In a Oracle database instance, there are several key components:
- SGA (System Global Area) : is a group of shared memory structure for data and control information of database instance. It includes database buffer cache, redo log buffer, shared pool, large pool, flashback buffer, java pool, stream pool and fixed SGA. The shared memory used by Oracle GoldenGate Integrated Extract ( used by the logmining server) is the Stream Pool portion (STREAMS_POOL_SIZE) of the System Global Area (SGA) .
- PGA (Process Global Area): is the memory allocated for an operating process.
Oracle DB has required processes. Some of the key process are listed as follows:
- Server: Server processes can be dedicated or shared which performs request for the client.
- SMON (System Monitor): maintains space and the crash recovery agent.
- PMON (Process Monitor): manages user processes.
- DBWn (Database Writer): writes dirty buffers from buffer cache to the disk.
- CKPT (Checkpoint): updates the control file and data files after DBWn writes data to the disk.
- LGWR (Log Writer): performs sequential writes from the redo log buffer to the redo log files on disk.
- DMON (Data Guard Borker)
- FBDA (Flashback Data Archive)
- CTWR (Change Tracking Write): used by RMAN support
3. Oracle GoldenGate - DBA Views
In Oracle Database 12c, the following DBA Views are available:
- DBA_GG_INBOUND_PROGRESS: includes process information about the the processes of all Oracle GoldenGate inbound servers.
- DBA_GOLDENGATE_INBOUND: includes the Oracle GoldenGate inbound server process summary.
- DBA_GOLDENGATE_PRIVILEGES: includes the database user and granted Oracle GoldenGate privileges.
- DBA_GOLDENGATE_RULES: include the server rules.
- DBA_GOLDENGATE_SUPPORT_MODE: include the information about the level of Oracle GoldenGate capture support for tables in the database.