Yesterday I suddenly faced ORA-38761 and ORA-38754 errors.
I checked all logs and backups which were available, but why I could not flashback db.
Let`s simulate.
-- First I will create new user and will create table under new user. This is for checking purpose after flashback.
SQL> create user ulfet identified by ulfet;
User created.
SQL> grant dba to ulfet;
Grant succeeded.
SQL> conn ulfet/ulfet
Connected.
-- Note date. If you desire you may note SCN
SQL> select systimestamp from dual;
SYSTIMESTAMP
---------------------------------------------------------------------------
09-JAN-14 09.13.23.721393 AM +04:00
SQL>
SQL> create table test (id number);
Table created.
SQL> insert into test values (1);
1 row created.
SQL> commit;
Commit complete.
SQL> select systimestamp from dual;
SYSTIMESTAMP
---------------------------------------------------------------------------
09-JAN-14 09.15.10.917401 AM +04:00
SQL>
-- Now create restore point for flashback db, but you may flashaback db using timestamp or scn too.
SQL> create restore point first_point_09102014_0917;
Restore point created.
-- Now drop table
SQL> drop table test;
Table dropped.
SQL> conn /as sysdba
Connected.
SQL> shut immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area  839282688 bytes
Fixed Size      2217992 bytes
Variable Size    499124216 bytes
Database Buffers   335544320 bytes
Redo Buffers      2396160 bytes
Database mounted.
SQL> flashback database to restore point first_point_09102014_0917;
Flashback complete.
SQL> alter database open resetlogs;
Database altered.
 
--After flashback db we have to open db with resetlogs option.
-- Now check table and data
SQL> conn ulfet/ulfet
Connected.
SQL> select * from test;
 ID
----------
  1
SQL> 
 
-- Take backup of db and archivelog all and delete input
RMAN> backup incremental level 0 device type disk tag 'FULL_BACKUP_0' database;
Starting backup at 09-JAN-14
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=37 device type=DISK
channel ORA_DISK_1: starting incremental level 0 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/DB11GR2/system01.dbf
input datafile file number=00002 name=/u01/app/oracle/oradata/DB11GR2/sysaux01.dbf
input datafile file number=00005 name=/u01/app/oracle/oradata/DB11GR2/example01.dbf
input datafile file number=00003 name=/u01/app/oracle/oradata/DB11GR2/undotbs01.dbf
input datafile file number=00004 name=/u01/app/oracle/oradata/DB11GR2/users01.dbf
channel ORA_DISK_1: starting piece 1 at 09-JAN-14
channel ORA_DISK_1: finished piece 1 at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_nnnd0_FULL_BACKUP_0_9dwdltvh_.bkp tag=FULL_BACKUP_0 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:26
Finished backup at 09-JAN-14
Starting Control File and SPFILE Autobackup at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/autobackup/2014_01_09/o1_mf_s_836385904_9dwdojxc_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 09-JAN-14
RMAN> backup  device type disk tag "ARCHIVELOG_BACKUP" archivelog all not backed up delete all input;
Starting backup at 09-JAN-14
current log archived
using channel ORA_DISK_1
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=2 RECID=3 STAMP=836385564
input archived log thread=1 sequence=3 RECID=4 STAMP=836385564
input archived log thread=1 sequence=4 RECID=2 STAMP=836385562
channel ORA_DISK_1: starting piece 1 at 09-JAN-14
channel ORA_DISK_1: finished piece 1 at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwdtrhj_.bkp tag=ARCHIVELOG_BACKUP comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
channel ORA_DISK_1: deleting archived log(s)
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_2_9dwdbtld_.arc RECID=3 STAMP=836385564
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_3_9dwdbwp4_.arc RECID=4 STAMP=836385564
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_3_9dwcdmhp_.arc RECID=1 STAMP=836384595
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_4_9dwdbtjj_.arc RECID=2 STAMP=836385562
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=1 RECID=5 STAMP=836386072
channel ORA_DISK_1: starting piece 1 at 09-JAN-14
channel ORA_DISK_1: finished piece 1 at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwdtvmf_.bkp tag=ARCHIVELOG_BACKUP comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: deleting archived log(s)
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_1_9dwdtr7r_.arc RECID=5 STAMP=836386072
Finished backup at 09-JAN-14
Starting Control File and SPFILE Autobackup at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/autobackup/2014_01_09/o1_mf_s_836386076_9dwdtww2_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 09-JAN-14
RMAN> 
 
-- Now make dml and ddl statement 
SQL> conn ulfet/ulfet
Connected.
SQL> select * from test;
 ID
----------
  1
SQL> update test set id=111 where id=1;
1 row updated.
SQL> commit;
Commit complete.
SQL> create table test2 as select * from test where 1=2;
Table created.
--Generate Archivelogs
SQL> alter system switch logfile;
System altered.
SQL> /
System altered.
SQL> 
-- Take again archivelogs backup
 
[oracle@dbserver Desktop]$ rman target /
Recovery Manager: Release 11.2.0.1.0 - Production on Thu Jan 9 09:33:39 2014
Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.
connected to target database: DB11GR2 (DBID=1660417640)
RMAN> backup  device type disk tag "ARCHIVELOG_BACKUP" archivelog all not backed up delete all input;
Starting backup at 09-JAN-14
current log archived
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=43 device type=DISK
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=2 RECID=6 STAMP=836386263
input archived log thread=1 sequence=3 RECID=7 STAMP=836386270
input archived log thread=1 sequence=4 RECID=8 STAMP=836386427
channel ORA_DISK_1: starting piece 1 at 09-JAN-14
channel ORA_DISK_1: finished piece 1 at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwf5w15_.bkp tag=ARCHIVELOG_BACKUP comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: deleting archived log(s)
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_2_9dwf0qnp_.arc RECID=6 STAMP=836386263
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_3_9dwf0y20_.arc RECID=7 STAMP=836386270
archived log file name=/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_4_9dwf5vld_.arc RECID=8 STAMP=836386427
Finished backup at 09-JAN-14
Starting Control File and SPFILE Autobackup at 09-JAN-14
piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/autobackup/2014_01_09/o1_mf_s_836386429_9dwf5xcm_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 09-JAN-14
RMAN> 
[oracle@dbserver 2014_01_09]$ pwd
/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09
[oracle@dbserver 2014_01_09]$ ls
[oracle@dbserver 2014_01_09]$ 
 
-- Now try to restore using flashback db
Jan 9 09:32:00 2014 -- before backup of archivelog
 
SQL> shut immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area  839282688 bytes
Fixed Size      2217992 bytes
Variable Size    499124216 bytes
Database Buffers   335544320 bytes
Redo Buffers      2396160 bytes
Database mounted.
SQL> FLASHBACK DATABASE TO TIMESTAMP timestamp '2014-01-09 09:32:00';
FLASHBACK DATABASE TO TIMESTAMP timestamp '2014-01-09 09:32:00'
*
ERROR at line 1:
ORA-38754: FLASHBACK DATABASE not started; required redo log is not available
ORA-38762: redo logs needed for SCN 989641 to SCN 990218
ORA-38761: redo log sequence 2 in thread 1, incarnation 3 could not be accessed
SQL> 
 
[oracle@dbserver ~]$ rman target /
Recovery Manager: Release 11.2.0.1.0 - Production on Thu Jan 9 09:43:22 2014
Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.
connected to target database: DB11GR2 (DBID=1660417640, not open)
RMAN> list incarnation;
using target database control file instead of recovery catalog
List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            STATUS  Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       1       DB11GR2  1660417640       PARENT  1          15-AUG-09
2       2       DB11GR2  1660417640       PARENT  945184     11-SEP-13
3       3       DB11GR2  1660417640       CURRENT 989483     09-JAN-14
RMAN> 
 
-- Take which archivelog need
SQL> SELECT NAME
  FROM V$ARCHIVED_LOG A, V$DATABASE_INCARNATION I 
 WHERE A.RESETLOGS_ID = I.RESETLOGS_ID
   AND A.SEQUENCE# = 2 
   AND A.THREAD# = 1
   AND I.INCARNATION# = 3  2    3    4    5    6  ;
NAME
--------------------------------------------------------------------------------
-- Try restore archivelog and select again
 
RMAN> restore archivelog from sequence 1;
Starting restore at 09-JAN-14
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=22 device type=DISK
channel ORA_DISK_1: starting archived log restore to default destination
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=1
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwdtvmf_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwdtvmf_.bkp tag=ARCHIVELOG_BACKUP
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
channel ORA_DISK_1: starting archived log restore to default destination
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=2
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=3
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=4
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwf5w15_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/flash_recovery_area/DB11GR2/backupset/2014_01_09/o1_mf_annnn_ARCHIVELOG_BACKUP_9dwf5w15_.bkp tag=ARCHIVELOG_BACKUP
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 09-JAN-14
RMAN> 
SQL> SELECT NAME
  FROM V$ARCHIVED_LOG A, V$DATABASE_INCARNATION I 
 WHERE A.RESETLOGS_ID = I.RESETLOGS_ID
   AND A.SEQUENCE# = 2 
   AND A.THREAD# = 1
   AND I.INCARNATION# = 3  2    3    4    5    6  ;
NAME
--------------------------------------------------------------------------------
/u01/app/oracle/flash_recovery_area/DB11GR2/archivelog/2014_01_09/o1_mf_1_2_9dwg
1v3r_.arc
 
-- Needed archivelog is available now try to flashback
SQL> FLASHBACK DATABASE TO TIMESTAMP timestamp '2014-01-09 09:32:00';
Flashback complete.
SQL> alter database open resetlogs;
Database altered.
SQL> 
-- Now check 
SQL> conn ulfet/ulfet
Connected.
 
SQL> select * from tab;
TNAME          TABTYPE CLUSTERID
------------------------------ ------- ----------
TEST          TABLE
TEST2          TABLE
SQL> select * from test;
 ID
----------
       111
SQL> select * from test2;
no rows selected
SQL> 
Thats all