Dataguard -- what if primary has deleted the archive logs standby have not applied yet

STANDBY:
1.Get last SCN  number on Standby database
SQL>  select current_scn from v$database;
2.Stop the managed standby apply process:
SQL> alter database recover managed standby database cancel;
3.Shutdown the standby database
 SQL> shutdown immediate;


PRIMARY:
4.On the primary, take an incremental backup from the SCN number where the standby has been stuck:
RMAN>
run {
  allocate channel c1 type disk;
  allocate channel c2 type disk;
  allocate channel c3 type disk;
  allocate channel c4 type disk;
  backup incremental from scn xxxx database
    FORMAT '/db_backup/RMAN/temp/incr_standby_%U';
  }

5.On the primary, create a new standby controlfile:
SQL> alter database create standby controlfile as '//DEL1_standby.ctl';
Copy these files to standby host:
6.Scp the files to standby server
$ scp * oracle@:

STANDBY:
7.Bring up the instance in nomount mode:
SQL>   startup nomount

8.Check the location of the controlfile and Replace all controlfiles with the one you just created in primary.
SQL>    show parameter control_files
cp //DEL1_standby.ctl 
--for ASM, use RMAN to restore control file
RMAN> restore controlfile from '/db_backup/RMAN/temp/xxxxx_4standby.ctl';

9.Mount the standby database:
SQL>   alter database mount standby database;

10.Make sure the recovery is not started
SQL>    alter database recover managed standby database cancel;

11.RMAN Catalog the files and recover database noredo.
$rman target=/
RMAN>  catalog start with '';
Recover these files:
RMAN> switch database to copy; --if primary and standby use different paths
$RMAN>   recover database noredo;

12.Restart the broker on standby.(if you are using dg broker)
SQL> alter system set dg_broker_start=false scope=both;
SQL> alter system set dg_broker_start=true scope=both;

13.Start recovery on standby.
SQL>   alter database recover managed standby database disconnect from session;

Dataguard -- Gap solutions

To manually resolve gap for physical standby
select * from v$archive_gap;
--to find out the low and high seq# so you know which archive logs are missing
scp these files from primary to standby archive log location
alter database register logfile 'xxxxxxx';

Dataguard -- useful views

V$MANAGED_STANDBY -- lgwr, rfs, lns, arch, mrp information
V$ARCHIVED_LOG -- logs received by standby
V$LOG_HISTORY -- archive history details
V$DATAGUARD_STATUS -- dataguard messages/errors written to alert log and/or trace files
V$RECOVERY_PROGRESS -- recovery information
V$STANDBY_EVENT_HISTOGRAM -- log applying lag histogram
DBA_LOGSTDBY_LOG -- applied log information
DBA_LOGSTDBY_EVENTS -- log applied events in alert log
V$LOGSTDBY_PROCESS -- log apply processes current status