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Notes:
Online Redo Logs
- Contains Redo and Undo info
- DML
- Inserts/Deletes
- DDL – Create alter drop
- Commits
- Need at least 2 files/groups
- Should be multiplexed each on different devices and controlers
- When each file fils, next one is started and old one is archived (if in Archivelogmode)
An Oracle database is comprised of datafiles, control files
and redo logs.
The second part is the memory – the SGA (system global area
or shared global memory)
Database Buffer Cache
Comprised of Oracle data blocks
There are 4 main types of data blocks, which are the same as the 4 types of data mentioned earlier:
- Data
- Index
- Rollback
- Temporary