| 1. Memory region
||The efficient allocation of the Oracle system global areas (SGA) can have a huge impact upon database performance. The larger the SGA, the more data and programs Oracle will be able to reside in RAM memory. The more memory in the SGA, the faster your database will perform.
|2. Disk data files
||The Oracle data files on disk constitute one of the largest components of response time. The more disk I/O, the slower the transaction. One of the goals of Oracle tuning is to minimize I/O and ensure that all disk files are evenly spread across the disks.
|3. Oracle processes
||The Oracle processes that make up the Oracle instance have an impact upon database performance. For example, when parallel query is used, Oracle will create additional server processes to speed the query.
| 4. External application connections
|| The external connections to Oracle and the SQL that they issue will also have a huge impact upon performance. Identifying inefficient SQL can help you tune your application.