TRAINING (ORA-10) - Shutting Down Database & Instance Recovery

Different Shutdown Modes of an Oracle Database

There can be four different shutdown mode.
1.) ABORT

2.) IMMEDIATE

3.) TRANSACTIONAL

4.) NORMAL

What can be done in different shutdown modes



A = ABORT        I = IMMEDIATE        T = TRANSACTIONAL        N = NORMAL

What happens During shutdown

A.) For a Consistent (Clean) Database

B.) For an Inconsistent (Dirty) Database

Instance or crash recovery

> Is caused by attempts to open a database whose files were not synchronized on shutdown

> Is automatic

> Uses information stored in redo log groups to synchronize files

> Involves two distinct operations

         Rolling Forward: Data files are restored to their state before the instance failed.

         Rolling Back: Changes made but not committed are returned to their original state.

Phase of Instance Recovery

- Data files out-of-sync

- Roll forward (redo)

- Committed and non-committed data in files

- Roll back (undo)

- Committed data in files