Oracle DBA on Unix and Linux
Database Versus Instance ......................................................................33
Oracle File Types ..................................................................................34
Control Files ....................................................................................34
Data Files ........................................................................................35
System ............................................................................................36
Data ..................................................................................................36
Index ................................................................................................37
Temp ................................................................................................38
Rollback ..........................................................................................38
Online Redo Logs ............................................................................40
Memory Structures ..............................................................................42
Shared Global Area (SGA) ..............................................................42
Shared Pool ......................................................................................46
Redo Log Buffer ..............................................................................47
Large Pool ......................................................................................48
Java Pool ..........................................................................................48
Oracle Processes ..................................................................................49
Server Processes ..............................................................................50
Background Processes ....................................................................52
System Monitor Process (SMON) ..................................................53
Process Monitor Process (PMON) ..................................................53
Database Writer Process (DBWn) ..................................................53
Log Writer Process (LGWR) ..........................................................54
Checkpoint Process (CKPT) ..........................................................55
Archiver Process (ARCn) ................................................................56
Recover Process (RECO) ................................................................56
Job Queue Processes (SNPnn) ........................................................56
Queue Monitor Processes (QMNnn) ..............................................56
Dispatcher Processes (Dnnn) ..........................................................56
Shared Server Processes (Snnn) ......................................................56
Transaction Control ..............................................................................57
Miscellaneous Database Files ..............................................................59
Oracle Database Parameter and Log Files ......................................59
Summary ..............................................................................................62
3. Planning a Database 63
System Architecture ..............................................................................64
Two-Tier Basic Client Server Architecture (2 Tier) ........................65
Three-Tier Client Server Architecture ............................................66
Capacity Planning/Sizing ......................................................................67
Optimal Flexible Architecture ..............................................................71
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