As it appeared, flashback to Guaranteed Restore Points with Flashback Logging Disabled does not require redo logs.
Indeed, restore point is made during database is mounted, and it does not need any recovery.
Otherwise, Oracle issues an error:
RMAN> shutdown abort
Oracle instance shut down
RMAN> startup mount
connected to target database (not started)
Oracle instance started
database mounted
Total System Global Area 415236096 bytes
Fixed Size 2924976 bytes
Variable Size 272633424 bytes
Database Buffers 134217728 bytes
Redo Buffers 5459968 bytes
RMAN> create restore point rp3 guarantee flashback database;
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of sql statement command at 03/14/2017 18:39:38
ORA-38784: Cannot create restore point 'RP3'.
ORA-38714: Instance recovery required.
Here is an experiment. The state of my database before that was the following. There was a cold RMAN backup, several guaranteed restore points and some changes made between them also stored in archive redo logs.
During the experiment, I just created one more backup and deleted all obsolete files. All archived redo logs happened to be obsolete. At the and I'm still able to flashback to any guaranteed restore points.
RMAN> backup as compressed backupset database;
Starting backup at 14-MAR-17
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=21 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00011 name=/u04/app/oracle/oradata/db12r102m/pdb1/example01.dbf
input datafile file number=00009 name=/u04/app/oracle/oradata/db12r102m/pdb1/sysaux01.dbf
input datafile file number=00008 name=/u04/app/oracle/oradata/db12r102m/pdb1/system01.dbf
input datafile file number=00010 name=/u04/app/oracle/oradata/db12r102m/pdb1/SAMPLE_SCHEMA_users01.dbf
channel ORA_DISK_1: starting piece 1 at 14-MAR-17
channel ORA_DISK_1: finished piece 1 at 14-MAR-17
piece handle=/u04/app/oracle/fast_recovery_area/DB12R102M/46C0EDA68AC32521E0530100007FF7AE/backupset/2017_03_14/o1_mf_nn ndf_TAG20170314T175412_ddj4k4q6_.bkp tag=TAG20170314T175412 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:15
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00003 name=/u04/app/oracle/oradata/db12r102m/sysaux01.dbf
input datafile file number=00001 name=/u04/app/oracle/oradata/db12r102m/system01.dbf
input datafile file number=00004 name=/u04/app/oracle/oradata/db12r102m/undotbs01.dbf
input datafile file number=00006 name=/u04/app/oracle/oradata/db12r102m/users01.dbf
channel ORA_DISK_1: starting piece 1 at 14-MAR-17
channel ORA_DISK_1: finished piece 1 at 14-MAR-17
piece handle=/u04/app/oracle/fast_recovery_area/DB12R102M/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T175412_ddj4mj0f_. bkp tag=TAG20170314T175412 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:02:15
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00007 name=/u04/app/oracle/oradata/db12r102m/pdbseed/sysaux01.dbf
input datafile file number=00005 name=/u04/app/oracle/oradata/db12r102m/pdbseed/system01.dbf
channel ORA_DISK_1: starting piece 1 at 14-MAR-17
channel ORA_DISK_1: finished piece 1 at 14-MAR-17
piece handle=/u04/app/oracle/fast_recovery_area/DB12R102M/46C09FC3D5701FE6E0530100007F94C7/backupset/2017_03_14/o1_mf_nn ndf_TAG20170314T175412_ddj4qq55_.bkp tag=TAG20170314T175412 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:55
Finished backup at 14-MAR-17
Starting Control File and SPFILE Autobackup at 14-MAR-17
piece handle=/u04/app/oracle/fast_recovery_area/DB12R102M/autobackup/2017_03_14/o1_mf_s_938627615_ddj4sj3c_.bkp comment= NONE
Finished Control File and SPFILE Autobackup at 14-MAR-17
RMAN> delete obsolete redundancy 1;
using channel ORA_DISK_1
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 1 14-MAR-17
Backup Piece 1 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/46C0EDA68AC32521E0530100007FF7AE/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T174036_ddj3qod4_.bkp
Backup Set 2 14-MAR-17
Backup Piece 2 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T174036_ddj3vwsn_.bkp
Backup Set 3 14-MAR-17
Backup Piece 3 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/46C09FC3D5701FE6E0530100007F94C7/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T174036_ddj40qz5_.bkp
Archive Log 1 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/archivelog/2017_03_14/o1_mf_1_38_ddj4794g_.arc
Backup Set 4 14-MAR-17
Backup Piece 4 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/autobackup/2017_03_14/o1_mf_s_938626762_ddj426rf_.bkp
Archive Log 2 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/archivelog/2017_03_14/o1_mf_1_39_ddj489c1_.arc
Archive Log 3 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/archivelog/2017_03_14/o1_mf_1_40_ddj4dr1h_.arc
Archive Log 4 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/archivelog/2017_03_14/o1_mf_1_40_ddj4gw4l_.arc
Archive Log 6 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/archivelog/2017_03_14/o1_mf_1_39_ddj4gwn1_.arc
Archive Log 5 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/archivelog/2017_03_14/o1_mf_1_41_ddj4gwft_.arc
Backup Set 5 14-MAR-17
Backup Piece 5 14-MAR-17 /u04/app/oracle/fast_recovery_area/DB12R102M/autobackup/2017_03_14/o1_mf_s_938627596_ddj4hf1o_.bkp
Do you really want to delete the above objects (enter YES or NO)? y
...
Deleted 11 objects
RMAN> alter database open;
Statement processed
RMAN> list copy;
specification does not match any datafile copy in the repository
specification does not match any control file copy in the repository
specification does not match any archived log in the repository
RMAN> list backup;
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
6 Full 189.07M DISK 00:01:09 14-MAR-17
BP Key: 6 Status: AVAILABLE Compressed: YES Tag: TAG20170314T175412
Piece Name: /u04/app/oracle/fast_recovery_area/DB12R102M/46C0EDA68AC32521E0530100007FF7AE/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T175412_ddj4k4q6_.bkp
List of Datafiles in backup set 6
Container ID: 3, PDB Name: PDB1
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
8 Full 2137619 14-MAR-17 /u04/app/oracle/oradata/db12r102m/pdb1/system01.dbf
9 Full 2137619 14-MAR-17 /u04/app/oracle/oradata/db12r102m/pdb1/sysaux01.dbf
10 Full 2137619 14-MAR-17 /u04/app/oracle/oradata/db12r102m/pdb1/SAMPLE_SCHEMA_users01.dbf
11 Full 2137619 14-MAR-17 /u04/app/oracle/oradata/db12r102m/pdb1/example01.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
7 Full 405.53M DISK 00:02:11 14-MAR-17
BP Key: 7 Status: AVAILABLE Compressed: YES Tag: TAG20170314T175412
Piece Name: /u04/app/oracle/fast_recovery_area/DB12R102M/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T175412_ddj4mj0f_.bkp
List of Datafiles in backup set 7
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
1 Full 2137631 14-MAR-17 /u04/app/oracle/oradata/db12r102m/system01.dbf
3 Full 2137631 14-MAR-17 /u04/app/oracle/oradata/db12r102m/sysaux01.dbf
4 Full 2137631 14-MAR-17 /u04/app/oracle/oradata/db12r102m/undotbs01.dbf
6 Full 2137631 14-MAR-17 /u04/app/oracle/oradata/db12r102m/users01.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
8 Full 157.07M DISK 00:00:44 14-MAR-17
BP Key: 8 Status: AVAILABLE Compressed: YES Tag: TAG20170314T175412
Piece Name: /u04/app/oracle/fast_recovery_area/DB12R102M/46C09FC3D5701FE6E0530100007F94C7/backupset/2017_03_14/o1_mf_nnndf_TAG20170314T175412_ddj4qq55_.bkp
List of Datafiles in backup set 8
Container ID: 2, PDB Name: PDB$SEED
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
5 Full 1824920 23-JAN-17 /u04/app/oracle/oradata/db12r102m/pdbseed/system01.dbf
7 Full 1824920 23-JAN-17 /u04/app/oracle/oradata/db12r102m/pdbseed/sysaux01.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
9 Full 17.20M DISK 00:00:02 14-MAR-17
BP Key: 9 Status: AVAILABLE Compressed: NO Tag: TAG20170314T175838
Piece Name: /u04/app/oracle/fast_recovery_area/DB12R102M/autobackup/2017_03_14/o1_mf_s_938627615_ddj4sj3c_.bkp
SPFILE Included: Modification time: 10-MAR-17
SPFILE db_unique_name: DB12R102M
Control File Included: Ckp SCN: 2137631 Ckp time: 14-MAR-17
RMAN> shutdown immediate
using target database control file instead of recovery catalog
database closed
database dismounted
Oracle instance shut down
RMAN> startup mount
connected to target database (not started)
Oracle instance started
database mounted
Total System Global Area 415236096 bytes
Fixed Size 2924976 bytes
Variable Size 272633424 bytes
Database Buffers 134217728 bytes
Redo Buffers 5459968 bytes
RMAN> flashback database to restore point rp2;
Starting flashback at 14-MAR-17
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=21 device type=DISK
starting media recovery
media recovery complete, elapsed time: 00:00:03
Finished flashback at 14-MAR-17
RMAN> alter database open resetlogs;
Statement processed
RMAN>
