Select name,open_mode,database_role from v$database;
NAME        OPEN_MODE        DATABASE_ROLE
------      ----------       --------------------
ORCL        READ WRITE       PRIMARY
select status,gap_Status from v$archive_Dest_Status where dest_id=2;
STATUS    GAP_STATUS
--------- ------------------------
ERROR     RESOLVABLE GAP
select max(sequence#) from v$archived_log;
MAX(SEQUENCE#)
--------------
        193254

Select name,open_mode,database_role from v$database;
NAME           DATABASE_ROLE
------        --------------------
ORCLDR           PHYSICAL STANDBY
select max(sequence#) from v$archived_log where applied='YES';
MAX(SEQUENCE#)
--------------
       193130

Connect standby server
conn sys as sysdba
startup mount;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;
OR
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;

Select status,gap_status from v$archive_dest_status where dest_id=2;
STATUS            GAP_STATUS
---------         ----------------------
VALID             NO_GAP