Oracle Startup & SCN Concept in Depth
514413May 27 2008 — edited May 28 2008I have few questions about Oracle SCN.
I will taking few different scenario.
( Note- The following condtions true in all cases.
(a)- No Recovery Catalog
(b)- Backup and Recovery with RMAN) )
Different Cases
Case 1. Oracle Instance shutdown with command
SQL > Shutdown immediate
Case 2. Oracle Instance shutdown with command
SQL > SHUTDOWN ABORT
Case 3.Oracle Datafile (system.dbf) file deleted with operating System Command
# rm -rf system01.dbf
SQL > SHUTDOWN ABORT
The following conditions true in Case3.
(a) Database is running in ARCHIVELOG Mode.
(b) No loss on Control File and Online Redo Log Files.
Case 4. All the Oracle Control File deleted with Operating System Command.
# rm -rf *.ctl
SQL > SHUTDOWN ABORT
The following conditions true in Case4.
(a) Database is running in ARCHIVELOG Mode.
(b) No loss on datafile File and Online Redo Log Files.
Case 5. All the Oracle Control File & System dbf deleted with Operating System Command.
# rm -rf *.ctl
# rm -rf system01.dbf
SQL > SHUTDOWN ABORT
The following conditions true in Case5.
(a) Database is running in ARCHIVELOG Mode.
(b) No loss on Online Redo Log Files.
Case 6. All the Oracle Control File & Online Redo Log File deleted with Operating System Command.
# rm -rf *.ctl
# rm -rf *.log
SQL > SHUTDOWN ABORT
The following conditions true in Case5.
(a) Database is running in ARCHIVELOG Mode.
(b) No loss on datafile Files.
Question-
A> Let me know How Oracle SCN concept will work in above mentioned scenario ?
B> How SCN Synronization will happen ?
C> How Oracle Database will understand what file Needs Restoration and Recovery ?
D> What the meaning of SCN Synronization ? If Database synronize Control File SCN number with DBF File SCN then how it will work when we loose Control File.