Chapter 2 Exploring the Database Architecture

Describe the Single-Instance Architecture
one instance on one computer, opening a database stored on local disks.

instance: memory structure (SGA, system global area) and background processes (transient)
database: files on disks (permanent, persists indefinitely - until you deliberately delete them)

user session is user process connected to server process

on demand server processes (foreground processes) + PGA, program global area (session's private memory) : read from the database

Distributed Systems Architecture
-RAC
-Streams
-Data Guard

Explain the Memory Structures, shared SGA (dynamically resized, automatically managed)
-The database buffer cache
-The log buffer (Exception for dynamically resized and automatically managed)
-The shared pool
-The Library Cache
-The Data Dictionary Cache
-The PL/SQL Area
-The SQL Query and PL/SQL Function Result Cache
-A large pool (Optional)
-A Java pool (Optional)
-A Streams pool (Optional)

Describe the Process Structures : write to the database
-SMON
-PMON
-DBWn
-LGWR
-CKPT
-MMON, MMNL
-MMAN
-ARCn
-RECO

Summarize the Storage Structures
Physical Database Structures:
The Controlfile : stores integrity information and pointers to the rest of the database
The Online Redo Log Files
The Datafile

Other files: Parameter File, Password File, Archive Redo Log Files, Alert Log and Trace Files

Logical Database Structures:
Tablespaces
Segments
Extents
Oracle blocks

Data Dictionary (SYSTEM & SYSAUX Tablespace): metadata (data about data)
Views:
USER_
ALL_
DBA_