Oracle Instance
An oracle instance is a set of different memory structures and the processes which manages all database activities, such as transaction processing, database recovery, form generation, and so on. There is different type of memory block which are accessed by different type of background processes SGA : It is also commonly known as System Global area. It solve many purpose like storing parsed SQL qyeries/ Parsed Pl-sqL code and redo buffer cache. It has below memory pools- shared pool :
- Data Dictionary Cache:
- Buffer Cache:
- Redo Log Buffer:
- Large Pool:
- Java Pool :
Oracle Background Process:
There some back ground process which keep on running to fulfill DB requests.- DBWR
- LGWR
- CKPT
- SMON
- PMON
- ARCH
- DISPATCHER PROCESSES
- RECO
- SNPn
- LCKn
- Pnnn