Database incarnation is a new version of the database that happens when you reset the online redo logs using alter database open resetlogs;
Database incarnation falls into following category Current, Parent, Ancestor and Sibling
i) Current Incarnation : The database incarnation in which the database is currently generating redo.
ii) Parent Incarnation : The database incarnation from which the current incarnation branched following an OPEN RESETLOGS operation.
iii) Ancestor Incarnation : The parent of the parent incarnation is an ancestor incarnation. Any parent of an ancestor incarnation is also an ancestor incarnation.
iv) Sibling Incarnation : Two incarnations that share a common ancestor are sibling incarnations if neither one is an ancestor of the other.
.
we can view the status of our database incarnation using the command,
select * from v$database_incarnation;
list incarnation;
in this I have recovered a deleted table in the previous incarnation.
RMAN> backup database;
SQL>
create
table test
as select * from
all_objects;
Table created.
SQL>
select
current_scn
from
v$database;
CURRENT_SCN
-----------
547181
SQL>
delete from
test;
49309 rows deleted.
SQL>
commit;
Commit complete.
SQL>
select
current_scn
from
v$database;
CURRENT_SCN
-----------
547891
SQL>
drop
table test;
Table dropped.
SQL>
select
current_scn
from
v$database;
CURRENT_SCN
-----------
547917
SQL>
alter
system switch logfile;
System altered.
SQL>
select
incarnation#, resetlogs_change#
from
v$database_incarnation;
INCARNATION# RESETLOGS_CHANGE#
------------ -----------------
1 1
2 534907
SQL>
shutdown immediate
SQL>
startup
mount
RMAN> run
2> {
3> set until scn=547891;
4> restore database;
5> recover database;
6> }
RMAN> alter database open resetlogs;
SQL>
select
incarnation#, resetlogs_change#
from
v$database_incarnation;
INCARNATION# RESETLOGS_CHANGE#
------------ -----------------
1 1
2 534907
3 547896
SQL>
select * from
test;
no rows selected
SQL>
RMAN> shutdown immediate
RMAN> startup mount
RMAN> reset database to incarnation 2;
database reset to incarnation 2
RMAN> run
2> {
3> set until scn=547181;
4> restore database;
5> recover database;
6> }
RMAN> alter database open resetlogs;
database opened
SQL>
select
count(1)
from
test;
COUNT(1)
----------
49309
SQL>
