Oracle 10g architechture

Oracle 10g Architechture

Oracle have two main componenets:
1. Instance (Memory)
2. Database (Physical datafiles)
One instance for one database.

Instance Consists of:

SGA and Background Processes

      1. SGA - System Global Area
                   1.Shared Pool
                         1.Data Dictionary Cache
                         2. Library Cache
                                  1.SQL Area
                                  2.PL/SQL Area
                   2. Data Buffer Cache
                         - Caches blocks of data from database
                   3. Redo-Log-buffer
                          - Caches redo entries untill it get written to redo-log files and this redo log files are used at 
                             instance recovery.
                  4. Large Pool
                          - Used in Shared Server environment to reduce the burden of Shared pool.
                  5. Java Pool
                          - All session specific java codes and data within JVM.
                  6. Streams Pool
                          - Used in Oracle streams

    2. Background Process
             1. SMON
             2. PMON
             3. DBWr
             4. LGWr