Performance tuning is the one area in which the Oracle DBA probably spends most of his or her time. If you’re a DBA helping developers to tune their SQL, you can improve performance by suggesting more efficient queries or table- and index-organization schemes. If you’re a production DBA, you’ll be dealing with user perceptions of a slow database, batch jobs taking longer and longer to complete, and so on. Performance tuning focuses primarily on writing efficient SQL, allocating appropriate computing resources, and analyzing wait events and contention in the system. Some Links for your kind reference.

Oracle Tuning References

• Oracle® Database Performance Tuning Guide 10g Release 2 (10.2)
• Oracle® Database 2 Day + Performance Tuning Guide 10g Release 2 (10.2)
• Jonathan Lewis tips
• Performance Tuning Steps
• STATSPACK Tuning Tips

Oracle Tuning Tools

Confio Ignite for Oracle
Confio Ignite provides bottleneck analysis by measuring wait events and allowing the DBA to drill into wait events to find the root cause behind performance issues.

Ion for Oracle
Ion for Oracle provides a sleek interface for trend identification and historical performance metrics. Metrics can be viewed over time with forecasting and trending options, and complex scripts allow historical and real-time views into database performance.