative computing resources of client, application servers and data server –Should checking be done in the middle tier? Location of information The nature of tasks: interaction with screen?

13. 13 Tuning Principles Be prepared for trade-offs Ex. Indices

14. 14 Tuning Mindset 1.Set reasonable performance tuning goals 2.Measure and document current performance 3.Identify current system performance bottleneck 4.Identify current OS bottleneck 5.Tune the required components eg: application, DB, I/O, contention, OS etc 6.Track and exercise change-control procedures 7.Measure and document current performance 8.Repeat step 3 through 7 until the goal is met