recovery-after-losing-undo-tablespace.md

Recovery after losing UNDO tablespace

• Reference

If you get the error ORA-01012: not logged on, remove the orphaned shared memory segments using sysresv. You can remove the shared memory segment using ipcrm -m.

$ sysresv
...
Shared Memory:
ID              KEY
2621451         0x00000000
2654220         0x00000000
2588682         0x00000000
2686989         0x43713384
Semaphores:
ID              KEY
...
Oracle Instance not alive for sid "SID"

$ ipcrm -m 2621451
$ ipcrm -m 2654220
$ ipcrm -m 2588682
$ ipcrm -m 2686989

Then, start the database.

$ sqlplus / as sysdba
...
SQL> startup
ORACLE instance started.

Total System Global Area 5637144576 bytes
Fixed Size                  8632784 bytes
Variable Size            4462741040 bytes
Database Buffers         1140850688 bytes
Redo Buffers               24920064 bytes
Database mounted.
Database opened.