In order to efficiently and intelligently manage an Oracle database, you have to have a sound knowledge of its underlying architectural details. This knowledge pays off because it is directly linked with DBA’s job. The real job of DBA starts after the installation of database, when he embarks on to setting-up a database and then maintaining it. Naturally, the configuration and maintenance of database cannot be done by a DBA unless he doesn’t know about the ins and outs of its architecture. The following section provides a short overview of Oracle architecture.
The Background processes are used to facilitate the working of instance with respect to database. Background processes are responsible for the efficient interaction of memory structures of instance and database. Some background processes are always there and some are added up as you configure more features of database. Some common background processes are:
Database Writer: It takes data from buffer cache and writes it to data files.
Checkpoint: It ensures that at continuous intervals, all modified data from buffer cache is written to data files.
System Monitor: It performs crash recovery and some space management.
Process Monitor: It performs process recovery, in case of failure of user process.
Archiver: It makes offline copies of online redo logs and helps to recover from media failure.