Dataguard # Oldest online log sequence 0

scenario # 

configured DR database for Oracle database version 12.1.0.2 

Archive logs are shipping to standby and logs are getting applied on standby database 

when I issue archive log list; Result as follows 

SQL> archive log list;

Database log mode       Archive Mode

Automatic archival       Enabled

Archive destination       /u02/archived/

Oldest online log sequence       0

Next log sequence to archive    0

Current log sequence                0

After I did alot of Investigation, I found information from metalink (Doc ID 2041137.1). This is a BUG. Do not use "archive log list" to compare primary and standby is in sync and use following Query's to compare both databases 

Primary: 

SQL> select thread#, max(sequence#) "Last Primary Seq Generated"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
group by thread# order by 1;

PhyStdby:

SQL> select thread#, max(sequence#) "Last Standby Seq Received"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
group by thread# order by 1;

PhyStdby:

SQL>select thread#, max(sequence#) "Last Standby Seq Applied"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
and val.applied in ('YES','IN-MEMORY')
group by thread# order by 1;

--Nikhil Tatineni--

--Oracle 12c--