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Oracle Architecture - Coggle Diagram
Oracle Architecture
Databases and Instances
Oracle Database Structures
Shemas
Logic isolation unit
Control of data structures within it
Tablespaces
Logical structure that allows to have a space to store the database elements.
Files of a database
Control files
Safeguards vital object information
Datafiles
Redo logfiles
Pluggable Databases
Is an isolation layer between a database instance and a schema.
Operations and entities are implemented in the CDB and operate in separate PDBs
Databases Initialization
When the database is initialized the initialization parameters are read
Instance : Software running the service that provides access to the database.
Database: Physical storage of information
Deploying Physical Components
Control Files
A database must have two copies of the control file on different physical disks to safeguard the data.
Datafiles
Datafile Structure
The first block of a data file is data file header
Maintains the integrity
Control point
Timestamp indicating which was the last change made
Extents and segments
Extension: sequence of data blocks within an oracle data file
Segment: object occupying a space in the database
Contain actual data stored in the database
Redo Logfiles
Multiplexing redo logfiles
Oracle uses a subprocess redo logs to record database changes.
How Oracle uses the redo logs
When a redo log file is filled, the following log file starts to be used
Naming conventions for redo logs
Clear identification of files by name
Archived redo logs
ARCHIVELOG mode and automatic archiving
Contain recordings of changes made in the database as a result of transactions
Instance Memory and Processes
Memory Structures for an Instance
Database buffer cache
cache memory that contains blocks of data where they can be consulted quickly without having to go to the disk.
Shared pool
Caches data that can be shared among users
Redo log buffer
Stores redo log information until rebuild log files are written to disk
Automatic PGA management
Manages the memory allocated to an instance
An instance can be defined as shared memory and background processes
The Data Dictionary
Tables and views containing metadata